Anyone else had grief with JK BMS dropping cells during cold weather?

Finally got round to wiring up my 280Ah LiFePO4 bank last month — four EVE cells in series, 12V setup, JK BMS (the 2A active balancer version). Works an absolute treat in the workshop but I've been leaving it in the van overnight and now that temps are dropping I'm getting random low-voltage cutoffs on cell 3. Pulled the logs this morning and it's hitting 2.8V before the BMS trips, while the other three are sat comfortably above 3.2V.

I'm fairly sure it's a contact or internal resistance issue that only shows up when it's cold — probably around 4–5°C in the van overnight. Connections are all torqued to spec (4Nm on the EVE terminals), busbars are nickel-plated copper, so I don't think it's a loose joint. Wondering if I've just got a duff cell or whether the JK BMS itself can throw phantom readings in the cold.

Has anyone else seen this with EVE cells specifically, or with the JK BMS? Keen to know whether it's worth doing a proper capacity test on cell 3 individually before I go chasing my tail on the BMS settings. Got a Juntek KG-F150 I could use for discharge testing if that helps.

@Tommo10 yeah, LiFePO4 gets grumpy below about 5°C — charge acceptance drops off a cliff and the JK will protect itself by disconnecting. Not a BMS fault, it's doing exactly what it should.

My setup in a uninsulated outbuilding had the same issue last winter. What actually sorted it was wrapping the battery box in 50mm celotex and adding a small self-regulating heat tape under the cells, wired to a cheap STC-1000 temperature controller. Keeps the bank above 8°C overnight for minimal power draw.

Also worth checking your JK app — there's a low temperature charge protection threshold in the settings. Some units ship with it set aggressively high (10°C+). You can nudge it down carefully, though I wouldn't go below 3°C with EVE cells.

Don't expect Renogy's support docs to help — they're useless for anything nuanced.

@Tommo10 had exactly this in my motorhome last winter — parked up overnight in Wales, woke up to the JK showing one cell at 2.8V while the others were fine. Turned out it wasn't actually a dodgy cell, the sensor was just reading cold-skewed.

Worth checking whether your BMS is triggering on under-voltage or temperature protection specifically — the JK app logs both and it's easy to miss which alarm actually fired.

Also, are your cells insulated at all? Even wrapping the battery box with some cheap camping mat foam made a noticeable difference for me. Not a fix exactly, but stops the temperature swings being so dramatic overnight.