Wellll, no dice... New thermistors in, board on the balcony for a few hours at +6 C and almost immediately triggered the same fault. Battery temp at that moment +11 C.
If anyone has some more pointers or measurements to take to narrow it down, please let me know. I'll be disassembling it again today or tomorrow :(
Also, any working BMS on offer?
Thanks!
@lia thanks for the thorough reply! Too bad I've already reassembled the battery box, and will be assembling the board first thing tomorrow. Then it'll hopefully be dry & cold enough to test it.
If the issue persists, I'll tear it down once again and take some good pics, and also perform the measurements you mentioned.
I do vaguely remember measuring the thermistor resistances from the BMS (the legs of the white connector) when the battery was attached, and remember seeing slightly varying results, between 4 and 6 kOhm at room temperature. Just found it odd at the time because it was way lower than the specified 10 kOhm but didn't think much of the difference... As soon as I removed the plug and measured straight from there, they were around 10 kOhm as specified.
I'm from eastern Europe where the OW isn't really popular so my best bet will be finding one online - maybe someone happens to have one which will fit my board? I'd happily take it even if just as a backup.
Hey!
I have a CBXR which is exhibiting identical symptoms. Outside temperatures around 6 C or lower and the board starts throwing error 17, even though diagnostics show battery temp around 15-17 C.
I have measured the resistance of the thermistors and they seemed fine-ish (between 10.2 and 10.3 kOhm at room temperature), but I went ahead and installed a new set of thermistors anyway. I have yet to test it out as the glue is still drying.
Here they are visible after plucking them out of the pack. It was strange to find them just hanging there, without actually being attached to anything, and covered by a thin layer of tape. I've decided to glue them to the cells to get a more accurate reading.
But I am still hesitant that this will fix the issue.
Is there a known problem with the BMS where its internal resistance becomes too high with cold weather that it triggers the fault itself, even with working thermistors?
Anything else I could check?
The board is a 4209 without a chip. Battery is around 4 years old and I am a new owner. Previous owner said he has never ridden in weather colder than 15 C ambient...
Thanks for any input!