Anyone know if a 200W panel can run a small chest freezer overnight?

Running a small chest freezer off solar is something I've been trying to wrap my head around for my van build, so keen to hear from anyone who's actually done it.

I've got a single 200W panel on the roof (Renogy mono), feeding into a 100Ah LiFePO4 from Fogstar, with a Victron 75/15 MPPT controller. The freezer I'm looking at is a 30L Alpicool — draws about 45W when the compressor kicks in but obviously cycles on and off throughout the day and night.

My concern is overnight specifically. During the day the panel can (in theory) keep up and top the battery back up, but once the sun goes down I'm relying entirely on whatever's stored. Running the numbers roughly:

• Freezer cycling maybe 30–40% of the time overnight (~8 hours)
• That's roughly 3–4 hours of actual compressor runtime
• At 45W that's around 135–180Wh drawn overnight

On paper my 100Ah (usable ~80Ah on LiFePO4, so ~960Wh) should handle it, but I'm also worried about the panel being able to recover that loss the next day — especially in winter here in Wales where I might only get 2–3 peak sun hours if I'm lucky.

Has anyone actually run this sort of setup long-term? Does the freezer temp setting make a big difference to how often it cycles? And is it worth bumping to a 300W panel or a second battery before committing to the freezer?

@RayPowell a single 200W panel alone won't cut it overnight — the panel produces nothing after dark, so you're entirely dependent on whatever battery capacity you've built up during the day.

The real question is: what's your battery bank size?

A typical small chest freezer (say, 30-60L) might draw 30-80Wh per day depending on ambient temperature. In theory a 200W panel in decent UK conditions might yield 600-800Wh on a good day — but UK irradiance is rarely reliable enough to count on that consistently.

Key things I'd want to know:

• What battery capacity do you have? (100Ah LiFePO4 minimum I'd suggest)
• What's the freezer's actual consumption — checked with a plug-in energy monitor?
• What time of year are you planning to run this?

Without adequate storage the panel output is largely irrelevant overnight.

@RayPowell the panel is just the charging source — what actually runs the freezer overnight is your battery bank.

Rough numbers: a small chest freezer (say 30-50L) might draw 30-60Wh actual per hour depending on ambient temp. So overnight (10hrs) you're looking at 300-600Wh minimum.

A single 200W panel in the UK will realistically give you maybe 60-90Wh on a grey day, 160Wh on a decent one. That's probably not enough to keep a battery topped up AND run the freezer 24/7.

I'd be looking at:

• At least 2x 200W panels
• 100Ah LiFePO4 minimum (Fogstar Drift is decent value)
• A proper Victron MPPT to squeeze every bit out of those panels

What battery have you got currently?

@RayPowell to build on what @JimKelly said — sizing the battery is the critical bit here. A decent 12V compressor freezer (like a Brass Monkey or similar) typically draws around 30–45Ah per 24 hours in a UK climate, though ambient temperature makes a big difference.

Your 200W panel in the UK will realistically yield 60–80Ah on a decent summer day, maybe half that in winter. So the maths can work, but you'll want at least 100Ah of usable lithium (not lead-acid, where you'd need double) to bridge overnight comfortably.

I run a Fogstar 200Ah LiFePO4 in my motorhome with two 200W panels keeping a compressor fridge fed — works brilliantly through summer. Winter requires more discipline.

What battery have you currently got spec'd?

Really good points from @JimKelly and @SimonKelly already. One thing worth adding from my motorhome experience — duty cycle is everything with compressor freezers. Mine runs maybe 30-40% of the time once it's up to temperature, so actual draw is much lower than the rated wattage suggests.

Also worth thinking about ambient temperature — a freezer working harder in a warm van will chew through a lot more power than the specs imply.

For the panel side, in the UK you're realistically getting 3-4 peak sun hours on a good day, so 200W gives you maybe 600-800Wh daily. That's tight even with a well-insulated chest freezer. I'd honestly look at adding a second panel if roof space allows — Renogy do decent affordable options.

What freezer model are you running? The actual amp draw figures would help nail this down properly.

Good thread. To add a practical angle — I've run a small Dometic chest freezer on my narrowboat through winter and the duty cycle thing @ExTrucker73 mentioned is massive. A well-insulated chest freezer barely runs its compressor compared to a poorly sited one. Mine's tucked away from any heat sources and the difference is noticeable on the battery draw.

Also worth considering: cloudy UK days are your real enemy, not overnight. A single 200W panel in November might give you 1-2 usable hours of decent output. That's where battery capacity and potentially a DC-DC charger from your van alternator becomes the actual safety net, not the solar panel itself.

Fogstar do decent value 100Ah LiFePO4 if you're budget-conscious on the battery side.