Microcontroller-based charge controller for stand-alone photovoltaic systems

Rural electrification using PV systems is widespread in the Third World. Charge controllers are needed to improve the efficiency of the system and to protect the storage batteries with special reference to automotive batteries. An intelligent charge controller, incorporating an SGS–Thompson microcontroller, ST62E20, has been designed with the object of prolonging battery life. The need for and advantages of such charge controllers are discussed. Tests have been performed on a working prototype which is versatile and has provision for more monitoring and control functions than are possible with the conventional logic or relay systems. A photovoltaic charge control algorithm is discussed.