Anyone else running Fogstar Drift LiFePO4 in a shepherd's hut through winter — how's yours holding up?

Picked up a 200Ah Fogstar Drift back in September, wired it into my hut alongside a Victron SmartSolar 100/30 and a couple of 200W panels on the roof. Summer was brilliant — never saw it dip below 90% SOC.

Now it's properly grim outside (sitting at about 4°C in the hut overnight) and I'm noticing the BMS cutting charge when temps drop below freezing at dawn. Expected that, but I'm losing more usable capacity than I'd budgeted for — running a small 240V inverter for the kettle and a 12V diesel heater, pulling maybe 30–40Ah on a bad day.

Anyone fitted a self-heating solution or just wrapped the battery in insulation and hoped for the best? Wondering if a heat mat on a thermostat is the sensible move or just faff.

@OffGridHamish similar setup in my cabin — Fogstar Drift 200Ah with a Victron 100/20. Winter definitely shows its limits.

Main thing I noticed is charging slows right down once temps drop below about 5°C, which obviously eats into your usable capacity. The BMS cuts charge at 0°C so on genuinely cold nights you can wake up to a battery that's barely topped up overnight.

Got round it partly by insulating the battery box with some old sleeping bag material — keeps it a few degrees warmer than ambient.

SOC sitting around 60-70% most days now vs the 90%+ you mentioned from summer, but it's managing fine for lights and a 12V blanket. Wouldn't push a big inverter load off it in January though.

@OffGridHamish the low-temp cutoff is the bit that catches people out. On the narrowboat I run a Fogstar Drift 200Ah and come January, if she drops below about 5°C overnight in the battery compartment, the BMS is pulling the handbrake before you've even switched the kettle on.

What saved me was wrapping the battery in a bit of closed-cell foam and tucking it somewhere with residual warmth — on the boat that's near the engine bay bulkhead. In a hut I'd imagine underneath the floor or near a wood burner wall might do similar work.

Worth checking your Victron app absorption logs too — mine showed voltage was hitting target but current dropped off sharpish in the cold, which tells you the battery's quietly throttling itself.

@OffGridHamish mine's been in the cabin since last winter now — second season with it and I've learned a few things the hard way.

The bit nobody really warns you about is how dramatically your usable capacity shrinks once ambient temps inside drop below around 5°C before the heating's kicked on. I started logging it obsessively on the Victron app and the difference between a cold morning start and mid-afternoon is genuinely startling.

My fix was wrapping the battery in a thin layer of closed-cell foam and tucking it low in the cabin where residual warmth lingers longer. Not glamorous, but it made a measurable difference — SoC held noticeably better overnight.

What's your charging profile set to? I dropped my absorption voltage slightly over winter and found the Drift responded well to it.

Hey @OffGridHamish — great timing on this thread, I've got a 200Ah Drift in my workshop setup so similar conditions.

One thing worth flagging that I don't think's been touched on yet: insulating the battery itself makes a surprisingly big difference. I wrapped mine in a bit of closed-cell foam last November and the resting temps stay noticeably warmer overnight. Means you're getting more usable capacity on those grey December days when the panels are barely producing anyway.

Also worth checking your absorption voltage settings in the Victron — I dropped mine slightly for winter to be kinder to the cells during the slower, cooler charges. The SmartSolar app makes it dead easy to tweak.

How's your panel orientation? South-facing and tilted steeper for winter makes a proper difference on a shepherd's hut roof. 🙂

Hey @OffGridHamish — good thread! I've had a 200Ah Drift in my shepherd's hut since last February so I've got a full winter cycle under my belt now.

One thing worth mentioning that I haven't seen covered yet — keep an eye on your Victron's absorption voltage as temps drop. I found mine was working harder than needed on cold mornings and tweaking the temperature compensation settings in the VictronConnect app made a noticeable difference to how efficiently the battery was actually taking charge.

Also worth insulating around the battery if you haven't already — not just for the low-temp cutoff protection, but a slightly warmer battery just performs better generally. I used some leftover loft insulation wrapped loosely around mine and it's made a real difference overnight.

What's your typical overnight load looking like? That'll help gauge what to expect heading into January.

Not a shepherd's hut but running a 200Ah Drift on my narrowboat — curious whether the low temperature cutoff has been an issue for any of you? Mine's in the engine bay so stays relatively warm from the engine, but I've noticed on cold mornings after a few days moored up without running the engine it gets a bit reluctant to accept charge below around 5°C.

Worth checking where your battery is actually sitting temperature-wise — not just ambient. Has anyone fitted a small heat mat under theirs? I've seen people recommend it for static installs but not sure if it's overkill for something that's occupied and presumably heated most of the time.

Also @OffGridHamish — what's your panel orientation like? Wondering if you're losing more to shading/angle in winter than the battery itself is causing.

Got the same 200Ah Drift in my motorhome and static van — both fine through winter so far, but I'm watching the low temp cutoff like a hawk once we hit proper sub-zero nights.

One thing nobody's mentioned: keep an eye on your SmartSolar charge settings. Mine was still trying to bulk charge at 2°C until I adjusted the low temp cutoff in Victron Connect. The Drift won't protect itself from incoming charge the same way it handles discharge.

Worth double-checking @OffGridHamish. Could explain any weird behaviour you're seeing.

Running a Drift on my narrowboat — similar boat to @BoatGemma I suspect. The low temp cutoff has triggered twice this winter when the cabin cooled overnight. Not a disaster, but worth knowing your Victron MPPT won't just override it; it'll simply see the battery as unavailable and sit idle until temps recover.

What I'd suggest: check your BMS threshold in the Fogstar documentation — it's around 0°C for charge cutoff. If your hut drops near that regularly, some basic insulation around the battery box makes a measurable difference. Mine's wrapped in 25mm Armaflex and hasn't cut off since.