IoT-Based Smart Battery Management System with Integrated Charge Monitoring and Fire Protection for Electric Vehicles

Abstract

The shift to electric mobility has made the lithium-ion pack critical to vehicle safety, cost and reliability. Field data show that repeated overcharging, deep discharge and poor heat dissipation rarely fail a pack suddenly; they cause slow capacity fade or, in the worst case, thermal runaway. This paper presents a low-cost Internet of Things (IoT) enabled smart Battery Management System (BMS) with continuous charge monitoring and active fire protection for light electric vehicles. Pack voltage is sensed by a calibrated resistive divider, current by an ACS712 Hall-effect sensor and surface temperature by an LM35. The firmware filters the samples, converts them to engineering units and compares them with configured safety windows. If any limit is exceeded, a ULN2003A driver de-energises a relay in about 1.2 s, isolating the pack while a buzzer and 16×2 LCD indicate the fault locally and an ESP8266 module pushes the values to a cloud dashboard and sends an SMS alert. Tested on a 12 V 7.4 Ah pack over 45 charge-discharge cycles, the prototype held voltage error within $\mathbf{\pm 1. 6} \%$, current error within $\mathbf{\pm 2. 4 \%}$ and temperature error within $\pm 0.8{}^{\circ} \mathrm{C}$, and cleared every injected fault before the pack reached an unsafe state, confirming that a reliable, connected and self-protecting BMS can be built for under INR 3,000.