So I've been running a 280Ah LiFePO4 bank in my van since last spring — four CATL cells wired up with a JK BMS (the 200A active balancer version). Worked brilliantly all summer but now we're heading into autumn and I've had it trip out twice this week when temps dropped overnight to around 4°C in the van. Woke up to a dead system both times, had to manually reset the BMS via the app to get it going again.
Looking at the logs in the JK app, it flagged a low temperature protection event. I've got the discharge low temp protection set to 5°C which I thought was sensible for LiFePO4, but I'm wondering if there's a bit of sensor lag or something causing it to trigger slightly above the actual cutoff. The cells themselves were reading 3.28V each when it happened so they weren't low — purely a temp event.
Has anyone tweaked the low temp settings on a JK to deal with this? I don't want to just drop the threshold recklessly and risk damaging the cells charging at sub-zero temps, but 4°C seems daft to be tripping out when the cells are perfectly healthy. I've also seen some chat about adding cell temp sensors rather than relying on the board sensor — is that worth doing on these units?