Anyone else had their Daly BMS cut out mid-charge on a cold morning?

Woke up yesterday to find my 200Ah LiFePO4 bank sitting at 48% SOC with the Daly 100A BMS having tripped overnight. Temps dropped to about 4°C in the van, and I'm fairly sure that's what did it — I've read the low-temp cutoff on these is around 5°C by default, but I didn't realise it would actually trigger at that point. No damage done as far as I can tell, just annoying waking up to a cold van with no heating running.

I'm running a 24V system with four 100Ah Eve cells in series, charged via a Victron SmartSolar 100/30 and a Renogy 40A DC-DC charger from the alternator. The BMS reset itself once things warmed up a bit, so it's not bricked or anything. But it got me thinking — should I be adding a heat pad to the cells for winter, or is the better fix to adjust the BMS parameters? I've got the PC software for the Daly but haven't dug into it properly yet.

Has anyone actually tweaked the low-temp protection settings, and how low is it safe to go before you're genuinely risking the cells? Or is everyone just fitting self-heating battery setups for winter van life? Keen to hear what others are doing — feels like this is going to be a recurring headache between now and March.

Hey @BorderExplorer, yes, classic cold temperature protection kicking in! Daly BMS units are quite conservative with their low-temp cutoffs — some are set as high as 5°C from the factory, so 4°C in the van would absolutely trigger it.

Worth grabbing the PC software and a cheap USB-UART cable to check your actual temp protection settings. You can often nudge the cutoff down to around 0°C safely for LiFePO4, though I'd be cautious going lower than that.

Longer term, a small self-regulating heat mat underneath the battery connected to a simple thermostat makes a massive difference through winter. Keeps the cells happy and your overnight charging uninterrupted.

Also worth checking — is your temp sensor actually making good contact with the cells? A loose sensor can give false low readings and trip the protection unnecessarily.

Just to add to what @ForestLover is saying — worth checking your Daly's low-temp charge cutoff setting in the PC software if you haven't already. The default from the factory is often set around 5°C, which means 4°C overnight will absolutely trigger it. You can nudge it down to 0°C if your cells are rated for it (most quality LiFePO4 cells handle charging down to 0°C fine, just derated).

Longer term, a small self-regulating heat mat on the battery with a simple thermostat controller sorted this completely for me over winter. Keeps the bank just above the threshold without drawing much. Dead cheap solution compared to the headache of waking up to a flat battery! 🙂

Yep, been there. My Daly on the workshop bank used to trip at anything below 5°C until I dug into the PC software and nudged the low-temp charge cutoff down to 2°C — which is about as far as I'd trust LiFePO4 chemistry anyway.

Worth knowing: the discharge path usually stays open even when charge protection trips, which is why your SOC held steady rather than draining. Small mercy!

If you're regularly seeing sub-5°C nights in the van, honestly consider wrapping the battery with some self-adhesive heat mat and a cheap thermostat. I used a 10W reptile mat on mine — looks ridiculous, works brilliantly. Fogstar cells don't love the cold regardless of what the BMS allows through.

Also double-check which firmware your Daly is running — some earlier versions have oddly aggressive temperature hysteresis that causes phantom trips even above the cutoff threshold.

Had this exact issue on my shepherd's hut setup last winter. The Daly low-temp cutoff is one thing, but worth also checking whether your charger is pushing full current right from the off — even if the BMS allows charging at 4°C, hammering it with 100A into a cold pack can still cause grief.

What's your charge source? If it's a Victron MPPT you can set a low-temp charge current limit in VictronConnect — I dropped mine to about 20A below 8°C and the nuisance trips stopped completely.

@Titch is right that the PC software adjustment helps, but pairing that with a derated charge current at low temps is the belt-and-braces fix. Fogstar cells in particular seem happier for it in my experience.