Tesla Pack Monitor – Project Guide

1 Mission

Create a portable, self-contained tool that plugs into a Tesla battery pack, reads live brick voltages and temperatures, and clearly shows imbalance and health — all without needing a laptop on site.

Short-term (v1 – working device)

Wake the pack and talk to the BMS over CAN

Read all 96 brick voltages and 32 temperatures via message 0x6F2

Calculate imbalance and highlight the weakest modules/bricks

Show results on the built-in 2.4" screen using physical buttons

Work standalone — no phone or computer required on site

Optionally generate a simple text/CSV report

Longer-term potential

Better diagnostics

Per-brick CAC estimates, historical trends, clearer fault interpretation

Web dashboard

SoftAP mode so you can view live data on a phone browser when desired

Multi-platform

Support newer Tesla packs (Model 3/Y, Raven) with profile switching

Reporting

Generate TPM-style PDF/text reports for records or resale

2 Current Status

Overall progress to first working device ~35%

What is already done

Done Hardware selected and ordered (Radxa, CAN HAT, display, buttons, enclosure, BMS connector)
Done Core data model (Pack → Modules → Bricks)
Done 0x6F2 decoder for brick voltages + temperatures
Done CLI summary tool with demo data
In progress CAN log file support (via Cursor)
Done GitHub repo + local development setup

3 Roadmap to a Working Device

High-level sequence from today to a fully usable standalone tool.

1

Project foundation Data model, decoder, CLI, GitHub repo, local dev environment
2

Log file support + better testing Load real or captured CAN logs, refine decoding against real data
3

Hardware arrives & assembly Build the enclosure, wire display, buttons, CAN HAT, and BMS pigtail
4

OS + SocketCAN on Radxa Boot the board, configure CAN interface, confirm 0x6F2 frames appear
5

Live CAN integration CLI (and later UI) reads live data from the pack instead of demo/logs
6

Display + button UI Simple menu system on the 2.4" screen controlled by external buttons
7

First full standalone test Plug into the real 2015 85D pack, wake it, read voltages, view on screen
8

Polish & report output Cleaner UI, saved reports, optional SoftAP web view

4 Near-term Focus

Right now the priority is software that can be developed offline.

Finish CAN log file support (in progress with Cursor)
Optionally improve the CLI (JSON output, focus on weak modules)
Prepare the SocketCAN listener skeleton so it’s ready when hardware arrives
Assemble hardware as parts come in
Bring up the Radxa + CAN HAT and capture first real frames

Hardware and software are progressing in parallel. Most of the hard decoding work is already done — the remaining software is mainly about connecting the pieces and building the UI.

5 Quick Reference

Repo

github.com/mikesudyk/tesla-pack-monitor

Run the CLI (demo)

PYTHONPATH=src python3 -m tesla_bms

Key CAN message

0x6F2 — 96 brick voltages + 32 temperatures

Target pack

2015 Tesla Model S 85D (Classic architecture, 16 modules)