You sure about that? Did you measure the charger voltage with a multimeter?
Can you also measure the voltage of each p pack to check they are all at 4v
With the chargers the voltage usually needs to be slightly higher then 25.2v when not under load. That way when load is connected the voltage can drop a little bit.
I think that is what’s happening here have you tied just leaving it plugged in for a few hours
It will usually be quick to charge up to around 4v and then the rest will take a while because the voltage slowly drops off as the battery becomes charged
the charger led works based on power draw. it can be posible the charge is going so slow that it cant triger the charging led while still rising the cell voltage.
It could also, as stated, be due to a bit of power loss on the bms, in whic case you would need a hguer V charger, but honestly 1.2V is to much of an acceptable power loss in a bms. If time doesnt fix this and other chargers have the same issue try witth the bms
since I dont have another bms, should I just disconnect the balance leads and plug the charger in? I’d keep tabs on the cell voltage so it doesnt overcharge one or the other…
If I did it this way, the charger + would be going to the battery + and the negative going to bms, then bms to batt negative. Which I dont think should mess anything up when balance leads are disconnected, just shouldnt balance.
I recommend hooking up a multimeter in current mode and directly measuring the current output of the charger. That way you know exactly what it’s doing. If current flows, it’s probably a BMS issue. If there’s no current, it could be the charger or the BMS.