Anyone else had their Daly BMS cut out randomly at low temps this winter?

Picked up a 100A Daly BMS late last year for my 280Ah LiFePO4 build in the van. All seemed fine through autumn but now we're hitting proper cold nights (we're talking 2–4°C inside the van in the morning) it's been randomly disconnecting on me. Wakes me up with the inverter alarm going off, check the battery terminal voltage and it's sitting at 13.1v — nowhere near low enough to trigger the low voltage cutoff I've set at 12v.

Done a bit of digging and I think it might be the low temperature protection kicking in, but I've got that set to -5°C so it shouldn't be triggering at 3°C. Running it via Bluetooth and the app is showing the temp sensors reading correctly as far as I can tell. Firmware is whatever came on it out of the box — not sure if that's the issue.

Has anyone else seen this with Daly units specifically, or BMS boards in general? Wondering if the temp sensors themselves are dodgy or if the settings don't quite behave the way the app suggests. Also open to whether I should just ditch it for something like a JK BMS — happy to spend a bit more if it means reliable behaviour through winter.

Hey @DanFisher89, yeah this is a pretty common one with Daly units. The low-temp cutoff protection kicks in around 0–5°C on a lot of them to prevent charging damage to the cells — which is actually the BMS doing its job correctly rather than faulty behaviour. The issue is the default threshold is often set quite conservatively from the factory.

Worth checking whether it's cutting out during charging specifically (solar/alternator) or also under load discharge. If it's only on charge, that's almost certainly the low-temp charge protection doing exactly what it should.

You can adjust the temperature parameters using the Daly PC software over USB if you fancy tweaking the thresholds, though I'd be cautious about disabling it entirely — charging LiFePO4 below 0°C genuinely does cause permanent cell damage. A small self-regulating heating pad on the battery bank might be the cleaner long-term solution.

@DanFisher89 mate, my Daly did exactly this in the garden office last January and I genuinely thought the whole build had died — turns out it was just the BMS having a proper sulk because it was technically doing its job protecting the cells from charging below 0°C, which is fair enough really but still infuriating at 7am when you just want a brew.

Worth knowing: discharge usually still works at those temps, it's specifically charging it gets precious about — so if your loads are cutting out too, double-check your wiring before blaming the cold entirely.

Some folks swap to a Victron Smart BMS or add a small self-regulating heat pad on the battery — dead simple fix and they're cheap on Amazon. Fogstar also sell cells pre-matched if you ever rebuild.

What @Turbo43 said is spot on. Worth noting the Daly low-temp threshold isn't always accurate either — mine was triggering at 4°C when the actual cell temps were fine.

Had the same issue in my cabin build last winter. Ended up wrapping the battery box in 25mm PIR insulation and chucking a small reptile heat mat underneath on a basic thermostat. Sorted it overnight.

If you want proper adjustable low-temp cutoff settings, honestly look at a Daly Smart BMS (the Bluetooth version) — you can tweak the parameters yourself. Or jump ship to JK BMS, the settings are much more granular.

Don't bother charging below 5°C though regardless — LiFePO4 cells genuinely don't like it and you'll degrade capacity faster than you'd think.