Automatic Solar Battery Charging System with Grid Backup

The increasing demand for sustainable and uninterrupted power supply has driven advancements in hybrid energy systems. This paper presents the design and implementation of an Arduino-based intelligent power switching and monitoring system for solar and grid hybrid energy sources. The system utilizes a solar panel to charge a battery through a charge controller, while also integrating grid power as a backup. A voltage sensor is used to monitor the battery level, and an Arduino microcontroller is employed to control a relay module, which intelligently switches the load between solar and grid power based on predefined thresholds. The LCD module displays real-time system status, enhancing user interaction. Additionally, a battery charge adaptor is included to ensure backup charging when solar input is insufficient. This system optimizes the use of renewable energy while maintaining uninterrupted power supply to the load, making it ideal for smart homes, rural electrification, and energy-efficient applications. Experimental results demonstrate reliable switching behavior and effective power utilization, validating the system’s practical viability.