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battery failure?

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    battery failure?

    I have a 750W shark 48v 13.5 Ah battery from Luna. It presently only charges to 52.7v I believe it should charge all the way to 54.7v. There is enough power to power the dashboard but not the motor. It did power the motor until a load was put on it and then it would cut out. Now it won't even do that. I tried another 48v battery and that wouldn't power the motor either. It came off a friend bike which ran well. So now I am concerned that the failure is maybe in the controller? Is the complete system done? I have done everything I can think of to find the problem to no avail. I'll take any suggestions or even recommendations to where I might be able to find some one smarter than me. The system is fairly new maybe there is a couple of 100 miles on it. Thanks

    Hub motor? Check the appropriate troubleshooting guide in the Knowledge base, here, for whatever you have.

    Random related tips:

    Unplug brake sensors, etc to rule those out.

    If a known good battery won't run it, chances are you have a wiring, controller, or motor issue.

    That pack still worked, when returned to the other bike, right?

    Look over wiring, first.

    Swap controller if you can borrow one.

    Check motor windings and phase wires for shorts, opens.

    Sounds like your pack is probably out of balance. Maybe damaged, but maybe just needs a long balance charge.
    Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.


      NO bottom bracket Bafang 500W motor. Yes the battery still worked on the other bike. I''l do the checks. What is a long balanced charge? So far it never seems to get above 52.7v
      Thanks for the response Stu


        The BMS in the battery needs time to equalize the voltage of the cell groups in the pack. Hours or days even. Leaving it on charger, at Max voltage, is generally the process to enable this balancing.

        A balanced pack should reach intended voltage, but an unbalanced one will not.

        Your whole kit is not shot, no. Probably just one component. Trick is figuring out which. Easiest strategy is parts swapping, if you have access to known good parts. Borrow, or buy.

        Again, look at the knowledge base, here. Charging, balancing, battery care info is there, too. Will explain better than I did.

        Good luck.
        Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.


          Foud the problem 4 dead cells and a BMS Replaced the cells now a new BMS I no nothing about BMS Guess I'll learn I assume it is just a circut board the plugs with a little solder.