Custom Battery Management System (Master Board)

January 1, 2026

Description and Purpose

The Master BMS is a custom board designed to replace an off-the-shelf battery management system, such as 2025's Orion BMS. It works in tandem with a Distributed BMS board which directly connects cell data and communicates with a Teensy4.1 microcontroller on the Master BMS via ISOSPI.

Schematic Overview of the Master BMS

Design Elements

The Master BMS is a multipurpose board to promote simplicity and reduce the number of PCBs on the vehicle.

As such it includes the following core elements:

  • Precharge circuitry
  • Discharge circuitry
  • ISOSPI communication
  • VCU (Vehicle Control Unit) communication
  • Integration within a broader shutdown circuit
    • Includes signals to the main interlocks
  • Energy meter communication (For rules compliance)
  • Tractive System Monitoring Points (For rules compliance)
  • High voltage indicator light circuitry
  • Ready to move light circuitry
  • IMD (Insulation Monitoring Device) communication

Due to the high and low voltage nature of this board, it features galvanic isolation between low and high voltage circuitry, as well as proper creepage and clearances for high voltage signals and components.

PCB View of the Master BMS Board Schematic Overview of the Master BMS

The Master BMS board measures at 180mm x 220mm and is designed to be mounted within our Tractive Battery penthouse.