Issue with Overkill Solar 16S BMS shutting down

Castaway Camper

New Member
Sep 15, 2021
First post here, but I've been reading you'll for sometime which has been invaluable for my recent off grid cabin build. Thanks ahead for any advise you may be able to share. My Overkill Solar 16S 48 Volt BMS is doing something strange. When charging the battery, cell #6 will cause battery to shut off due to cell over voltage, as soon as it does shut off, it shows all cells well within acceptable Delta instantly, and within acceptable voltage range. Conversely, when discharging cell #6 will show a significantly lower voltage than the others, to the point of shutting down the battery due to cell under voltage, once shut off, all cells are well within the acceptable Delta, then it automatically cuts itself on again and repeat, repeat, repeat. I was away for a couple weeks and when I reconnected to the BLU Tooth I apparently had over 31,000 BMS overvoltage times. I have checked all cable connections. Thanks in advance!

Bob B

Photon Sorcerer
Sep 21, 2019
Good chance you have a bad connection .... could be a bad cell.

I would disassemble the pack, clean all terminals and bus bars, treat the bus bars with a thin coat of noalox ... or similar .... re-assemble with the cell you are having problems with in a different position .... test again.
Label the cells before moving them around.