As part of the CBU Motorsports Formula SAE Electric team, I have developed a custom distributed Battery Management System (BMS) designed specifically for high-performance electric racing applications. The BMS is lightweight, scalable, and highly efficient — built from the ground up to support our team's competitive electric vehicle.

The system’s core functions include:

• Voltage sensing
• Current sensing
• Temperature monitoring
• Cell balancing
• Charging management

Architecture and Innovation

The BMS consists of:

• One central controller board powered by an STM32 microcontroller
• Ten slave boards each based on the LTC6811 for high-accuracy cell monitoring

This configuration enables the system to monitor up to 100 parallel cell packs, significantly reducing weight compared to commercial solutions — a critical advantage in race applications.

The controller board handles two main communication interfaces:

• ISOSPI for daisy-chained communication with the slave boards
• CAN Bus for interfacing with the vehicle’s ECU and charger

With over 180,000 lines of embedded C code, the controller supports advanced safety features, system diagnostics, and fault protection, ensuring the integrity and performance of the battery pack in real time.

Each slave board connects directly to the battery cells, handling:

• Cell voltage sensing
• Balancing control via transistor circuits
• Temperature monitoring through thermistor-connected GPIOs, enabling precise thermal protection and preventing runaway conditions

Software: BMS Tool for Live Monitoring

We developed a custom BMS Tool GUI for live monitoring, diagnostics, and debugging. It displays:

• Pack voltage
• Charge/discharge current
• Temperature data
• Individual cell voltages
• State machine and system fault status

This tool is essential for tuning the system and verifying safe operation under dynamic race conditions.

^BMS Controller Board

^BMS Slave Board

^BMS Tool

^BMS Benchtop Test

^Battery Fully Assembled

• High Voltage
• Race Car
• Electric Vehicle
• Ennoid
• Analog Devices
• STM32
• CBU
• Formula SAE
• FSAE
• Battery Managment System