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Re: [solectria_ev] Re: Prius NiMH Batteries

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  • Dorothy Swann
    Thanks for the math. I have not gotten around to doing that yet. I had just looked at the watt-hours per pound which was favorable. I inquired at a local
    Message 1 of 19 , Dec 1, 2007
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      Thanks for the math. I have not gotten around to doing that yet. I had just looked at the watt-hours per pound which was favorable. I inquired at a local surplus parts dealer, and battery packs in wrecked Priuss are available beginning at $ 400. My plan will be to acquire enough packs and build up a series/parallel combination on the bench, and start doing some load tests. The Prius pack I have seems to look at the voltage of 2 modules at a time. The voltage sampling electronics is being developed. First for 13 batteries for the Force, then for a higher number of cells.
      Bill S


      ----- Original Message ----
      From: Todd Martin <larsthelean@...>
      To: solectria_ev@yahoogroups.com
      Sent: Friday, November 30, 2007 7:47:57 AM
      Subject: [solectria_ev] Re: Prius NiMH Batteries

      Hi Bill,

      This sounds like an interesting project.

      I took the liberty of checking the specs on the Prius Nimh modules:

      Each module is 11" long by 5" wide by 3/4" thick and require a 2mm
      gap between modules for forced air cooling. They weigh 2.3 lbs and
      have 6 cells that total 7.2V at 6.5Ahr. With a standard 80% depth
      of discharge for Nimh, 5Ahr are usable.

      A Solectria Force has battery boxes that can accommodate 13 group 27
      batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall). This
      works out to about 1119 sq. inches of battery box floor space.

      IF you can orient the Prius Nimh modules so they the 11" long is
      vertical (not a real problem in the back box since you can always
      add a spacer between the bottom and lid if necessary, but it MAY be
      a real problem for the front box), then I figure you can fit roughly
      270 modules into a Force. This is a rough calculation without doing
      an actual layout.

      Since you will need to arrange the modules into multiple sets of
      strings of around 156V, I see the math as:
      22 modules * 7.2V = 158.4V string linked in series.
      12 strings linked in paralles * 5Ahr = 60Ahr usable.
      264 modules used total weigh 264 * 2.3 lbs = 607 lbs.

      In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you will
      save 214 lbs by making the switch and increase your range from 50
      miles to approximately 60 miles.

      Provided you still have a BRUSA NLG4 (or got an NLG5) charger, I
      don't see a real problem with charging the batteries. You just need
      to find out the charging profile and set the program using the free
      DOS program. For a Zivan charger, you'd need to send it to the
      manufacturer for a re-programming.

      I agree that a BMS would be a big obstacle. Perhaps placing a
      Powercheq between each string would be enough to get by. Otherwise,
      that is a LOT of regs to be installing if you have to do every
      module.

      I'm curious as to the market rate for used Prius Nimh modules. If
      you can share the price for them, we can compare them to other
      battery choices.

      Thanks!

      Todd Martin
      1997 Solectria Force
      VP, FVEAA

      --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@.. .>
      wrote:
      >
      > I understand all the precautions you enumerate. I may purchase the
      > first of several surplus Prius battery packs tomorrow. Is there a
      > chance I can e-mail the person who put together a NiMH pack for
      the S-
      > 10. I am open to tips and tricks/opinions.
      > Thanks,Bill S
      > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky" <Pohorsky@>
      > wrote:
      > >
      > > Howdy,
      > >
      > > The batteries in the Prius are not very suitable for the Force
      > unless you disassemble the pack, rewire the modules and come up
      with
      > a suitable charger and BMS. NiMH batteries have a unique charging
      > profile and the standard lead acid battery chargers are not
      > appropriate. The batteries themselves are an odd physical size
      and
      > voltage. I believe they are something like a 7.2 volt battery
      with a
      > 6.5 Amp-hour rating. That amp-hour rating is suitable for
      > intermittent duty in a hybrid but totally inadequate for an EV.
      > >
      > > You would need several strings in parallel to get the amp-hour
      > rating you need. A fellow EAA member bought several used Prius
      packs
      > on eBay and wired them in parallel for use in his US Electricar S-
      10
      > pickup truck. He needed to invent a battery management system as
      > well as a fan-forced cooling system. The weight reduction gave
      him
      > an improvement in acceleration over his old lead acid pack and
      > slightly more range, but eventually he got rid of them. They took
      up
      > the entire bed of the truck. He is now running a flooded NiCad
      pack
      > that he got from a military surplus supplier. He was able to
      mount
      > the NiCads under the bed of the truck.
      > >
      > > Not all non-lead packs are series parallel combinations. I saw
      > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries. With
      > these, you would just have a series string although there would be
      a
      > large number of cells - they between 3 and 4 volts each.
      > >
      > > Stephen Taylor has a series string of the Valence Lithium
      batteries
      > in his Force.
      > >
      > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4 EV.
      > Unfortunately, these Panasonic batteries have been taken off the
      > market due to a lawsuit filed by Chevron - but it is another
      example
      > where a series parallel combo was not needed.
      > >
      > > Adios,
      > >
      > > Jerry Pohorsky
      > >
      > > ----- Original Message -----
      > > From: Bill Swann
      > > To: solectria_ev@ yahoogroups. com
      > > Sent: Tuesday, November 20, 2007 6:13 PM
      > > Subject: [solectria_ev] Prius NiMH Batteries
      > >
      > >
      > > I am surprised that someone has not taken some surplus
      batteries
      > from a
      > > Prius and adapted it to the Force. The energy density is
      double
      > over
      > > lead. As it is with battery packs other that SLA, the pack
      ends
      > up
      > > being a series/parallel combination.
      > > Bill S
      > >
      > >
      > >
      > >
      > >
      > > [Non-text portions of this message have been removed]
      > >
      >




      [Non-text portions of this message have been removed]
    • Bill Swann
      I dis-assembled a Prius battery pack. What I understand about the design I like. The cells are bolted to a common baseplate. There are series copper jumpers
      Message 2 of 19 , Dec 2, 2007
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        I dis-assembled a Prius battery pack. What I understand about the
        design I like. The cells are bolted to a common baseplate. There are
        series copper jumpers between the 38 cells. I saw a 125 amp fuse and
        a computer, into which the 5 temp sensors and 19 voltage measurments
        were fed. Also there are 2 single pole relays to disconnect the pack
        from the outside world. I saw what would appear to be a current
        measuring coil, but I do not undestend what it might do in a DC
        system except to verify the the reley worked. There are thermo wells
        in every cell, where the temp sensors are placed. Additionally, all
        38 cells were vented into a common tube to carry off gasses. There
        was one temp sensor in a plenum below the pack to verify air flow.
        And all of the cells had dimples on the sides so there would be a
        gaps between cells for cooling air flow. My next step is to see how
        many series combinations will fit in the Force battery boxes. It is a
        squeeze, but 4 might fit in the front battery box.
        Bill S

        --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@...>
        wrote:
        >
        > Thanks for the math. I have not gotten around to doing that yet. I
        had just looked at the watt-hours per pound which was favorable. I
        inquired at a local surplus parts dealer, and battery packs in
        wrecked Priuss are available beginning at $ 400. My plan will be to
        acquire enough packs and build up a series/parallel combination on
        the bench, and start doing some load tests. The Prius pack I have
        seems to look at the voltage of 2 modules at a time. The voltage
        sampling electronics is being developed. First for 13 batteries for
        the Force, then for a higher number of cells.
        > Bill S
        >
        >
        > ----- Original Message ----
        > From: Todd Martin <larsthelean@...>
        > To: solectria_ev@yahoogroups.com
        > Sent: Friday, November 30, 2007 7:47:57 AM
        > Subject: [solectria_ev] Re: Prius NiMH Batteries
        >
        > Hi Bill,
        >
        > This sounds like an interesting project.
        >
        > I took the liberty of checking the specs on the Prius Nimh modules:
        >
        > Each module is 11" long by 5" wide by 3/4" thick and require a 2mm
        > gap between modules for forced air cooling. They weigh 2.3 lbs and
        > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80% depth
        > of discharge for Nimh, 5Ahr are usable.
        >
        > A Solectria Force has battery boxes that can accommodate 13 group
        27
        > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall). This
        > works out to about 1119 sq. inches of battery box floor space.
        >
        > IF you can orient the Prius Nimh modules so they the 11" long is
        > vertical (not a real problem in the back box since you can always
        > add a spacer between the bottom and lid if necessary, but it MAY be
        > a real problem for the front box), then I figure you can fit
        roughly
        > 270 modules into a Force. This is a rough calculation without doing
        > an actual layout.
        >
        > Since you will need to arrange the modules into multiple sets of
        > strings of around 156V, I see the math as:
        > 22 modules * 7.2V = 158.4V string linked in series.
        > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
        > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
        >
        > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you will
        > save 214 lbs by making the switch and increase your range from 50
        > miles to approximately 60 miles.
        >
        > Provided you still have a BRUSA NLG4 (or got an NLG5) charger, I
        > don't see a real problem with charging the batteries. You just need
        > to find out the charging profile and set the program using the free
        > DOS program. For a Zivan charger, you'd need to send it to the
        > manufacturer for a re-programming.
        >
        > I agree that a BMS would be a big obstacle. Perhaps placing a
        > Powercheq between each string would be enough to get by. Otherwise,
        > that is a LOT of regs to be installing if you have to do every
        > module.
        >
        > I'm curious as to the market rate for used Prius Nimh modules. If
        > you can share the price for them, we can compare them to other
        > battery choices.
        >
        > Thanks!
        >
        > Todd Martin
        > 1997 Solectria Force
        > VP, FVEAA
        >
        > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@ .>
        > wrote:
        > >
        > > I understand all the precautions you enumerate. I may purchase
        the
        > > first of several surplus Prius battery packs tomorrow. Is there a
        > > chance I can e-mail the person who put together a NiMH pack for
        > the S-
        > > 10. I am open to tips and tricks/opinions.
        > > Thanks,Bill S
        > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
        <Pohorsky@>
        > > wrote:
        > > >
        > > > Howdy,
        > > >
        > > > The batteries in the Prius are not very suitable for the Force
        > > unless you disassemble the pack, rewire the modules and come up
        > with
        > > a suitable charger and BMS. NiMH batteries have a unique charging
        > > profile and the standard lead acid battery chargers are not
        > > appropriate. The batteries themselves are an odd physical size
        > and
        > > voltage. I believe they are something like a 7.2 volt battery
        > with a
        > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
        > > intermittent duty in a hybrid but totally inadequate for an EV.
        > > >
        > > > You would need several strings in parallel to get the amp-hour
        > > rating you need. A fellow EAA member bought several used Prius
        > packs
        > > on eBay and wired them in parallel for use in his US Electricar S-
        > 10
        > > pickup truck. He needed to invent a battery management system as
        > > well as a fan-forced cooling system. The weight reduction gave
        > him
        > > an improvement in acceleration over his old lead acid pack and
        > > slightly more range, but eventually he got rid of them. They took
        > up
        > > the entire bed of the truck. He is now running a flooded NiCad
        > pack
        > > that he got from a military surplus supplier. He was able to
        > mount
        > > the NiCads under the bed of the truck.
        > > >
        > > > Not all non-lead packs are series parallel combinations. I saw
        > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries. With
        > > these, you would just have a series string although there would
        be
        > a
        > > large number of cells - they between 3 and 4 volts each.
        > > >
        > > > Stephen Taylor has a series string of the Valence Lithium
        > batteries
        > > in his Force.
        > > >
        > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4 EV.
        > > Unfortunately, these Panasonic batteries have been taken off the
        > > market due to a lawsuit filed by Chevron - but it is another
        > example
        > > where a series parallel combo was not needed.
        > > >
        > > > Adios,
        > > >
        > > > Jerry Pohorsky
        > > >
        > > > ----- Original Message -----
        > > > From: Bill Swann
        > > > To: solectria_ev@ yahoogroups. com
        > > > Sent: Tuesday, November 20, 2007 6:13 PM
        > > > Subject: [solectria_ev] Prius NiMH Batteries
        > > >
        > > >
        > > > I am surprised that someone has not taken some surplus
        > batteries
        > > from a
        > > > Prius and adapted it to the Force. The energy density is
        > double
        > > over
        > > > lead. As it is with battery packs other that SLA, the pack
        > ends
        > > up
        > > > being a series/parallel combination.
        > > > Bill S
        > > >
        > > >
        > > >
        > > >
        > > >
        > > > [Non-text portions of this message have been removed]
        > > >
        > >
        >
        >
        >
        >
        > [Non-text portions of this message have been removed]
        >
      • Mike Phillips
        The absolute most important thing with these Prius modules is cooling them. Just 1 amp during charge can smoke them without cooling. If you look at the side
        Message 3 of 19 , Dec 2, 2007
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          The absolute most important thing with these Prius modules is cooling
          them. Just 1 amp during charge can smoke them without cooling. If you
          look at the side view of the chassis you will see a slope in lower
          plenum. It keeps the airflow rate the same across all of the cells.

          The second most important thing is that the cells must absolutely be
          held in compression. Even when they are stone cold, just 1 amp during
          charge causes them to pressurize and expand a lot, thus ruining them.

          If you overheat the modules they will not flow KOH into the black
          overflow tubes that go across the top of the cells. The thermal vents
          will each crack and thus vent gaseous and liquid KOH.

          The 4 thermistors on the top of the cells are 10k NTC types. Using
          them to adjust air flow is important.

          That sheetmetal chassis that they come in from the factory is
          engineered the way it is for list full of reasons.

          You have to ask yourself if you have enough room for all of the
          support hardware in each battery box.

          That 'current measuring coil' is for telling the hardware how much
          current is being put into or taken out of the pack.

          These are not the same NIMH cells that you can read about in books and
          on the web. They are in the same family but have been very optimized
          for efficiently accepting regen energy, far better than anything else
          on the planet. That makes them less energy dense and more prone to
          thermal failure.

          I'm buried up to my eyeballs in projects now, so I cannot give you
          much more than this right now.

          Good Luck.

