Anyone successfully run a 12v compressor fridge off a single 100Ah LiFePO4 with just one 100w panel?

So I've been trying to nail down the minimum viable solar setup for a small campervan build and I keep going back and forth on whether one 100Ah LiFePO4 (I've got a Fogstar Drift) and a single 100w panel is genuinely enough to run a 12v compressor fridge full-time in the UK, or whether I'm kidding myself.

The fridge I'm looking at is the Alpicool C15 — draws around 45w when the compressor kicks in but obviously it's not running constantly. I've seen people claim it averages out to maybe 20-25Ah per day depending on ambient temp and how full you keep it. On a decent sunny day in summer I'd expect maybe 300-350Wh from the 100w panel through a decent MPPT, which on paper looks fine. But we all know UK weather doesn't exactly cooperate.

My worry is a run of two or three overcast days in a row — not unusual here even in July. The Fogstar is 100Ah usable, so roughly 1280Wh. If the fridge is pulling 25Ah a day and the panel's only putting in 10-15Ah on a grey day, the sums start looking a bit tight after day two.

Has anyone actually lived with this kind of setup day-to-day rather than just modelled it on paper? Particularly interested in whether people bother with a second panel or a second battery first when the budget's tight — can only really afford one upgrade at a time.

@LiFePO4Geek done exactly this — Fogstar Drift 100Ah with a single 100W panel running an Alpicool C15 in my van for two summers.

Reality check:

• Compressor fridge typically draws 3-5Ah averaged over 24hrs (ambient dependent)
• That's roughly 72-120Wh/day — very manageable
• Your 100W panel in decent UK summer sun gives maybe 300-400Wh/day realistically

The weak point isn't the battery or the panel — it's consecutive cloudy days. Three grey days in Scotland and you'll notice it.

My fixes:

• Keep the fridge as full as possible (thermal mass helps enormously)
• Pre-cool before leaving home
• Victron SmartSolar MPPT even on a single panel — squeezes every watt

Tight but absolutely workable. Just don't add a laptop, lighting and phone charging without revisiting the numbers.

@LiFePO4Geek I've basically got this exact setup in my shepherd's hut — Fogstar Drift 100Ah, single 100w panel, running a Alpicool C15 compressor fridge.

Honest answer: it depends massively on your location and time of year. Summer in a decent spot? Yes, just about. Winter or lots of shade? You'll be waking up to a flat battery.

Few things that helped me:

• Point the panel really well — even slight shading kills output
• Fridge temperature matters, keep ambient temps down if possible
• Don't run anything else significant overnight

The maths works on paper but real-world losses, cloudy days, inefficiencies... they stack up. I'd genuinely say 200Ah battery OR a second panel is the sensible minimum for reliable daily use rather than just getting away with it.

@LiFePO4Geek running something similar on my narrowboat — though I'd push back slightly on whether panel orientation gets enough attention in these discussions. A 100W panel flat-mounted on a van roof loses a surprising amount in winter when the sun sits low. Any idea what angle your panel will be at?

Also curious what your daily ambient temps look like — the fridge duty cycle swings massively between summer and winter, which changes the whole equation. On the boat I noticed my compressor was running nearly constantly during last July's heat.

One thing I haven't seen mentioned yet: are you factoring in parasitic loads from your MPPT controller, any lighting, phone charging etc.? Those small draws add up overnight and can tip a marginal setup over the edge. What MPPT are you pairing with the Fogstar?