Battery problem

1boris

Esteemed Pedelecer
Sep 10, 2013
344
58
I have a battery of 13 packages in serie consisting of 3 paralell cells each. The battery has been exposed to water and will not function. The charger stops charging after a short time and the light turn green. I have tested each of the 13 packages with voltmeter and it turns out that all but one has uniform voltage. The 12 packages are measured to 4,05v while one is 3,75v. When I try to start the display the current and voltage drops and the display shuts down. It seems that the one 3-cell package is low voltage - although not critical - but I am uncertain about the reason.

Is it the BMS that is not working properly or is the cell package damaged?

Is it possible to change single cells in

If a shortcut caused by water has made one of the 3 cell-packages drop voltage I wonder if it is posslible to do an isolated charge of that package or if it is preferreable to discharge the other packages in order to even voltage levels?

Links

BMS: http://www.bmsbattery.com/bmspcm/566-10s-lithium-ion-bms-for-bottle-battery-case.html
Battery: http://www.bmsbattery.com/48v/248-48v-10ah-lithium-ion-electric-bicycle-battery-pack.html
.
 
D

Deleted member 4366

Guest
Those batteries are pretty well glued together, which will make repair difficult.
there's a couple of things to do. firstly, charge up the low cell. It could be that the water only drained it down a it to knock it out of balance. Use a USB charger (5v) or anything similar to charge it up to the same voltage as the others. Hopefully, everything will go back to normal.

If that doesn't solve it, and that cell-group is knackered, You can bypass that cell and go down to 12S, You simply remove the connections to those cells (Dremmel if you have to) and bridge across them so that they're taken out of the circuit. You then need to bridge the two sense wires on the BMS so that it gets the same voltage on two pins.

if you can get it apart, I think that BMSB sell the individual 5aH pouches to repair it. I'm pretty sure that they're stuck together with strong double-sided film. Could you check and report back?