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Identifying a laggard battery

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  • Bill Swann
    I am trying to identify which batteries I should replace. I severely deplete the battery set, and stop the car with the lights and heat on. Then I measure and
    Message 1 of 15 , Nov 18, 2007
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      I am trying to identify which batteries I should replace. I severely
      deplete the battery set, and stop the car with the lights and heat on.
      Then I measure and plot the individual battery voltages. I do this
      repeatedly with inconsistent results. That is, the same battery is not
      the laggard. What is the trick? Do you have to deplete the battery set
      to the same voltage each time?
      Bill S
    • Ken Olum
      Why do you think that some and only some of your batteries are bad? Maybe the pack just needs replacement. When I had a single bad battery, its voltage dropped
      Message 2 of 15 , Nov 18, 2007
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        Why do you think that some and only some of your batteries are bad?
        Maybe the pack just needs replacement.

        When I had a single bad battery, its voltage dropped to 10V after
        drawing a few amp hours. There was not any question about which one
        was bad.

        Ken
      • ldr214
        Bill, I have the Paktrakr in my car and I can see that more than one battery shows signs of being a laggard but not under the conditions you are talking
        Message 3 of 15 , Nov 18, 2007
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          Bill,
          I have the Paktrakr in my car and I can see that more than one battery
          shows signs of being a "laggard" but not under the conditions you are
          talking about. And some of the ones that look weak early aren't the
          ones that sag the worst under heavy loads. They all bounce back really
          well when not under the kind of load that actually driving creates.

          Running the battery check as written in the service manual takes the
          batteries down pretty deep (which isn't good) and if you have
          batteries that can support the lights and heater you may not find a
          laggard as you have found out. The heater is nothing compared to the
          motor/controller when it comes to eating amps.

          Mike

          --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@...> wrote:
          >
          > I am trying to identify which batteries I should replace. I severely
          > deplete the battery set, and stop the car with the lights and heat on.
          > Then I measure and plot the individual battery voltages. I do this
          > repeatedly with inconsistent results. That is, the same battery is not
          > the laggard. What is the trick? Do you have to deplete the battery set
          > to the same voltage each time?
          > Bill S
          >
        • Bill Swann
          It states on the car visor that the range is 45-50 under conservative driving conditions. I only get 35, and wanted to see waht I could to short of replacing
          Message 4 of 15 , Nov 18, 2007
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            It states on the car visor that the range is 45-50 under conservative
            driving conditions. I only get 35, and wanted to see waht I could to
            short of replacing the whole pack. So I started taking voltage
            readings, and seeing inconsistent results. That is, the one with the
            lowest voltage after a hard drain is not consistently the same one.
            Bill s
            --- In solectria_ev@yahoogroups.com, Ken Olum <kdo@...> wrote:
            >
            > Why do you think that some and only some of your batteries are bad?
            > Maybe the pack just needs replacement.
            >
            > When I had a single bad battery, its voltage dropped to 10V after
            > drawing a few amp hours. There was not any question about which one
            > was bad.
            >
            > Ken
            >
          • Dorothy Swann
            Are you saying that the ones to replace are the ones with the lower voltage under normal driving conditions, not severely drained conditions. My objective is
            Message 5 of 15 , Nov 18, 2007
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              Are you saying that the ones to replace are the ones with the lower voltage under normal driving conditions, not severely drained conditions. My objective is to increase overall range.
              Bill S


              ----- Original Message ----
              From: ldr214 <replytome@...>
              To: solectria_ev@yahoogroups.com
              Sent: Sunday, November 18, 2007 8:53:05 PM
              Subject: [solectria_ev] Re: Identifying a laggard battery

              Bill,
              I have the Paktrakr in my car and I can see that more than one battery
              shows signs of being a "laggard" but not under the conditions you are
              talking about. And some of the ones that look weak early aren't the
              ones that sag the worst under heavy loads. They all bounce back really
              well when not under the kind of load that actually driving creates.

              Running the battery check as written in the service manual takes the
              batteries down pretty deep (which isn't good) and if you have
              batteries that can support the lights and heater you may not find a
              laggard as you have found out. The heater is nothing compared to the
              motor/controller when it comes to eating amps.

              Mike

              --- In solectria_ev@ yahoogroups. com, "Bill Swann" <dbswann4@.. .> wrote:
              >
              > I am trying to identify which batteries I should replace. I severely
              > deplete the battery set, and stop the car with the lights and heat on.
              > Then I measure and plot the individual battery voltages. I do this
              > repeatedly with inconsistent results. That is, the same battery is not
              > the laggard. What is the trick? Do you have to deplete the battery set
              > to the same voltage each time?
              > Bill S
              >




              [Non-text portions of this message have been removed]
            • Gerard (Gary) Carlson
              Greetings: I brought out test wires from each of my batteries (through fuses).? I am able to monitor the voltage across each battery while driving.? I have an
              Message 6 of 15 , Nov 18, 2007
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                Greetings:



                I brought out test wires from each of my batteries (through fuses).? I am able to monitor the voltage across each battery while driving.? I have an assistant sit in the front seat with a digital volt meter and a switch box.



                I set the economy knob to 100 amps max draw and then measure the voltage across each battery while under the 100 amp load.? I have done this several times over the 28K mile life of my battery pack and I consistently see two weak batteries that are up to a volt below the rest of the pack.

                The test wires can also be arranged to measure the voltage drop across the inter-battery connections.? This is useful to check for bad connections.? This test only works under a heavy current load such as 100 amps.? For example, a 1 volt reading across a inter-battery connection at 100 amps translates into 1/100 or 10 milliohms.

