"How big a solar panel do I actually need for my fridge?" is one of the most common questions we field at Elevate Automotive — usually from someone halfway through building out a canopy or camper setup who's just realised the fridge is going to be running around the clock, not just on the odd weekend trip.

The short answer is: it depends on your fridge, your battery, and how much sun you can realistically count on. The longer answer — the one that actually stops you from getting stranded with warm food — is below.

Why This Is Worth Getting Right

A fridge isn't a static load like a light bar. It cycles the compressor on and off all day and night, and that compressor draws a real spike of current every time it kicks in. A solar and battery setup that's sized for "average" draw without accounting for that cycling — and for the days you don't get much sun — is exactly how people end up with a flat battery on day three of a week-long trip.

To keep a fridge running full-time off-grid, your system needs to do three things at once: generate enough power during daylight, store enough to get through the night (and a cloudy day or two), and cope with that startup surge without your battery voltage sagging.

Step 1: Work Out What Your Fridge Actually Draws

Before you can size anything, you need real numbers, not guesses. Check your fridge's spec sheet or compressor plate for:

• Running draw — the continuous current it pulls while the compressor is active (usually listed in amps)
• Startup surge — the brief spike when the compressor kicks in, which can be several times the running draw for a second or two

As a working example: a 12V fridge drawing around 4A continuously works out to roughly 48W. In practice, because the compressor cycles rather than running constantly, most fridges settle somewhere around 40–60Wh per hour once you average it out — which puts a typical day's usage at roughly 960–1,440Wh.

That range moves depending on ambient temperature, how often the lid or door gets opened, and how well-insulated the fridge is. A fridge baking in a canopy on a 38°C day in the Pilbara is going to draw noticeably more than the same fridge on a mild coastal trip — so treat your calculated number as a floor, not a ceiling.

Step 2: Size Your Solar Panels

Once you've got a daily energy figure, sizing your panels comes down to how many usable sun-hours you can realistically bank on.

Daily fridge usage (Wh) ÷ usable sun-hours = minimum panel wattage

Take a fridge using 1,200Wh a day, with around 5 hours of decent sun — common enough across most of Australia outside deep winter. That's 1,200 ÷ 5 = 240W as your bare minimum.

In the real world, that number needs padding for wiring losses, charge/discharge inefficiency in the battery, and whatever else is sharing that circuit — lights, a water pump, phone charging. Most setups running a single 12V fridge full-time land somewhere in the 300–400W range once you build in that margin, rather than sitting right on the calculated minimum.

Step 3: Size Your Battery Bank

Solar only does anything while the sun's up, which means your battery is what actually keeps the fridge running overnight — and through however many overcast days you want to plan for.

A simple way to think about it: take your daily usage and decide how many days of "no meaningful solar input" you want to be covered for.

• Daily fridge use: 1.2kWh
• Buffer for 2 days without much sun: 2.4kWh of storage
• On a 12V system, that works out to roughly 200Ah — though the exact figure depends on whether you're running AGM or lithium, since usable depth of discharge differs significantly between the two (we've covered that comparison in detail in our starter vs deep-cycle battery guide).

If you're still deciding between chemistries or battery sizes generally, our battery range is worth a browse — AGM is still a solid, budget-friendly option, but lithium's higher usable capacity means you can often get away with a smaller, lighter battery for the same real-world runtime.

Step 4: Build In Room for Real-World Conditions

The numbers above are a solid starting point, not a guarantee. A few things consistently push real-world consumption higher than the textbook calculation:

• Hot weather makes the compressor work harder and run longer
• Frequent door openings (day-tripping with an esky mentality, rather than a "grab everything at once" habit) adds load
• Wiring, inverter, and battery inefficiencies all eat a slice of what you generate
• Small extras — LED strip lighting, a fan, charging phones and cameras overnight — add up faster than people expect

The practical takeaway: if your calculations put you right on the edge of a panel or battery size, round up. The cost difference between a 300W and 400W panel setup is a lot smaller than the cost of a fridge full of spoiled food 400km from the nearest shop.

A Typical Full-Time Fridge Setup

That combination comfortably keeps a fridge running through a few overcast days in a row, with enough headroom left for the small accessories that inevitably end up sharing the circuit.

Get Your Setup Sized Properly

Running a fridge full-time off-grid is genuinely straightforward once the solar and battery side is sized for real conditions rather than best-case numbers. If you'd rather not do the maths yourself, our team can size a full setup — panels, battery, and the power management gear that ties it all together — based on your actual fridge, vehicle, and how you travel.

Browse our fridges and power management ranges, or get in touch and we'll help you build a setup that doesn't leave you guessing.