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Bafang Battery Troubleshooting

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    Bafang Battery Troubleshooting

    I have Bafang 450wh 43V battery carrier mount with charger as part of my Bambu ebike conversion kit. The bike was idle for 2-3 months and now will not charge. The onbattery lights and the charger all indicate the battery is charged but it is not.
    i have placed a multimeter on output.
    Nominal battery voltage 43V
    the push button on battery shows all lights green.

    Open circuit voltage measured around 20V.
    To check this OC voltage I connect the charger disconnected from supply, this puts a small load on battery. Then read the multi meter.

    When turning on the charger the green light flashes battery voltage climbs to 34V, the red charge light comes on for about 5 second (sometimes) then goes to solid green = fully charged with voltage of 34V only.
    Occasionally when turning on charger the red light does not come on the green light flashes, the voltage climbs to 48V then goes to solid green= fully charged with voltage of 34V only.

    I suspect I have damaged bms, or damaged cells shutting down the bms.
    This bike and pack have seen very little action in this time since new just 60km of riding and storage under a roof. A lot of down time not used.

    I believe leaving battery connected but not used for a long time has caused extreme discharge.

    The problem is that I cannot buy a new pack in this country. I cannot even find those pack online anymore.
    My pack is Bafang HT1204DA 43V 10.4ah
    12C 1R 18 65 4 10.4ah
    Mfr Hi-Tech
    Before I start breaking into this thing is there some way to test if issue is battery, bms or smart charger??
    is there something I can do before opening the sealed battery?

    I have access to voltmeter, soldering equipment and understand a 'medium' amount about concept of bms battery protection.

    Last edited by TonyVov; 08-10-2019, 10:23 AM.

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