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BotoX / xiaomi-m365-compatible-bms

Xiaomi M365 compatible, open source firmware for ATMega328p+BQ769x0 BMS. Ninebot in proto_test branch

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Development of Bafang UART BMS

iamniels opened this issue · comments

commented

I read your request here https://endless-sphere.com/forums/viewtopic.php?t=99137 and was wondering whether you are still interested? 2nd hand market places here in Europe are filled with "defect" Bafang batteries, because the BMS gives up, while (most of) the cells are fine.

I'm an electrical engineer, but it would be my first time reverse engineering a foreign protocol, so I can use some help :-)

commented

The protocol should be easy enough that I can reverse engineer / implement it in this BMS firmware.
I've already written a parser/proxy for the bafang protcol on esp32, to implement on the fly programming.
Code here: https://git.botox.bz/BotoX/bafang-esp32

If you have access to bikes/batteries that talk this bafang battery protocol I'd love to get a communication dump.
Serial converters and logic analyzers are still cheap and plenty from aliexpress.

fyi. Serial on my BBSHD/DPC18 is using 1200 baud 8N1

commented

9600 baud 8N2. See the attached file. I have called one line BikeTX, because BatteryTX comes shortly after BikeTX.

One capture: Packet.txt

Is this enough?

commented 
[0x3A, 0x16, 0x0F, 0x01, 0x00, 0x26, 0x00, 0x0D, 0x0A]
[0x3A, 0x16, 0x0F, 0x04, 0xF5, 0x12, 0x00, 0x00, 0x30, 0x01, 0x0D, 0x0A]

[0x3A, 0x16, 0x09, 0x01, 0x00, 0x20, 0x00, 0x0D, 0x0A]
[0x3A, 0x16, 0x09, 0x02, 0x39, 0xA9, 0x03, 0x01, 0x0D, 0x0A]

[0x3A, 0x16, 0x0A, 0x01, 0x00, 0x21, 0x00, 0x0D, 0x0A]
[0x3A, 0x16, 0x0A, 0x02, 0x00, 0x00, 0x22, 0x00, 0x0D, 0x0A]

This is definitely not part of the Bafang BBS protocol, looks like Kingmeter 901U to me:
https://github.com/jenkie/Arduino-Pedelec-Controller/blob/master/Arduino_Pedelec_Controller/display_kingmeter.cpp#L268

https://github.com/EBiCS/EBiCS_Firmware/blob/master/Src/display_kingmeter.c#L351

Or this "NCM Venice" / "C7 Display"
https://www.pedelecforum.de/forum/index.php?threads/kommunikation-zwischen-c7-display-und-motorkontroller-ncm-venice-das-kit.57050/
https://www.pedelecforum.de/forum/index.php?threads/kommunikation-zwischen-c7-display-und-motorkontroller-ncm-venice-das-kit.57050/page-11#post-1710403

commented

Thanks for those links! it is a Bafang M420 controller.