Unbalanced escooter battery

[madrian]

Hi. I disassembled my escooter battery and found that several contacts were broken. I repaired it with my spot welder. The second problem is that the battery pack is unbalanced and the charger shuts off before all the cells are charged to maximum voltage. I found out that 3 cells are at 4.15V while the rest are at 4.05V.

Should I leave the battery connected to the charger and the BMS will eventually balance the cells?

 

[lnanek]

Depends on the BMS. Some will balance if left on, some won't. BMS on my biggest battery cuts everything off if cells differ by more than .1V, for example, so it wouldn't attempt to balance that.

You can use the balance wires to charge individual cells, however. Hobby RC chargers and old cell phone 1S chargers are easy to find. Also possible to attach an active balancer circuit.

 

[The Battery Doctor]

No, if there is unbalance then the BMS is not doing its job, or the cells are dying, you can balance them with a hobbycharger but either way imballance will trike again.