Introduction
Updated in 2023:
1. The solution described in this post is also suitable for repairing Xiaomi 1S/Essential/Mi3/PRO/PRO2 batteries with minor differences.
2. The newest BMS version has some changes in design, but it almost does not affect the installation process. The only difference is temperature sensors: the old version has 3 sensors, while the newest version is equipped with a single temperature sensor.
3. If you want to make a custom compatible battery, you’d better use a special Happy BMS, which is much more suitable for that purpose.
Xiaomi M365 is an excellent e-scooter, but its weak point is the battery, which can fail for a number of reasons. In the video below I explain how to replace the battery BMS, fixing most of the typical issues at once.
Please remember that good condition of battery cells itself is required for successful repair. This can be checked by measuring voltages: every cells must be between 2.5V and 4.2V, otherwise it is dead and have to be replaced. The dead cells issue can not be sorted out by BMS replacing!
The text below is a short text version for people who prefer reading rather than watch a video. But this text contains only like 30% of information, so I still highly recommend to watch the videos.
Repair process
Throw away all Xiaomi electronics, getting a bare battery assembly
Install the repair board inside
Connect the power wires
Connect the balancing wires
Install the temperature sensors
Wrap the battery back into the film and seal it
Install the battery back into the scooter
All done!
Wiring diagram and user manual
You can download Repair BMS wiring diagram and user manual using the link below:
https://public.embedden.com/Repair_BMS/Docs/English/repair_bms_manual_latest_en.pdf
Here are few screenshots from the user manual:
Parameters setting
Repair BMS makes it possible to configure battery paramentes, such as capacity, serial number, maximum current and many others. The parameters are described in the user manual.
Keep default values if you just repair an original Xiaomi M365/1S/3 battery. But if you repair a PRO/PRO2 battery, then you have to set proper capacity: 12800 mAh.
There is a special application to configure the battery:
Link to the application:
https://play.google.com/store/apps/details?id=embedden.m365.bms.tool
Conclusion
Well, the battery has been repaired and works fine.
Here are the links to the parts I used:
If you like this post, please share it on your social networks and e-scooter communities you belong to. It will really help me to get more customers, grow my small business, and release new cool devices. =)
I also invite you to join my telegram group related to Xiaomi and Ninebot electric scooters, where I share the newest inventions and answer the questions:
https://t.me/m365_custom_electronics_en
Thanks for your attention!