          Mike



          --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@...> wrote:
          >
          > I dis-assembled a Prius battery pack. What I understand about the
          > design I like. The cells are bolted to a common baseplate. There are
          > series copper jumpers between the 38 cells. I saw a 125 amp fuse and
          > a computer, into which the 5 temp sensors and 19 voltage measurments
          > were fed. Also there are 2 single pole relays to disconnect the pack
          > from the outside world. I saw what would appear to be a current
          > measuring coil, but I do not undestend what it might do in a DC
          > system except to verify the the reley worked. There are thermo wells
          > in every cell, where the temp sensors are placed. Additionally, all
          > 38 cells were vented into a common tube to carry off gasses. There
          > was one temp sensor in a plenum below the pack to verify air flow.
          > And all of the cells had dimples on the sides so there would be a
          > gaps between cells for cooling air flow. My next step is to see how
          > many series combinations will fit in the Force battery boxes. It is a
          > squeeze, but 4 might fit in the front battery box.
          > Bill S
          >
          > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
          > wrote:
          > >
          > > Thanks for the math. I have not gotten around to doing that yet. I
          > had just looked at the watt-hours per pound which was favorable. I
          > inquired at a local surplus parts dealer, and battery packs in
          > wrecked Priuss are available beginning at $ 400. My plan will be to
          > acquire enough packs and build up a series/parallel combination on
          > the bench, and start doing some load tests. The Prius pack I have
          > seems to look at the voltage of 2 modules at a time. The voltage
          > sampling electronics is being developed. First for 13 batteries for
          > the Force, then for a higher number of cells.
          > > Bill S
          > >
          > >
          > > ----- Original Message ----
          > > From: Todd Martin <larsthelean@>
          > > To: solectria_ev@yahoogroups.com
          > > Sent: Friday, November 30, 2007 7:47:57 AM
          > > Subject: [solectria_ev] Re: Prius NiMH Batteries
          > >
          > > Hi Bill,
          > >
          > > This sounds like an interesting project.
          > >
          > > I took the liberty of checking the specs on the Prius Nimh modules:
          > >
          > > Each module is 11" long by 5" wide by 3/4" thick and require a 2mm
          > > gap between modules for forced air cooling. They weigh 2.3 lbs and
          > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80% depth
          > > of discharge for Nimh, 5Ahr are usable.
          > >
          > > A Solectria Force has battery boxes that can accommodate 13 group
          > 27
          > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall). This
          > > works out to about 1119 sq. inches of battery box floor space.
          > >
          > > IF you can orient the Prius Nimh modules so they the 11" long is
          > > vertical (not a real problem in the back box since you can always
          > > add a spacer between the bottom and lid if necessary, but it MAY be
          > > a real problem for the front box), then I figure you can fit
          > roughly
          > > 270 modules into a Force. This is a rough calculation without doing
          > > an actual layout.
          > >
          > > Since you will need to arrange the modules into multiple sets of
          > > strings of around 156V, I see the math as:
          > > 22 modules * 7.2V = 158.4V string linked in series.
          > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
          > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
          > >
          > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you will
          > > save 214 lbs by making the switch and increase your range from 50
          > > miles to approximately 60 miles.
          > >
          > > Provided you still have a BRUSA NLG4 (or got an NLG5) charger, I
          > > don't see a real problem with charging the batteries. You just need
          > > to find out the charging profile and set the program using the free
          > > DOS program. For a Zivan charger, you'd need to send it to the
          > > manufacturer for a re-programming.
          > >
          > > I agree that a BMS would be a big obstacle. Perhaps placing a
          > > Powercheq between each string would be enough to get by. Otherwise,
          > > that is a LOT of regs to be installing if you have to do every
          > > module.
          > >
          > > I'm curious as to the market rate for used Prius Nimh modules. If
          > > you can share the price for them, we can compare them to other
          > > battery choices.
          > >
          > > Thanks!
          > >
          > > Todd Martin
          > > 1997 Solectria Force
          > > VP, FVEAA
          > >
          > > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@ .>
          > > wrote:
          > > >
          > > > I understand all the precautions you enumerate. I may purchase
          > the
          > > > first of several surplus Prius battery packs tomorrow. Is there a
          > > > chance I can e-mail the person who put together a NiMH pack for
          > > the S-
          > > > 10. I am open to tips and tricks/opinions.
          > > > Thanks,Bill S
          > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
          > <Pohorsky@>
          > > > wrote:
          > > > >
          > > > > Howdy,
          > > > >
          > > > > The batteries in the Prius are not very suitable for the Force
          > > > unless you disassemble the pack, rewire the modules and come up
          > > with
          > > > a suitable charger and BMS. NiMH batteries have a unique charging
          > > > profile and the standard lead acid battery chargers are not
          > > > appropriate. The batteries themselves are an odd physical size
          > > and
          > > > voltage. I believe they are something like a 7.2 volt battery
          > > with a
          > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
          > > > intermittent duty in a hybrid but totally inadequate for an EV.
          > > > >
          > > > > You would need several strings in parallel to get the amp-hour
          > > > rating you need. A fellow EAA member bought several used Prius
          > > packs
          > > > on eBay and wired them in parallel for use in his US Electricar S-
          > > 10
          > > > pickup truck. He needed to invent a battery management system as
          > > > well as a fan-forced cooling system. The weight reduction gave
          > > him
          > > > an improvement in acceleration over his old lead acid pack and
          > > > slightly more range, but eventually he got rid of them. They took
          > > up
          > > > the entire bed of the truck. He is now running a flooded NiCad
          > > pack
          > > > that he got from a military surplus supplier. He was able to
          > > mount
          > > > the NiCads under the bed of the truck.
          > > > >
          > > > > Not all non-lead packs are series parallel combinations. I saw
          > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries. With
          > > > these, you would just have a series string although there would
          > be
          > > a
          > > > large number of cells - they between 3 and 4 volts each.
          > > > >
          > > > > Stephen Taylor has a series string of the Valence Lithium
          > > batteries
          > > > in his Force.
          > > > >
          > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4 EV.
          > > > Unfortunately, these Panasonic batteries have been taken off the
          > > > market due to a lawsuit filed by Chevron - but it is another
          > > example
          > > > where a series parallel combo was not needed.
          > > > >
          > > > > Adios,
          > > > >
          > > > > Jerry Pohorsky
          > > > >
          > > > > ----- Original Message -----
          > > > > From: Bill Swann
          > > > > To: solectria_ev@ yahoogroups. com
          > > > > Sent: Tuesday, November 20, 2007 6:13 PM
          > > > > Subject: [solectria_ev] Prius NiMH Batteries
          > > > >
          > > > >
          > > > > I am surprised that someone has not taken some surplus
          > > batteries
          > > > from a
          > > > > Prius and adapted it to the Force. The energy density is
          > > double
          > > > over
          > > > > lead. As it is with battery packs other that SLA, the pack
          > > ends
          > > > up
          > > > > being a series/parallel combination.
          > > > > Bill S
          > > > >
          > > > >
          > > > >
          > > > >
          > > > >
          > > > > [Non-text portions of this message have been removed]
          > > > >
          > > >
          > >
          > >
          > >
          > >
          > > [Non-text portions of this message have been removed]
          > >
          >
        • Mike Phillips
          This information was derived from experience driving several hundred miles in a vehicle with 5 Prius packs in parallel for the pack. There were 11 packs total
          Message 4 of 19 , Dec 6, 2007
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            This information was derived from experience driving several hundred
            miles in a vehicle with 5 Prius packs in parallel for the pack. There
            were 11 packs total used in testing.

            Mike



            --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@...>
            wrote:
            >
            > The absolute most important thing with these Prius modules is cooling
            > them. Just 1 amp during charge can smoke them without cooling. If you
            > look at the side view of the chassis you will see a slope in lower
            > plenum. It keeps the airflow rate the same across all of the cells.
            >
            > The second most important thing is that the cells must absolutely be
            > held in compression. Even when they are stone cold, just 1 amp during
            > charge causes them to pressurize and expand a lot, thus ruining them.
            >
            > If you overheat the modules they will not flow KOH into the black
            > overflow tubes that go across the top of the cells. The thermal vents
            > will each crack and thus vent gaseous and liquid KOH.
            >
            > The 4 thermistors on the top of the cells are 10k NTC types. Using
            > them to adjust air flow is important.
            >
            > That sheetmetal chassis that they come in from the factory is
            > engineered the way it is for list full of reasons.
            >
            > You have to ask yourself if you have enough room for all of the
            > support hardware in each battery box.
            >
            > That 'current measuring coil' is for telling the hardware how much
            > current is being put into or taken out of the pack.
            >
            > These are not the same NIMH cells that you can read about in books and
            > on the web. They are in the same family but have been very optimized
            > for efficiently accepting regen energy, far better than anything else
            > on the planet. That makes them less energy dense and more prone to
            > thermal failure.
            >
            > I'm buried up to my eyeballs in projects now, so I cannot give you
            > much more than this right now.
            >
            > Good Luck.
            >
            > Mike
            >
            >
            >
            > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@> wrote:
            > >
            > > I dis-assembled a Prius battery pack. What I understand about the
            > > design I like. The cells are bolted to a common baseplate. There are
            > > series copper jumpers between the 38 cells. I saw a 125 amp fuse and
            > > a computer, into which the 5 temp sensors and 19 voltage measurments
            > > were fed. Also there are 2 single pole relays to disconnect the pack
            > > from the outside world. I saw what would appear to be a current
            > > measuring coil, but I do not undestend what it might do in a DC
            > > system except to verify the the reley worked. There are thermo wells
            > > in every cell, where the temp sensors are placed. Additionally, all
            > > 38 cells were vented into a common tube to carry off gasses. There
            > > was one temp sensor in a plenum below the pack to verify air flow.
            > > And all of the cells had dimples on the sides so there would be a
            > > gaps between cells for cooling air flow. My next step is to see how
            > > many series combinations will fit in the Force battery boxes. It is a
            > > squeeze, but 4 might fit in the front battery box.
            > > Bill S
            > >
            > > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
            > > wrote:
            > > >
            > > > Thanks for the math. I have not gotten around to doing that yet. I
            > > had just looked at the watt-hours per pound which was favorable. I
            > > inquired at a local surplus parts dealer, and battery packs in
            > > wrecked Priuss are available beginning at $ 400. My plan will be to
            > > acquire enough packs and build up a series/parallel combination on
            > > the bench, and start doing some load tests. The Prius pack I have
            > > seems to look at the voltage of 2 modules at a time. The voltage
            > > sampling electronics is being developed. First for 13 batteries for
            > > the Force, then for a higher number of cells.
            > > > Bill S
            > > >
            > > >
            > > > ----- Original Message ----
            > > > From: Todd Martin <larsthelean@>
            > > > To: solectria_ev@yahoogroups.com
            > > > Sent: Friday, November 30, 2007 7:47:57 AM
            > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
            > > >
            > > > Hi Bill,
            > > >
            > > > This sounds like an interesting project.
            > > >
            > > > I took the liberty of checking the specs on the Prius Nimh modules:
            > > >
            > > > Each module is 11" long by 5" wide by 3/4" thick and require a 2mm
            > > > gap between modules for forced air cooling. They weigh 2.3 lbs and
            > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80% depth
            > > > of discharge for Nimh, 5Ahr are usable.
            > > >
            > > > A Solectria Force has battery boxes that can accommodate 13 group
            > > 27
            > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall). This
            > > > works out to about 1119 sq. inches of battery box floor space.
            > > >
            > > > IF you can orient the Prius Nimh modules so they the 11" long is
            > > > vertical (not a real problem in the back box since you can always
            > > > add a spacer between the bottom and lid if necessary, but it MAY be
            > > > a real problem for the front box), then I figure you can fit
            > > roughly
            > > > 270 modules into a Force. This is a rough calculation without doing
            > > > an actual layout.
            > > >
            > > > Since you will need to arrange the modules into multiple sets of
            > > > strings of around 156V, I see the math as:
            > > > 22 modules * 7.2V = 158.4V string linked in series.
            > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
            > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
            > > >
            > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you will
            > > > save 214 lbs by making the switch and increase your range from 50
            > > > miles to approximately 60 miles.
            > > >
            > > > Provided you still have a BRUSA NLG4 (or got an NLG5) charger, I
            > > > don't see a real problem with charging the batteries. You just need
            > > > to find out the charging profile and set the program using the free
            > > > DOS program. For a Zivan charger, you'd need to send it to the
            > > > manufacturer for a re-programming.
            > > >
            > > > I agree that a BMS would be a big obstacle. Perhaps placing a
            > > > Powercheq between each string would be enough to get by. Otherwise,
            > > > that is a LOT of regs to be installing if you have to do every
            > > > module.
            > > >
            > > > I'm curious as to the market rate for used Prius Nimh modules. If
            > > > you can share the price for them, we can compare them to other
            > > > battery choices.
            > > >
            > > > Thanks!
            > > >
            > > > Todd Martin
            > > > 1997 Solectria Force
            > > > VP, FVEAA
            > > >
            > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@ .>
            > > > wrote:
            > > > >
            > > > > I understand all the precautions you enumerate. I may purchase
            > > the
            > > > > first of several surplus Prius battery packs tomorrow. Is there a
            > > > > chance I can e-mail the person who put together a NiMH pack for
            > > > the S-
            > > > > 10. I am open to tips and tricks/opinions.
            > > > > Thanks,Bill S
            > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
            > > <Pohorsky@>
            > > > > wrote:
            > > > > >
            > > > > > Howdy,
            > > > > >
            > > > > > The batteries in the Prius are not very suitable for the Force
            > > > > unless you disassemble the pack, rewire the modules and come up
            > > > with
            > > > > a suitable charger and BMS. NiMH batteries have a unique charging
            > > > > profile and the standard lead acid battery chargers are not
            > > > > appropriate. The batteries themselves are an odd physical size
            > > > and
            > > > > voltage. I believe they are something like a 7.2 volt battery
            > > > with a
            > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
            > > > > intermittent duty in a hybrid but totally inadequate for an EV.
            > > > > >
            > > > > > You would need several strings in parallel to get the amp-hour
            > > > > rating you need. A fellow EAA member bought several used Prius
            > > > packs
            > > > > on eBay and wired them in parallel for use in his US Electricar S-
            > > > 10
            > > > > pickup truck. He needed to invent a battery management system as
            > > > > well as a fan-forced cooling system. The weight reduction gave
            > > > him
            > > > > an improvement in acceleration over his old lead acid pack and
            > > > > slightly more range, but eventually he got rid of them. They took
            > > > up
            > > > > the entire bed of the truck. He is now running a flooded NiCad
            > > > pack
            > > > > that he got from a military surplus supplier. He was able to
            > > > mount
            > > > > the NiCads under the bed of the truck.
            > > > > >
            > > > > > Not all non-lead packs are series parallel combinations. I saw
            > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries. With
            > > > > these, you would just have a series string although there would
            > > be
            > > > a
            > > > > large number of cells - they between 3 and 4 volts each.
            > > > > >
            > > > > > Stephen Taylor has a series string of the Valence Lithium
            > > > batteries
            > > > > in his Force.
            > > > > >
            > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4 EV.
            > > > > Unfortunately, these Panasonic batteries have been taken off the
            > > > > market due to a lawsuit filed by Chevron - but it is another
            > > > example
            > > > > where a series parallel combo was not needed.
            > > > > >
            > > > > > Adios,
            > > > > >
            > > > > > Jerry Pohorsky
            > > > > >
            > > > > > ----- Original Message -----
            > > > > > From: Bill Swann
            > > > > > To: solectria_ev@ yahoogroups. com
            > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
            > > > > > Subject: [solectria_ev] Prius NiMH Batteries
            > > > > >
            > > > > >
            > > > > > I am surprised that someone has not taken some surplus
            > > > batteries
            > > > > from a
            > > > > > Prius and adapted it to the Force. The energy density is
            > > > double
            > > > > over
            > > > > > lead. As it is with battery packs other that SLA, the pack
            > > > ends
            > > > > up
            > > > > > being a series/parallel combination.
            > > > > > Bill S
            > > > > >
            > > > > >
            > > > > >
            > > > > >
            > > > > >
            > > > > > [Non-text portions of this message have been removed]
            > > > > >
            > > > >
            > > >
            > > >
            > > >
            > > >
            > > > [Non-text portions of this message have been removed]
            > > >
            > >
            >
          • Bill Swann
            Thanks for the feedback. And for alerting me to the pitfalls of re- engineering a battery pack. I do not fully understand your comment the Prius batteries
            Message 5 of 19 , Dec 24, 2007
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              Thanks for the feedback. And for alerting me to the pitfalls of re-
              engineering a battery pack. I do not fully understand your comment "
              the Prius batteries have been optimized for efficiently accepting
              regen energy". Are you suggesting that making a Solectria battery
              pack with 5-6 Prius packs is ill advised because the Prius battery is
              not designed for this? The price is certainly right for used packs,
              assuming a high % of the cells are good.
              Thanks, Bill S

