bm6-battery-monitor

Read data from BM6 BLE battery monitors without the invasive app.

Python application

usage: bm6-battery-monitor.py [-h] [--format {ascii,json}] (--address <address> | --scan)

bm6-battery-monitor.py --scan
Address           RSSI
50:54:7B:xx:xx:xx -83

bm6-battery-monitor.py --address 50:54:7B:xx:xx:xx
Voltage: 11.93
Temperature: 24

bm6-battery-monitor.py --address 50:54:7B:xx:xx:xx --format=json
{"voltage": 11.93, "temperature": 24}

Tested on a Linux VM with a USB Bluetooth dongle and a Windows laptop with built in Bluetooth. Have not tested this on MacOS but in theory it should work.

Linux testing environment:

• Ubuntu 22.04
• Python 3.10.12
• bleak 0.22.2
• pycryptodome 3.20.0

Windows testing environment:

• Windows 11
• Python 3.12.5
• bleak 0.22.2
• pycryptodome 3.20.0

ESPHome

Under the ESPHome directory you can find a configuration that will allow you to read your BM6 battery monitor using an ESP32 and ESPHome. This was tested on ESPHome 2024.8.0 and may break at any time...

Reverse Engineering

For details on how I reverse engineered this, see the below post:
https://www.tarball.ca/posts/reverse-engineering-the-bm6-ble-battery-monitor/

Credits

I wouldn't have been able to create this without the following resources:
https://github.com/KrystianD/bm2-battery-monitor/blob/master/.docs/reverse_engineering.md
https://doubleagent.net/bm2-reversing-the-ble-protocol-of-the-bm2-battery-monitor/
https://www.youtube.com/watch?v=lhLff9VACU4