Renogy 40 Amp Commander MPPT Solar Charge Controller Advanced maximum power point tracking technology with high tracking efficiency up to 99%. Multiphase synchronous rectification technology ensuring peak conversion efficiency up to 98%. Reverse protection: Any combination of solar module and battery, without causing damage to any component. Electronic protection against overcharging, over-discharging, overload, and short circuit. This controllers default battery parameters are set to Sealed Lead Acid. In order to adjust the parameters, Renogys MT-50 Meter will be needed.