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Re: [RoboMower] Re: Which brand and type of batteries are used in the current RL1000 models

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  • Joseph Karaisz
    I would hazard a guess that the battery packs that you have used that are several years old are Yuasa brand? Is that correct? ... [Non-text portions of this
    Message 1 of 14 , Jul 31, 2007
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      I would hazard a guess that the battery packs that you have used that
      are several years old are Yuasa brand? Is that correct?
      On Jul 31, 2007, at 10:55 AM, Christopher Zach wrote:

      > I'm really curious as to all these battery problems. Partially because
      > my 500 Robomower is using packs that are several years old and still
      > gets >2 hours per charge.
      >
      > Has anyone hooked a meter to one of these packs and watched it when
      > the
      > mower poops out? What happens to the voltage on each battery? Is one
      > sagging low under load? Do they both sag? Is one reading 10 volts with
      > the other reading 12?
      >
      > How about on charge? When the mower says "full" are both batteries
      > over
      > 14 volts? Do they have a nice 13.0 volts at rest? How about when you
      > first start charging? Is one still at 12.8 while the second drops to
      > 11.0 right out of the gate?
      >
      > Something here doesn't make sense.
      >
      > Chris
      >
      >



      [Non-text portions of this message have been removed]
    • doodieb2001
      I measured all the voltages, 11.1 and 11.0V when the mower goes back to the dock, 13.1 and 13.2V after the docking station is done charging. I suspect that the
      Message 2 of 14 , Jul 31, 2007
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        I measured all the voltages, 11.1 and 11.0V when the mower goes back
        to the dock, 13.1 and 13.2V after the docking station is done
        charging. I suspect that the charging algorithm is not very good for
        SLA type batteries (it uses a constant charging current of about 1A
        and a voltage limit of 28V). In my mind the batteries don't get
        charged well under these conditions (manufacturers recommend way
        higher charing currents and constant voltage chargers). In addition
        the charging is interrupted if the FET is getting hotter than 125°C,
        which happens frequently. It will restart the charging when the
        temperature gets below 110°C. Manufacturers recommend to charge the
        battery w/o interruptions until it is full.

        ALso: The battery pack gets too hot during charge due to sun exposure
        of the mower and the vibration of the mower are not good for SLA
        batteries either.

        Just my 2c, I will buy a original replacement pack since they give
        you a 1 yr warranty.

        --- In RoboMower@yahoogroups.com, Christopher Zach <cz@...> wrote:
        >
        > I'm really curious as to all these battery problems. Partially
        because
        > my 500 Robomower is using packs that are several years old and
        still
        > gets >2 hours per charge.
        >
        > Has anyone hooked a meter to one of these packs and watched it when
        the
        > mower poops out? What happens to the voltage on each battery? Is
        one
        > sagging low under load? Do they both sag? Is one reading 10 volts
        with
        > the other reading 12?
        >
        > How about on charge? When the mower says "full" are both batteries
        over
        > 14 volts? Do they have a nice 13.0 volts at rest? How about when
        you
        > first start charging? Is one still at 12.8 while the second drops
        to
        > 11.0 right out of the gate?
        >
        > Something here doesn't make sense.
        >
        > Chris
        >
      • Christopher Zach
        ... 14.0 volts could be part of the problem. If the batteries are out of balance, then it s quite possible for battery 1 to get to 14.4 while battery 2 is at
        Message 3 of 14 , Aug 1, 2007
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          doodieb2001 wrote:
          > I measured all the voltages, 11.1 and 11.0V when the mower goes back
          > to the dock, 13.1 and 13.2V after the docking station is done
          > charging. I suspect that the charging algorithm is not very good for
          > SLA type batteries (it uses a constant charging current of about 1A
          > and a voltage limit of 28V). In my mind the batteries don't get
          > charged well under these conditions (manufacturers recommend way
          > higher charing currents and constant voltage chargers). In addition
          > the charging is interrupted if the FET is getting hotter than 125°C,
          > which happens frequently. It will restart the charging when the
          > temperature gets below 110°C. Manufacturers recommend to charge the
          > battery w/o interruptions until it is full.

          14.0 volts could be part of the problem. If the batteries are out of
          balance, then it's quite possible for battery 1 to get to 14.4 while
          battery 2 is at 13.6 (still charging) when the Robomower says "done".
          Then the next drive they get more out of sync, the dead battery gets
          dead-er, etc.

          > ALso: The battery pack gets too hot during charge due to sun exposure
          > of the mower and the vibration of the mower are not good for SLA
          > batteries either.

          Probably minor in this case. Batteries usually fail due to three causes:
          Overcharge, Undercharge, and Damage. Overcharge results in the batteries
          drying out. Undercharge results in sulfated batteries that don't accept
          a charge anymore. And damage is when you hit them or short a cell by
          pulling very high currents.

          The Robomower is not pulling very high currents :-)

          A sulfated battery will appear to charge quickly, will zip up to full
          but will fail pretty quickly. A dry battery will charge up, maybe get
          hot during charge, and will have very little voltage drop for awhile
          then fall like a brick. A shorted cell battery will appear normal under
          load with the exception that the voltage is 2 volts less than what you
          think it should be (ie: "Full" at 10, drops to 9 under load, ending at 8
          volts or so).