              --- In solectria_ev@yahoogroups.com, "Mike Phillips"
              <mikep_95133@...> wrote:
              >
              > This information was derived from experience driving several hundred
              > miles in a vehicle with 5 Prius packs in parallel for the pack.
              There
              > were 11 packs total used in testing.
              >
              > Mike
              >
              >
              >
              > --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@>
              > wrote:
              > >
              > > The absolute most important thing with these Prius modules is
              cooling
              > > them. Just 1 amp during charge can smoke them without cooling. If
              you
              > > look at the side view of the chassis you will see a slope in lower
              > > plenum. It keeps the airflow rate the same across all of the
              cells.
              > >
              > > The second most important thing is that the cells must absolutely
              be
              > > held in compression. Even when they are stone cold, just 1 amp
              during
              > > charge causes them to pressurize and expand a lot, thus ruining
              them.
              > >
              > > If you overheat the modules they will not flow KOH into the black
              > > overflow tubes that go across the top of the cells. The thermal
              vents
              > > will each crack and thus vent gaseous and liquid KOH.
              > >
              > > The 4 thermistors on the top of the cells are 10k NTC types. Using
              > > them to adjust air flow is important.
              > >
              > > That sheetmetal chassis that they come in from the factory is
              > > engineered the way it is for list full of reasons.
              > >
              > > You have to ask yourself if you have enough room for all of the
              > > support hardware in each battery box.
              > >
              > > That 'current measuring coil' is for telling the hardware how much
              > > current is being put into or taken out of the pack.
              > >
              > > These are not the same NIMH cells that you can read about in
              books and
              > > on the web. They are in the same family but have been very
              optimized
              > > for efficiently accepting regen energy, far better than anything
              else
              > > on the planet. That makes them less energy dense and more prone to
              > > thermal failure.
              > >
              > > I'm buried up to my eyeballs in projects now, so I cannot give you
              > > much more than this right now.
              > >
              > > Good Luck.
              > >
              > > Mike
              > >
              > >
              > >
              > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@>
              wrote:
              > > >
              > > > I dis-assembled a Prius battery pack. What I understand about
              the
              > > > design I like. The cells are bolted to a common baseplate.
              There are
              > > > series copper jumpers between the 38 cells. I saw a 125 amp
              fuse and
              > > > a computer, into which the 5 temp sensors and 19 voltage
              measurments
              > > > were fed. Also there are 2 single pole relays to disconnect the
              pack
              > > > from the outside world. I saw what would appear to be a current
              > > > measuring coil, but I do not undestend what it might do in a DC
              > > > system except to verify the the reley worked. There are thermo
              wells
              > > > in every cell, where the temp sensors are placed. Additionally,
              all
              > > > 38 cells were vented into a common tube to carry off gasses.
              There
              > > > was one temp sensor in a plenum below the pack to verify air
              flow.
              > > > And all of the cells had dimples on the sides so there would be
              a
              > > > gaps between cells for cooling air flow. My next step is to see
              how
              > > > many series combinations will fit in the Force battery boxes.
              It is a
              > > > squeeze, but 4 might fit in the front battery box.
              > > > Bill S
              > > >
              > > > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
              > > > wrote:
              > > > >
              > > > > Thanks for the math. I have not gotten around to doing that
              yet. I
              > > > had just looked at the watt-hours per pound which was
              favorable. I
              > > > inquired at a local surplus parts dealer, and battery packs in
              > > > wrecked Priuss are available beginning at $ 400. My plan will
              be to
              > > > acquire enough packs and build up a series/parallel combination
              on
              > > > the bench, and start doing some load tests. The Prius pack I
              have
              > > > seems to look at the voltage of 2 modules at a time. The
              voltage
              > > > sampling electronics is being developed. First for 13 batteries
              for
              > > > the Force, then for a higher number of cells.
              > > > > Bill S
              > > > >
              > > > >
              > > > > ----- Original Message ----
              > > > > From: Todd Martin <larsthelean@>
              > > > > To: solectria_ev@yahoogroups.com
              > > > > Sent: Friday, November 30, 2007 7:47:57 AM
              > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
              > > > >
              > > > > Hi Bill,
              > > > >
              > > > > This sounds like an interesting project.
              > > > >
              > > > > I took the liberty of checking the specs on the Prius Nimh
              modules:
              > > > >
              > > > > Each module is 11" long by 5" wide by 3/4" thick and require
              a 2mm
              > > > > gap between modules for forced air cooling. They weigh 2.3
              lbs and
              > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
              depth
              > > > > of discharge for Nimh, 5Ahr are usable.
              > > > >
              > > > > A Solectria Force has battery boxes that can accommodate 13
              group
              > > > 27
              > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
              This
              > > > > works out to about 1119 sq. inches of battery box floor space.
              > > > >
              > > > > IF you can orient the Prius Nimh modules so they the 11" long
              is
              > > > > vertical (not a real problem in the back box since you can
              always
              > > > > add a spacer between the bottom and lid if necessary, but it
              MAY be
              > > > > a real problem for the front box), then I figure you can fit
              > > > roughly
              > > > > 270 modules into a Force. This is a rough calculation without
              doing
              > > > > an actual layout.
              > > > >
              > > > > Since you will need to arrange the modules into multiple sets
              of
              > > > > strings of around 156V, I see the math as:
              > > > > 22 modules * 7.2V = 158.4V string linked in series.
              > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
              > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
              > > > >
              > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
              will
              > > > > save 214 lbs by making the switch and increase your range
              from 50
              > > > > miles to approximately 60 miles.
              > > > >
              > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
              charger, I
              > > > > don't see a real problem with charging the batteries. You
              just need
              > > > > to find out the charging profile and set the program using
              the free
              > > > > DOS program. For a Zivan charger, you'd need to send it to
              the
              > > > > manufacturer for a re-programming.
              > > > >
              > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
              > > > > Powercheq between each string would be enough to get by.
              Otherwise,
              > > > > that is a LOT of regs to be installing if you have to do
              every
              > > > > module.
              > > > >
              > > > > I'm curious as to the market rate for used Prius Nimh
              modules. If
              > > > > you can share the price for them, we can compare them to
              other
              > > > > battery choices.
              > > > >
              > > > > Thanks!
              > > > >
              > > > > Todd Martin
              > > > > 1997 Solectria Force
              > > > > VP, FVEAA
              > > > >
              > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
              <dbswann4@ .>
              > > > > wrote:
              > > > > >
              > > > > > I understand all the precautions you enumerate. I may
              purchase
              > > > the
              > > > > > first of several surplus Prius battery packs tomorrow. Is
              there a
              > > > > > chance I can e-mail the person who put together a NiMH pack
              for
              > > > > the S-
              > > > > > 10. I am open to tips and tricks/opinions.
              > > > > > Thanks,Bill S
              > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
              > > > <Pohorsky@>
              > > > > > wrote:
              > > > > > >
              > > > > > > Howdy,
              > > > > > >
              > > > > > > The batteries in the Prius are not very suitable for the
              Force
              > > > > > unless you disassemble the pack, rewire the modules and
              come up
              > > > > with
              > > > > > a suitable charger and BMS. NiMH batteries have a unique
              charging
              > > > > > profile and the standard lead acid battery chargers are not
              > > > > > appropriate. The batteries themselves are an odd physical
              size
              > > > > and
              > > > > > voltage. I believe they are something like a 7.2 volt
              battery
              > > > > with a
              > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
              > > > > > intermittent duty in a hybrid but totally inadequate for an
              EV.
              > > > > > >
              > > > > > > You would need several strings in parallel to get the amp-
              hour
              > > > > > rating you need. A fellow EAA member bought several used
              Prius
              > > > > packs
              > > > > > on eBay and wired them in parallel for use in his US
              Electricar S-
              > > > > 10
              > > > > > pickup truck. He needed to invent a battery management
              system as
              > > > > > well as a fan-forced cooling system. The weight reduction
              gave
              > > > > him
              > > > > > an improvement in acceleration over his old lead acid pack
              and
              > > > > > slightly more range, but eventually he got rid of them.
              They took
              > > > > up
              > > > > > the entire bed of the truck. He is now running a flooded
              NiCad
              > > > > pack
              > > > > > that he got from a military surplus supplier. He was able
              to
              > > > > mount
              > > > > > the NiCads under the bed of the truck.
              > > > > > >
              > > > > > > Not all non-lead packs are series parallel combinations.
              I saw
              > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
              With
              > > > > > these, you would just have a series string although there
              would
              > > > be
              > > > > a
              > > > > > large number of cells - they between 3 and 4 volts each.
              > > > > > >
              > > > > > > Stephen Taylor has a series string of the Valence Lithium
              > > > > batteries
              > > > > > in his Force.
              > > > > > >
              > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
              EV.
              > > > > > Unfortunately, these Panasonic batteries have been taken
              off the
              > > > > > market due to a lawsuit filed by Chevron - but it is
              another
              > > > > example
              > > > > > where a series parallel combo was not needed.
              > > > > > >
              > > > > > > Adios,
              > > > > > >
              > > > > > > Jerry Pohorsky
              > > > > > >
              > > > > > > ----- Original Message -----
              > > > > > > From: Bill Swann
              > > > > > > To: solectria_ev@ yahoogroups. com
              > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
              > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
              > > > > > >
              > > > > > >
              > > > > > > I am surprised that someone has not taken some surplus
              > > > > batteries
              > > > > > from a
              > > > > > > Prius and adapted it to the Force. The energy density is
              > > > > double
              > > > > > over
              > > > > > > lead. As it is with battery packs other that SLA, the
              pack
              > > > > ends
              > > > > > up
              > > > > > > being a series/parallel combination.
              > > > > > > Bill S
              > > > > > >
              > > > > > >
              > > > > > >
              > > > > > >
              > > > > > >
              > > > > > > [Non-text portions of this message have been removed]
              > > > > > >
              > > > > >
              > > > >
              > > > >
              > > > >
              > > > >
              > > > > [Non-text portions of this message have been removed]
              > > > >
              > > >
              > >
              >
            • theoldcars@aol.com
              Hello Bill I am not an expert on the Prius NiMH packs. I have though done quite a bit of research on NiMH batteries and have been using them for several
              Message 6 of 19 , Dec 24, 2007
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                Hello Bill

                I am not an expert on the Prius NiMH packs. I have though done quite a bit
                of research on NiMH batteries and have been using them for several years now.

                What Mike has pointed out to you about the Prius being optimized for
                accepting regen is true. I have read information from different NiMH battery
                manufacturers web sites. It is used as a sales tool to sell their batteries for
                Hybrid vehicles. The Prius pack is never fully charged and never deeply
                discharged. I recall it is 50 to 80 percent SOC they are maintained within.

                Heat is a real killer of all NiMH batteries regardless of the battery mix or
                use. In the Ranger and RAV4 they will stop charging if the batteries are not
                cool enough. The S-10 and EV1 use A/C to keep the NiMH batteries from
                exceeding 86 degrees during charging. It is the last 20 percent of a full charge
                that NiMH batteries temperature really takes off. As I see it the Prius
                batteries were never to go the last 20 percent of a full charge. The packs were
                never intended to have to deal with this much heat.

                Also the NiMH battery does heat up under large current draws. They also heat
                up even more during hard draws in a lower discharged state. This is not
                because the Prius pack was never to deliver the power for full EV use. The more
                power you pull from them the more they will heat up. You could very well kill
                these batteries during both charging and discharging this would destroy them
                even faster.

                The used Prius packs may be a real buy however I doubt they would provide
                long life if used as an EV battery. Unless you really oversized the pack and
                kept them within their design temperature range and power draw. I am certain
                the results would be very disappointing.

                It would be interesting to know more about Mikes testing.

                Don Blazer
                1998 S-10 NiMH





                **************************************See AOL's top rated recipes
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                [Non-text portions of this message have been removed]
              • ldr214
                Bill, I have followed these post and have also been a avid follower of the tech postings and newsletters at www.calcars.org where they have been at the front
                Message 7 of 19 , Dec 25, 2007
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                  Bill,
                  I have followed these post and have also been a avid follower of the
                  tech postings and newsletters at www.calcars.org where they have been
                  at the front of the PHEV effort. You may not be aware that one of the
                  first batteries that was rejected for the ideal PHEV (think modified
                  Prius) was in fact the Prius battery itself.

                  Some of the conversions leave the Prius battery in the vehicle but
                  none of them that I'm aware of add anymore of these batteries. For the
                  reasons that Mike and Don have mentioned it does not have the
                  characteristics of a good traction battery. I think you can search the
                  archives via: http://www.eaa-phev.org/maillist/eaa-phev.html?show=
                  Mike Rydjord

