Anyone know if a 200Ah lithium battery will run a small chest freezer overnight?

Running a small chest freezer off-grid is something I've been looking into seriously for my cabin setup, so curious whether anyone's got real-world experience here.

I've got a 200Ah lithium (Fogstar Drift 12V) paired with a modest solar array, but overnight obviously means no generation. If I'm understanding correctly, usable capacity at 80% DoD gives me roughly 160Ah to play with before I'd want to worry about cell stress.

The freezer I'm eyeing is a Cookology 60L chest freezer, rated at around 90W. I know these things don't run continuously — duty cycle seems to be roughly 30-50% depending on ambient temperature and how full it's loaded. So I'm thinking somewhere between 45-75Wh per hour averaged out?

Over say 10 hours overnight that's potentially 450-750Wh, which on a 12V system translates to 37-62Ah. On paper that looks very manageable, but I suspect I'm missing something — maybe inverter losses, startup surge, or the fact that UK summer vs winter ambient temps massively affect duty cycle?

A few specific questions:

• Does a chest freezer draw significantly more when first cooling down versus maintaining temperature?
• Would a pure sine wave inverter (I've got a Victron Phoenix 12/375) handle the compressor startup surge on that size unit?
• Any brands known to be particularly efficient for off-grid use?

I'd rather not run the battery down overnight only to have insufficient solar recovery the next day if it's overcast. Happy to share more about the full setup if it helps diagnose whether this is actually viable long-term.

@TransitAdventure worth checking what your freezer's actual compressor duty cycle is rather than just the rated wattage. Mine's listed as 85W but only runs maybe 30-40% of the time overnight when ambient is cool — so actual draw is far lower than worst-case maths suggests.

That said, I'm only using mine for emergency backup, so my use case is shorter bursts rather than full overnight runs. What's your ambient temperature at the cabin? A freezer in a warm outbuilding works considerably harder than one in a cool space.

Have you stuck a plug-in energy monitor on it for 24 hours first? Wouldn't commit to a setup without knowing real consumption figures. The Fogstar 200Ah should handle it comfortably if your freezer's efficient, but that monitoring step is non-negotiable really.

@WheresMeWires31 makes a fair point on duty cycle — that's the figure that'll make or break it.

I ran a Shoreline chest freezer through a full winter night on my boat with a 200Ah Fogstar Drift and it was absolutely fine. Sitting around 12–15Ah consumed overnight once the contents were already frozen solid.

The key thing nobody mentions: pre-chill your freezer contents thoroughly before going off-grid. A warm load forces the compressor to work brutally hard in those first few hours and that's where your capacity disappears.

@TransitAdventure if your 200Ah is properly sized with a decent BMS and you're not also running lights, a pump, and a phone charger off the same bank simultaneously, you'll likely wake up with 70–80% remaining. Real-world is kinder than the maths suggests here.

Yeah this is dead doable in my experience. I've got a similar setup at the cabin and the key thing nobody's mentioned yet is ambient temperature — a freezer working hard in a warm space will chew through your bank way faster than the specs suggest.

Also worth thinking about what else is pulling from that 200Ah overnight. Even small parasitic loads add up.

My rule of thumb: don't plan to use more than 80% of your usable capacity with lithium, so you're really working with ~160Ah in practice. Run your numbers from there.

A decent Victron BMV will show you exactly what's actually being consumed — worth every penny for this kind of monitoring rather than guessing.

My static van runs a chest freezer off a 200Ah Fogstar Drift and it's fine overnight — but ambient temperature is the wildcard nobody's flagging here; stick that freezer in a hot garden office in July and your duty cycle goes mental compared to a cool cabin floor.