ESP32 Based Battery Management System with Passive Balancing and Smartphone Monitoring

Abstract

A Battery Management System (BMS) is an electronic system designed to protect batteries from potentially harmfull operating conditions. However, conventional BMS still have limitations in cell balancing, protection, voltage monitoring, and State of Charge (SOC) estimation, which may reduce battery performance and increase the risk of battery damage. This study  aims to design and implement an ESP32-based Battery Management System equipped with voltage and SOC monitoring, overcharge and undervoltage protection, and passive balancing, enabling real-time battery monitoring through a smartphone application. The proposed system was developed using an ESP32 microcontroller and DC voltage divider sensor to measure the voltage of series-connected battery cells. The measured data were processed using the Arduino IDE and displayed on the Blynk application, including battery voltage, SOC, and protection status indicators. The system performance was evaluated through sensor characterization, measurement error analysis, and assessments of the passive balancing and monitoring functions. The experimental results demonstrated that the proposed system achieved a measurement error of less than 2% a relative accuracy of 99%, and a precision of up to 99.8%. Furthermore, the passive balancing function successfully equalized the voltage of each battery cell, resulting in a total battery voltage of 12 V and an SOC of 100% after the charging process. These findings indicate that the proposed system operates effectively in accordance with its intended functions. Therefore, the developed Battery Management System has the potential to provide an effective solution for improving battery safety, extending battery lifespan, and optimizing battery utilization.