But there are caveats as well, I run 4 packs in a bank and indeed have tripped over a few, some forcibly.
- Monitoring amps to determine charge cutoff is pointless, it's unreliable.
- Each BMS has to be able to handle the full charge/charge potential. Any one could be left as the "last man standing" if the others cutoff.
- Each battery will share load/charge if properly wired in parallel. If there is too much difference between battery capacities, the "share" can become uneven.
Fortunately, with 4S packs you have a few advantages by having less cells.
Ideally, top charging the cells to 3.60 and then top balancing in sets of four is the way to go.
Preferably, if you have a method to capacity test or test the Resistance & Impedance of the cells to match them up as close to each other as possible would be best. With 16 cells to make 4x4S packs you could probably manually match them up.
Another way is to capacity test each cell and match them up that way, many capacity testers also report the mOhm resistance values for the cells.
SOURCE:
Pre-Balancing Cells | Orion Li-Ion Battery Management System