Design and construction of a smart battery charger

This article presents the design and construction of a smart battery charger that ensures efficient, safe, and reliable charging of a 12 V lead-acid battery. The aim is to design and implement a smart charger with adaptive charging algorithms, on-site/ real-time monitoring, and IoT-based remote monitoring. The system used an ESP32 microcontroller to detect battery voltage, adjust charging current, and disconnect the charger once the battery is fully charged. It integrated voltage, current and temperature sensors to prevent overcharging, overheating, and other faults that reduce battery lifespan. An IoT feature enabled remote monitoring and status updates through the Blynk app using Wi-Fi connectivity. The methodology involves an ESP32 microcontroller, buck converter, voltage and current sensors, relay module, LCD, and buzzer. The system operates in constant voltage mode only with automatic cut-off at 14.4V. Testing showed the battery voltage rising from 11.8 V to 14.4 V with a gradual current decrease, confirming correct charging behaviour. Overall, the system provides a practical, low-cost, and intelligent smart battery charger suitable for unstable power conditions.