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Wolf Battery Pack Cutting Out at 51V

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    Wolf Battery Pack Cutting Out at 51V

    Hello,

    I have a BBSHD motor with the 52V Wolf Battery pack.

    I used my setup on a fat bike last winter season with great success for my 28 km commute, I probably put about 2000 km on my bike. I didn't ride the fat bike for the summer and stored the battery pack at what I thought was about an 80% charge and topped it up every couple months.

    I went to use the system again a couple weeks ago and everything seemed fine at the start of my ride:
    -Charger seemed to work, fan was on, red charging light on for a few hours.
    -Controller read ~57V (fullish charge for this pack)
    -Bike delivered power as it always had on assist level 2 and I even used the throttle a bit.

    Now the problem I am having is that as soon as the battery hits around 51V (nominal voltage for this pack), about halfway through my commute, the whole system shuts down without warning. Screen on the controller goes black and cannot get it to power back on unless I wait several minutes and unplug and plug the battery back in. Voltage reading is now generally 53V and things work for a little bit until I cross 51V and everything shuts down again. This battery used to go down to 42V no problem, but I would rarely discharge it that much.

    When I measure the output wires with a multimeter, I get 0 V. I believe one time I checked the charge wires and the pack read 24V, I think.

    I have tired to "jumpstart" the BMS several times now but the battery pack does the same thing, shuts completely down at 51V. It seems to take a good couple hours to charge again back up to 57V and I can draw a great deal of power out of the system until I cross the 51V barrier again.

    This was a very expensive battery and it is making my commute very frustrating, I would be open to tinkering with the BMS, but as I understand it, it's completely encased in epoxy...

    Is there any other "balancing" or reset procedure?

    Thank you,

    DKW

    #2
    I should also add, the rate of discharge seems to be normal as well... It's not going from a full charge and immediately dropping to 51V under load or anything like that.

    Comment


      #3
      Could be unbalanced. Full charge should be 58.8 volts on a 52V pack using the multimeter, not 57V. Your meter could be inaccurate. Compare both the unloaded charger output and the battery at "full" charge to see if there is a difference.

      How do you fix unbalance? Let it charge for a long time.

      Comment


        #4
        I agree, the low charge voltage at full says it's unbalanced. That is, not really full, one parallel group of cells (or more) is still below 4.2 V. You should be able to see 58.8V even after unplugging the charger and letting it sit, ideally. Don't trust the charger or bike display, use a DVM.

        You probably just need to give it a bunch of rest time on the charger at 'full' and will see the voltage creep up.
        Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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          #5
          Roger. Thanks for the advice. I haven't really left it on charge for a long time, I will try what you are suggesting and hopefully can get it to bounce back...
          N.B.: I have been using a $500 Fluke multi-meter (two individual ones, in fact) so I'd say that is fairly accurate... ;)

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