Can I charge LiFePO4 below freezing?

@Lefty72 Right, Scotland in winter—respect for that. I've been running a similar setup in the van and learned this the hard way.

The BMS cutoff is there for a reason: lithium doesn't like charging when cold. Charge it below 0°C and you risk lithium plating on the cells, which degrades capacity and can eventually cause internal shorts. Not worth the risk.

What actually worked for me was passive insulation round the battery box—decent foam panels and a reflective barrier. Keeps ambient swings from hitting the cells directly. On really cold nights, I'd run a small heating pad on a separate low-amp circuit, just enough to creep the battery temp above that 0°C threshold before charging.

The Fogstar manual will tell you the exact cutoff point (usually around 5°C for charging, 0°C for rapid). @DevonDweller's right that there's no safe workaround that bypasses the BMS.

Your Victron should be reporting the battery temperature anyway—worth checking your logs if you've got the MK3 interface set up. That'll show you

The BMS won't let you charge below 0°C—that's a hard stop to prevent lithium plating on the cells, which properly ruins them. No way around it without disabling protections, which is a terrible idea.

What actually matters for winter wild camping is discharging at low temps, which LiFePO4 handles fine. Your real problem is keeping the battery warm enough to accept charge.

I've got a 300Ah Fogstar in my van setup, and what works is passive insulation—decent thermal blanket around the battery box. If you're running a heater or any decent load, the battery heat-soaks enough during the day to take a morning/afternoon charge window. Victron's battery monitor will tell you the actual temp anyway.

If you're genuinely stuck in sub-zero for days with minimal solar, you might need to accept slower charging cycles or look at a small heating pad (12V), but honestly most van winters in Scotland don't sit at -5°C constantly. The bigger issue is your solar panels icing over.

What's your charging setup? Solar only or are you running an alternator too?

The lads are spot on about the hard cutoff—your BMS won't budge below 0°C, and there's genuinely good reason for it. Lithium plating isn't just bad for performance, it can create internal shorts that turn your battery into a fire hazard.

What they haven't mentioned yet is the practical workaround: passive heating. I've got a Victron SmartBMS on my setup and paired it with a basic 100W silicone heating pad wrapped around the battery casing (controlled via a simple thermostat, roughly £30). Not elegant, but it keeps the cells above freezing without draining much—maybe 2-3% of your 200Ah over a cold night.

Alternatively, if you're van camping, the thermal mass of the battery itself plus any ambient heat from the van usually keeps it above freezing unless you're properly cold. Just avoid parking in direct wind if possible.

The real question is discharge—you can discharge LiFePO4 below 0°C without damage (unlike charging), but capacity drops significantly. Scotland winter means you'll be looking at maybe 60-

Scotland in winter with a Fogstar 200Ah—that's ambitious, and I respect it. @RayWatson81 and @RetiredSquaddie have nailed the technical bit about the BMS lockout, but here's what I've learned the hard way with my own setup.

The real problem isn't just the charging cutoff—it's that your battery capacity absolutely tanks in cold. I've got a similar Victron system in the shepherds hut and noticed my usable capacity drops by about 40% when it dips below 5°C. Charge it whilst it's warm, let it cool down afterwards, and you'll be fine. But trying to charge a genuinely frozen battery? The BMS will just reject it flat.

What actually saved my arse was insulation. Built a simple foam box around mine with a 12V heating pad. Sounds overkill, but when you're wild camping and the temperature's dropping to minus numbers, keeping that battery at 5°C minimum means you've actually got usable power.

Also worth mentioning—discharge rates suffer too in the cold. Your Victron's MP

Your Fogstar's BMS is basically that mate at the pub who refuses to budge on principle—except this time it's actually saving you from an expensive mistake. Below 0°C and you're looking at permanent capacity loss that no amount of sunny days will fix.

Wild camping in Scottish winter though? Chuck a heated blanket around the battery (properly insulated box with a 12V heating pad) and suddenly you're the genius who thought ahead instead of the bloke with a brick for a battery come spring. Victron's monitoring will tell you exactly when you're getting dodgy, which is half the battle.

Realistically, keep the van moving enough to generate some heat into the pack, or accept you're in "emergency backup only" mode until March.

The BMS won't let you charge below 0°C—that's a hard stop, not a suggestion. Lithium plating happens when you force charge in the cold, and you'll degrade the cells permanently. Not worth it.

What you can do: keep the battery insulated. I've got mine wrapped in a Fogstar thermal blanket in the caravan, and it makes a measurable difference—you're retaining heat from the Victron's conversion losses and the van itself. Even passive insulation buys you several degrees.

If you're serious about wild camping in Scotland winter, consider a smaller lead battery for auxiliary loads (fridge, lights) and reserve the LiFePO4 strictly for high-draw stuff like heating or the EV charger when you've got proper shore power. That way the battery isn't constantly cycling in the cold.

Also—what's your charging source? If you're relying on solar panels in Scottish winter, you'll struggle regardless of the battery chemistry. Might be worth planning around a generator or hookup sites for top-ups.

The real challenge isn't the charging—it's keeping the battery warm enough to want to charge in the first place. I learned this the hard way with my Fogstar during a January trip to the Scottish Borders with the shepherds hut.

What worked for me: immersion heater running off solar during daylight, and wrapping the battery box with rockwool insulation. Sounds daft, but that thermal mass makes a genuine difference. You're looking at maybe 15-20W of heating to keep things above 5°C, which is entirely manageable if you've got decent panel coverage.

@BlownFuse is right about the BMS being obstinate—the Fogstar won't budge below 0°C, full stop. But here's the thing: if you're wild camping, you're probably not needing rapid charging. Trickle charge it during the day when it's warmer, and your Victron setup should handle that fine.

