Lithium battery BMS warning - fix or discard whole battery?
Disclaimer- not super knowledgeable about lithium so go easy if I’ve got anything wrong here.
I have a 12v lithium battery that was run down to 3v, had an alternator issue where it didn’t charge in vehicle.
Recharged the battery on a bench and it took the charge fine, but a warning LED light on the battery lit, indicating a BMS electronic problem was indicated and stayed lit.
I opened the battery case and checked the voltage across the cells, c1 3.35v, c2 3.37v, c3 3.46v, c4 3.58v. I disconnected the pos and neg leads to the terminals, waited 5 minutes, reconnected, no LED any more.
The cells balanced a bit when left for 18 hours. Hooked up a 12v halogen globe, under load the readings were c1 3.33v, c2 3.34v, c3 3.34v, c4 3.38v.
I let it run under load for 15 minutes and the cells read 3.31v on all cells while powering the light, removed load and got 3.32v on all cells.
As far as battery life and health it seems fine to me, my only question is around the BMS. Surely if there was an issue it would have lit the LED again? Or are they not self clearing? Is it likely to have some hard state locked in where it won’t warn of an issue if one arises again due to it already having an issue previously?
I don’t mind replacing the battery if it needs to be, but the wait time for this battery from the supplier is close to a month.