Recommendations for a 20s 72v BMS?
- Thread starter Rover4444
- Start date
If you're using differnet cells in different groups, or the cells are not all matched, or didnt' start out at the same voltage / state of charge, any common BMS is unlikely to get / keep them balanced, depending on how hard they are used.
What specifically is the pack configuration?
What specifically are the group voltages?
What specifically is the typical pack usage?
Any other info you can provide may be useful in helping you fix your pack problem(s).
What specifically is the pack configuration?
What specifically are the group voltages?
What specifically is the typical pack usage?
Any other info you can provide may be useful in helping you fix your pack problem(s).
Disable BMS from balancing
possibly by keeping stop-charge voltage below the start-balance setpoint
and use a dedicated balancer ("non-protective BMS") to do your balancing - at whatever voltage you like, and at a higher rate, some go to multiple amps
and/or "active" type where rate is independent of cell V delta.
Personally I would've done a serial'd split pack, the any old hobby charger could do your balancing for you.
possibly by keeping stop-charge voltage below the start-balance setpoint
and use a dedicated balancer ("non-protective BMS") to do your balancing - at whatever voltage you like, and at a higher rate, some go to multiple amps
and/or "active" type where rate is independent of cell V delta.
Personally I would've done a serial'd split pack, the any old hobby charger could do your balancing for you.
Sorry for the really late reply, but it's a 20s 5p pack, with 17s 5p being the PF cells and the other 3s 5p being the GA cells.
I had a couple of cells in a group die on me so I slapped some new PF cells in there and fully charged that group and the group next to it that was at 3.35v.
Current group voltages are:
3.72 (GA)
3.72 (GA)
3.72 (GA)
4.02
4.12
3.88
3.83
3.83
3.88
3.66
3.76
3.83
3.82
3.66
3.73
3.83
3.83
3.83
3.78
3.83
I haven't used the pack in around a month now so the groups would discharge on their own, but it looks like that wasn't enough. I don't want to tear up the pack and put it back together again, is there any way I can just charge/discharge via the balance leads?
Typical pack usage is street riding.
I had a couple of cells in a group die on me so I slapped some new PF cells in there and fully charged that group and the group next to it that was at 3.35v.
Current group voltages are:
3.72 (GA)
3.72 (GA)
3.72 (GA)
4.02
4.12
3.88
3.83
3.83
3.88
3.66
3.76
3.83
3.82
3.66
3.73
3.83
3.83
3.83
3.78
3.83
I haven't used the pack in around a month now so the groups would discharge on their own, but it looks like that wasn't enough. I don't want to tear up the pack and put it back together again, is there any way I can just charge/discharge via the balance leads?
Typical pack usage is street riding.
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