The bigger question is whether you've got enough insulation round the whole lot. Cold batteries lose capacity anyway—expect 30-40% range loss at freezing. Plan your

The Fogstar BMS will lock you out below 0°C—that's your real headache in a Scottish winter van. @BlownFuse is spot on about lithium plating, it's not worth the risk.

What actually works: stick a heated blanket or thermal wrap around the battery before you head north. Keeps it in the sweet spot (10-25°C ideally) without much draw. I use a cheap 12V heated pad from Amazon, thermostat-controlled—pulls maybe 5-10A when it's really cold but you're not running it constantly.

The Victron MultiPlus will help generate some warmth via charging efficiency losses, but don't rely on that alone in deep winter. You'll also want to pre-warm the battery with whatever heating you've got before you actually try to charge it.

Honestly, if you're wild camping for weeks, consider dropping the charge to 80% and keep it there. Reduces stress on the pack in cold conditions anyway. Fogstar's built solid but that BMS is conservative for a reason.

The lads have nailed the core issue—your Fogstar's BMS will hard-lock charging below 0°C to prevent lithium plating. Non-negotiable, that one.

Where it gets practical though: you're not actually stuck. I've done similar trips and the trick is thermal management. Your battery generates heat during discharge (even inefficiently), so insulate it properly. Decent foam wrap or a purpose-built battery box keeps residual warmth in. More importantly, run your heating and lighting before you need to charge—that load generates heat that warms the battery back above freezing.

If you're genuinely stuck in prolonged sub-zero temps, a small 12V heating pad (controlled by your Victron) works, but it's a drain spiral you want to avoid. Better bet: plan your high-draw activities for the afternoon when ambient temp peaks, charge then, and let the battery rest insulated overnight.

The real win? Scotland's winter rarely stays below freezing all day. You'll get your charging window. Just can't force it during the overnight dips.

What's your current insulation setup in the van?

The lads are spot on about the BMS lockout, but there's a practical workaround worth considering if you're serious about winter wildcamping.

You can heat the battery itself without heating the entire van—a silicone heating pad wrapped around the cells with a simple thermostat (£15-20 from Screwfix) will keep the LiFePO4 above ~5°C, which is the typical threshold where most BMS systems allow charging again. Won't cost you much in amp-hours either; a 50W pad draws maybe 4-5A at 12V, only running intermittently when the battery temperature dips.

The real consideration is why you're charging below freezing. If it's just topping up from solar during winter days, you might find the battery won't accept charge anyway because your panel output will be pathetic in December Scotland—the heating pad becomes irrelevant. But if you're planning to run a portable charger or generator, then yes, the heating pad approach makes sense.

I'd honestly suggest monitoring your actual winter usage first. Most nomads find their consumption drops dramatically when stationary in cold

The Scottish winter van life—bold choice. I've been through this headache on the narrowboat, actually. That BMS lockout isn't negotiable, but here's what actually worked for me:

Pre-warming the battery itself before charging is the move. Sounds fussy, but grab a basic 12V heating pad (the kind used for reptile tanks, about £15) and wrap it round the Fogstar casing. Run it for 15-20 mins before you start charging—gets the cells up to operating temperature without stressing them. Your Victron MPPT will sit there twiddling its thumbs until the BMS stops being grumpy.

The second layer: keep your battery insulated in the van. I used 50mm Celotex round mine in the engine bay on my old narrowboat and it made a measurable difference to overnight temperature stability. Heat loss is your real enemy.

Don't try the "warm it with load then charge" trick either—I've seen that wreck cells faster than you'd think.

What's your current van insulation like? That matters more than most people realise for

Your Fogstar will absolutely refuse to play ball below freezing—that BMS lockout is there because lithium plating is basically the battery equivalent of a bad divorce, expensive and messy. But here's the thing: if you're serious about Scottish winter wildcamping, stick a heated blanket around it (or even just some decent insulation + a small 12V heater triggered by a thermostat) and you'll keep it in the happy zone whilst barely denting your solar harvest. Alternatively, pre-charge during daylight when temperatures are less catastrophic, or run your alternator whilst parked up. The motorhome lot do this all the time—it's tedious but beats watching your expensive battery become a very expensive paperweight.

Ah, this is exactly the situation I was worried about when I spec'd my setup for the garden office—figured winter camping would be even trickier.

Question for the folks who've actually done this: has anyone successfully used a battery blanket or heated enclosure to keep the Fogstar above ~5°C? I'm wondering if a simple insulated box with a low-watt heater (powered by your alternator whilst driving) would be practical, or if that's just adding complexity you don't need.

@KangooNomad and @MarineOllie seem to be saying the BMS lockout is unavoidable, but I'm curious—is the lockout temperature consistent across brands, or does Fogstar's implementation differ from, say, a Victron LiFePO4?

Also, would you be better off downsizing to a smaller LiFePO4 that you can genuinely keep warm, rather than having 200Ah sitting there doing nowt? Seems like capacity you can't access isn't really capacity at all in a Scottish winter.

Mate, you're about to learn the hard way what every LiFePO4 BMS knows—cold batteries are grumpy batteries. That Fogstar won't charge below 0°C, full stop. It's not being difficult, it's literally protecting itself from lithium plating which turns your shiny new pack into an expensive paperweight.

Scotland in winter

Your Fogstar won't charge below 0°C—BMS will lock you out properly. Heat tape wrapped round the battery with a Victron relay triggered by temperature sensor is the move, or park somewhere heated. Scottish winter + lithium = expensive lesson otherwise.