                  --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@...> wrote:
                  >
                  > Thanks for the feedback. And for alerting me to the pitfalls of re-
                  > engineering a battery pack. I do not fully understand your comment "
                  > the Prius batteries have been optimized for efficiently accepting
                  > regen energy". Are you suggesting that making a Solectria battery
                  > pack with 5-6 Prius packs is ill advised because the Prius battery is
                  > not designed for this? The price is certainly right for used packs,
                  > assuming a high % of the cells are good.
                  > Thanks, Bill S
                  >
                  > --- In solectria_ev@yahoogroups.com, "Mike Phillips"
                  > <mikep_95133@> wrote:
                  > >
                  > > This information was derived from experience driving several hundred
                  > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                  > There
                  > > were 11 packs total used in testing.
                  > >
                  > > Mike
                  > >
                  > >
                  > >
                  > > --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@>
                  > > wrote:
                  > > >
                  > > > The absolute most important thing with these Prius modules is
                  > cooling
                  > > > them. Just 1 amp during charge can smoke them without cooling. If
                  > you
                  > > > look at the side view of the chassis you will see a slope in lower
                  > > > plenum. It keeps the airflow rate the same across all of the
                  > cells.
                  > > >
                  > > > The second most important thing is that the cells must absolutely
                  > be
                  > > > held in compression. Even when they are stone cold, just 1 amp
                  > during
                  > > > charge causes them to pressurize and expand a lot, thus ruining
                  > them.
                  > > >
                  > > > If you overheat the modules they will not flow KOH into the black
                  > > > overflow tubes that go across the top of the cells. The thermal
                  > vents
                  > > > will each crack and thus vent gaseous and liquid KOH.
                  > > >
                  > > > The 4 thermistors on the top of the cells are 10k NTC types. Using
                  > > > them to adjust air flow is important.
                  > > >
                  > > > That sheetmetal chassis that they come in from the factory is
                  > > > engineered the way it is for list full of reasons.
                  > > >
                  > > > You have to ask yourself if you have enough room for all of the
                  > > > support hardware in each battery box.
                  > > >
                  > > > That 'current measuring coil' is for telling the hardware how much
                  > > > current is being put into or taken out of the pack.
                  > > >
                  > > > These are not the same NIMH cells that you can read about in
                  > books and
                  > > > on the web. They are in the same family but have been very
                  > optimized
                  > > > for efficiently accepting regen energy, far better than anything
                  > else
                  > > > on the planet. That makes them less energy dense and more prone to
                  > > > thermal failure.
                  > > >
                  > > > I'm buried up to my eyeballs in projects now, so I cannot give you
                  > > > much more than this right now.
                  > > >
                  > > > Good Luck.
                  > > >
                  > > > Mike
                  > > >
                  > > >
                  > > >
                  > > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@>
                  > wrote:
                  > > > >
                  > > > > I dis-assembled a Prius battery pack. What I understand about
                  > the
                  > > > > design I like. The cells are bolted to a common baseplate.
                  > There are
                  > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                  > fuse and
                  > > > > a computer, into which the 5 temp sensors and 19 voltage
                  > measurments
                  > > > > were fed. Also there are 2 single pole relays to disconnect the
                  > pack
                  > > > > from the outside world. I saw what would appear to be a current
                  > > > > measuring coil, but I do not undestend what it might do in a DC
                  > > > > system except to verify the the reley worked. There are thermo
                  > wells
                  > > > > in every cell, where the temp sensors are placed. Additionally,
                  > all
                  > > > > 38 cells were vented into a common tube to carry off gasses.
                  > There
                  > > > > was one temp sensor in a plenum below the pack to verify air
                  > flow.
                  > > > > And all of the cells had dimples on the sides so there would be
                  > a
                  > > > > gaps between cells for cooling air flow. My next step is to see
                  > how
                  > > > > many series combinations will fit in the Force battery boxes.
                  > It is a
                  > > > > squeeze, but 4 might fit in the front battery box.
                  > > > > Bill S
                  > > > >
                  > > > > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
                  > > > > wrote:
                  > > > > >
                  > > > > > Thanks for the math. I have not gotten around to doing that
                  > yet. I
                  > > > > had just looked at the watt-hours per pound which was
                  > favorable. I
                  > > > > inquired at a local surplus parts dealer, and battery packs in
                  > > > > wrecked Priuss are available beginning at $ 400. My plan will
                  > be to
                  > > > > acquire enough packs and build up a series/parallel combination
                  > on
                  > > > > the bench, and start doing some load tests. The Prius pack I
                  > have
                  > > > > seems to look at the voltage of 2 modules at a time. The
                  > voltage
                  > > > > sampling electronics is being developed. First for 13 batteries
                  > for
                  > > > > the Force, then for a higher number of cells.
                  > > > > > Bill S
                  > > > > >
                  > > > > >
                  > > > > > ----- Original Message ----
                  > > > > > From: Todd Martin <larsthelean@>
                  > > > > > To: solectria_ev@yahoogroups.com
                  > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                  > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                  > > > > >
                  > > > > > Hi Bill,
                  > > > > >
                  > > > > > This sounds like an interesting project.
                  > > > > >
                  > > > > > I took the liberty of checking the specs on the Prius Nimh
                  > modules:
                  > > > > >
                  > > > > > Each module is 11" long by 5" wide by 3/4" thick and require
                  > a 2mm
                  > > > > > gap between modules for forced air cooling. They weigh 2.3
                  > lbs and
                  > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                  > depth
                  > > > > > of discharge for Nimh, 5Ahr are usable.
                  > > > > >
                  > > > > > A Solectria Force has battery boxes that can accommodate 13
                  > group
                  > > > > 27
                  > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
                  > This
                  > > > > > works out to about 1119 sq. inches of battery box floor space.
                  > > > > >
                  > > > > > IF you can orient the Prius Nimh modules so they the 11" long
                  > is
                  > > > > > vertical (not a real problem in the back box since you can
                  > always
                  > > > > > add a spacer between the bottom and lid if necessary, but it
                  > MAY be
                  > > > > > a real problem for the front box), then I figure you can fit
                  > > > > roughly
                  > > > > > 270 modules into a Force. This is a rough calculation without
                  > doing
                  > > > > > an actual layout.
                  > > > > >
                  > > > > > Since you will need to arrange the modules into multiple sets
                  > of
                  > > > > > strings of around 156V, I see the math as:
                  > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                  > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                  > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                  > > > > >
                  > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                  > will
                  > > > > > save 214 lbs by making the switch and increase your range
                  > from 50
                  > > > > > miles to approximately 60 miles.
                  > > > > >
                  > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                  > charger, I
                  > > > > > don't see a real problem with charging the batteries. You
                  > just need
                  > > > > > to find out the charging profile and set the program using
                  > the free
                  > > > > > DOS program. For a Zivan charger, you'd need to send it to
                  > the
                  > > > > > manufacturer for a re-programming.
                  > > > > >
                  > > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
                  > > > > > Powercheq between each string would be enough to get by.
                  > Otherwise,
                  > > > > > that is a LOT of regs to be installing if you have to do
                  > every
                  > > > > > module.
                  > > > > >
                  > > > > > I'm curious as to the market rate for used Prius Nimh
                  > modules. If
                  > > > > > you can share the price for them, we can compare them to
                  > other
                  > > > > > battery choices.
                  > > > > >
                  > > > > > Thanks!
                  > > > > >
                  > > > > > Todd Martin
                  > > > > > 1997 Solectria Force
                  > > > > > VP, FVEAA
                  > > > > >
                  > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                  > <dbswann4@ .>
                  > > > > > wrote:
                  > > > > > >
                  > > > > > > I understand all the precautions you enumerate. I may
                  > purchase
                  > > > > the
                  > > > > > > first of several surplus Prius battery packs tomorrow. Is
                  > there a
                  > > > > > > chance I can e-mail the person who put together a NiMH pack
                  > for
                  > > > > > the S-
                  > > > > > > 10. I am open to tips and tricks/opinions.
                  > > > > > > Thanks,Bill S
                  > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                  > > > > <Pohorsky@>
                  > > > > > > wrote:
                  > > > > > > >
                  > > > > > > > Howdy,
                  > > > > > > >
                  > > > > > > > The batteries in the Prius are not very suitable for the
                  > Force
                  > > > > > > unless you disassemble the pack, rewire the modules and
                  > come up
                  > > > > > with
                  > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                  > charging
                  > > > > > > profile and the standard lead acid battery chargers are not
                  > > > > > > appropriate. The batteries themselves are an odd physical
                  > size
                  > > > > > and
                  > > > > > > voltage. I believe they are something like a 7.2 volt
                  > battery
                  > > > > > with a
                  > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                  > > > > > > intermittent duty in a hybrid but totally inadequate for an
                  > EV.
                  > > > > > > >
                  > > > > > > > You would need several strings in parallel to get the amp-
                  > hour
                  > > > > > > rating you need. A fellow EAA member bought several used
                  > Prius
                  > > > > > packs
                  > > > > > > on eBay and wired them in parallel for use in his US
                  > Electricar S-
                  > > > > > 10
                  > > > > > > pickup truck. He needed to invent a battery management
                  > system as
                  > > > > > > well as a fan-forced cooling system. The weight reduction
                  > gave
                  > > > > > him
                  > > > > > > an improvement in acceleration over his old lead acid pack
                  > and
                  > > > > > > slightly more range, but eventually he got rid of them.
                  > They took
                  > > > > > up
                  > > > > > > the entire bed of the truck. He is now running a flooded
                  > NiCad
                  > > > > > pack
                  > > > > > > that he got from a military surplus supplier. He was able
                  > to
                  > > > > > mount
                  > > > > > > the NiCads under the bed of the truck.
                  > > > > > > >
                  > > > > > > > Not all non-lead packs are series parallel combinations.
                  > I saw
                  > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
                  > With
                  > > > > > > these, you would just have a series string although there
                  > would
                  > > > > be
                  > > > > > a
                  > > > > > > large number of cells - they between 3 and 4 volts each.
                  > > > > > > >
                  > > > > > > > Stephen Taylor has a series string of the Valence Lithium
                  > > > > > batteries
                  > > > > > > in his Force.
                  > > > > > > >
                  > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
                  > EV.
                  > > > > > > Unfortunately, these Panasonic batteries have been taken
                  > off the
                  > > > > > > market due to a lawsuit filed by Chevron - but it is
                  > another
                  > > > > > example
                  > > > > > > where a series parallel combo was not needed.
                  > > > > > > >
                  > > > > > > > Adios,
                  > > > > > > >
                  > > > > > > > Jerry Pohorsky
                  > > > > > > >
                  > > > > > > > ----- Original Message -----
                  > > > > > > > From: Bill Swann
                  > > > > > > > To: solectria_ev@ yahoogroups. com
                  > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                  > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                  > > > > > > >
                  > > > > > > >
                  > > > > > > > I am surprised that someone has not taken some surplus
                  > > > > > batteries
                  > > > > > > from a
                  > > > > > > > Prius and adapted it to the Force. The energy density is
                  > > > > > double
                  > > > > > > over
                  > > > > > > > lead. As it is with battery packs other that SLA, the
                  > pack
                  > > > > > ends
                  > > > > > > up
                  > > > > > > > being a series/parallel combination.
                  > > > > > > > Bill S
                  > > > > > > >
                  > > > > > > >
                  > > > > > > >
                  > > > > > > >
                  > > > > > > >
                  > > > > > > > [Non-text portions of this message have been removed]
                  > > > > > > >
                  > > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > > [Non-text portions of this message have been removed]
                  > > > > >
                  > > > >
                  > > >
                  > >
                  >
                • Bill or Dorothy Swann
                  Thanks. Since the PHEV has rejected the idea - that s convincing enough. Does anyone know of the most promising battery replacemant technology? $ wise, that
                  Message 8 of 19 , Dec 25, 2007
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                    Thanks. Since the PHEV has rejected the idea - that's convincing enough. Does anyone know of the most promising battery replacemant technology? $ wise, that is.
                    Bill s

                    ----- Original Message ----
                    From: ldr214 <replytome@...>
                    To: solectria_ev@yahoogroups.com
                    Sent: Tuesday, December 25, 2007 10:01:04 AM
                    Subject: [solectria_ev] Re: Prius NiMH Batteries

                    Bill,
                    I have followed these post and have also been a avid follower of the
                    tech postings and newsletters at www.calcars. org where they have been
                    at the front of the PHEV effort. You may not be aware that one of the
                    first batteries that was rejected for the ideal PHEV (think modified
                    Prius) was in fact the Prius battery itself.

                    Some of the conversions leave the Prius battery in the vehicle but
                    none of them that I'm aware of add anymore of these batteries. For the
                    reasons that Mike and Don have mentioned it does not have the
                    characteristics of a good traction battery. I think you can search the
                    archives via: http://www.eaa- phev.org/ maillist/ eaa-phev. html?show=
                    Mike Rydjord

                    --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@.. .> wrote:
                    >
                    > Thanks for the feedback. And for alerting me to the pitfalls of re-
                    > engineering a battery pack. I do not fully understand your comment "
                    > the Prius batteries have been optimized for efficiently accepting
                    > regen energy". Are you suggesting that making a Solectria battery
                    > pack with 5-6 Prius packs is ill advised because the Prius battery is
                    > not designed for this? The price is certainly right for used packs,
                    > assuming a high % of the cells are good.
                    > Thanks, Bill S
                    >
                    > --- In solectria_ev@ yahoogroups. com, "Mike Phillips"
                    > <mikep_95133@ > wrote:
                    > >
                    > > This information was derived from experience driving several hundred
                    > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                    > There
                    > > were 11 packs total used in testing.
                    > >
                    > > Mike
                    > >
                    > >
                    > >
                    > > --- In solectria_ev@ yahoogroups. com, "Mike Phillips" <mikep_95133@ >
                    > > wrote:
                    > > >
                    > > > The absolute most important thing with these Prius modules is
                    > cooling
                    > > > them. Just 1 amp during charge can smoke them without cooling. If
                    > you
                    > > > look at the side view of the chassis you will see a slope in lower
                    > > > plenum. It keeps the airflow rate the same across all of the
                    > cells.
                    > > >
                    > > > The second most important thing is that the cells must absolutely
                    > be
                    > > > held in compression. Even when they are stone cold, just 1 amp
                    > during
                    > > > charge causes them to pressurize and expand a lot, thus ruining
                    > them.
                    > > >
                    > > > If you overheat the modules they will not flow KOH into the black
                    > > > overflow tubes that go across the top of the cells. The thermal
                    > vents
                    > > > will each crack and thus vent gaseous and liquid KOH.
                    > > >
                    > > > The 4 thermistors on the top of the cells are 10k NTC types. Using
                    > > > them to adjust air flow is important.
                    > > >
                    > > > That sheetmetal chassis that they come in from the factory is
                    > > > engineered the way it is for list full of reasons.
                    > > >
                    > > > You have to ask yourself if you have enough room for all of the
                    > > > support hardware in each battery box.
                    > > >
                    > > > That 'current measuring coil' is for telling the hardware how much
                    > > > current is being put into or taken out of the pack.
                    > > >
                    > > > These are not the same NIMH cells that you can read about in
                    > books and
                    > > > on the web. They are in the same family but have been very
                    > optimized
                    > > > for efficiently accepting regen energy, far better than anything
                    > else
                    > > > on the planet. That makes them less energy dense and more prone to
                    > > > thermal failure.
                    > > >
                    > > > I'm buried up to my eyeballs in projects now, so I cannot give you
                    > > > much more than this right now.
                    > > >
                    > > > Good Luck.
                    > > >
                    > > > Mike
                    > > >
                    > > >
                    > > >
                    > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@>
                    > wrote:
                    > > > >
                    > > > > I dis-assembled a Prius battery pack. What I understand about
                    > the
                    > > > > design I like. The cells are bolted to a common baseplate.
                    > There are
                    > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                    > fuse and
                    > > > > a computer, into which the 5 temp sensors and 19 voltage
                    > measurments
                    > > > > were fed. Also there are 2 single pole relays to disconnect the
                    > pack
                    > > > > from the outside world. I saw what would appear to be a current
                    > > > > measuring coil, but I do not undestend what it might do in a DC
                    > > > > system except to verify the the reley worked. There are thermo
                    > wells
                    > > > > in every cell, where the temp sensors are placed. Additionally,
                    > all
                    > > > > 38 cells were vented into a common tube to carry off gasses.
                    > There
                    > > > > was one temp sensor in a plenum below the pack to verify air
                    > flow.
                    > > > > And all of the cells had dimples on the sides so there would be
                    > a
                    > > > > gaps between cells for cooling air flow. My next step is to see
                    > how
                    > > > > many series combinations will fit in the Force battery boxes.
                    > It is a
                    > > > > squeeze, but 4 might fit in the front battery box.
                    > > > > Bill S
                    > > > >
                    > > > > --- In solectria_ev@ yahoogroups. com, Dorothy Swann <dbswann4@>
                    > > > > wrote:
                    > > > > >
                    > > > > > Thanks for the math. I have not gotten around to doing that
                    > yet. I
                    > > > > had just looked at the watt-hours per pound which was
                    > favorable. I
                    > > > > inquired at a local surplus parts dealer, and battery packs in
                    > > > > wrecked Priuss are available beginning at $ 400. My plan will
                    > be to
                    > > > > acquire enough packs and build up a series/parallel combination
                    > on
                    > > > > the bench, and start doing some load tests. The Prius pack I
                    > have
                    > > > > seems to look at the voltage of 2 modules at a time. The
                    > voltage
                    > > > > sampling electronics is being developed. First for 13 batteries
                    > for
                    > > > > the Force, then for a higher number of cells.
                    > > > > > Bill S
                    > > > > >
                    > > > > >
                    > > > > > ----- Original Message ----
                    > > > > > From: Todd Martin <larsthelean@ >
                    > > > > > To: solectria_ev@ yahoogroups. com
                    > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                    > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                    > > > > >
                    > > > > > Hi Bill,
                    > > > > >
                    > > > > > This sounds like an interesting project.
                    > > > > >
                    > > > > > I took the liberty of checking the specs on the Prius Nimh
                    > modules:
                    > > > > >
                    > > > > > Each module is 11" long by 5" wide by 3/4" thick and require
                    > a 2mm
                    > > > > > gap between modules for forced air cooling. They weigh 2.3
                    > lbs and
                    > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                    > depth
                    > > > > > of discharge for Nimh, 5Ahr are usable.
                    > > > > >
                    > > > > > A Solectria Force has battery boxes that can accommodate 13
                    > group
                    > > > > 27
                    > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
                    > This
                    > > > > > works out to about 1119 sq. inches of battery box floor space.
                    > > > > >
                    > > > > > IF you can orient the Prius Nimh modules so they the 11" long
                    > is
                    > > > > > vertical (not a real problem in the back box since you can
                    > always
                    > > > > > add a spacer between the bottom and lid if necessary, but it
                    > MAY be
                    > > > > > a real problem for the front box), then I figure you can fit
                    > > > > roughly
                    > > > > > 270 modules into a Force. This is a rough calculation without
                    > doing
                    > > > > > an actual layout.
                    > > > > >
                    > > > > > Since you will need to arrange the modules into multiple sets
                    > of
                    > > > > > strings of around 156V, I see the math as:
                    > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                    > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                    > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                    > > > > >
                    > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                    > will
                    > > > > > save 214 lbs by making the switch and increase your range
                    > from 50
                    > > > > > miles to approximately 60 miles.
                    > > > > >
                    > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                    > charger, I
                    > > > > > don't see a real problem with charging the batteries. You
                    > just need
                    > > > > > to find out the charging profile and set the program using
                    > the free
                    > > > > > DOS program. For a Zivan charger, you'd need to send it to
                    > the
                    > > > > > manufacturer for a re-programming.
                    > > > > >
                    > > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
                    > > > > > Powercheq between each string would be enough to get by.
                    > Otherwise,
                    > > > > > that is a LOT of regs to be installing if you have to do
                    > every
                    > > > > > module.
                    > > > > >
                    > > > > > I'm curious as to the market rate for used Prius Nimh
                    > modules. If
                    > > > > > you can share the price for them, we can compare them to
                    > other
                    > > > > > battery choices.
                    > > > > >
                    > > > > > Thanks!
                    > > > > >
                    > > > > > Todd Martin
                    > > > > > 1997 Solectria Force
                    > > > > > VP, FVEAA
                    > > > > >
                    > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                    > <dbswann4@ .>
                    > > > > > wrote:
                    > > > > > >
                    > > > > > > I understand all the precautions you enumerate. I may
                    > purchase
                    > > > > the
                    > > > > > > first of several surplus Prius battery packs tomorrow. Is
                    > there a
                    > > > > > > chance I can e-mail the person who put together a NiMH pack
                    > for
                    > > > > > the S-
                    > > > > > > 10. I am open to tips and tricks/opinions.
                    > > > > > > Thanks,Bill S
                    > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                    > > > > <Pohorsky@>
                    > > > > > > wrote:
                    > > > > > > >
                    > > > > > > > Howdy,
                    > > > > > > >
                    > > > > > > > The batteries in the Prius are not very suitable for the
                    > Force
                    > > > > > > unless you disassemble the pack, rewire the modules and
                    > come up
                    > > > > > with
                    > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                    > charging
                    > > > > > > profile and the standard lead acid battery chargers are not
                    > > > > > > appropriate. The batteries themselves are an odd physical
                    > size
                    > > > > > and
                    > > > > > > voltage. I believe they are something like a 7.2 volt
                    > battery
                    > > > > > with a
                    > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                    > > > > > > intermittent duty in a hybrid but totally inadequate for an
                    > EV.
                    > > > > > > >
                    > > > > > > > You would need several strings in parallel to get the amp-
                    > hour
                    > > > > > > rating you need. A fellow EAA member bought several used
                    > Prius
                    > > > > > packs
                    > > > > > > on eBay and wired them in parallel for use in his US
                    > Electricar S-
                    > > > > > 10
                    > > > > > > pickup truck. He needed to invent a battery management
                    > system as
                    > > > > > > well as a fan-forced cooling system. The weight reduction
                    > gave
                    > > > > > him
                    > > > > > > an improvement in acceleration over his old lead acid pack
                    > and
                    > > > > > > slightly more range, but eventually he got rid of them.
                    > They took
                    > > > > > up
                    > > > > > > the entire bed of the truck. He is now running a flooded
                    > NiCad
                    > > > > > pack
                    > > > > > > that he got from a military surplus supplier. He was able
                    > to
                    > > > > > mount
                    > > > > > > the NiCads under the bed of the truck.
                    > > > > > > >
                    > > > > > > > Not all non-lead packs are series parallel combinations.
                    > I saw
                    > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
                    > With
                    > > > > > > these, you would just have a series string although there
                    > would
                    > > > > be
                    > > > > > a
                    > > > > > > large number of cells - they between 3 and 4 volts each.
                    > > > > > > >
                    > > > > > > > Stephen Taylor has a series string of the Valence Lithium
                    > > > > > batteries
                    > > > > > > in his Force.
                    > > > > > > >
                    > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
                    > EV.
                    > > > > > > Unfortunately, these Panasonic batteries have been taken
                    > off the
                    > > > > > > market due to a lawsuit filed by Chevron - but it is
                    > another
                    > > > > > example
                    > > > > > > where a series parallel combo was not needed.
                    > > > > > > >
                    > > > > > > > Adios,
                    > > > > > > >
                    > > > > > > > Jerry Pohorsky
                    > > > > > > >
                    > > > > > > > ----- Original Message -----
                    > > > > > > > From: Bill Swann
                    > > > > > > > To: solectria_ev@ yahoogroups. com
                    > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                    > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                    > > > > > > >
                    > > > > > > >
                    > > > > > > > I am surprised that someone has not taken some surplus
                    > > > > > batteries
                    > > > > > > from a
                    > > > > > > > Prius and adapted it to the Force. The energy density is
                    > > > > > double
                    > > > > > > over
                    > > > > > > > lead. As it is with battery packs other that SLA, the
                    > pack
                    > > > > > ends
                    > > > > > > up
                    > > > > > > > being a series/parallel combination.
                    > > > > > > > Bill S
                    > > > > > > >
                    > > > > > > >
                    > > > > > > >
                    > > > > > > >
                    > > > > > > >
                    > > > > > > > [Non-text portions of this message have been removed]
                    > > > > > > >
                    > > > > > >
                    > > > > >
                    > > > > >
                    > > > > >
                    > > > > >
                    > > > > > [Non-text portions of this message have been removed]
                    > > > > >
                    > > > >
                    > > >
                    > >
                    >