                Sincerely
                Gary Carlson
                1992 Solectria Force
                ID License:? AMPEATR


                -----Original Message-----
                From: Bill Swann <dbswann4@...>
                To: solectria_ev@yahoogroups.com
                Sent: Sun, 18 Nov 2007 5:43 pm
                Subject: [solectria_ev] Identifying a laggard battery







                I am trying to identify which batteries I should replace. I severely
                deplete the battery set, and stop the car with the lights and heat on.
                Then I measure and plot the individual battery voltages. I do this
                repeatedly with inconsistent results. That is, the same battery is not
                the laggard. What is the trick? Do you have to deplete the battery set
                to the same voltage each time?
                Bill S





                ________________________________________________________________________
                Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail.aol.com


                [Non-text portions of this message have been removed]
              • Dorothy Swann
                I have also brought out wires from each battery box-9 from the back, and 6 from the front. Would you say that the weak batteries-the ones that are 1 volt or so
                Message 7 of 15 , Nov 19, 2007
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                  I have also brought out wires from each battery box-9 from the back, and 6 from the front. Would you say that the weak batteries-the ones that are 1 volt or so less than the pack- are the ones to replace? The goal is to increase the range as shown on the visor-45 to 50 miles.
                  Thanks Bill S


                  ----- Original Message ----
                  From: Gerard (Gary) Carlson <gjc0@...>
                  To: solectria_ev@yahoogroups.com
                  Sent: Sunday, November 18, 2007 11:04:08 PM
                  Subject: Re: [solectria_ev] Identifying a laggard battery


                  Greetings:

                  I brought out test wires from each of my batteries (through fuses).? I am able to monitor the voltage across each battery while driving.? I have an assistant sit in the front seat with a digital volt meter and a switch box.

                  I set the economy knob to 100 amps max draw and then measure the voltage across each battery while under the 100 amp load.? I have done this several times over the 28K mile life of my battery pack and I consistently see two weak batteries that are up to a volt below the rest of the pack.

                  The test wires can also be arranged to measure the voltage drop across the inter-battery connections. ? This is useful to check for bad connections. ? This test only works under a heavy current load such as 100 amps.? For example, a 1 volt reading across a inter-battery connection at 100 amps translates into 1/100 or 10 milliohms.

                  Sincerely
                  Gary Carlson
                  1992 Solectria Force
                  ID License:? AMPEATR

                  -----Original Message-----
                  From: Bill Swann <dbswann4@yahoo. com>
                  To: solectria_ev@ yahoogroups. com
                  Sent: Sun, 18 Nov 2007 5:43 pm
                  Subject: [solectria_ev] Identifying a laggard battery

                  I am trying to identify which batteries I should replace. I severely
                  deplete the battery set, and stop the car with the lights and heat on.
                  Then I measure and plot the individual battery voltages. I do this
                  repeatedly with inconsistent results. That is, the same battery is not
                  the laggard. What is the trick? Do you have to deplete the battery set
                  to the same voltage each time?
                  Bill S

                  ____________ _________ _________ _________ _________ _________ _
                  Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail. aol.com

                  [Non-text portions of this message have been removed]




                  [Non-text portions of this message have been removed]
                • Jim Coate
                  ... I think that 45-50 miles is optimistic, as in obtainable only under *very* conservative conditions. I d take that to mean driving at modest speeds on flat
                  Message 8 of 15 , Nov 19, 2007
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                    Bill Swann wrote:
                    > It states on the car visor that the range is 45-50 under conservative
                    > driving conditions. I only get 35, and wanted to see what I could to
                    > short of replacing the whole pack.

                    I think that 45-50 miles is optimistic, as in obtainable only under
                    *very* conservative conditions. I'd take that to mean driving at modest
                    speeds on flat roads in "economy" mode with few starts & stops. In nice
                    weather. Anything else will reduce the range.

                    My impression is that 35 miles of range with typical driving is pretty
                    close to normal. I get less than that, but most trips around here
                    involve multiple steep hills requiring maximum power mode for much of
                    the drive.


                    --
                    Jim Coate, Spencertown, New York
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                    NOTE: Mail sent to the "NO_REPLY" address will *not* reach me.
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                    http://www.coate.org/contact_jim/
                    = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

                    1998 Electric S-10, 1997 Solectria Force, 1970's Elec-Traks
                    http://www.eeevee.com

                    The Electric Tractor Store is now open!
                    http://www.electrictractorstore.com
                  • Ken Olum
                    Bill, how many amp hours are you using in your 35 miles? What kind of conditions are you driving in? How many miles do you have on your pack? At the end of
                    Message 9 of 15 , Nov 19, 2007
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                      Bill, how many amp hours are you using in your 35 miles? What kind of
                      conditions are you driving in? How many miles do you have on your
                      pack? At the end of the 35 miles is your car in "limp home mode"
                      (will only go 5 or 10 mph), or is it just a bit sluggish? If your
                      Force can go 35 miles in winter with a mix of city and highway
                      driving, you really have nothing to complain about. If it's in limp
                      home mode after 35 miles of driving on rural roads at moderate speed
                      on a hot summer day, something is wrong, but it could be the pack as a
                      whole.

                      Replacing individual batteries in an old pack is a big gamble. Unless
                      there are one or two prematurely bad batteries, it's not worth it.
                      After a little while, the new batteries will not be new anymore, and
                      you'll have to replace them again when you replace the whole pack, or
                      your pack will not start out balanced.

