Can anyone please help me diagnose my persistent BMS issues? My charge-only BMSs won’t charge 12S liion packs past 45.3V. I’ve tried 3 different 5p12S battery packs (built by me) and multiple BMSs from BesTech and batterysupports.com. Though new to BMSs, I’m an engineer, and the skateboard otherwise works great. I just noticed before connecting the latest BMS that the BMS instructions seem to say to connect the battery ground before the balance wires, so maybe I burned up the other BMSs by not doing so, and maybe because one of the bad BMSs charged one of the P-groups to 4.2V, the other P-groups aren’t charging on the latest (presumably undamaged) BMS? Before first charge, all voltages were 3.45v per cell. On 7 June the P-group voltages were 3.74, 7.48, 11.22, 14.96, 18.70, 22.30, 26.50, 30.20, 33.90, 37.70, 41.40, and 45.20. To save you the math, that means all P-groups were 3.6v-3.8v except for group 7 which was 4.2v. Left plugged in until 10 June, the voltages changed very slightly, raising overall pack voltage from 45.2v to 45.3v per my inexpensive multimeter.
All three liion chargers output 50.4V at no load.
This is the battery compartment (with balance leads currently disconnected).
Do you think the several other BMSs were either burned out or defective, and the current one is balancing the P-groups, just extremely slowly?