          If one battery is shot and the other good, it will show up pretty
          clearly in the Robomower due to it's tight voltage standards (22 volt
          cut off could be 11 one each battery or 10 on one and 12 on the other).
          I'm curious as to if the batteries are dry or sulfated.

          Chris
        • Keith Duff
          Any experience with the following? TR18-12A TEMPEST SEALED LEAD-ACID AGM BATTERY $35 each, 14 LBS
          Message 4 of 14 , Aug 3, 2007
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            Any experience with the following?



            TR18-12A TEMPEST SEALED LEAD-ACID AGM BATTERY $35 each, 14 LBS
            http://www.batteryspec.com/cgi-bin/cart.cgi?action=link&product=125
            <http://www.batteryspec.com/cgi-bin/cart.cgi?action=link&product=125>

            MK ES17-12 BATTERY, $35 each, 14 LBS
            http://www.thebestguard.com/es1712.html
            <http://www.thebestguard.com/es1712.html>
            http://www.infinigi.com/battery-vrlaagm-es1712-battery-p-928.html
            <http://www.infinigi.com/battery-vrlaagm-es1712-battery-p-928.html>

            BB Battery

            ??? Not sure which to order. http://www.batteryweb.com/bb-batteries.cfm
            <http://www.batteryweb.com/bb-batteries.cfm>
            http://www.bb-battery.com/ <http://www.bb-battery.com/>



            THANKS!


            --- In RoboMower@yahoogroups.com, "beekilher"
            <spamlesskb-contests0204@...> wrote:
            >
            > MK, BB, and Full River are what some one has posted before. But if
            > you have read this form you will notice that even these batteries
            > when bought as replacements fail prematurely. Strange that so many
            > different battery brands fail in robomowers! Maybe FR is telling the
            > truth when they say it's a faulty mower and not the battery. I
            > suggest that if you use the onboard charger you UNPLUG IT AFTER 24
            > HOURS. My onboard charger fried two of my battery packs read post
            > #10735. MK is a battery distributor and not a manufacturer. BB I
            > believe makes their own batteries. I don't think Full River is sold
            > in the US at the retail level. So know who you buy your battery from
            > buy local if possible. All battery dealers must take back used
            > batteries to recycle, some will sell these as new so beware! If you
            > look at the BB spec sheets the weight of their bottom battery is a
            > pound less than their top battery less lead in the cheap one. Don't
            > dwell on the charts and graphs there all about the same, but do look
            > at the weight. Most batteries don't live up to them anyway unless
            > locked in a closet. If you buy a 21ah battery you have more thin
            > plates, an 18ah battery will have less but thicker plates, or should.
            > 21ah gives you more mow time maybe 15 minutes but the battery life
            > will be shorten by the thin plates. The 18ah battery will give less
            > mow time but have a longer life and be more durable to bumping and
            > bouncing. Good luck!
            > You pays your money and you takes your chances.
            > P.S. I bought my 4 batteries in May 2005 for $93.55 shipped on
            > ebay. The company doesn't sell batteries now. They are Yuasa NP-18. 2
            > plus hours mow time for 2 years now in an rl500. I still use an
            > original Yuasa NPC-17 with 2 plus hours mow time. With the price of
            > lead and shipping charges those deals may be over.
            > Buzz! Swat! Splat! The BeeKilHer
            >
            >
            > --- In RoboMower@yahoogroups.com, "tinapropes" tinapropes@ wrote:
            > >
            > > I am looking for the same information. I am on my second set of
            > > MK batteries and neither of them have lasted a year. My current set
            > > only lasts about 40 minutes and when they return to the dock one
            > > battery is drained down to 12.4 volts but the other cell has dropped
            > > down to 10 volts. I obviously have a bad cell but I understand that
            > > it is best to replace them in pairs. I run my mower about 200 times
            > > per year so I do not expect them to last 4 years but I would like to
            > > get a full season out of them.
            > > I know that some people have purchased from DigiKey but I think
            > > they have a long lead time before delivery and I need new batteries
            > > now. I know batteries.com was selling some helios batteries cheaply
            > > several weeks ago, but by the time I saw the message the coupon code
            > > for 35% off had expired so they are not a good deal anymore. I
            > think
            > > that BeeKilher stated that he got 4 batteries for less than $100
            > > shipped. Maybe he would share his source with us.
            > > I would love to hear some recommendations or experiences of
            > other
            > > users who have had to purchase batteries in the past.
            > >
            > > Thanks,
            > > William Propes
            > >
            > >
            > >
            > > --- In RoboMower@yahoogroups.com, "doodieb2001" <doodieb@> wrote:
            > > >
            > > > I have my robomower for over 3 Years now and it is time to
            > replace the
            > > > battery. My mower was shipped with Yuasa Batteries NPC17-12. In a
            > > > different forum I read that Friendly has changed the brand of
            > > > batteries. Can anyone confirm which batteries are used in the
            > current
            > > > models. I tried already Power-Sonic but they died after 4 months.
            > > >
            > > > Thank you!
            > > >
            > >
            >




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