How Many Solar Panels to Run a Refrigerator? (Watts, Batteries, and Sizing)

Most modern full-size refrigerators can run on about 400 to 800 watts of solar panels paired with a battery of roughly 1.5 to 2.5 kWh and a pure sine inverter. A compact fridge needs less, and an older or extra-large fridge needs more. The panels never run the fridge directly: they charge a battery, and the battery runs the fridge day and night.

The exact answer comes from one number on your refrigerator: how many kilowatt-hours it uses in a day. Below is how to find that number, how to turn it into panels and battery, and the kits we carry that can do the job.

How many watts does a refrigerator use?

There are two numbers people mix up, and only one of them matters for solar.

• Running watts are what the fridge draws while the compressor is on. A modern full-size refrigerator typically draws somewhere around 100 to 250 watts while running. The compressor cycles on and off all day, so this is not a constant draw.
• Daily energy use, in watt-hours or kilowatt-hours, is what the fridge actually uses over 24 hours once all that cycling is added up. This is the number you size solar panels and batteries to.

The easiest place to find it is the yellow EnergyGuide label on the fridge or in its manual. It lists estimated yearly electricity use in kWh. Divide that number by 365 to get daily use. A fridge rated at 400 kWh a year, for example, uses about 1,100 watt-hours (1.1 kWh) a day.

As a rough guide, many modern full-size refrigerators are rated somewhere around 300 to 600 kWh a year. Older refrigerators, extra fridges in a hot garage, and large French door or side-by-side models with ice makers can use considerably more.

Startup surge matters too. When the compressor kicks on, it briefly pulls several times its running watts. That does not change how many panels you need, but it does decide how big your inverter has to be.

How many solar panels do you need to run a refrigerator?

Use this formula:

Solar watts = daily watt-hours / (peak sun hours x 0.75)

The 0.75 covers real-world losses from heat, dust, wiring, and charging. With 4 peak sun hours, a common figure for much of the US, that works out to about 1 watt of panel for every 3 watt-hours a day. If your fridge plugs into an inverter, add another 10 to 20 percent for inverter losses.

Fewer sun hours in winter, a hot kitchen, or a fridge that gets opened constantly all push these numbers up. Panels are the cheapest part of the system to oversize, so round up.

How big a battery do you need?

The battery runs the fridge overnight and through cloudy days. A 12V 100Ah LiFePO4 battery stores about 1,280 Wh, and you can use roughly 90 percent of it, so about 1,150 Wh.

• Compact fridge (about 685 Wh a day): one 12V 100Ah battery covers about a day and a half.
• Efficient full-size fridge (about 1,100 Wh a day): one 12V 100Ah battery covers about one day, less inverter losses. A 12V 200Ah battery (about 2,560 Wh) gives you two days and a margin for cloudy weather.
• Large or older fridge (1,600 Wh a day and up): plan on 2.5 kWh or more, or step up to a 24V or 48V system.

For bigger builds, see our guides on building an off-grid battery bank and how big a battery you need to run a house.

What inverter do you need for a refrigerator?

A standard household refrigerator runs on 120V AC, so it needs a pure sine wave inverter. Modified sine inverters can make compressors run hot and noisy. Size the inverter to the startup surge, not the running watts. The 2,000 watt inverter included in the Rich Solar kits below gives a typical household refrigerator plenty of headroom; if you have a very large or older fridge, check its manual for the startup draw before you buy.

Keep in mind that an inverter uses some power just being switched on. On a small system that runs only the fridge, that idle draw adds up over 24 hours, which is one reason the 10 to 20 percent allowance above matters.

Solar kits we carry that can run a refrigerator

Every product below is carried by Krato Power and in stock as of this writing.

Best for a full-size refrigerator: Rich Solar RS-CK800 800W 12V Complete Solar Kit. Four 200W panels (800W), a 60A MPPT charge controller, 200Ah of 12V lithium battery, and a 2,000W 12V inverter. That covers an efficient full-size fridge with room to spare, plus a few lights and device charging. $2,869.99.

Best for a compact fridge or a small cabin: Rich Solar RS-CK400 400W 12V Complete Solar Kit. Two 200W panels, a 40A MPPT charge controller, a 12V 100Ah lithium battery, and a 2,000W inverter. A good fit for a compact refrigerator or an efficient chest unit. $1,679.99.

Building your own: start with MEGA 200 12V solar panels ($239.99 each), a BRAVO 40 MPPT charge controller ($159.99), and ALPHA 1 12V 100Ah LiFePO4 batteries ($499.99 each), then add a pure sine inverter sized to your fridge. Browse complete options in our solar panel kits collection.

The efficient option: a solar chest refrigerator

If you are building an off-grid system around the fridge, the cheapest way to shrink it is a more efficient fridge. SunStar chest units have a two-in-one thermostat, so they can run as a refrigerator instead of a freezer. Set as a refrigerator, SunStar rates the ST-8CF DC chest unit ($1,298.97) at about 145 Wh a day and the ST-15CF-AC ($1,598.97) at about 190 Wh a day, in a 77 degree F room. That is a fraction of a typical upright refrigerator, so a 100 to 200 watt array and a single battery can carry it. The DC model runs straight from a 12V or 24V battery with no inverter at all.

See the details in our solar freezer guide and the full solar refrigerators and freezers collection. Still deciding between a DC fridge, a propane fridge, and a standard fridge on solar? Compare them in our off-grid refrigerator options guide.

Frequently asked questions

Can I run a fridge straight off a solar panel? Not a standard one. Panel output rises and falls with the sun and drops to zero at night, so the panels charge a battery and the fridge runs from the battery through a charge controller and, for an AC fridge, an inverter.

Will a 400W solar panel run a fridge? In about 4 sun hours, 400 watts of panels make roughly 1,200 Wh a day after losses. That covers an efficient full-size refrigerator rated near 400 kWh a year, as long as a battery carries it overnight. A large or older fridge will need more.

Can a 300 watt solar panel run a refrigerator? A 300W array makes roughly 900 Wh on a good 4 sun hour day. That is enough for a compact fridge, and it is borderline for an efficient full-size model, with little margin for cloudy days.

Can a 100 watt solar panel run a refrigerator? Not a standard refrigerator. A 100W panel makes about 300 Wh on a good day. It can carry a very efficient chest unit set as a refrigerator. See what a 100 watt solar panel can run.

How long will a battery run a refrigerator? Divide the battery's usable watt-hours by the fridge's daily use. A 12V 100Ah LiFePO4 battery (about 1,150 usable Wh) runs a fridge that uses 1,100 Wh a day for about one day with no sun.

Can a portable power station run a refrigerator? Yes, for outages and short off-grid trips. See how to run a refrigerator on a portable power station.

Not sure what size system you need? Call our team at 888-855-7286 with the kWh figure from your fridge's EnergyGuide label and where you live, and we will size the panels, battery, and inverter with you.

Energy figures are estimates. Actual refrigerator use varies with model, room temperature, settings, and how often the door is opened. This guide is general information, not electrical advice. Have your system wired and fused by a qualified installer.

Reviewed by the Krato Power team. Questions? Reach us at 888-855-7286.