So, its finally happened, Lester Beaver Pearson needs a new battery pack, or a sketchy repair on the existing. Right now its using a 6 year old 24v 20ah LiFePO4 v2.5 pack from ping battery with a bad cell.
Details below, but does anyone have experience repairing these? or have recommendations on where to source a replacement?
(for those of you unfamiliar with Lester, he lives in the furnace room, generally comes out for parties, Canada day, and welcome to being a Canadian citizen beaver rides).
Anyhoo, he didn’t get charged regularly and I think it got left with the charger plugged in but not plugged into the wall for a bit.
Net result is I got one cell on the BMS that isn’t lighting up, this is the manufactures info on the BMS
Measured voltage on the balance leads and that cell is reading at .200v while the rest are at ~3.9, so I think its dead jim.
Need 24v, and has to be capable of kicking out at least 20 amps peak, more would be better as I was occasionally tripping the BMS on this baby when the motors got hot under higher loads.
The motors are 24v mobility scooter motors, brushed, theoretical stall is 12 amps each, but they seem to draw more when they get warm.
You can sometimes recover the dead cells by trickle charging with a bench power supply until it hits the “good” voltage range. But only when you’re standing right there, don’t want anything exciting to happen.
Tried putting it on a 100ma trickle (I am warry about heating it too much), it climbed up to about .7v and I held it there for an hour and it didn’t budge. Dropped back to .2 after I unplugged everything. Am I being too wussy?
I think I might just replace this one with a lead acid, looks like a replacement LiFePO4 is around $500 plus a charger, and I am looking at $140 in batteries and $120 for a charger if I go the SLA/AGM route. Goal would be to rig it so the charger just lives onboard and you just plug the beaver back in whenever hes not moving.
Got the lead acids in, plus an onboard charger hardwired to the batteries so we can just plug the beaver in to the wall whenever its not running around.
I still gotta clean up the wires some, mount those thermal breakers, and make a “so you want to ride the beaver” checklist, but its getting there.
Any suggestions on what to do with a formerly 8 cell, now 7 cell LIFePo4 battery pack and charger?
