I’m using the charger WW supplied with the bikes. WW currently doesn’t have replacement 52v batteries and don’t know when they will get any. I was willing to pay full price for them just because the monetary loss on the bikes is far greater than the cost of the batteries. I’m not a fan of rebuilding batteries so that’s not an option either. I’m considering parting the bikes out and just be done with the whole situation.Not sure if WW is using the same company here in CA, but when my first battery was damaged in shipping the 'new' battery they sent had blue painters tape over a crack in the case and scratch evidence showed it was used.
Six months later I was curious, so I checked the first battery. At first it seemed dead, display would not come on. I checked w/ a meter and it was live. Close inspection showed one of the plastic, bottom end nubs was damaged. I sanded it a bit, reinstalled and it worked.
It was 52v - near 60% charge.
The odds against two battery's in a row having a bad cell are up there with two damaged in shipping.
What are the odds of two batteries in a row with a bad BMS or having a voltage leak ???
Could this be your charger? Overvoltage damaging a cell? I'd think by now you'd know if that was it.
TPEHAK or evixone would be sources of reliable information, but I assume you resolved the matter.