                      Ken
                    • ldr214
                      Bill, I think replacing a couple of batteries that sag under load in a aged pack will likely improve performance but IMO it isn t going to get you into that
                      Message 10 of 15 , Nov 19, 2007
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                        Bill,
                        I think replacing a couple of batteries that sag under load in a aged
                        pack will likely improve performance but IMO it isn't going to get you
                        into that 45-50 mile range. My point was that a couple of batteries
                        with weak cells will show under a heavy load and you might not see
                        that with just the heater. But if you aren't seeing drops while
                        driving of any great difference then replacing one or two isn't going
                        to help.

                        As others have posted, I also think that 45-50 is a bit optimistic for
                        a regular driving range. If you really need that kind of range on a
                        single charge I'd say you need 13 new batteries and you'll likely need
                        to replace them frequently. You just aren't going to get that kind of
                        performance out of anything with any weakness. The 8g27 is about a
                        85AH battery at the 20 hr rate and about a 45-50 AH battery at the 1
                        hour rate. So if you drive very very conservatively and only use 1 amp
                        per mile you'll make 45-50 miles. But you have taken the battery to at
                        least 80% depth of discharge each time and longevity isn't going to
                        happen.

                        Eric made some mods to his battery configuration and is using a higher
                        AH pack and getting the kind of range you are seeking. I don't think
                        he can answer the longevity question quite yet.

                        The Force is as you have written about a 35 mile vehicle and that
                        takes a pretty fresh set of batteries in the pack. Your voltage
                        variation on every run likely also means your entire pack is very
                        close to the same condition. On each charge and discharge there are
                        going to be slight variations because they are not managed
                        individually. Eventially a couple will break from the group and start
                        to show up as "weak". The more often you drive 35 miles on a single
                        charge the sooner that is going to happen.

                        Not saying you shouldn't drive 35 miles just saying that with a Pba
                        battery pack you just shouldn't expect it to last a long time. Pba
                        batteries have limitations no matter what "they" wrote on the visor...

                        Mike

                        --- In solectria_ev@yahoogroups.com, "Bill Swann" <dbswann4@...> wrote:
                        >
                        > It states on the car visor that the range is 45-50 under conservative
                        > driving conditions. I only get 35, and wanted to see waht I could to
                        > short of replacing the whole pack. So I started taking voltage
                        > readings, and seeing inconsistent results. That is, the one with the
                        > lowest voltage after a hard drain is not consistently the same one.
                        > Bill s
                        > --- In solectria_ev@yahoogroups.com, Ken Olum <kdo@> wrote:
                        > >
                        > > Why do you think that some and only some of your batteries are bad?
                        > > Maybe the pack just needs replacement.
                        > >
                        > > When I had a single bad battery, its voltage dropped to 10V after
                        > > drawing a few amp hours. There was not any question about which one
                        > > was bad.
                        > >
                        > > Ken
                        > >
                        >
                      • Dorothy Swann
                        The numbers are 30 amp hours and a few more miles. The driving is
                        Message 11 of 15 , Nov 19, 2007
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                          The numbers are 30 amp hours and a few more miles. The driving is <35 mph in Houston climate. I was looking to increase the range for an occational 40 mile round trip. I had been doing 35 miles; but as this is a deep discharge, I know better now, so as to not reduce the pack life. The vehicle specs (on the visor) show 45-50 miles.
                          Bill S


                          ----- Original Message ----
                          From: Ken Olum <kdo@...>
                          To: solectria_ev@yahoogroups.com
                          Cc: solectria_ev@yahoogroups.com
                          Sent: Monday, November 19, 2007 7:27:09 AM
                          Subject: Re: [solectria_ev] Re: Identifying a laggard battery

                          Bill, how many amp hours are you using in your 35 miles? What kind of
                          conditions are you driving in? How many miles do you have on your
                          pack? At the end of the 35 miles is your car in "limp home mode"
                          (will only go 5 or 10 mph), or is it just a bit sluggish? If your
                          Force can go 35 miles in winter with a mix of city and highway
                          driving, you really have nothing to complain about. If it's in limp
                          home mode after 35 miles of driving on rural roads at moderate speed
                          on a hot summer day, something is wrong, but it could be the pack as a
                          whole.

                          Replacing individual batteries in an old pack is a big gamble. Unless
                          there are one or two prematurely bad batteries, it's not worth it.
                          After a little while, the new batteries will not be new anymore, and
                          you'll have to replace them again when you replace the whole pack, or
                          your pack will not start out balanced.

                          Ken



                          [Non-text portions of this message have been removed]
                        • Gerard (Gary) Carlson
                          Greetings all: Let me share some of the intimate details of my battery pack. I have 12 MK gel batteries labeled 1 -12.? Here is the battery voltage taken on
                          Message 12 of 15 , Nov 19, 2007
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                            Greetings all:

                            Let me share some of the intimate details of my battery pack.
                            I have 12 MK gel batteries labeled 1 -12.? Here is the battery voltage taken on 12/19/2004 while driving at a economy knob limited 100 amps.? At this time the batteries had less than 5,000 miles on them:

                            #1? 11.81 V
                            #2? 11.75 V
                            #3? 11.64 V
                            #4? 11.72 V
                            #5? 11.80 V
                            #6? 11.75 V
                            #7? 11.77 V
                            #8? 11.77 V
                            #9 ?11.70 V
                            #10 11.67 V
                            #11 11.69 V
                            #12 11.69 V
                            Note that the biggest voltage difference is between #1 & #3 = 0.17 volts.

