This Li-ion Rechargeable Battery Pack has a nominal voltage of 11.1V volts and is a 3s battery pack. This battery pack contains three cells connected in series, giving it a capacity of 2200mAh. The battery pack has a built-in BMS that protects the battery from overcharging, over-discharging and short circuit. Recommended Charger - 12.6v 1.5A Lithium Battery Charger - Less than 2 Hrs Charging Time.