I have a Headway BMS (16s, 10Ah). Charger cuts off (light turns green) at 58.4V (3.65V/cell). Does balancing occur during charging, at the end of charging, after charging, or "all the time? I have cell logs on the pack (2 x 8s) which show that during charging a couple of cells are slower to come up to 3.65, and sometimes don't quite make it when the charger cuts off. If I leave it on (green light) for a few hours, sometimes they come up, sometimes not. If I take the charger off, the cells all settle down to about 3.41V, all within 0.02V of each other. As the pack discharges, all the cells seem to discharge at the same rate (voltages within 0.02V of each other). I have never discharged the pack to LVC, so I don't know what the LVC is for this particular BMS. It seems that the pack is balanced an performs fine. I have not tried logging data from the cell-logs, which would be more meaningful, but as long as the pack works with a minimum of fussing, I am happy.
I have no idea if the BMS gets hot during or after charging. It is stuck inside a plastic frame that holds the battery and BMS securely. I stuck an old cooling fan from a broken PC power supply on the frame so it 'blows' on the heatsink and MOSFETS on the BMS board, power comes from the charger (12V tapped off the cooling fan in the charger fed through extra wires in the charging plug). The fan only runs when the charger fan runs, so this may be completely useless, but hey, it was free!
The lack of documentation or instructions that these things come with, and may lack of electronics knowledge makes me worry, that's why I have never really pushed the pack to see what kind of range I can get (have had for about 7 months, purchased from EV components before that company imploded). Most of my trips are less than 5 miles, but hilly. I would like to use this bike for a long (22 mi each way) commute, and am in the process of adding more capacity.
Anybody know the factory specs on these things?