                            On 4/28/2007 while driving at 100 amps with over 25,000 miles on the battery pack we get:

                            #1?? 11.77 V
                            #2?? 9.47 V
                            #3?? 11.41 V
                            #4?? 11.20 V
                            #5?? 11.20 V
                            #6?? 11.70 V
                            #7?? 11.71 V
                            #8?? 11.76 V
                            #9?? 11.65 V
                            #10? 11.55 V
                            #11? 11.06 V
                            #12? 11.42 V
                            Note that the biggest voltage difference is between #1 & #2 = 2.3 volts.
                            Battery #2 is really starting to lag the pack.

                            The voltage difference is more pronounced at higher discharge depths.? As a result you can imaging the the car starts becoming sluggish at 25 miles of range instead of 35.? Because my commute is typically 12 miles between chargings, I am able to nurse this pack to (I hope) 30,000 miles.

                            My plan is to try and limp the pack to 30,000 miles (I have 28,000 now) and then replace everything at once.? The MK battery web site has charts for number of charge cycles vs depth of discharge.? I am estimating that if I get between 25,000 and 30,000 on a battery pack, I have gotten my money's worth

                            Sincerely,
                            Gary Carlson
                            1992 Solectria Force
                            ID License:? AMPEATR



                            -----Original Message-----
                            From: Dorothy Swann <dbswann4@...>
                            To: solectria_ev@yahoogroups.com
                            Sent: Mon, 19 Nov 2007 6:01 am
                            Subject: Re: [solectria_ev] Identifying a laggard battery






                            I have also brought out wires from each battery box-9 from the back, and 6 from the front. Would you say that the weak batteries-the ones that are 1 volt or so less than the pack- are the ones to replace? The goal is to increase the range as shown on the visor-45 to 50 miles.
                            Thanks Bill S

                            ----- Original Message ----
                            From: Gerard (Gary) Carlson <gjc0@...>
                            To: solectria_ev@yahoogroups.com
                            Sent: Sunday, November 18, 2007 11:04:08 PM
                            Subject: Re: [solectria_ev] Identifying a laggard battery

                            Greetings:

                            I brought out test wires from each of my batteries (through fuses).? I am able to monitor the voltage across each battery while driving.? I have an assistant sit in the front seat with a digital volt meter and a switch box.

                            I set the economy knob to 100 amps max draw and then measure the voltage across each battery while under the 100 amp load.? I have done this several times over the 28K mile life of my battery pack and I consistently see two weak batteries that are up to a volt below the rest of the pack.

                            The test wires can also be arranged to measure the voltage drop across the inter-battery connections. ? This is useful to check for bad connections. ? This test only works under a heavy current load such as 100 amps.? For example, a 1 volt reading across a inter-battery connection at 100 amps translates into 1/100 or 10 milliohms.

                            Sincerely
                            Gary Carlson
                            1992 Solectria Force
                            ID License:? AMPEATR

                            -----Original Message-----
                            From: Bill Swann <dbswann4@yahoo. com>
                            To: solectria_ev@ yahoogroups. com
                            Sent: Sun, 18 Nov 2007 5:43 pm
                            Subject: [solectria_ev] Identifying a laggard battery

                            I am trying to identify which batteries I should replace. I severely
                            deplete the battery set, and stop the car with the lights and heat on.
                            Then I measure and plot the individual battery voltages. I do this
                            repeatedly with inconsistent results. That is, the same battery is not
                            the laggard. What is the trick? Do you have to deplete the battery set
                            to the same voltage each time?
                            Bill S

                            ____________ _________ _________ _________ _________ _________ _
                            Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail. aol.com

                            [Non-text portions of this message have been removed]

                            [Non-text portions of this message have been removed]





                            ________________________________________________________________________
                            Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail.aol.com


                            [Non-text portions of this message have been removed]
                          • ldr214
                            Gary, Do you recall how many AH s off the charger the batteries were in your data. You have to love these gels assuming you don t have any balancers or BMS.
                            Message 13 of 15 , Nov 19, 2007
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                              Gary,
                              Do you recall how many AH's off the charger the batteries were in your
                              data.

                              You have to love these gels assuming you don't have any balancers or
                              BMS. I'll bet you can make 30K if you don't need to pull a lot of amps
                              in that 12 miles and keep them warm.

                              Are they still on a Brusa charger?

