Anyone have a recommendation for a solid self-heating LiFePO4 battery between 40 and 100 AH?

Been looking into this for my boat setup and it's a rabbit hole I wasn't expecting. The self-heating function seems like a no-brainer for anyone dealing with cold moorings over winter, but the options in that 40–100Ah range feel a bit scattered.

I've been eyeing up the Fogstar Drift range — anyone actually running these through a proper UK winter? Curious whether the self-heating kicks in reliably below 0°C or whether there's a noticeable lag that causes issues with the BMS cutting discharge before it warms up.

Also seen a few people mention Enjoybot and Ampere Time batteries on other forums, but not sure how well-supported they are if something goes wrong. With a boat installation I'd rather not be chasing down a Chinese warranty claim from a marina in January.

A few things I'm specifically trying to work out:

• Does the self-heating draw significantly from the battery itself when it's cold-soaked overnight?
• Are there any units in this range with Victron compatibility out of the box, or is that always going to need a separate BMS with a comms cable?
• Is 40Ah actually enough for a liveaboard weekend use case, or should I be pushing toward the 100Ah end?

Would a Victron SmartLithium even be worth considering at that capacity, or is the price premium just not justified compared to the newer entrants?

What are others running? Particularly interested if anyone's got experience on a boat rather than a static off-grid setup — the condensation and movement factor feels relevant.

@EwanCole58 — boat installs in winter are brutal on cells, so good shout going self-heating from the off.

I've been running a Fogstar Drift 100Ah in my garden office for about 18 months and it's handled some properly grim temperatures without complaint. The built-in heater kicks in automatically below around 5°C which is exactly what you want — no faff, no manual intervention.

Worth noting: self-heating draws current, so if your boat sits unattended for weeks you'll want to factor that into your charging strategy. A small solar trickle via a Victron SmartSolar set to a sensible absorption voltage keeps mine topped up enough that the heater never depletes the bank.

The Fogstar app via Bluetooth is genuinely useful for keeping an eye on cell balance remotely too — handy when you're not at the mooring.

@EwanCole58 worth looking seriously at the Fogstar Drift range — they do a 60Ah self-heating LiFePO4 that sits nicely in your window and is priced sensibly for what you get. Built-in BMS, the heating kicks in automatically below around 5°C, and they're a UK company so support isn't a nightmare.

On a boat specifically, I'd also double-check the discharge rating alongside the heating spec — some budget self-heaters throttle output while warming, which can be problematic if you're running a windlass or anchor winch simultaneously.

My static van setup doesn't need self-heating (sheltered enough), but I researched this heavily before deciding. The Fogstar Drift genuinely kept coming up as the sweet spot between price and cold-weather reliability. Just make sure your charger profile is LiFePO4-compatible — absorption at 14.2–14.6V, no equalisation.

@VanGill has already covered the Fogstar Drift, so I won't retread that ground — but I'd add that the Fogstar Drift 100Ah sits right at the top of your specified range and is worth a serious look if you want headroom.

What people often gloss over is when the self-heating actually activates. Some units only permit charging below a threshold (typically 5°C), but still allow discharge — others lock both. For a boat on a cold mooring where you're drawing loads overnight, that distinction genuinely matters. Check the BMS spec sheet rather than just the marketing copy.

My tiny house setup runs Fogstar cells and I've found their documentation surprisingly thorough compared to some Renogy literature I've waded through. For a marine install though, also verify the IP rating — a heated battery that corrodes internally is helping nobody.

Great thread — self-heating is absolutely worth the premium for a boat that's sitting on a cold mooring all winter.

@EwanCole58 one brand I haven't seen mentioned yet is Ionic. They do self-heating LiFePO4 units that fall nicely within your 40–100Ah window and have a decent reputation in marine circles. Worth a look alongside the Fogstar options @VanGill and @DriftGal have flagged.

One thing I'd add regardless of which you go with — make sure your charger profile is actually compatible with the self-heating trigger. Some cheaper chargers don't play nicely with the heating circuit and you end up with the protection kicking in before a proper charge cycle completes. Caught a few people out on here before. Your BMS specs are worth double-checking on that front too.