                    [Non-text portions of this message have been removed]
                  • Mike Phillips
                    There are a few directions to approach the Prius packs for use in an EV. Energy content is about 1.0-1.2 kwhrs per pack from the testing that I did. Five in
                    Message 9 of 19 , Dec 25, 2007
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                      There are a few directions to approach the Prius packs for use in an EV.

                      Energy content is about 1.0-1.2 kwhrs per pack from the testing that I
                      did. Five in parallel give you 5.0-6.0 kwhrs of energy. That might get
                      you 20-25 miles of range if you drain the pack dead. I'm assuming 250
                      watt-hours per mile. Following the rule of thumb to not go lower than
                      50% state of charge, you might have a range of 10-12 miles. Imagine
                      having this kind of range after spending the time it takes to
                      mechanically restrain every module so they don't expand and wiring it
                      all up. A 1 amp charge rate will ruin an unrestrained Prius module.
                      Then there is how to charge nimh in parallel. Some say it's
                      impossible. Ask them how many times they have tried it. It can be done
                      but requires even more of a complicated pack. The built in relays in
                      the Prius packs make parallel charging and it's associated maintenance
                      possible. Every now and then the pack needs to be separated into
                      individual packs and charged separately.

                      Then there is the cooling issue. That's an entire page all by itself.

                      The Prius modules are rated to last 150k miles because they do in fact
                      run in a narrow band of soc. I forget the exact number, if I ever knew
                      it, but guessing at 40-80% is pretty close. That tight band is how
                      they get millions of very shallow charge/discharge cycles. In an EV
                      one hopes to get to 1000 cycles. The plates that make up each module
                      are just thinner looking to me, than say the EV95 in the RAV4/Ranger
                      nimh cells. That relates to being more efficient at accepting
                      regen energy. Not all batteries are good at taking short dumps of
                      energy and actually converting it chemically and storing it as
                      electrical energy. Some of it is absorbed and turned into heat instead.

                      Having several packs in Parallel will help distribute the load. But
                      you only get a very short range for all of your work. I can tell you
                      that having 5 Prius packs in parallel gave me the lowest pack
                      impedance I will ever have. My regen was so severe it would almost
                      break the rear tires lose on deceleration.

                      Anyway, it sure is fun to tell your friends that your EV drives on
                      Prius batteries. Unless the EV is something light like a golf cart, I
                      suspect the lifetime will be short. If nothing else the range is just
                      not worth the effort, to me anyway. I started to figure this out after
                      spending weeks making up fan control circuits and lots of testing.

                      The guy I sold all of my perfectly good packs to, smoked several of
                      them right off the bat. I can promise you he is much more educated
                      than I am. A professor in fact. The bottom line is that these
                      different versions of nimh batteries, Cobasys, Prius, Sanyo, are so
                      different in chacteristics that each should be considered a completely
                      different chemistry.

                      Here is a pic of the packs in the bed of my truck. There are more in
                      that folder.

                      http://www.rotordesign.com/s10/priuspack/P5270196.JPG

                      Mike







                      --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@...> wrote:
                      >
                      > Thanks for the feedback. And for alerting me to the pitfalls of re-
                      > engineering a battery pack. I do not fully understand your comment "
                      > the Prius batteries have been optimized for efficiently accepting
                      > regen energy". Are you suggesting that making a Solectria battery
                      > pack with 5-6 Prius packs is ill advised because the Prius battery is
                      > not designed for this? The price is certainly right for used packs,
                      > assuming a high % of the cells are good.
                      > Thanks, Bill S
                      >

                      > --- In solectria_ev@yahoogroups.com, "Mike Phillips"
                      > <mikep_95133@> wrote:
                      > >
                      > > This information was derived from experience driving several hundred
                      > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                      > There
                      > > were 11 packs total used in testing.
                      > >
                      > > Mike
                      > >
                      > >
                      > >
                      > > --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@>
                      > > wrote:
                      > > >
                      > > > The absolute most important thing with these Prius modules is
                      > cooling
                      > > > them. Just 1 amp during charge can smoke them without cooling. If
                      > you
                      > > > look at the side view of the chassis you will see a slope in lower
                      > > > plenum. It keeps the airflow rate the same across all of the
                      > cells.
                      > > >
                      > > > The second most important thing is that the cells must absolutely
                      > be
                      > > > held in compression. Even when they are stone cold, just 1 amp
                      > during
                      > > > charge causes them to pressurize and expand a lot, thus ruining
                      > them.
                      > > >
                      > > > If you overheat the modules they will not flow KOH into the black
                      > > > overflow tubes that go across the top of the cells. The thermal
                      > vents
                      > > > will each crack and thus vent gaseous and liquid KOH.
                      > > >
                      > > > The 4 thermistors on the top of the cells are 10k NTC types. Using
                      > > > them to adjust air flow is important.
                      > > >
                      > > > That sheetmetal chassis that they come in from the factory is
                      > > > engineered the way it is for list full of reasons.
                      > > >
                      > > > You have to ask yourself if you have enough room for all of the
                      > > > support hardware in each battery box.
                      > > >
                      > > > That 'current measuring coil' is for telling the hardware how much
                      > > > current is being put into or taken out of the pack.
                      > > >
                      > > > These are not the same NIMH cells that you can read about in
                      > books and
                      > > > on the web. They are in the same family but have been very
                      > optimized
                      > > > for efficiently accepting regen energy, far better than anything
                      > else
                      > > > on the planet. That makes them less energy dense and more prone to
                      > > > thermal failure.
                      > > >
                      > > > I'm buried up to my eyeballs in projects now, so I cannot give you
                      > > > much more than this right now.
                      > > >
                      > > > Good Luck.
                      > > >
                      > > > Mike
                      > > >
                      > > >
                      > > >
                      > > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@>
                      > wrote:
                      > > > >
                      > > > > I dis-assembled a Prius battery pack. What I understand about
                      > the
                      > > > > design I like. The cells are bolted to a common baseplate.
                      > There are
                      > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                      > fuse and
                      > > > > a computer, into which the 5 temp sensors and 19 voltage
                      > measurments
                      > > > > were fed. Also there are 2 single pole relays to disconnect the
                      > pack
                      > > > > from the outside world. I saw what would appear to be a current
                      > > > > measuring coil, but I do not undestend what it might do in a DC
                      > > > > system except to verify the the reley worked. There are thermo
                      > wells
                      > > > > in every cell, where the temp sensors are placed. Additionally,
                      > all
                      > > > > 38 cells were vented into a common tube to carry off gasses.
                      > There
                      > > > > was one temp sensor in a plenum below the pack to verify air
                      > flow.
                      > > > > And all of the cells had dimples on the sides so there would be
                      > a
                      > > > > gaps between cells for cooling air flow. My next step is to see
                      > how
                      > > > > many series combinations will fit in the Force battery boxes.
                      > It is a
                      > > > > squeeze, but 4 might fit in the front battery box.
                      > > > > Bill S
                      > > > >
                      > > > > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
                      > > > > wrote:
                      > > > > >
                      > > > > > Thanks for the math. I have not gotten around to doing that
                      > yet. I
                      > > > > had just looked at the watt-hours per pound which was
                      > favorable. I
                      > > > > inquired at a local surplus parts dealer, and battery packs in
                      > > > > wrecked Priuss are available beginning at $ 400. My plan will
                      > be to
                      > > > > acquire enough packs and build up a series/parallel combination
                      > on
                      > > > > the bench, and start doing some load tests. The Prius pack I
                      > have
                      > > > > seems to look at the voltage of 2 modules at a time. The
                      > voltage
                      > > > > sampling electronics is being developed. First for 13 batteries
                      > for
                      > > > > the Force, then for a higher number of cells.
                      > > > > > Bill S
                      > > > > >
                      > > > > >
                      > > > > > ----- Original Message ----
                      > > > > > From: Todd Martin <larsthelean@>
                      > > > > > To: solectria_ev@yahoogroups.com
                      > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                      > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                      > > > > >
                      > > > > > Hi Bill,
                      > > > > >
                      > > > > > This sounds like an interesting project.
                      > > > > >
                      > > > > > I took the liberty of checking the specs on the Prius Nimh
                      > modules:
                      > > > > >
                      > > > > > Each module is 11" long by 5" wide by 3/4" thick and require
                      > a 2mm
                      > > > > > gap between modules for forced air cooling. They weigh 2.3
                      > lbs and
                      > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                      > depth
                      > > > > > of discharge for Nimh, 5Ahr are usable.
                      > > > > >
                      > > > > > A Solectria Force has battery boxes that can accommodate 13
                      > group
                      > > > > 27
                      > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
                      > This
                      > > > > > works out to about 1119 sq. inches of battery box floor space.
                      > > > > >
                      > > > > > IF you can orient the Prius Nimh modules so they the 11" long
                      > is
                      > > > > > vertical (not a real problem in the back box since you can
                      > always
                      > > > > > add a spacer between the bottom and lid if necessary, but it
                      > MAY be
                      > > > > > a real problem for the front box), then I figure you can fit
                      > > > > roughly
                      > > > > > 270 modules into a Force. This is a rough calculation without
                      > doing
                      > > > > > an actual layout.
                      > > > > >
                      > > > > > Since you will need to arrange the modules into multiple sets
                      > of
                      > > > > > strings of around 156V, I see the math as:
                      > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                      > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                      > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                      > > > > >
                      > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                      > will
                      > > > > > save 214 lbs by making the switch and increase your range
                      > from 50
                      > > > > > miles to approximately 60 miles.
                      > > > > >
                      > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                      > charger, I
                      > > > > > don't see a real problem with charging the batteries. You
                      > just need
                      > > > > > to find out the charging profile and set the program using
                      > the free
                      > > > > > DOS program. For a Zivan charger, you'd need to send it to
                      > the
                      > > > > > manufacturer for a re-programming.
                      > > > > >
                      > > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
                      > > > > > Powercheq between each string would be enough to get by.
                      > Otherwise,
                      > > > > > that is a LOT of regs to be installing if you have to do
                      > every
                      > > > > > module.
                      > > > > >
                      > > > > > I'm curious as to the market rate for used Prius Nimh
                      > modules. If
                      > > > > > you can share the price for them, we can compare them to
                      > other
                      > > > > > battery choices.
                      > > > > >
                      > > > > > Thanks!
                      > > > > >
                      > > > > > Todd Martin
                      > > > > > 1997 Solectria Force
                      > > > > > VP, FVEAA
                      > > > > >
                      > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                      > <dbswann4@ .>
                      > > > > > wrote:
                      > > > > > >
                      > > > > > > I understand all the precautions you enumerate. I may
                      > purchase
                      > > > > the
                      > > > > > > first of several surplus Prius battery packs tomorrow. Is
                      > there a
                      > > > > > > chance I can e-mail the person who put together a NiMH pack
                      > for
                      > > > > > the S-
                      > > > > > > 10. I am open to tips and tricks/opinions.
                      > > > > > > Thanks,Bill S
                      > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                      > > > > <Pohorsky@>
                      > > > > > > wrote:
                      > > > > > > >
                      > > > > > > > Howdy,
                      > > > > > > >
                      > > > > > > > The batteries in the Prius are not very suitable for the
                      > Force
                      > > > > > > unless you disassemble the pack, rewire the modules and
                      > come up
                      > > > > > with
                      > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                      > charging
                      > > > > > > profile and the standard lead acid battery chargers are not
                      > > > > > > appropriate. The batteries themselves are an odd physical
                      > size
                      > > > > > and
                      > > > > > > voltage. I believe they are something like a 7.2 volt
                      > battery
                      > > > > > with a
                      > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                      > > > > > > intermittent duty in a hybrid but totally inadequate for an
                      > EV.
                      > > > > > > >
                      > > > > > > > You would need several strings in parallel to get the amp-
                      > hour
                      > > > > > > rating you need. A fellow EAA member bought several used
                      > Prius
                      > > > > > packs
                      > > > > > > on eBay and wired them in parallel for use in his US
                      > Electricar S-
                      > > > > > 10
                      > > > > > > pickup truck. He needed to invent a battery management
                      > system as
                      > > > > > > well as a fan-forced cooling system. The weight reduction
                      > gave
                      > > > > > him
                      > > > > > > an improvement in acceleration over his old lead acid pack
                      > and
                      > > > > > > slightly more range, but eventually he got rid of them.
                      > They took
                      > > > > > up
                      > > > > > > the entire bed of the truck. He is now running a flooded
                      > NiCad
                      > > > > > pack
                      > > > > > > that he got from a military surplus supplier. He was able
                      > to
                      > > > > > mount
                      > > > > > > the NiCads under the bed of the truck.
                      > > > > > > >
                      > > > > > > > Not all non-lead packs are series parallel combinations.
                      > I saw
                      > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
                      > With
                      > > > > > > these, you would just have a series string although there
                      > would
                      > > > > be
                      > > > > > a
                      > > > > > > large number of cells - they between 3 and 4 volts each.
                      > > > > > > >
                      > > > > > > > Stephen Taylor has a series string of the Valence Lithium
                      > > > > > batteries
                      > > > > > > in his Force.
                      > > > > > > >
                      > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
                      > EV.
                      > > > > > > Unfortunately, these Panasonic batteries have been taken
                      > off the
                      > > > > > > market due to a lawsuit filed by Chevron - but it is
                      > another
                      > > > > > example
                      > > > > > > where a series parallel combo was not needed.
                      > > > > > > >
                      > > > > > > > Adios,
                      > > > > > > >
                      > > > > > > > Jerry Pohorsky
                      > > > > > > >
                      > > > > > > > ----- Original Message -----
                      > > > > > > > From: Bill Swann
                      > > > > > > > To: solectria_ev@ yahoogroups. com
                      > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                      > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                      > > > > > > >
                      > > > > > > >
                      > > > > > > > I am surprised that someone has not taken some surplus
                      > > > > > batteries
                      > > > > > > from a
                      > > > > > > > Prius and adapted it to the Force. The energy density is
                      > > > > > double
                      > > > > > > over
                      > > > > > > > lead. As it is with battery packs other that SLA, the
                      > pack
                      > > > > > ends
                      > > > > > > up
                      > > > > > > > being a series/parallel combination.
                      > > > > > > > Bill S
                      > > > > > > >
                      > > > > > > >
                      > > > > > > >
                      > > > > > > >
                      > > > > > > >
                      > > > > > > > [Non-text portions of this message have been removed]
                      > > > > > > >
                      > > > > > >
                      > > > > >
                      > > > > >
                      > > > > >
                      > > > > >
                      > > > > > [Non-text portions of this message have been removed]
                      > > > > >
                      > > > >
                      > > >
                      > >
                      >
                    • Mike Phillips
                      I think the most cost effective pack now is nimh. But it s all locked up in patent lawsuits. So you can t get a module large enough to do any good. The good
                      Message 10 of 19 , Dec 25, 2007
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                        I think the most cost effective pack now is nimh. But it's all locked
                        up in patent lawsuits. So you can't get a module large enough to do
                        any good.