                              Mike

                              --- In solectria_ev@yahoogroups.com, "Gerard (Gary) Carlson "
                              <gjc0@...> wrote:
                              >
                              > Greetings all:
                              >
                              > Let me share some of the intimate details of my battery pack.
                              > I have 12 MK gel batteries labeled 1 -12.? Here is the battery
                              voltage taken on 12/19/2004 while driving at a economy knob limited
                              100 amps.? At this time the batteries had less than 5,000 miles on them:
                              >
                              > #1? 11.81 V
                              > #2? 11.75 V
                              > #3? 11.64 V
                              > #4? 11.72 V
                              > #5? 11.80 V
                              > #6? 11.75 V
                              > #7? 11.77 V
                              > #8? 11.77 V
                              > #9 ?11.70 V
                              > #10 11.67 V
                              > #11 11.69 V
                              > #12 11.69 V
                              > Note that the biggest voltage difference is between #1 & #3 = 0.17
                              volts.
                              >
                              > On 4/28/2007 while driving at 100 amps with over 25,000 miles on the
                              battery pack we get:
                              >
                              > #1?? 11.77 V
                              > #2?? 9.47 V
                              > #3?? 11.41 V
                              > #4?? 11.20 V
                              > #5?? 11.20 V
                              > #6?? 11.70 V
                              > #7?? 11.71 V
                              > #8?? 11.76 V
                              > #9?? 11.65 V
                              > #10? 11.55 V
                              > #11? 11.06 V
                              > #12? 11.42 V
                              > Note that the biggest voltage difference is between #1 & #2 = 2.3 volts.
                              > Battery #2 is really starting to lag the pack.
                              >
                              > The voltage difference is more pronounced at higher discharge
                              depths.? As a result you can imaging the the car starts becoming
                              sluggish at 25 miles of range instead of 35.? Because my commute is
                              typically 12 miles between chargings, I am able to nurse this pack to
                              (I hope) 30,000 miles.
                              >
                              > My plan is to try and limp the pack to 30,000 miles (I have 28,000
                              now) and then replace everything at once.? The MK battery web site has
                              charts for number of charge cycles vs depth of discharge.? I am
                              estimating that if I get between 25,000 and 30,000 on a battery pack,
                              I have gotten my money's worth
                              >
                              > Sincerely,
                              > Gary Carlson
                              > 1992 Solectria Force
                              > ID License:? AMPEATR
                              >
                              >
                              >
                              > -----Original Message-----
                              > From: Dorothy Swann <dbswann4@...>
                              > To: solectria_ev@yahoogroups.com
                              > Sent: Mon, 19 Nov 2007 6:01 am
                              > Subject: Re: [solectria_ev] Identifying a laggard battery
                              >
                              >
                              >
                              >
                              >
                              >
                              > I have also brought out wires from each battery box-9 from the back,
                              and 6 from the front. Would you say that the weak batteries-the ones
                              that are 1 volt or so less than the pack- are the ones to replace? The
                              goal is to increase the range as shown on the visor-45 to 50 miles.
                              > Thanks Bill S
                              >
                              > ----- Original Message ----
                              > From: Gerard (Gary) Carlson <gjc0@...>
                              > To: solectria_ev@yahoogroups.com
                              > Sent: Sunday, November 18, 2007 11:04:08 PM
                              > Subject: Re: [solectria_ev] Identifying a laggard battery
                              >
                              > Greetings:
                              >
                              > I brought out test wires from each of my batteries (through fuses).?
                              I am able to monitor the voltage across each battery while driving.? I
                              have an assistant sit in the front seat with a digital volt meter and
                              a switch box.
                              >
                              > I set the economy knob to 100 amps max draw and then measure the
                              voltage across each battery while under the 100 amp load.? I have done
                              this several times over the 28K mile life of my battery pack and I
                              consistently see two weak batteries that are up to a volt below the
                              rest of the pack.
                              >
                              > The test wires can also be arranged to measure the voltage drop
                              across the inter-battery connections. ? This is useful to check for
                              bad connections. ? This test only works under a heavy current load
                              such as 100 amps.? For example, a 1 volt reading across a
                              inter-battery connection at 100 amps translates into 1/100 or 10
                              milliohms.
                              >
                              > Sincerely
                              > Gary Carlson
                              > 1992 Solectria Force
                              > ID License:? AMPEATR
                              >
                              > -----Original Message-----
                              > From: Bill Swann <dbswann4@yahoo. com>
                              > To: solectria_ev@ yahoogroups. com
                              > Sent: Sun, 18 Nov 2007 5:43 pm
                              > Subject: [solectria_ev] Identifying a laggard battery
                              >
                              > I am trying to identify which batteries I should replace. I severely
                              > deplete the battery set, and stop the car with the lights and heat on.
                              > Then I measure and plot the individual battery voltages. I do this
                              > repeatedly with inconsistent results. That is, the same battery is not
                              > the laggard. What is the trick? Do you have to deplete the battery set
                              > to the same voltage each time?
                              > Bill S
                              >
                              > ____________ _________ _________ _________ _________ _________ _
                              > Email and AIM finally together. You've gotta check out free AOL
                              Mail! - http://mail. aol.com
                              >
                              > [Non-text portions of this message have been removed]
                              >
                              > [Non-text portions of this message have been removed]
                              >
                              >
                              >
                              >
                              >
                              > ________________________________________________________________________
                              > Email and AIM finally together. You've gotta check out free AOL
                              Mail! - http://mail.aol.com
                              >
                              >
                              > [Non-text portions of this message have been removed]
                              >
                            • Gerard (Gary) Carlson
                              Mike: I do not understand the question:? : How many AH hours off of the charger the batteries were in my data? Many times I will perform the individual battery
                              Message 14 of 15 , Nov 19, 2007
                              • 0 Attachment
                                Mike:

                                I do not understand the question:? : How many AH hours off of the charger the batteries were in my data?

                                Many times I will perform the individual battery voltage test with the pack fully charged.? If the pack is sitting at a lower state of charge like 75%, the voltage difference between the highest and lowest battery will be greater.

                                I do not have any battery management system, but rather rely on the batteries being well matched.? As you can see in the data, as they age, they are no longer well matched.

                                My car spends most of its time in an unheated garage.? So it is typically above 50 degrees F even when it is 32 degrees outside.? I do not have any battery heaters, although I am considering it for the next pack.? Anyone have any suggestions for a good brand of battery heater?

