liamcaff wrote: ↑Mar 02 2020 10:01am
What kind of BMS and chargers are you guys using with these cells?
72V 20s 1p battery setup
for me, no bms; i just monitor pack voltage and ah/wh used via the cycle analyst, and be sure to charge up before longer trips (or plug in at destination while there). the cells i have are old and were used before i got them, and even now (at least several years after i got them) they're still working about the same, with a little lower capacity, but still staying balanced on their own, since they are good quality and pretty well matched (good qc at the factory to keep all the cells they ship out within a narrow range of specifications), and they seem to stay matched as they age.
i have used the cycle satiator, but at present am using a meanwell hlg-600h-54a to charge my 14s2p pack at a little more than 0.25c (about 12a) to a bit more than 57v.
for a 72v pack, you could use two meanwells in series; not sure if the 54a will turn down low enough (about 83v, or 41.5v each, for your pack) to use two of them in series for it, or if you would need one to be a lower voltage model, or use two identical lower voltage models.
if you use lower voltage models they will be capable of higher current, as the systems are watt-limited by the heat they can shed (fanless, potted and sealed, so good for mounting right on the bike or vehicle. the one on my sb cruiser trike is mounted under the deck, and has been submerged in flash flood waters at least twice with no issues over the years).
but since 0.5c on a 20ah pack is about 10a, you wouldn't want to charge them at a higher current anyway, so the 54a would work for you if two in series can be adjusted down to the 83v or so.