                        The good news is that Solectria's in particular have a long life with
                        their gel cells. Especially considering that they don't have a BMS,
                        it's fairly amazing actually.

                        If I had a Solectria vehicle, I'd go with what ever the long mileage
                        guys are using and then add some kind of monitoring/clamper/regulator
                        to each battery.

                        I think A123 cells are the rockstars of Lithium, but pricey. They also
                        require a BMS. As an experiment I'm putting a module of them in series
                        with my nicad pack to see how they hold up. Of course the lithium
                        module will have a BMS.

                        Mike




                        --- In solectria_ev@yahoogroups.com, Bill or Dorothy Swann
                        <dbswann4@...> wrote:
                        >
                        > Thanks. Since the PHEV has rejected the idea - that's convincing
                        enough. Does anyone know of the most promising battery replacemant
                        technology? $ wise, that is.
                        > Bill s
                        >
                        > ----- Original Message ----
                        > From: ldr214 <replytome@...>
                        > To: solectria_ev@yahoogroups.com
                        > Sent: Tuesday, December 25, 2007 10:01:04 AM
                        > Subject: [solectria_ev] Re: Prius NiMH Batteries
                        >
                        > Bill,
                        > I have followed these post and have also been a avid follower of the
                        > tech postings and newsletters at www.calcars. org where they have been
                        > at the front of the PHEV effort. You may not be aware that one of the
                        > first batteries that was rejected for the ideal PHEV (think modified
                        > Prius) was in fact the Prius battery itself.
                        >
                        > Some of the conversions leave the Prius battery in the vehicle but
                        > none of them that I'm aware of add anymore of these batteries. For the
                        > reasons that Mike and Don have mentioned it does not have the
                        > characteristics of a good traction battery. I think you can search the
                        > archives via: http://www.eaa- phev.org/ maillist/ eaa-phev. html?show=
                        > Mike Rydjord
                        >
                        > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@ .> wrote:
                        > >
                        > > Thanks for the feedback. And for alerting me to the pitfalls of re-
                        > > engineering a battery pack. I do not fully understand your comment "
                        > > the Prius batteries have been optimized for efficiently accepting
                        > > regen energy". Are you suggesting that making a Solectria battery
                        > > pack with 5-6 Prius packs is ill advised because the Prius battery is
                        > > not designed for this? The price is certainly right for used packs,
                        > > assuming a high % of the cells are good.
                        > > Thanks, Bill S
                        > >
                        > > --- In solectria_ev@ yahoogroups. com, "Mike Phillips"
                        > > <mikep_95133@ > wrote:
                        > > >
                        > > > This information was derived from experience driving several hundred
                        > > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                        > > There
                        > > > were 11 packs total used in testing.
                        > > >
                        > > > Mike
                        > > >
                        > > >
                        > > >
                        > > > --- In solectria_ev@ yahoogroups. com, "Mike Phillips"
                        <mikep_95133@ >
                        > > > wrote:
                        > > > >
                        > > > > The absolute most important thing with these Prius modules is
                        > > cooling
                        > > > > them. Just 1 amp during charge can smoke them without cooling. If
                        > > you
                        > > > > look at the side view of the chassis you will see a slope in lower
                        > > > > plenum. It keeps the airflow rate the same across all of the
                        > > cells.
                        > > > >
                        > > > > The second most important thing is that the cells must absolutely
                        > > be
                        > > > > held in compression. Even when they are stone cold, just 1 amp
                        > > during
                        > > > > charge causes them to pressurize and expand a lot, thus ruining
                        > > them.
                        > > > >
                        > > > > If you overheat the modules they will not flow KOH into the black
                        > > > > overflow tubes that go across the top of the cells. The thermal
                        > > vents
                        > > > > will each crack and thus vent gaseous and liquid KOH.
                        > > > >
                        > > > > The 4 thermistors on the top of the cells are 10k NTC types. Using
                        > > > > them to adjust air flow is important.
                        > > > >
                        > > > > That sheetmetal chassis that they come in from the factory is
                        > > > > engineered the way it is for list full of reasons.
                        > > > >
                        > > > > You have to ask yourself if you have enough room for all of the
                        > > > > support hardware in each battery box.
                        > > > >
                        > > > > That 'current measuring coil' is for telling the hardware how much
                        > > > > current is being put into or taken out of the pack.
                        > > > >
                        > > > > These are not the same NIMH cells that you can read about in
                        > > books and
                        > > > > on the web. They are in the same family but have been very
                        > > optimized
                        > > > > for efficiently accepting regen energy, far better than anything
                        > > else
                        > > > > on the planet. That makes them less energy dense and more prone to
                        > > > > thermal failure.
                        > > > >
                        > > > > I'm buried up to my eyeballs in projects now, so I cannot give you
                        > > > > much more than this right now.
                        > > > >
                        > > > > Good Luck.
                        > > > >
                        > > > > Mike
                        > > > >
                        > > > >
                        > > > >
                        > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@>
                        > > wrote:
                        > > > > >
                        > > > > > I dis-assembled a Prius battery pack. What I understand about
                        > > the
                        > > > > > design I like. The cells are bolted to a common baseplate.
                        > > There are
                        > > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                        > > fuse and
                        > > > > > a computer, into which the 5 temp sensors and 19 voltage
                        > > measurments
                        > > > > > were fed. Also there are 2 single pole relays to disconnect the
                        > > pack
                        > > > > > from the outside world. I saw what would appear to be a current
                        > > > > > measuring coil, but I do not undestend what it might do in a DC
                        > > > > > system except to verify the the reley worked. There are thermo
                        > > wells
                        > > > > > in every cell, where the temp sensors are placed. Additionally,
                        > > all
                        > > > > > 38 cells were vented into a common tube to carry off gasses.
                        > > There
                        > > > > > was one temp sensor in a plenum below the pack to verify air
                        > > flow.
                        > > > > > And all of the cells had dimples on the sides so there would be
                        > > a
                        > > > > > gaps between cells for cooling air flow. My next step is to see
                        > > how
                        > > > > > many series combinations will fit in the Force battery boxes.
                        > > It is a
                        > > > > > squeeze, but 4 might fit in the front battery box.
                        > > > > > Bill S
                        > > > > >
                        > > > > > --- In solectria_ev@ yahoogroups. com, Dorothy Swann
                        <dbswann4@>
                        > > > > > wrote:
                        > > > > > >
                        > > > > > > Thanks for the math. I have not gotten around to doing that
                        > > yet. I
                        > > > > > had just looked at the watt-hours per pound which was
                        > > favorable. I
                        > > > > > inquired at a local surplus parts dealer, and battery packs in
                        > > > > > wrecked Priuss are available beginning at $ 400. My plan will
                        > > be to
                        > > > > > acquire enough packs and build up a series/parallel combination
                        > > on
                        > > > > > the bench, and start doing some load tests. The Prius pack I
                        > > have
                        > > > > > seems to look at the voltage of 2 modules at a time. The
                        > > voltage
                        > > > > > sampling electronics is being developed. First for 13 batteries
                        > > for
                        > > > > > the Force, then for a higher number of cells.
                        > > > > > > Bill S
                        > > > > > >
                        > > > > > >
                        > > > > > > ----- Original Message ----
                        > > > > > > From: Todd Martin <larsthelean@ >
                        > > > > > > To: solectria_ev@ yahoogroups. com
                        > > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                        > > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                        > > > > > >
                        > > > > > > Hi Bill,
                        > > > > > >
                        > > > > > > This sounds like an interesting project.
                        > > > > > >
                        > > > > > > I took the liberty of checking the specs on the Prius Nimh
                        > > modules:
                        > > > > > >
                        > > > > > > Each module is 11" long by 5" wide by 3/4" thick and require
                        > > a 2mm
                        > > > > > > gap between modules for forced air cooling. They weigh 2.3
                        > > lbs and
                        > > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                        > > depth
                        > > > > > > of discharge for Nimh, 5Ahr are usable.
                        > > > > > >
                        > > > > > > A Solectria Force has battery boxes that can accommodate 13
                        > > group
                        > > > > > 27
                        > > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
                        > > This
                        > > > > > > works out to about 1119 sq. inches of battery box floor space.
                        > > > > > >
                        > > > > > > IF you can orient the Prius Nimh modules so they the 11" long
                        > > is
                        > > > > > > vertical (not a real problem in the back box since you can
                        > > always
                        > > > > > > add a spacer between the bottom and lid if necessary, but it
                        > > MAY be
                        > > > > > > a real problem for the front box), then I figure you can fit
                        > > > > > roughly
                        > > > > > > 270 modules into a Force. This is a rough calculation without
                        > > doing
                        > > > > > > an actual layout.
                        > > > > > >
                        > > > > > > Since you will need to arrange the modules into multiple sets
                        > > of
                        > > > > > > strings of around 156V, I see the math as:
                        > > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                        > > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                        > > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                        > > > > > >
                        > > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                        > > will
                        > > > > > > save 214 lbs by making the switch and increase your range
                        > > from 50
                        > > > > > > miles to approximately 60 miles.
                        > > > > > >
                        > > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                        > > charger, I
                        > > > > > > don't see a real problem with charging the batteries. You
                        > > just need
                        > > > > > > to find out the charging profile and set the program using
                        > > the free
                        > > > > > > DOS program. For a Zivan charger, you'd need to send it to
                        > > the
                        > > > > > > manufacturer for a re-programming.
                        > > > > > >
                        > > > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
                        > > > > > > Powercheq between each string would be enough to get by.
                        > > Otherwise,
                        > > > > > > that is a LOT of regs to be installing if you have to do
                        > > every
                        > > > > > > module.
                        > > > > > >
                        > > > > > > I'm curious as to the market rate for used Prius Nimh
                        > > modules. If
                        > > > > > > you can share the price for them, we can compare them to
                        > > other
                        > > > > > > battery choices.
                        > > > > > >
                        > > > > > > Thanks!
                        > > > > > >
                        > > > > > > Todd Martin
                        > > > > > > 1997 Solectria Force
                        > > > > > > VP, FVEAA
                        > > > > > >
                        > > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                        > > <dbswann4@ .>
                        > > > > > > wrote:
                        > > > > > > >
                        > > > > > > > I understand all the precautions you enumerate. I may
                        > > purchase
                        > > > > > the
                        > > > > > > > first of several surplus Prius battery packs tomorrow. Is
                        > > there a
                        > > > > > > > chance I can e-mail the person who put together a NiMH pack
                        > > for
                        > > > > > > the S-
                        > > > > > > > 10. I am open to tips and tricks/opinions.
                        > > > > > > > Thanks,Bill S
                        > > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                        > > > > > <Pohorsky@>
                        > > > > > > > wrote:
                        > > > > > > > >
                        > > > > > > > > Howdy,
                        > > > > > > > >
                        > > > > > > > > The batteries in the Prius are not very suitable for the
                        > > Force
                        > > > > > > > unless you disassemble the pack, rewire the modules and
                        > > come up
                        > > > > > > with
                        > > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                        > > charging
                        > > > > > > > profile and the standard lead acid battery chargers are not
                        > > > > > > > appropriate. The batteries themselves are an odd physical
                        > > size
                        > > > > > > and
                        > > > > > > > voltage. I believe they are something like a 7.2 volt
                        > > battery
                        > > > > > > with a
                        > > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                        > > > > > > > intermittent duty in a hybrid but totally inadequate for an
                        > > EV.
                        > > > > > > > >
                        > > > > > > > > You would need several strings in parallel to get the amp-
                        > > hour
                        > > > > > > > rating you need. A fellow EAA member bought several used
                        > > Prius
                        > > > > > > packs
                        > > > > > > > on eBay and wired them in parallel for use in his US
                        > > Electricar S-
                        > > > > > > 10
                        > > > > > > > pickup truck. He needed to invent a battery management
                        > > system as
                        > > > > > > > well as a fan-forced cooling system. The weight reduction
                        > > gave
                        > > > > > > him
                        > > > > > > > an improvement in acceleration over his old lead acid pack
                        > > and
                        > > > > > > > slightly more range, but eventually he got rid of them.
                        > > They took
                        > > > > > > up
                        > > > > > > > the entire bed of the truck. He is now running a flooded
                        > > NiCad
                        > > > > > > pack
                        > > > > > > > that he got from a military surplus supplier. He was able
                        > > to
                        > > > > > > mount
                        > > > > > > > the NiCads under the bed of the truck.
                        > > > > > > > >
                        > > > > > > > > Not all non-lead packs are series parallel combinations.
                        > > I saw
                        > > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
                        > > With
                        > > > > > > > these, you would just have a series string although there
                        > > would
                        > > > > > be
                        > > > > > > a
                        > > > > > > > large number of cells - they between 3 and 4 volts each.
                        > > > > > > > >
                        > > > > > > > > Stephen Taylor has a series string of the Valence Lithium
                        > > > > > > batteries
                        > > > > > > > in his Force.
                        > > > > > > > >
                        > > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
                        > > EV.
                        > > > > > > > Unfortunately, these Panasonic batteries have been taken
                        > > off the
                        > > > > > > > market due to a lawsuit filed by Chevron - but it is
                        > > another
                        > > > > > > example
                        > > > > > > > where a series parallel combo was not needed.
                        > > > > > > > >
                        > > > > > > > > Adios,
                        > > > > > > > >
                        > > > > > > > > Jerry Pohorsky
                        > > > > > > > >
                        > > > > > > > > ----- Original Message -----
                        > > > > > > > > From: Bill Swann
                        > > > > > > > > To: solectria_ev@ yahoogroups. com
                        > > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                        > > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                        > > > > > > > >
                        > > > > > > > >
                        > > > > > > > > I am surprised that someone has not taken some surplus
                        > > > > > > batteries
                        > > > > > > > from a
                        > > > > > > > > Prius and adapted it to the Force. The energy density is
                        > > > > > > double
                        > > > > > > > over
                        > > > > > > > > lead. As it is with battery packs other that SLA, the
                        > > pack
                        > > > > > > ends
                        > > > > > > > up
                        > > > > > > > > being a series/parallel combination.
                        > > > > > > > > Bill S
                        > > > > > > > >
                        > > > > > > > >
                        > > > > > > > >
                        > > > > > > > >
                        > > > > > > > >
                        > > > > > > > > [Non-text portions of this message have been removed]
                        > > > > > > > >
                        > > > > > > >
                        > > > > > >
                        > > > > > >
                        > > > > > >
                        > > > > > >
                        > > > > > > [Non-text portions of this message have been removed]
                        > > > > > >
                        > > > > >
                        > > > >
                        > > >
                        > >
                        >
                        >
                        >
                        >
                        > [Non-text portions of this message have been removed]
                        >
                      • ldr214
                        Mike, In the parent folder there are some shots of a burned up board, smoked resistors , is that inside the controller on the E-10 pick-up? You obviously stay
                        Message 11 of 19 , Dec 25, 2007
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                          Mike,
                          In the parent folder there are some shots of a burned up board,
                          "smoked resistors", is that inside the controller on the E-10 pick-up?
                          You obviously stay busy with a lot of projects.
                          Thanks for sharing.