                                I have two Zivan NG3 chargers, a 120 volt and a 240 volt.? They are wired in parallel with the battery pack through 20 amp fuses.? The 120 V unit is used for convenience charging and the 240 V unit is used at home and at friend's who has a 50 amp welding outlet in his garage.? It would be really nice if Zivan made a universal charger ( 90 - 250 volt, autoranging) that also had decent power factor correction and filtering.? The Zivans raise Cain with the AM radio.

                                Sincerely,
                                Gary Carlson
                                1992 Solectria Force
                                ID License: AMPEATR




                                -----Original Message-----
                                From: ldr214 <replytome@...>
                                To: solectria_ev@yahoogroups.com
                                Sent: Mon, 19 Nov 2007 6:14 pm
                                Subject: [solectria_ev] Re: Data identifying a laggard battery






                                Gary,
                                Do you recall how many AH's off the charger the batteries were in your
                                data.

                                You have to love these gels assuming you don't have any balancers or
                                BMS. I'll bet you can make 30K if you don't need to pull a lot of amps
                                in that 12 miles and keep them warm.

                                Are they still on a Brusa charger?

                                Mike

                                --- In solectria_ev@yahoogroups.com, "Gerard (Gary) Carlson "
                                <gjc0@...> wrote:
                                >
                                > Greetings all:
                                >
                                > Let me share some of the intimate details of my battery pack.
                                > I have 12 MK gel batteries labeled 1 -12.? Here is the battery
                                voltage taken on 12/19/2004 while driving at a economy knob limited
                                100 amps.? At this time the batteries had less than 5,000 miles on them:
                                >
                                > #1? 11.81 V
                                > #2? 11.75 V
                                > #3? 11.64 V
                                > #4? 11.72 V
                                > #5? 11.80 V
                                > #6? 11.75 V
                                > #7? 11.77 V
                                > #8? 11.77 V
                                > #9 ?11.70 V
                                > #10 11.67 V
                                > #11 11.69 V
                                > #12 11.69 V
                                > Note that the biggest voltage difference is between #1 & #3 = 0.17
                                volts.
                                >
                                > On 4/28/2007 while driving at 100 amps with over 25,000 miles on the
                                battery pack we get:
                                >
                                > #1?? 11.77 V
                                > #2?? 9.47 V
                                > #3?? 11.41 V
                                > #4?? 11.20 V
                                > #5?? 11.20 V
                                > #6?? 11.70 V
                                > #7?? 11.71 V
                                > #8?? 11.76 V
                                > #9?? 11.65 V
                                > #10? 11.55 V
                                > #11? 11.06 V
                                > #12? 11.42 V
                                > Note that the biggest voltage difference is between #1 & #2 = 2.3 volts.
                                > Battery #2 is really starting to lag the pack.
                                >
                                > The voltage difference is more pronounced at higher discharge
                                depths.? As a result you can imaging the the car starts becoming
                                sluggish at 25 miles of range instead of 35.? Because my commute is
                                typically 12 miles between chargings, I am able to nurse this pack to
                                (I hope) 30,000 miles.
                                >
                                > My plan is to try and limp the pack to 30,000 miles (I have 28,000
                                now) and then replace everything at once.? The MK battery web site has
                                charts for number of charge cycles vs depth of discharge.? I am
                                estimating that if I get between 25,000 and 30,000 on a battery pack,
                                I have gotten my money's worth
                                >
                                > Sincerely,
                                > Gary Carlson
                                > 1992 Solectria Force
                                > ID License:? AMPEATR
                                >
                                >
                                >
                                > -----Original Message-----
                                > From: Dorothy Swann <dbswann4@...>
                                > To: solectria_ev@yahoogroups.com
                                > Sent: Mon, 19 Nov 2007 6:01 am
                                > Subject: Re: [solectria_ev] Identifying a laggard battery
                                >
                                >
                                >
                                >
                                >
                                >
                                > I have also brought out wires from each battery box-9 from the back,
                                and 6 from the front. Would you say that the weak batteries-the ones
                                that are 1 volt or so less than the pack- are the ones to replace? The
                                goal is to increase the range as shown on the visor-45 to 50 miles.
                                > Thanks Bill S
                                >
                                > ----- Original Message ----
                                > From: Gerard (Gary) Carlson <gjc0@...>
                                > To: solectria_ev@yahoogroups.com
                                > Sent: Sunday, November 18, 2007 11:04:08 PM
                                > Subject: Re: [solectria_ev] Identifying a laggard battery
                                >
                                > Greetings:
                                >
                                > I brought out test wires from each of my batteries (through fuses).?
                                I am able to monitor the voltage across each battery while driving.? I
                                have an assistant sit in the front seat with a digital volt meter and
                                a switch box.
                                >
                                > I set the economy knob to 100 amps max draw and then measure the
                                voltage across each battery while under the 100 amp load.? I have done
                                this several times over the 28K mile life of my battery pack and I
                                consistently see two weak batteries that are up to a volt below the
                                rest of the pack.
                                >
                                > The test wires can also be arranged to measure the voltage drop
                                across the inter-battery connections. ? This is useful to check for
                                bad connections. ? This test only works under a heavy current load
                                such as 100 amps.? For example, a 1 volt reading across a
                                inter-battery connection at 100 amps translates into 1/100 or 10
                                milliohms.
                                >
                                > Sincerely
                                > Gary Carlson
                                > 1992 Solectria Force
                                > ID License:? AMPEATR
                                >
                                > -----Original Message-----
                                > From: Bill Swann <dbswann4@yahoo. com>
                                > To: solectria_ev@ yahoogroups. com
                                > Sent: Sun, 18 Nov 2007 5:43 pm
                                > Subject: [solectria_ev] Identifying a laggard battery
                                >
                                > I am trying to identify which batteries I should replace. I severely
                                > deplete the battery set, and stop the car with the lights and heat on.
                                > Then I measure and plot the individual battery voltages. I do this
                                > repeatedly with inconsistent results. That is, the same battery is not
                                > the laggard. What is the trick? Do you have to deplete the battery set
                                > to the same voltage each time?
                                > Bill S
                                >
                                > ____________ _________ _________ _________ _________ _________ _
                                > Email and AIM finally together. You've gotta check out free AOL
                                Mail! - http://mail. aol.com
                                >
                                > [Non-text portions of this message have been removed]
                                >
                                > [Non-text portions of this message have been removed]
                                >
                                >
                                >
                                >
                                >
                                > __________________________________________________________
                                > Email and AIM finally together. You've gotta check out free AOL
                                Mail! - http://mail.aol.com
                                >
                                >
                                > [Non-text portions of this message have been removed]
                                >





