rhizomatic said:
A friend has a Polaris Strive, and it needs a new charger. It was working fine, I am told. The charger no longer lights up. It appears to have died. Battery pack still shows roughly 27 volts charge and the indicator calls that "low." New these bikes had a few battery configurations. I was assuming this was the unusual 8s 29.6v variety. However, the charger is on brand (evantage) and rated output 52v and 2 amps, which seems like a 48volt battery charger. I think there were some Polaris Strive 48 volt bikes, but not sure. Is this a 48volt version of the Strive?
If the charger is 52v, then the battery would have to be 13s, which is very dead at 27v, no longer safe to charge at about 2v per cell, if that's the voltage at the actual battery pack inside, and not just at the BMS output.
If it's at the BMS output, then you should measure at the input of the BMS, where the main wires come off the battery pack, and/or at the balance wires to the cells, to make sure the cells are all more like 2.8v or higher, before trying to recharge it. Often when a BMS shuts off to protect a pack, there is leakage voltage at the output, which looks like a much lower voltage than what the pack is actually at. When this happens, even a tiny load will collapse this "false voltage" to zero, which is normal.
If the pack itself is ok, then you can plug in the charger to the wall, and measure the charger output to make sure it's not working. I recommend checking it not just at the cable output, but at the board inside it. If there's voltage at the inside but not at the output end, theres probably just a broken wire. If no voltage inside either, then it's possibly dead. You could check for a fuse, just in case.
If it's dead, then to replace it you can get any Li charger that is rated the same as this one, but you will need to move the output cable from the old one over to the new one.