                          Mike Rydjord

                          --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@...>
                          wrote:
                          >

                          >
                          > Here is a pic of the packs in the bed of my truck. There are more in
                          > that folder.
                          >
                          > http://www.rotordesign.com/s10/priuspack/P5270196.JPG
                          >
                          > Mike
                          >
                          >
                          >
                          >
                          >
                          >
                          >
                          > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@> wrote:
                          > >
                          > > Thanks for the feedback. And for alerting me to the pitfalls of re-
                          > > engineering a battery pack. I do not fully understand your comment "
                          > > the Prius batteries have been optimized for efficiently accepting
                          > > regen energy". Are you suggesting that making a Solectria battery
                          > > pack with 5-6 Prius packs is ill advised because the Prius battery is
                          > > not designed for this? The price is certainly right for used packs,
                          > > assuming a high % of the cells are good.
                          > > Thanks, Bill S
                          > >
                          >
                          > > --- In solectria_ev@yahoogroups.com, "Mike Phillips"
                          > > <mikep_95133@> wrote:
                          > > >
                          > > > This information was derived from experience driving several hundred
                          > > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                          > > There
                          > > > were 11 packs total used in testing.
                          > > >
                          > > > Mike
                          > > >
                          > > >
                          > > >
                          > > > --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@>
                          > > > wrote:
                          > > > >
                          > > > > The absolute most important thing with these Prius modules is
                          > > cooling
                          > > > > them. Just 1 amp during charge can smoke them without cooling. If
                          > > you
                          > > > > look at the side view of the chassis you will see a slope in lower
                          > > > > plenum. It keeps the airflow rate the same across all of the
                          > > cells.
                          > > > >
                          > > > > The second most important thing is that the cells must absolutely
                          > > be
                          > > > > held in compression. Even when they are stone cold, just 1 amp
                          > > during
                          > > > > charge causes them to pressurize and expand a lot, thus ruining
                          > > them.
                          > > > >
                          > > > > If you overheat the modules they will not flow KOH into the black
                          > > > > overflow tubes that go across the top of the cells. The thermal
                          > > vents
                          > > > > will each crack and thus vent gaseous and liquid KOH.
                          > > > >
                          > > > > The 4 thermistors on the top of the cells are 10k NTC types. Using
                          > > > > them to adjust air flow is important.
                          > > > >
                          > > > > That sheetmetal chassis that they come in from the factory is
                          > > > > engineered the way it is for list full of reasons.
                          > > > >
                          > > > > You have to ask yourself if you have enough room for all of the
                          > > > > support hardware in each battery box.
                          > > > >
                          > > > > That 'current measuring coil' is for telling the hardware how much
                          > > > > current is being put into or taken out of the pack.
                          > > > >
                          > > > > These are not the same NIMH cells that you can read about in
                          > > books and
                          > > > > on the web. They are in the same family but have been very
                          > > optimized
                          > > > > for efficiently accepting regen energy, far better than anything
                          > > else
                          > > > > on the planet. That makes them less energy dense and more prone to
                          > > > > thermal failure.
                          > > > >
                          > > > > I'm buried up to my eyeballs in projects now, so I cannot give you
                          > > > > much more than this right now.
                          > > > >
                          > > > > Good Luck.
                          > > > >
                          > > > > Mike
                          > > > >
                          > > > >
                          > > > >
                          > > > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@>
                          > > wrote:
                          > > > > >
                          > > > > > I dis-assembled a Prius battery pack. What I understand about
                          > > the
                          > > > > > design I like. The cells are bolted to a common baseplate.
                          > > There are
                          > > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                          > > fuse and
                          > > > > > a computer, into which the 5 temp sensors and 19 voltage
                          > > measurments
                          > > > > > were fed. Also there are 2 single pole relays to disconnect the
                          > > pack
                          > > > > > from the outside world. I saw what would appear to be a current
                          > > > > > measuring coil, but I do not undestend what it might do in a DC
                          > > > > > system except to verify the the reley worked. There are thermo
                          > > wells
                          > > > > > in every cell, where the temp sensors are placed. Additionally,
                          > > all
                          > > > > > 38 cells were vented into a common tube to carry off gasses.
                          > > There
                          > > > > > was one temp sensor in a plenum below the pack to verify air
                          > > flow.
                          > > > > > And all of the cells had dimples on the sides so there would be
                          > > a
                          > > > > > gaps between cells for cooling air flow. My next step is to see
                          > > how
                          > > > > > many series combinations will fit in the Force battery boxes.
                          > > It is a
                          > > > > > squeeze, but 4 might fit in the front battery box.
                          > > > > > Bill S
                          > > > > >
                          > > > > > --- In solectria_ev@yahoogroups.com, Dorothy Swann <dbswann4@>
                          > > > > > wrote:
                          > > > > > >
                          > > > > > > Thanks for the math. I have not gotten around to doing that
                          > > yet. I
                          > > > > > had just looked at the watt-hours per pound which was
                          > > favorable. I
                          > > > > > inquired at a local surplus parts dealer, and battery packs in
                          > > > > > wrecked Priuss are available beginning at $ 400. My plan will
                          > > be to
                          > > > > > acquire enough packs and build up a series/parallel combination
                          > > on
                          > > > > > the bench, and start doing some load tests. The Prius pack I
                          > > have
                          > > > > > seems to look at the voltage of 2 modules at a time. The
                          > > voltage
                          > > > > > sampling electronics is being developed. First for 13 batteries
                          > > for
                          > > > > > the Force, then for a higher number of cells.
                          > > > > > > Bill S
                          > > > > > >
                          > > > > > >
                          > > > > > > ----- Original Message ----
                          > > > > > > From: Todd Martin <larsthelean@>
                          > > > > > > To: solectria_ev@yahoogroups.com
                          > > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                          > > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                          > > > > > >
                          > > > > > > Hi Bill,
                          > > > > > >
                          > > > > > > This sounds like an interesting project.
                          > > > > > >
                          > > > > > > I took the liberty of checking the specs on the Prius Nimh
                          > > modules:
                          > > > > > >
                          > > > > > > Each module is 11" long by 5" wide by 3/4" thick and require
                          > > a 2mm
                          > > > > > > gap between modules for forced air cooling. They weigh 2.3
                          > > lbs and
                          > > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                          > > depth
                          > > > > > > of discharge for Nimh, 5Ahr are usable.
                          > > > > > >
                          > > > > > > A Solectria Force has battery boxes that can accommodate 13
                          > > group
                          > > > > > 27
                          > > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8" tall).
                          > > This
                          > > > > > > works out to about 1119 sq. inches of battery box floor space.
                          > > > > > >
                          > > > > > > IF you can orient the Prius Nimh modules so they the 11" long
                          > > is
                          > > > > > > vertical (not a real problem in the back box since you can
                          > > always
                          > > > > > > add a spacer between the bottom and lid if necessary, but it
                          > > MAY be
                          > > > > > > a real problem for the front box), then I figure you can fit
                          > > > > > roughly
                          > > > > > > 270 modules into a Force. This is a rough calculation without
                          > > doing
                          > > > > > > an actual layout.
                          > > > > > >
                          > > > > > > Since you will need to arrange the modules into multiple sets
                          > > of
                          > > > > > > strings of around 156V, I see the math as:
                          > > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                          > > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                          > > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                          > > > > > >
                          > > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                          > > will
                          > > > > > > save 214 lbs by making the switch and increase your range
                          > > from 50
                          > > > > > > miles to approximately 60 miles.
                          > > > > > >
                          > > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                          > > charger, I
                          > > > > > > don't see a real problem with charging the batteries. You
                          > > just need
                          > > > > > > to find out the charging profile and set the program using
                          > > the free
                          > > > > > > DOS program. For a Zivan charger, you'd need to send it to
                          > > the
                          > > > > > > manufacturer for a re-programming.
                          > > > > > >
                          > > > > > > I agree that a BMS would be a big obstacle. Perhaps placing a
                          > > > > > > Powercheq between each string would be enough to get by.
                          > > Otherwise,
                          > > > > > > that is a LOT of regs to be installing if you have to do
                          > > every
                          > > > > > > module.
                          > > > > > >
                          > > > > > > I'm curious as to the market rate for used Prius Nimh
                          > > modules. If
                          > > > > > > you can share the price for them, we can compare them to
                          > > other
                          > > > > > > battery choices.
                          > > > > > >
                          > > > > > > Thanks!
                          > > > > > >
                          > > > > > > Todd Martin
                          > > > > > > 1997 Solectria Force
                          > > > > > > VP, FVEAA
                          > > > > > >
                          > > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                          > > <dbswann4@ .>
                          > > > > > > wrote:
                          > > > > > > >
                          > > > > > > > I understand all the precautions you enumerate. I may
                          > > purchase
                          > > > > > the
                          > > > > > > > first of several surplus Prius battery packs tomorrow. Is
                          > > there a
                          > > > > > > > chance I can e-mail the person who put together a NiMH pack
                          > > for
                          > > > > > > the S-
                          > > > > > > > 10. I am open to tips and tricks/opinions.
                          > > > > > > > Thanks,Bill S
                          > > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                          > > > > > <Pohorsky@>
                          > > > > > > > wrote:
                          > > > > > > > >
                          > > > > > > > > Howdy,
                          > > > > > > > >
                          > > > > > > > > The batteries in the Prius are not very suitable for the
                          > > Force
                          > > > > > > > unless you disassemble the pack, rewire the modules and
                          > > come up
                          > > > > > > with
                          > > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                          > > charging
                          > > > > > > > profile and the standard lead acid battery chargers are not
                          > > > > > > > appropriate. The batteries themselves are an odd physical
                          > > size
                          > > > > > > and
                          > > > > > > > voltage. I believe they are something like a 7.2 volt
                          > > battery
                          > > > > > > with a
                          > > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                          > > > > > > > intermittent duty in a hybrid but totally inadequate for an
                          > > EV.
                          > > > > > > > >
                          > > > > > > > > You would need several strings in parallel to get the amp-
                          > > hour
                          > > > > > > > rating you need. A fellow EAA member bought several used
                          > > Prius
                          > > > > > > packs
                          > > > > > > > on eBay and wired them in parallel for use in his US
                          > > Electricar S-
                          > > > > > > 10
                          > > > > > > > pickup truck. He needed to invent a battery management
                          > > system as
                          > > > > > > > well as a fan-forced cooling system. The weight reduction
                          > > gave
                          > > > > > > him
                          > > > > > > > an improvement in acceleration over his old lead acid pack
                          > > and
                          > > > > > > > slightly more range, but eventually he got rid of them.
                          > > They took
                          > > > > > > up
                          > > > > > > > the entire bed of the truck. He is now running a flooded
                          > > NiCad
                          > > > > > > pack
                          > > > > > > > that he got from a military surplus supplier. He was able
                          > > to
                          > > > > > > mount
                          > > > > > > > the NiCads under the bed of the truck.
                          > > > > > > > >
                          > > > > > > > > Not all non-lead packs are series parallel combinations.
                          > > I saw
                          > > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4 batteries.
                          > > With
                          > > > > > > > these, you would just have a series string although there
                          > > would
                          > > > > > be
                          > > > > > > a
                          > > > > > > > large number of cells - they between 3 and 4 volts each.
                          > > > > > > > >
                          > > > > > > > > Stephen Taylor has a series string of the Valence Lithium
                          > > > > > > batteries
                          > > > > > > > in his Force.
                          > > > > > > > >
                          > > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my RAV 4
                          > > EV.
                          > > > > > > > Unfortunately, these Panasonic batteries have been taken
                          > > off the
                          > > > > > > > market due to a lawsuit filed by Chevron - but it is
                          > > another
                          > > > > > > example
                          > > > > > > > where a series parallel combo was not needed.
                          > > > > > > > >
                          > > > > > > > > Adios,
                          > > > > > > > >
                          > > > > > > > > Jerry Pohorsky
                          > > > > > > > >
                          > > > > > > > > ----- Original Message -----
                          > > > > > > > > From: Bill Swann
                          > > > > > > > > To: solectria_ev@ yahoogroups. com
                          > > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                          > > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                          > > > > > > > >
                          > > > > > > > >
                          > > > > > > > > I am surprised that someone has not taken some surplus
                          > > > > > > batteries
                          > > > > > > > from a
                          > > > > > > > > Prius and adapted it to the Force. The energy density is
                          > > > > > > double
                          > > > > > > > over
                          > > > > > > > > lead. As it is with battery packs other that SLA, the
                          > > pack
                          > > > > > > ends
                          > > > > > > > up
                          > > > > > > > > being a series/parallel combination.
                          > > > > > > > > Bill S
                          > > > > > > > >
                          > > > > > > > >
                          > > > > > > > >
                          > > > > > > > >
                          > > > > > > > >
                          > > > > > > > > [Non-text portions of this message have been removed]
                          > > > > > > > >
                          > > > > > > >
                          > > > > > >
                          > > > > > >
                          > > > > > >
                          > > > > > >
                          > > > > > > [Non-text portions of this message have been removed]
                          > > > > > >
                          > > > > >
                          > > > >
                          > > >
                          > >
                          >
                        • Mike Phillips
                          That was probably the smoked 10 ohm resistors that the factory added in an attempt to help with another problem that the USE boards have. It didn t help at all
                          Message 12 of 19 , Dec 27, 2007
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                            That was probably the smoked 10 ohm resistors that the factory added
                            in an attempt to help with another problem that the USE boards have.
                            It didn't help at all as it turns out. I came up with a fix for it
                            latter that seems to be working.

                            Glad to help out.

