Product parameters:LiFePO4 batteryCapacity: 15000mah or 15AhMaximum charging voltage: 3.45VNormal voltage: 3.20VMinimum discharge voltage: 2.20VWith BMS: Compatible to solar floodlight and solar streetlights The battery voltage may drop due to storage time Please do not charge in series. And wrong use of positive and negative charging. This will cause battery cell death.