Anyone else finding this winter particularly rough on their battery bank?

Genuinely struggling this year compared to last. Running a 200Ah Fogstar Drift LiFePO4 in my van conversion and even parked up in the south of England I'm seeing the BMS kick in low-temp protection more mornings than I'd like. Hadn't really factored in that LFP cells just don't want to charge below about 5°C — something I perhaps naively glossed over when I bought lithium.

Currently relying on my Victron SmartSolar to push what little the panels are generating into the bank, but with the short days and constant overcast we've had since November, I'm sometimes only getting 20–30 minutes of meaningful absorption per day. It's a bit grim.

A few things I'm curious about from others:

• Are those of you with AGM actually having a better time of it this winter? I know lithium gets all the hype but wondering if the cold tolerance argument for AGM is more valid than I initially thought
• Has anyone added any kind of battery heating solution — heat mat, self-heating cells, etc.? Worth the faff?
• Is anyone finding that parking orientation (maximising whatever weak sun there is) has made a measurable difference, or is it negligible when it's this overcast?

Also wondering if a small 240V hook-up for occasional top-ups is just the sensible winter fallback rather than fighting the solar battle. Would love to know how others are managing their state of charge through these darker months without just accepting a permanently half-full bank.

@VoltVicky the low-temp cutoff is doing exactly what it should, but it's frustrating nonetheless. Worth knowing that Fogstar Drift cells typically lock out charging below around 5°C — discharging usually remains available down to -20°C, so you're not completely powerless at least.

Practical fix I've used in my tiny house backup setup: a small self-regulating PTC heating pad wired directly to the battery output (not through the BMS charge path), set to maintain the pack above 8°C. Draws maybe 15-20W continuously in hard frost conditions.

Also worth checking — is your battery in an insulated enclosure? Even 50mm of Celotex around the box makes a measurable difference overnight. Thermal mass helps enormously; the Drift pack holds heat reasonably well once it's at temperature from daytime charging.

What's your overnight ambient actually dropping to inside the van?

@VoltVicky had the same issue in my motorhome last winter. Ended up wrapping the battery compartment with 25mm Kingspan and adding a small self-regulating heat mat on a thermostat — kicks in around 5°C. Sorted it completely.

The Fogstar Drift's low-temp cutoff is around 0°C from memory, so if you're parked on a cold night you'll hit it faster than you'd think even in the south.

Also worth checking if your Victron (or whatever you're running) has a low-temp charge disconnect setting — belt and braces approach rather than relying purely on the BMS.

Insulation is the cheap fix before you start throwing money at anything else.

@VoltVicky worth noting that LiFePO4 chemistry genuinely struggles below around 5°C for charging — discharge is usually fine down to -20°C or so, but pushing charge current into cold cells degrades them permanently over time, so the BMS is earning its keep there.

In my cabin setup I run a small self-regulating heating mat directly against the battery casing, wired through a cheap STC-1000 temperature controller set to kick in at 5°C. Draws maybe 15–20W but keeps the bank in the safe charging window overnight. Total cost was under £30.

If you're grid-tied or have any hook-up access, this is genuinely the simplest fix. If you're purely solar-dependent in winter, the harder truth is you may need to prioritise keeping that compartment thermally managed before worrying about anything else.

Really interesting thread — I'm dealing with similar in my garden office setup rather than a van but the principle's the same.

@WezWhite72 makes a good point about discharge vs charging temps being different thresholds. One thing nobody's mentioned yet — have you looked at setting a lower absorption voltage through winter? I adjusted mine on the Victron MPPT down slightly and found it reduced the stress on the cells during marginal temperature days when the BMS is borderline on allowing a charge.

Also curious whether anyone's tried the heated Fogstar models vs the standard Drift? Seems like a significant premium but potentially worth it for van life where you can't insulate the compartment as readily as a fixed install.