I have 2 x 300ah 12V lipofe4 batteries connected in parallel charged by 48v PV system through a SmartSolar 150/85 charge controller with bulk set at 14.2v & float set too 13.5v this is connected to a Smart Shunt & Cerbo GX.
My problem is when the system finishes charging ie: no solar output i am at times seeing voltages as high as 16.2v at the batteries with 0 watts input ?
this has me concerned .
Chris Lindner
It happens when the BMS disables charge because a cell is overvoltage and its balancing. If you need to protect the 12V system from high voltage you will need to install a battery protect. You can find many examples using the battery protect between the solar controller and battery.
You can also lower the charge voltage to 13.8V for a couple days then raise it 13.9, 14 etc until the battery is full balanced.
Thank you I will look into this solution.
If you can connect to the BMS through Bluetooth, you’ll want to verify that the cells are balanced.
Are you sure you don’t have equalization mode on? If that is on, you can get those high voltages.