52V Battery wont charge past 80%

My 52V 13.5ah shark battery cant seem to get charged past 80%. Stops charging at 55.7 everytime. I have the Luna mini advanced charger. It was a switch to select 80-90-100% charged. Doesnt seem to make a difference which percentage setting I have it on. Maybe its just the switch?

I have been riding my bike for a week now. I thought I had been balancing my battery. Should I stop using the bike? Worried I may have weakened my battery.

Thanks!

That happened to me and it was the switch on the charger. Do you have a spare to try?

No that would be ideal. Trying to find one locally but its a bit of a longshot. I am hoping thats it, charges to exactly 80% consistently.

Sadly chargers are one of the items we should always have a backup for IMO. Especially those Kingpan selectable percentage of charge units. Chances are better that it's the charger not the battery.

On my current selectable setting charger the selection switch needs to be set before the unit is plugged in. 100% is the down position. Try unplugging then set the switch then plug in to battery and power see if it works like mine.

Measure the voltage of the charger when it's not connected to the battery. Measure the voltage again, when the charger is connected to the battery.

The voltage should be about 58.8V in the max setting when not connected to the battery. If the voltage drops to around 55V and stays there, when it's connected to the battery, then that suggests a charger issue. If the voltage is around 58V on the connected charger, yet battery is only around 55V once charger is removed. then that suggests a battery issue of some sort.

Good to have a cheap 2a charger for back up.