FESB Racing: Battery Monitoring & Safety

BMS MASTER

Our battery monitoring system is built around a master-slave topology, with the master PCB serving as the main control unit for the entire accumulator. At the center of the board is an STM32F446 microcontroller, which provides the processing power and communication interfaces needed to handle multiple real-time tasks. The master is in charge of collecting and processing cell voltage and temperature data, keeping track of the accumulator current, and running the control routines that ensure safe and efficient operation.

Beyond that, it also takes care of cell balancing, making sure the cells stay evenly charged to extend pack life and maintain performance. It handles communication with higher-level vehicle control units, carries out fault detection and protection functions, and coordinates the activity of the BMS slaves without relying on them for critical decisions. With all of these tasks centralized, the master becomes the core of the system, tying together data acquisition, monitoring, and control into one reliable platform.

VOLTAGE INDICATOR (VI)

Voltage Indicator (VI) is a key safety system on our electric vehicle. Its function is to activate a visual indicator on the vehicle when the voltage on the Tractive System (TS) exceeds or reaches the threshold of 50 V, signaling a potential electrical hazard.

One of the main challenges in designing this circuit was ensuring its power supply across a wide voltage range—from 5 V all the way up to 500 V. We solved this problem by using the RM9003B, which enables a constant current supply to the circuit at voltages up to 600 V. For voltage detection and indicator control, we implemented a simple circuit consisting of a voltage divider and a zener diode on the MOSFET gate, achieving reliable and efficient indicator activation.

For more information please visit the FESB Racing website.