Hacking "JBLTools" Chinese Bluetooth BMS boards

[simat]

Great post. Please can you share details about communication between BMS and PC? I want to make ESP32 display using this BMS.
thank you!

The comms protocol for these boards is explained in this thread

Simon

 

[Chapeau]

I like the idea of a LCD screen for these BMS, probably adding a coulometer. But beware that if you source power from the communication port, the protection circuit will not trigger. I've killed my battery by leaving the FTDI module connected for couple months.

Would you know how much power it's possible to draw from the VCC of the communication port ?

 

[fordtheriver]

I don’t have a max continuous current rating but the amount of current you can draw is very low. My first prototype powered the arduino off VCC and the 5V voltage regulator circuit got super hot. Never actually burnt anything out but it sure felt like I was stressing it. That power rail was just designed to power a bluetooth module so I wasn’t suprised to see it heat up so much. I think I was drawing around 100mA from it when it heated up

 

[Chapeau]

Thank you for your fast answer !

So it won't be a good idea to power a STM32 with a LCD screen from time to time ... I'll add a step down !