                                ________________________________________________________________________
                                Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail.aol.com


                                [Non-text portions of this message have been removed]
                              • ldr214
                                Gary, I was wondering how far or how many AHs used the reflected data was in both cases, the SOC, and what it was. Had you just unplugged from the charger and
                                Message 15 of 15 , Nov 20, 2007
                                • 0 Attachment
                                  Gary,
                                  I was wondering how far or how many AHs used the reflected data was in
                                  both cases, the SOC, and what it was. Had you just unplugged from the
                                  charger and recorded the numbers or had you driven a number of miles
                                  first? Was it the same distance or amount of AH in both cases? As you
                                  just wrote the spread usually will get much greater as the SOC drops.

                                  I see 7 Volts these days on a couple of my weak one when the AHs are
                                  in the 20's, controller in normal or power and pedal to the floor. Not
                                  nearly so low in econ but econ doesn't keep up with traffic.

                                  My guess was that the data reflected a very high state of charge
                                  considering the rather small spread in the pack with 28000 miles on it.

                                  I sent you a email in regards to heaters so you might check your spam
                                  if you didn't see it.


                                  Mike

                                  --- In solectria_ev@yahoogroups.com, "Gerard (Gary) Carlson "
                                  <gjc0@...> wrote:
                                  >
                                  > Mike:
                                  >
                                  > I do not understand the question:? : How many AH hours off of the
                                  charger the batteries were in my data?
                                  >
                                  > Many times I will perform the individual battery voltage test with
                                  the pack fully charged.? If the pack is sitting at a lower state of
                                  charge like 75%, the voltage difference between the highest and lowest
                                  battery will be greater.
                                  >
                                  > I do not have any battery management system, but rather rely on the
                                  batteries being well matched.? As you can see in the data, as they
                                  age, they are no longer well matched.
                                  >
                                  > My car spends most of its time in an unheated garage.? So it is
                                  typically above 50 degrees F even when it is 32 degrees outside.? I do
                                  not have any battery heaters, although I am considering it for the
                                  next pack.? Anyone have any suggestions for a good brand of battery
                                  heater?
                                  >
                                  > I have two Zivan NG3 chargers, a 120 volt and a 240 volt.? They are
                                  wired in parallel with the battery pack through 20 amp fuses.? The 120
                                  V unit is used for convenience charging and the 240 V unit is used at
                                  home and at friend's who has a 50 amp welding outlet in his garage.?
                                  It would be really nice if Zivan made a universal charger ( 90 - 250
                                  volt, autoranging) that also had decent power factor correction and
                                  filtering.? The Zivans raise Cain with the AM radio.
                                  >
                                  > Sincerely,
                                  > Gary Carlson
                                  > 1992 Solectria Force
                                  > ID License: AMPEATR
                                  >
                                  >
                                  >
                                  >
                                  > -----Original Message-----
                                  > From: ldr214 <replytome@...>
                                  > To: solectria_ev@yahoogroups.com
                                  > Sent: Mon, 19 Nov 2007 6:14 pm
                                  > Subject: [solectria_ev] Re: Data identifying a laggard battery
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > Gary,
                                  > Do you recall how many AH's off the charger the batteries were in your
                                  > data.
                                  >
                                  > You have to love these gels assuming you don't have any balancers or
                                  > BMS. I'll bet you can make 30K if you don't need to pull a lot of amps
                                  > in that 12 miles and keep them warm.
                                  >
                                  > Are they still on a Brusa charger?
                                  >
                                  > Mike
                                  >
                                  > --- In solectria_ev@yahoogroups.com, "Gerard (Gary) Carlson "
                                  > <gjc0@> wrote:
                                  > >
                                  > > Greetings all:
                                  > >
                                  > > Let me share some of the intimate details of my battery pack.
                                  > > I have 12 MK gel batteries labeled 1 -12.? Here is the battery
                                  > voltage taken on 12/19/2004 while driving at a economy knob limited
                                  > 100 amps.? At this time the batteries had less than 5,000 miles on them:
                                  > >
                                  > > #1? 11.81 V
                                  > > #2? 11.75 V
                                  > > #3? 11.64 V
                                  > > #4? 11.72 V
                                  > > #5? 11.80 V
                                  > > #6? 11.75 V
                                  > > #7? 11.77 V
                                  > > #8? 11.77 V
                                  > > #9 ?11.70 V
                                  > > #10 11.67 V
                                  > > #11 11.69 V
                                  > > #12 11.69 V
                                  > > Note that the biggest voltage difference is between #1 & #3 = 0.17
                                  > volts.
                                  > >
                                  > > On 4/28/2007 while driving at 100 amps with over 25,000 miles on the
                                  > battery pack we get:
                                  > >
                                  > > #1?? 11.77 V
                                  > > #2?? 9.47 V
                                  > > #3?? 11.41 V
                                  > > #4?? 11.20 V
                                  > > #5?? 11.20 V
                                  > > #6?? 11.70 V
                                  > > #7?? 11.71 V
                                  > > #8?? 11.76 V
                                  > > #9?? 11.65 V
                                  > > #10? 11.55 V
