Modified photovoltaic battery charging system using microcontroller based on resistive control

A novel design for a battery charging system has been developed which is completely dependent on solar energy. The proposed system uses resistive control to limit the output of the converter as voltage or current limit control, combined with the non-linear characteristics of the solar panel, may cause instability in the system. The design uses a back-up battery (Sealed Maintenance Free Lead Acid Battery in prototype) which is charged by the solar panel in times of absence of a load (cell phone) battery and uses the charge stored to supply loads, if any, during times of absence of sunlight, through another buck converter. The performance studies on the prototype of the system indicate efficiencies as high as 36 percent. The system is targeted to be used in public places like malls, railway stations, airports, hotels, etc and for electrification of remote villages through distributed generation.