OptiMATE Lithium 4s 0.8A, TM-471, 8-step 12.8V 0.8A sealed battery saving charger & maintainer Longer battery life and more battery power guaranteed. Ultimate protection for your high-performance Lithium (LiFePO4 / LiFe / LFP) battery. Saves dead batteries other chargers can't! BMS (Battery Management System) wake up mode safely wakes battery with integrated BMS protection out of sleep mode.