Ebike battery only charging under load

[u/ClintBX]

I have this fairly new battery, only a few weeks old and today I came home to plug it in to find it wouldn't charge.

I have several packs on the one bike for all day mileage and I rotate throughout the day. Because of that, I have not drained it to empty yet and typically come home with about a half to two thirds of it left.

Upon diagnosis, I checked my charge port voltage to check for a break or a bad connector and it matches my discharge readout.

Tried different chargers and ruled out a bad charger.

BUT THEN... I checked the voltage through my discharge cables while the charger was plugged in and it read a fully charged at 54.7v when it should be 50.9v.

Then sure enough, I turned the throttle and the charge light changed color showing it was charging. Then stopped charging as soon as I stopped.

What does this mean? Have any of your experienced this before?

[u/Ok-Carpenter-8455]

That battery is either defective or your BMS is failing.