Due Dates:

• Schematic - 9/27/25

• Layout - 10/4/25

• Rev. A Ordered - 10/13/25

• Firmware/Testing - 11/1/25

Description/Purpose

• The BPS Leader monitors the status of all 8 VoltTemp boards, the Amperes board, an on-board temperature/humidity sensor, and ESTOPs to determine whether the HV+ and HV- contactors are safe to close (to energize the high-voltage system). In addition, control battery fans and indication board.

Requirements

• Uses an LSOM for MCU and CAN circuitry → connects to both CarCAN and BPS CAN

• Control and sense status of 4 contactors: HV+, HV-, Array, and Array Precharge

• Reads precharge resistor voltage into ADC from precharge board

• Control 2 fans using fan control IC from pump board

• Uses an ESP32 for debugging and remote flashing of STM32 on LSOM

• Drive LEDs on indication board to display battery status

• Read the status of 3 discrete emergency stop buttons - these should be in series with the contactor drive signal to open contactors when the button is pressed

• CAN stub for both CarCAN and BPS CAN - to allow charger & rear boards to connect to CAN buses

• Strobe light connector on board - normally this will just be a CAN message to the lighting board, but we need a way to show the strobe when the shell is off at scrutineering

• Measure temperature/humidity inside battery box using SHT45 sensor

Application Note

Context

Location of the board: Battery Box

Connection List

Main

Schematics

Open

Main Schematic page

Open

ESP Circuit

Open

Fan Control Circuit

Open

RPP (theoretically) Circuit

Open

Contactor Control & Sense Circuit

Open

Onboard LED Shiftreg Circuit

Open

Indication Board Connection (24V to 5V Buck) Circuit

Circuit Components

Layout

Github link:

PCB:

Open

3D Model

Open

Firmware

Drivers

High-Level (Block Diagram)