Design and Development of an Automatic Solar Charge Controller

Abstract

As the sources of conventional energy deplete day by day, resorting to alternative sources of energy like solar and wind energy has become essential of the hour. Solar-powered lighting systems are readily available in rural as well as urban areas. These include solar lanterns, solar home lighting systems, solar street lights, solar garden lights and solar power packs. All of them consist of four components: solar photovoltaic module, rechargeable battery, charge controller and load. In the solar-powered lighting system, the solar charge controller plays an important role as the battery’s overall life depends mainly on it. In this point of view, this project presents designing a Solar Charge Controller for the Solar Battery Charging Station with the function to disconnect and reconnect battery and load during battery over charging or discharging. Instead of using readily available microcontroller board (Eg. Arduino), here Arduino microcontroller (Atmega328) has been used to make the system cost-effective. The source code for the Arduino microcontroller is written in Arduino software. Furthermore, to ensure the full charge and to avoid over discharge the SOC of the battery has been properly determined by sensing the terminal voltage of the battery and the charging or discharging current. Normal charge controller has four set-points which are fixed, but here the set-points will be automatically adjusted depending on the level of charging and discharging current. As a current sensor ACS712 hall current sensor has been used. The system has been simulated and practically implemented. Performance study of the system shows that it works properly within the range 10A maximum.