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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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UVP Doesn't recover #8

Open ryci-us opened 5 years ago

ryci-us commented 5 years ago

Hi,

I have custom made battery in 12s3p configuration. Today when i was going home i totally discharged my scooter battery and UVP protection engaged. I came back home and connected charger - i was not charging. I let it sit for 2 hours and it didn't started to charge. So i removed cover, measured voltage between B+ ant B- ant it was 39,6V. So i disconnected/connected balancing connector and it started to work. Looks like that UVP doesn't automatically recover from fault. Can you fix it?

After unplugging/plugging balancing wires i also noticed that full charge/ charge count counters was also reset to 0.

Bye the way i would like to thank you for great project :)

BotoX commented 5 years ago

By unplugging / replugging the balance connector your reset the MCU, thus the data got lost and also the issue you were having was fixed. It would've been interesting which exact error condition was triggered so that the charging port was disabled. If this happens again please paste the full output of debug_print()

ryci-us commented 5 years ago

Ok, i will do that. At this time i had a mind to check what is going, but i left my USB-TTL adapter at work :(

About counters: maybe i would be better idea to write these counters to eeprom each time charger is plugged in? Atmel states that atmega328 eeprom endurance is 100,000 write cycles, so bms can outlive a lot of battery packs.

BotoX commented 5 years ago

I write the data every time the cycle counter is increased.

BotoX commented 5 years ago

Could be fixed by the latest commit.

ryci-us commented 5 years ago

I didn't updated firmware, today i had same issue again. This time again i didn't had USB-TTL adapter, but this time with M365 Battery inspected all parameters, and i think i found what protection i have triggered, it was Over Temperature, because temperature was 44 and 46C. Then battery dropped temperature to 24/24C charging was not enabled.

BotoX commented 5 years ago

I'd suggest you to flash to the latest firmware, I fixed a few things that might cause this. If it still happens then I'll investigate this further, never happened to me but it's not that hot here.