APOLLO S-120AM series is high efficiency stand-alone inverter with MPPT solar charge controller, designed to install independently and controlled the operation by microprocessor. The solar charge controller's function is to charge DC output power from solar arrays to the battery and the inverter's function is to convert DC from the battery into AC electricity to supply to AC appliances. For the charging, it uses 3-step charging method to provide quick and safe charging for the battery and MPPT (Maximum Power Point Tracking) algorithm to extract the maximum power generated by PV array. This stand-alone inverter is suitable for solar home system that can be applied for rural electrification for house, health center and more.