                                  > > #11? 11.06 V
                                  > > #12? 11.42 V
                                  > > Note that the biggest voltage difference is between #1 & #2 = 2.3
                                  volts.
                                  > > Battery #2 is really starting to lag the pack.
                                  > >
                                  > > The voltage difference is more pronounced at higher discharge
                                  > depths.? As a result you can imaging the the car starts becoming
                                  > sluggish at 25 miles of range instead of 35.? Because my commute is
                                  > typically 12 miles between chargings, I am able to nurse this pack to
                                  > (I hope) 30,000 miles.
                                  > >
                                  > > My plan is to try and limp the pack to 30,000 miles (I have 28,000
                                  > now) and then replace everything at once.? The MK battery web site has
                                  > charts for number of charge cycles vs depth of discharge.? I am
                                  > estimating that if I get between 25,000 and 30,000 on a battery pack,
                                  > I have gotten my money's worth
                                  > >
                                  > > Sincerely,
                                  > > Gary Carlson
                                  > > 1992 Solectria Force
                                  > > ID License:? AMPEATR
                                  > >
                                  > >
                                  > >
                                  > > -----Original Message-----
                                  > > From: Dorothy Swann <dbswann4@>
                                  > > To: solectria_ev@yahoogroups.com
                                  > > Sent: Mon, 19 Nov 2007 6:01 am
                                  > > Subject: Re: [solectria_ev] Identifying a laggard battery
                                  > >
                                  > >
                                  > >
                                  > >
                                  > >
                                  > >
                                  > > I have also brought out wires from each battery box-9 from the back,
                                  > and 6 from the front. Would you say that the weak batteries-the ones
                                  > that are 1 volt or so less than the pack- are the ones to replace? The
                                  > goal is to increase the range as shown on the visor-45 to 50 miles.
                                  > > Thanks Bill S
                                  > >
                                  > > ----- Original Message ----
                                  > > From: Gerard (Gary) Carlson <gjc0@>
                                  > > To: solectria_ev@yahoogroups.com
                                  > > Sent: Sunday, November 18, 2007 11:04:08 PM
                                  > > Subject: Re: [solectria_ev] Identifying a laggard battery
                                  > >
                                  > > Greetings:
                                  > >
                                  > > I brought out test wires from each of my batteries (through fuses).?
                                  > I am able to monitor the voltage across each battery while driving.? I
                                  > have an assistant sit in the front seat with a digital volt meter and
                                  > a switch box.
                                  > >
                                  > > I set the economy knob to 100 amps max draw and then measure the
                                  > voltage across each battery while under the 100 amp load.? I have done
                                  > this several times over the 28K mile life of my battery pack and I
                                  > consistently see two weak batteries that are up to a volt below the
                                  > rest of the pack.
                                  > >
                                  > > The test wires can also be arranged to measure the voltage drop
                                  > across the inter-battery connections. ? This is useful to check for
                                  > bad connections. ? This test only works under a heavy current load
                                  > such as 100 amps.? For example, a 1 volt reading across a
                                  > inter-battery connection at 100 amps translates into 1/100 or 10
                                  > milliohms.
                                  > >
                                  > > Sincerely
                                  > > Gary Carlson
                                  > > 1992 Solectria Force
                                  > > ID License:? AMPEATR
                                  > >
                                  > > -----Original Message-----
                                  > > From: Bill Swann <dbswann4@yahoo. com>
                                  > > To: solectria_ev@ yahoogroups. com
                                  > > Sent: Sun, 18 Nov 2007 5:43 pm
                                  > > Subject: [solectria_ev] Identifying a laggard battery
                                  > >
                                  > > I am trying to identify which batteries I should replace. I severely
                                  > > deplete the battery set, and stop the car with the lights and heat
                                  on.
                                  > > Then I measure and plot the individual battery voltages. I do this
                                  > > repeatedly with inconsistent results. That is, the same battery is
                                  not
                                  > > the laggard. What is the trick? Do you have to deplete the battery
                                  set
                                  > > to the same voltage each time?
                                  > > Bill S
                                  > >
                                  > > ____________ _________ _________ _________ _________ _________ _
                                  > > Email and AIM finally together. You've gotta check out free AOL
                                  > Mail! - http://mail. aol.com
                                  > >
                                  > > [Non-text portions of this message have been removed]
                                  > >
                                  > > [Non-text portions of this message have been removed]
                                  > >
                                  > >
                                  > >
                                  > >
                                  > >
                                  > > __________________________________________________________
                                  > > Email and AIM finally together. You've gotta check out free AOL
                                  > Mail! - http://mail.aol.com
                                  > >
                                  > >
                                  > > [Non-text portions of this message have been removed]
                                  > >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > ________________________________________________________________________
                                  > Email and AIM finally together. You've gotta check out free AOL
                                  Mail! - http://mail.aol.com
                                  >
                                  >
                                  > [Non-text portions of this message have been removed]
                                  >
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