Anyone else running LiFePO4 in a motorhome and finding the BMS trips in cold weather?

Picked up a 200Ah Fogstar Drift last spring and it's been brilliant all summer. Now temps are dropping I'm getting the low-temp cutoff kicking in around 4–5°C, usually early morning before the solar's had a chance to warm things up. Annoying when you just want to boil the kettle.

I've got it mounted under the bed with no insulation around it. Wondering if that's the main issue — the space gets pretty cold overnight since there's no heating down there.

Anyone wrapped their battery in foam board or a heat blanket? Seen a few setups using a small self-regulating heat mat wired to a thermostat, but not sure if that's overkill for UK winters or actually necessary. Running a Victron SmartShunt so I can monitor temps, just need to stop the cutoffs happening.

What's your cold-weather setup?

@BatteryRay yes, same issue here with my setup. Worth checking whether your Fogstar has the low-temp charging cutoff or the low-temp discharge cutoff triggering — they're quite different problems with different solutions.

Mine was cutting charging from the solar when the battery dropped overnight, but discharge was still fine. Ended up fitting a small self-regulating heat mat on a simple thermostat from Amazon, runs off a tiny trickle from the battery itself and keeps it above 5°C without much parasitic drain.

Have you got any insulation around the battery currently? Even wrapping it in closed-cell foam made a noticeable difference for me before I went the heat mat route.

Also curious — is yours in an external locker or inside the vehicle? Makes a big difference to how quickly it drops overnight.

@BatteryRay this is pretty much expected behaviour — LiFePO4 cells genuinely don't want to be charged below around 5°C, the BMS is doing its job rather than misbehaving.

On the narrowboat I've dealt with similar. A few options worth considering:

• Self-heating batteries (Fogstar do a Drift version with built-in heating) — pricier but solves it cleanly
• A small DC-DC heater mat under the battery, triggered by a thermostat around 8°C
• Simply not charging until ambient rises — if you're on hookup you can delay via a timer

What's your charging source triggering the cutoff — solar, alternator, or mains? Makes a difference to which solution is practical. Alternator cuts on a cold start are the most annoying to deal with since you can't easily delay them without a DC-DC charger like the Victron Orion in the loop.

@BatteryRay had the same grief in my shepherd's hut last winter. Ended up wrapping the battery in a bit of closed-cell foam insulation — thermal mass does a surprising amount of work overnight when ambient isn't too brutal.

Also worth looking at a small self-heating pad on a thermostat if you're regularly parked somewhere cold. Victron do a decent write-up on battery heating in their docs, worth a read.

One thing nobody's mentioned — check your Victron (or whatever) charger settings. Some profiles will keep attempting charge cycles and hammering the BMS repeatedly rather than just waiting. Better to have it back off until temps rise.