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

Mine did it again this morning — woke up to find my 280Ah LiFePO4 bank sitting at 48V with the solar doing nothing. Checked the Daly app and sure enough, low temperature protection had kicked in at around 4°C. I've got the cutoff set to 5°C which I thought was sensible, but it's getting annoying now that we're into autumn and overnight temps are regularly dropping that low in the van.

I'm running a 4S 280Ah cell pack I built myself from EVE cells, with a 60A Daly Smart BMS and a Victron MPPT 100/30 doing the charging. The cells themselves are rated down to -20°C for discharge but only 0°C for charging, so I get why the protection exists — I just don't want to lose a whole morning of solar because it's a touch chilly. I've been thinking about adding a small self-heating pad under the cells triggered by a thermostat, but not sure if that's overkill or the right approach.

Has anyone sorted this properly on a budget? Seen some people mention nichrome wire heating mats and others using 12V reptile heating pads. Curious what's actually working for people out there before I go spending money on something that doesn't fix it.

@Turbo34 had exactly this last February with my garden office setup. Daly cut out overnight when temps dropped to around 3°C — protection kicked in before I'd even had my morning coffee.

What helped me was adding a small self-regulating heat mat directly to the cells, wired to a Victron temperature sensor so it kicks in before the BMS threshold. Bit of faff to set up but hasn't tripped once since.

Worth checking what your low-temp cutoff is actually set to in the app — mine had shipped with an overly cautious 5°C threshold. Some people nudge it down to 2°C, though obviously charge rates at that point aren't ideal for the cells anyway.

Is your bank insulated at all? Even basic foam board made a noticeable difference to my overnight temps before I sorted the heating properly.

Oh this is so familiar — had the same thing happen on the narrowboat last winter! Mine cut out around 5°C if I remember right, which honestly isn't even that cold.

Quick question for you both — did either of you adjust the low temp protection threshold in the Daly app? I had a poke around mine and the default settings seemed quite conservative. I've also seen people mention adding a small self-heating element to the battery box, which I'm seriously considering before next winter.

Also wondering — is this purely a Daly thing or would something like a Victron SmartShunt setup with a proper heated battery enclosure solve it at a deeper level? Or am I overcomplicating this? The narrowboat can get absolutely Baltic at night so I need something reliable before temperatures really drop. What did you end up doing @LazyWarden?

@Turbo34 worth knowing that LiFePO4 genuinely shouldn't be charged below around 0°C — the BMS is actually doing its job there, not misbehaving. The issue is that Daly's default low-temp threshold is often set conservatively high, sometimes 5-10°C, which is overly cautious for decent quality cells.

On my narrowboat setup I solved this by adding a cheap self-regulating heating pad directly to the battery enclosure — draws minimal watts overnight and keeps cells above the cutoff threshold. Fogstar cells I'm running seem perfectly happy once the pack stays above 5°C.

Alternatively, if you can access the Daly PC software (not just the app), you can actually adjust the low-temp protection threshold down, though I'd be careful going below 0°C regardless. What are your cells — do you know the manufacturer's actual low-temp charge spec? That matters more than whatever the BMS defaulted to.

@Turbo34 — just to add to what @Boycie's saying, the protection threshold on most Daly units is configurable via the app. Mine was factory-set to cut out at 5°C which felt overly cautious for my setup. I nudged it down to around 2°C after doing a bit of research, which gave me a bit more flexibility on those marginal mornings without pushing into genuinely risky territory.

The other thing worth considering is a small self-regulating heating pad under or around the battery bank — they draw very little and can keep temperatures just above the threshold overnight. Plenty of folk on here have gone that route rather than fighting the BMS settings. Might be worth a search in the thread archive as there's been some decent discussion about it previously.

@TrevorEvans is right about the configurability, but worth flagging that lowering that threshold is genuinely risky territory — lithium plating on the anode is a real degradation mechanism, not just manufacturer overcaution.

What I did on my shepherd's hut setup was add a small self-regulating PTC heat mat wired to a Victron BMV relay output — triggers at 5°C to warm the cells before the BMS even considers allowing charge current. Keeps everything within safe parameters without you having to babysit it.

The Fogstar cells I'm running have a stated lower charge limit of 0°C, so rather than fight the BMS I just ensure the cells never reach that threshold in the first place. Takes the problem off the table entirely rather than just masking it by adjusting protection values downward.

Had this exact scenario with my shepherd's hut build last February. The Daly did its job perfectly — I just hadn't planned for it.

What actually solved it for me was wrapping the battery box with a cheap seedling heat mat on a 5° thermostat. Total cost maybe £15 from a garden centre. Bank never drops below 8°C now even on the nastiest nights.

Worth mentioning: when I added EV charging to the setup the thermal management became even more critical — bigger draw cycles meant bigger temperature swings. A small investment in passive or active battery warming pays back quickly.

@Trigger makes a fair point about the risk, but there's a middle ground worth considering — a self-heating battery or wrapping the bank in insulation with a small thermostatically-controlled heat mat.

In my shepherd's hut setup I use a basic reptile heat mat (the kind you'd find on Amazon for a tenner) under the battery box, wired to a simple thermostat probe set to kick in around 5°C. Sorted the cold morning cutouts completely without touching the BMS thresholds.

Fogstar and some other UK suppliers now sell LiFePO4 cells with built-in heating elements too — worth looking at if you're replacing anyway. Keeps everything within safe parameters rather than papering over the cracks by lowering protection settings.

@Turbo34 — worth adding that a simple workaround many of us down here in Cornwall use is a small thermostatically controlled heat mat underneath or wrapped around the battery bank. Keeps the cells above the protection threshold overnight without needing to mess with BMS settings or splash out on a self-heating pack. A £15-20 reptile heat mat on a basic thermostat does the job nicely. Just make sure it's rated for continuous use and not touching anything flammable. Minimal parasitic draw too — barely noticeable on your overall system.

Great thread this. @CornishSolar's thermostat-controlled heat mat idea is dead simple and works a treat — I've got exactly that setup running on a 12V feed from my auxiliary bank, so it's not even drawing from the main pack when it's cold. One thing I'd add: check what temperature your Daly is actually set to trip at. Mine came from the factory set to 5°C which felt overly cautious, so I nudged it down to 0°C in the app. Still protecting the cells properly but gives you a bit more flexibility on those borderline mornings.

Just to add to what @CornishSolar and @Dizzy60 are saying about the heat mat approach — worth making sure you're powering it from a separate small lead-acid or similar rather than the LiFePO4 bank itself. Otherwise you're drawing from the very battery you're trying to protect, and if temps drop far enough the BMS cuts out anyway, taking your heat source with it. A cheap 7Ah SLA tucked in the battery box keeps the mat running independently. Bit belt-and-braces but it's saved me a few times over winter.