Does anyone run a 12V compressor fridge directly off solar without a dedicated fridge battery?

I've been trying to work out whether it's worth running my Alpicool C20 straight from a 200Ah LiFePO4 bank that's also powering everything else in the van — lights, USB charging, a small inverter for the occasional laptop. The fridge pulls around 3–4A when the compressor kicks in, and I've got a 400W solar setup (two 200W panels in series into a Victron SmartSolar 100/30).

Most of the advice I've found online seems to assume you'll wire the fridge to a dedicated second battery, but that feels like overkill when I've already got decent capacity. I'm parked up in the UK, so I'm not banking on wall-to-wall sunshine — more like 2–4 hours of decent solar gain on a good day. Wondering if the single bank approach just runs into trouble overnight or on overcast days in autumn and winter.

Has anyone actually done this long-term and tracked the numbers? Curious whether the fridge cycling is causing any real issues with other loads, or whether I'm overthinking the whole thing.

Hey @TonyRoss, I run my Alpicool T36 pretty much exactly like that — straight off a shared 200Ah LiFePO4 bank with no dedicated fridge circuit. Works an absolute treat honestly. The key thing I'd flag is that compressor fridges draw heavily on startup, so make sure your wiring to the bank is decent gauge and your BMS can handle those brief spikes without tripping.

The LiFePO4 chemistry genuinely helps here compared to AGM — much flatter discharge curve means the fridge controller doesn't see voltage sag and start behaving oddly. I'd just keep an eye on your overall daily consumption versus solar input for the first week or so and adjust from there. What's your panel wattage looking like?

One thing worth adding — compressor fridges can pull a decent spike on startup, so worth checking your BMS can handle it without tripping. Mine on the shepherd's hut setup caused occasional nuisance disconnects until I bumped the short-circuit tolerance settings on my Victron SmartShunt and checked the BMS rating matched reality.

Also, shading matters more than people expect. A 200Ah bank looks great on paper but if your panels drop off mid-afternoon you're running on stored capacity faster than you think. I'd log a few days with the Victron app before assuming it's sustainable long-term.

The Alpicool units are fairly efficient but they do cycle constantly in warm weather — that adds up overnight.

My garden office Alpicool has been on a shared Victron/Fogstar setup for two years — the fridge doesn't care that it's sharing, but your other loads will care when the fridge thermostat kicks in and nicks a big slice of amps right as you're doing something else.

Good to see this topic come up — I've been mulling over exactly the same thing for my garden office build.

@BayFrank that's reassuring to hear about the two-year run. One thing I haven't seen mentioned yet: has anyone noticed the fridge causing voltage sag that affects other loads during peak summer days when the solar input is strong but the battery is only at, say, 50%?

My concern is less about the BMS spike (cheers @WD40Wizard11) and more about whether a shared bank causes issues with sensitive kit — I've got a Raspberry Pi running 24/7 in my setup and I'm wondering if the compressor cycling creates enough noise on the 12V line to cause instability. Would a small capacitor or a dedicated fuse run solve that, or is it a non-issue in practice?