Quote Originally Posted by yapoy86 View Post
ah i see, is the charging port passes thru the ESC? i was confused why the battery will have 3.2V only

its possible that one of the lithium packs are not in sync with the other packs. in my power tool battery pack, sometimes i need to charge the cells individually.
The charging port bypasses the ESC. The wires go straight to the BMS/Battery pack.

Yes, the battery pack was apparently overdischarged. I may try back-feed charging again through the main discharge lines to get the individual cell voltages higher. I hope by doing so opens up the BMS to accept regular charging.... if it's not yet beyond repair.