                            Mike


                            --- In solectria_ev@yahoogroups.com, "ldr214" <replytome@...> wrote:
                            >
                            > Mike,
                            > In the parent folder there are some shots of a burned up board,
                            > "smoked resistors", is that inside the controller on the E-10 pick-up?
                            > You obviously stay busy with a lot of projects.
                            > Thanks for sharing.
                            >
                            > Mike Rydjord
                            >
                            > --- In solectria_ev@yahoogroups.com, "Mike Phillips" <mikep_95133@>
                            > wrote:
                            > >
                            >
                            > >
                            > > Here is a pic of the packs in the bed of my truck. There are more in
                            > > that folder.
                            > >
                            > > http://www.rotordesign.com/s10/priuspack/P5270196.JPG
                            > >
                            > > Mike
                            > >
                            > >
                            > >
                            > >
                            > >
                            > >
                            > >
                            > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@> wrote:
                            > > >
                            > > > Thanks for the feedback. And for alerting me to the pitfalls of re-
                            > > > engineering a battery pack. I do not fully understand your
                            comment "
                            > > > the Prius batteries have been optimized for efficiently accepting
                            > > > regen energy". Are you suggesting that making a Solectria battery
                            > > > pack with 5-6 Prius packs is ill advised because the Prius
                            battery is
                            > > > not designed for this? The price is certainly right for used packs,
                            > > > assuming a high % of the cells are good.
                            > > > Thanks, Bill S
                            > > >
                            > >
                            > > > --- In solectria_ev@yahoogroups.com, "Mike Phillips"
                            > > > <mikep_95133@> wrote:
                            > > > >
                            > > > > This information was derived from experience driving several
                            hundred
                            > > > > miles in a vehicle with 5 Prius packs in parallel for the pack.
                            > > > There
                            > > > > were 11 packs total used in testing.
                            > > > >
                            > > > > Mike
                            > > > >
                            > > > >
                            > > > >
                            > > > > --- In solectria_ev@yahoogroups.com, "Mike Phillips"
                            <mikep_95133@>
                            > > > > wrote:
                            > > > > >
                            > > > > > The absolute most important thing with these Prius modules is
                            > > > cooling
                            > > > > > them. Just 1 amp during charge can smoke them without
                            cooling. If
                            > > > you
                            > > > > > look at the side view of the chassis you will see a slope in
                            lower
                            > > > > > plenum. It keeps the airflow rate the same across all of the
                            > > > cells.
                            > > > > >
                            > > > > > The second most important thing is that the cells must
                            absolutely
                            > > > be
                            > > > > > held in compression. Even when they are stone cold, just 1 amp
                            > > > during
                            > > > > > charge causes them to pressurize and expand a lot, thus ruining
                            > > > them.
                            > > > > >
                            > > > > > If you overheat the modules they will not flow KOH into the
                            black
                            > > > > > overflow tubes that go across the top of the cells. The thermal
                            > > > vents
                            > > > > > will each crack and thus vent gaseous and liquid KOH.
                            > > > > >
                            > > > > > The 4 thermistors on the top of the cells are 10k NTC types.
                            Using
                            > > > > > them to adjust air flow is important.
                            > > > > >
                            > > > > > That sheetmetal chassis that they come in from the factory is
                            > > > > > engineered the way it is for list full of reasons.
                            > > > > >
                            > > > > > You have to ask yourself if you have enough room for all of the
                            > > > > > support hardware in each battery box.
                            > > > > >
                            > > > > > That 'current measuring coil' is for telling the hardware
                            how much
                            > > > > > current is being put into or taken out of the pack.
                            > > > > >
                            > > > > > These are not the same NIMH cells that you can read about in
                            > > > books and
                            > > > > > on the web. They are in the same family but have been very
                            > > > optimized
                            > > > > > for efficiently accepting regen energy, far better than
                            anything
                            > > > else
                            > > > > > on the planet. That makes them less energy dense and more
                            prone to
                            > > > > > thermal failure.
                            > > > > >
                            > > > > > I'm buried up to my eyeballs in projects now, so I cannot
                            give you
                            > > > > > much more than this right now.
                            > > > > >
                            > > > > > Good Luck.
                            > > > > >
                            > > > > > Mike
                            > > > > >
                            > > > > >
                            > > > > >
                            > > > > > --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@>
                            > > > wrote:
                            > > > > > >
                            > > > > > > I dis-assembled a Prius battery pack. What I understand about
                            > > > the
                            > > > > > > design I like. The cells are bolted to a common baseplate.
                            > > > There are
                            > > > > > > series copper jumpers between the 38 cells. I saw a 125 amp
                            > > > fuse and
                            > > > > > > a computer, into which the 5 temp sensors and 19 voltage
                            > > > measurments
                            > > > > > > were fed. Also there are 2 single pole relays to
                            disconnect the
                            > > > pack
                            > > > > > > from the outside world. I saw what would appear to be a
                            current
                            > > > > > > measuring coil, but I do not undestend what it might do in
                            a DC
                            > > > > > > system except to verify the the reley worked. There are
                            thermo
                            > > > wells
                            > > > > > > in every cell, where the temp sensors are placed.
                            Additionally,
                            > > > all
                            > > > > > > 38 cells were vented into a common tube to carry off gasses.
                            > > > There
                            > > > > > > was one temp sensor in a plenum below the pack to verify air
                            > > > flow.
                            > > > > > > And all of the cells had dimples on the sides so there
                            would be
                            > > > a
                            > > > > > > gaps between cells for cooling air flow. My next step is
                            to see
                            > > > how
                            > > > > > > many series combinations will fit in the Force battery boxes.
                            > > > It is a
                            > > > > > > squeeze, but 4 might fit in the front battery box.
                            > > > > > > Bill S
                            > > > > > >
                            > > > > > > --- In solectria_ev@yahoogroups.com, Dorothy Swann
                            <dbswann4@>
                            > > > > > > wrote:
                            > > > > > > >
                            > > > > > > > Thanks for the math. I have not gotten around to doing that
                            > > > yet. I
                            > > > > > > had just looked at the watt-hours per pound which was
                            > > > favorable. I
                            > > > > > > inquired at a local surplus parts dealer, and battery
                            packs in
                            > > > > > > wrecked Priuss are available beginning at $ 400. My plan will
                            > > > be to
                            > > > > > > acquire enough packs and build up a series/parallel
                            combination
                            > > > on
                            > > > > > > the bench, and start doing some load tests. The Prius pack I
                            > > > have
                            > > > > > > seems to look at the voltage of 2 modules at a time. The
                            > > > voltage
                            > > > > > > sampling electronics is being developed. First for 13
                            batteries
                            > > > for
                            > > > > > > the Force, then for a higher number of cells.
                            > > > > > > > Bill S
                            > > > > > > >
                            > > > > > > >
                            > > > > > > > ----- Original Message ----
                            > > > > > > > From: Todd Martin <larsthelean@>
                            > > > > > > > To: solectria_ev@yahoogroups.com
                            > > > > > > > Sent: Friday, November 30, 2007 7:47:57 AM
                            > > > > > > > Subject: [solectria_ev] Re: Prius NiMH Batteries
                            > > > > > > >
                            > > > > > > > Hi Bill,
                            > > > > > > >
                            > > > > > > > This sounds like an interesting project.
                            > > > > > > >
                            > > > > > > > I took the liberty of checking the specs on the Prius Nimh
                            > > > modules:
                            > > > > > > >
                            > > > > > > > Each module is 11" long by 5" wide by 3/4" thick and
                            require
                            > > > a 2mm
                            > > > > > > > gap between modules for forced air cooling. They weigh 2.3
                            > > > lbs and
                            > > > > > > > have 6 cells that total 7.2V at 6.5Ahr. With a standard 80%
                            > > > depth
                            > > > > > > > of discharge for Nimh, 5Ahr are usable.
                            > > > > > > >
                            > > > > > > > A Solectria Force has battery boxes that can accommodate 13
                            > > > group
                            > > > > > > 27
                            > > > > > > > batteries (size 12-3/4" long by 6-3/4" wide by 9-7/8"
                            tall).
                            > > > This
                            > > > > > > > works out to about 1119 sq. inches of battery box floor
                            space.
                            > > > > > > >
                            > > > > > > > IF you can orient the Prius Nimh modules so they the 11"
                            long
                            > > > is
                            > > > > > > > vertical (not a real problem in the back box since you can
                            > > > always
                            > > > > > > > add a spacer between the bottom and lid if necessary,
                            but it
                            > > > MAY be
                            > > > > > > > a real problem for the front box), then I figure you can
                            fit
                            > > > > > > roughly
                            > > > > > > > 270 modules into a Force. This is a rough calculation
                            without
                            > > > doing
                            > > > > > > > an actual layout.
                            > > > > > > >
                            > > > > > > > Since you will need to arrange the modules into multiple
                            sets
                            > > > of
                            > > > > > > > strings of around 156V, I see the math as:
                            > > > > > > > 22 modules * 7.2V = 158.4V string linked in series.
                            > > > > > > > 12 strings linked in paralles * 5Ahr = 60Ahr usable.
                            > > > > > > > 264 modules used total weigh 264 * 2.3 lbs = 607 lbs.
                            > > > > > > >
                            > > > > > > > In comparison, a Lead Acid Gel pack weighs 821 lbs. So, you
                            > > > will
                            > > > > > > > save 214 lbs by making the switch and increase your range
                            > > > from 50
                            > > > > > > > miles to approximately 60 miles.
                            > > > > > > >
                            > > > > > > > Provided you still have a BRUSA NLG4 (or got an NLG5)
                            > > > charger, I
                            > > > > > > > don't see a real problem with charging the batteries. You
                            > > > just need
                            > > > > > > > to find out the charging profile and set the program using
                            > > > the free
                            > > > > > > > DOS program. For a Zivan charger, you'd need to send it to
                            > > > the
                            > > > > > > > manufacturer for a re-programming.
                            > > > > > > >
                            > > > > > > > I agree that a BMS would be a big obstacle. Perhaps
                            placing a
                            > > > > > > > Powercheq between each string would be enough to get by.
                            > > > Otherwise,
                            > > > > > > > that is a LOT of regs to be installing if you have to do
                            > > > every
                            > > > > > > > module.
                            > > > > > > >
                            > > > > > > > I'm curious as to the market rate for used Prius Nimh
                            > > > modules. If
                            > > > > > > > you can share the price for them, we can compare them to
                            > > > other
                            > > > > > > > battery choices.
                            > > > > > > >
                            > > > > > > > Thanks!
                            > > > > > > >
                            > > > > > > > Todd Martin
                            > > > > > > > 1997 Solectria Force
                            > > > > > > > VP, FVEAA
                            > > > > > > >
                            > > > > > > > --- In solectria_ev@ yahoogroups. com, "Bill Swann"
                            > > > <dbswann4@ .>
                            > > > > > > > wrote:
                            > > > > > > > >
                            > > > > > > > > I understand all the precautions you enumerate. I may
                            > > > purchase
                            > > > > > > the
                            > > > > > > > > first of several surplus Prius battery packs tomorrow. Is
                            > > > there a
                            > > > > > > > > chance I can e-mail the person who put together a NiMH
                            pack
                            > > > for
                            > > > > > > > the S-
                            > > > > > > > > 10. I am open to tips and tricks/opinions.
                            > > > > > > > > Thanks,Bill S
                            > > > > > > > > --- In solectria_ev@ yahoogroups. com, "Jerry Pohorsky"
                            > > > > > > <Pohorsky@>
                            > > > > > > > > wrote:
                            > > > > > > > > >
                            > > > > > > > > > Howdy,
                            > > > > > > > > >
                            > > > > > > > > > The batteries in the Prius are not very suitable for
                            the
                            > > > Force
                            > > > > > > > > unless you disassemble the pack, rewire the modules and
                            > > > come up
                            > > > > > > > with
                            > > > > > > > > a suitable charger and BMS. NiMH batteries have a unique
                            > > > charging
                            > > > > > > > > profile and the standard lead acid battery chargers
                            are not
                            > > > > > > > > appropriate. The batteries themselves are an odd physical
                            > > > size
                            > > > > > > > and
                            > > > > > > > > voltage. I believe they are something like a 7.2 volt
                            > > > battery
                            > > > > > > > with a
                            > > > > > > > > 6.5 Amp-hour rating. That amp-hour rating is suitable for
                            > > > > > > > > intermittent duty in a hybrid but totally inadequate
                            for an
                            > > > EV.
                            > > > > > > > > >
                            > > > > > > > > > You would need several strings in parallel to get
                            the amp-
                            > > > hour
                            > > > > > > > > rating you need. A fellow EAA member bought several used
                            > > > Prius
                            > > > > > > > packs
                            > > > > > > > > on eBay and wired them in parallel for use in his US
                            > > > Electricar S-
                            > > > > > > > 10
                            > > > > > > > > pickup truck. He needed to invent a battery management
                            > > > system as
                            > > > > > > > > well as a fan-forced cooling system. The weight reduction
                            > > > gave
                            > > > > > > > him
                            > > > > > > > > an improvement in acceleration over his old lead acid
                            pack
                            > > > and
                            > > > > > > > > slightly more range, but eventually he got rid of them.
                            > > > They took
                            > > > > > > > up
                            > > > > > > > > the entire bed of the truck. He is now running a flooded
                            > > > NiCad
                            > > > > > > > pack
                            > > > > > > > > that he got from a military surplus supplier. He was able
                            > > > to
                            > > > > > > > mount
                            > > > > > > > > the NiCads under the bed of the truck.
                            > > > > > > > > >
                            > > > > > > > > > Not all non-lead packs are series parallel
                            combinations.
                            > > > I saw
                            > > > > > > > > someone selling Thunder Sky 90 Amp-Hour LiFePO4
                            batteries.
                            > > > With
                            > > > > > > > > these, you would just have a series string although there
                            > > > would
                            > > > > > > be
                            > > > > > > > a
                            > > > > > > > > large number of cells - they between 3 and 4 volts each.
                            > > > > > > > > >
                            > > > > > > > > > Stephen Taylor has a series string of the Valence
                            Lithium
                            > > > > > > > batteries
                            > > > > > > > > in his Force.
                            > > > > > > > > >
                            > > > > > > > > > Similarly, I have 95 Amp-hour NiMH batteries in my
                            RAV 4
                            > > > EV.
                            > > > > > > > > Unfortunately, these Panasonic batteries have been taken
                            > > > off the
                            > > > > > > > > market due to a lawsuit filed by Chevron - but it is
                            > > > another
                            > > > > > > > example
                            > > > > > > > > where a series parallel combo was not needed.
                            > > > > > > > > >
                            > > > > > > > > > Adios,
                            > > > > > > > > >
                            > > > > > > > > > Jerry Pohorsky
                            > > > > > > > > >
                            > > > > > > > > > ----- Original Message -----
                            > > > > > > > > > From: Bill Swann
                            > > > > > > > > > To: solectria_ev@ yahoogroups. com
                            > > > > > > > > > Sent: Tuesday, November 20, 2007 6:13 PM
                            > > > > > > > > > Subject: [solectria_ev] Prius NiMH Batteries
                            > > > > > > > > >
                            > > > > > > > > >
                            > > > > > > > > > I am surprised that someone has not taken some surplus
                            > > > > > > > batteries
                            > > > > > > > > from a
                            > > > > > > > > > Prius and adapted it to the Force. The energy
                            density is
                            > > > > > > > double
                            > > > > > > > > over
                            > > > > > > > > > lead. As it is with battery packs other that SLA, the
                            > > > pack
                            > > > > > > > ends
                            > > > > > > > > up
                            > > > > > > > > > being a series/parallel combination.
                            > > > > > > > > > Bill S
                            > > > > > > > > >
                            > > > > > > > > >
                            > > > > > > > > >
                            > > > > > > > > >
                            > > > > > > > > >
                            > > > > > > > > > [Non-text portions of this message have been removed]
                            > > > > > > > > >
                            > > > > > > > >
                            > > > > > > >
                            > > > > > > >
                            > > > > > > >
                            > > > > > > >
                            > > > > > > > [Non-text portions of this message have been removed]
                            > > > > > > >
                            > > > > > >
                            > > > > >
                            > > > >
                            > > >
                            > >
                            >
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