# What Size Solar Panel for a 12V Fridge? (Worked Math) > How many watts of solar a 12V fridge needs: daily Wh divided by peak sun hours and losses, with worked examples for small, 45-quart and dual-zone fridges. - Source: https://portablefridgeguide.com/posts/solar-panel-size-for-12v-fridge/ - Markdown version: https://portablefridgeguide.com/posts/solar-panel-size-for-12v-fridge.md - Last updated: 2026-10-30 --- - [Home](https://portablefridgeguide.com/) - [Guides](https://portablefridgeguide.com/guides/) - What Size Solar Panel Do You Need for a 12V Fridge? Solar # What Size Solar Panel Do You Need for a 12V Fridge? Updated October 30, 2026 By [Portable Fridge Guide Editorial Team](https://portablefridgeguide.com/about/) [How we research](https://portablefridgeguide.com/how-we-research/) Prices are approximate and change often, so check the current price before you buy. ## Key takeaways - **Solar watts ≈ daily Wh ÷ peak sun hours ÷ 0.75.** The 0.75 covers controller, wiring and panel-angle losses. - A typical 45-quart fridge in 85°F weather needs about **75 W** of solar with 5 peak sun hours. Buy 100 W for margin, more for clouds or short winter days. - Dual zones with a freezer running are a different class: Dometic's CFX5 75DZ figure works out to about 800 Wh a day, or 200 W+ of solar. - Solar always needs a battery. Panels only produce in daylight, and Dometic says you need a battery to store the energy. ## Our top picks - 1![EcoFlow GLACIER Classic 35L](https://portablefridgeguide.com/_astro/ecoflow-glacier-classic-35.BOvSiZZQ_ZK515Y.webp)Built-in 110 W solar input and a published 165 Wh/day draw[EcoFlow GLACIER Classic 35L](https://portablefridgeguide.com/fridges/ecoflow-glacier-classic-35/)37 qt · Single zone · Down to -4°F · 45 lb7.6**$$$**$PremiumPrice tier: Premium[Check price on Amazon](https://www.amazon.com/dp/B0F62HMKBX?tag=portablefridgeguide.com-20) - 2![BougeRV CRD2 V2.0 43QT with 240Wh Battery](https://portablefridgeguide.com/_astro/bougerv-crd2-v2-43-battery.Bgu122Jl_ZhSvDt.webp)Battery in the box with a 150 W solar input, the most of any fridge we track[BougeRV CRD2 V2.0 43QT with 240Wh Battery](https://portablefridgeguide.com/fridges/bougerv-crd2-v2-43-battery/)43 qt · Dual zone · Down to -4°F · 50.7 lb7.9**$$**$$Mid-rangePrice tier: Mid-range[Check price](https://www.amazon.com/dp/B0GJYCVHJN?tag=portablefridgeguide.com-20) ### On this page 9 sections - [What’s the formula?](#whats-the-formula) - [Step 1: How much energy does your fridge use per day?](#step-1-how-much-energy-does-your-fridge-use-per-day) - [Step 2: How many peak sun hours will you get?](#step-2-how-many-peak-sun-hours-will-you-get) - [Worked examples](#worked-examples) - [Step 3: Size the battery to cover the gaps](#step-3-size-the-battery-to-cover-the-gaps) - [How do you connect the panel?](#how-do-you-connect-the-panel) - [Mistakes that leave you with a flat battery](#mistakes-that-leave-you-with-a-flat-battery) - [Bottom line](#bottom-line) - [FAQ](#faq) ## Before you choose - [How to Power a Portable Fridge: Car Socket, Second Battery, Power Station or Solar](https://portablefridgeguide.com/posts/how-to-power-a-portable-fridge/) - [How Long Will a Battery Run a 12V Fridge? The Math, With Worked Examples](https://portablefridgeguide.com/posts/how-long-will-a-battery-run-a-12v-fridge/) - [Portable Fridge Power Consumption Explained: Watts, Ah/h and Wh per Day](https://portablefridgeguide.com/posts/portable-fridge-power-consumption-explained/) Solar is what turns a fridge setup from “two or three days” into “as long as the food lasts.” The sizing question has a straightforward answer once you know how much energy your fridge uses in a day and how much sun you’ll actually get. This guide gives the formula we use in our [battery runtime calculator](https://portablefridgeguide.com/tools/battery-runtime-calculator/), worked examples for different fridges, and the mistakes that leave people with a flat battery under a sunny sky. We haven’t tested panels ourselves. The inputs come from maker specs and our own published estimates. ## What’s the formula? ``` solar watts needed = daily Wh ÷ peak sun hours ÷ 0.75 ``` - **Daily Wh** is what your fridge uses in 24 hours, at your temperatures. - **Peak sun hours** is the equivalent number of hours of full, bright sun your panel gets in a day. Five hours of “peak sun” usually means a whole day of real sunshine, not five hours of daylight. - **0.75** covers the losses between the panel’s label and your battery: charge controller, wiring, heat, dust and a panel that isn’t aimed perfectly. Portable panels rarely make their nameplate watts. The result is the panel size that breaks even, replacing what the fridge used that day. You’ll want some margin above it. ## Step 1: How much energy does your fridge use per day? Only one fridge we track publishes a fridge-mode daily figure. EcoFlow rates the [GLACIER Classic 35L](https://portablefridgeguide.com/fridges/ecoflow-glacier-classic-35/) at 165 Wh per 24 hours at 77°F outside and 39°F inside, in Eco mode. Dometic publishes an hourly figure for the CFX3 45 (1.03 Ah/h at 90°F), which works out to about 300 Wh a day. For every other model we estimate from capacity. Our chart shows those estimates at 90°F outside and 37°F inside: Estimated power use per day (Wh) Energy per 24 hours at 90°F outside and 37°F inside, scaled from each maker's published average draw. Lower is better. Single zone Dual zone [C20* 190](https://portablefridgeguide.com/fridges/alpicool-c20/)[BougeRV 23 qt* 190](https://portablefridgeguide.com/fridges/bougerv-cr22-23/)[CFX2 28* 220](https://portablefridgeguide.com/fridges/dometic-cfx2-28/)[GO20* 220](https://portablefridgeguide.com/fridges/iceco-go20/)[Glacier Classic 35L 230](https://portablefridgeguide.com/fridges/ecoflow-glacier-classic-35/)[EverFrost 2 40L* 260](https://portablefridgeguide.com/fridges/anker-everfrost-2-40/)[VL45 ProS* 280](https://portablefridgeguide.com/fridges/iceco-vl45-pros/)[CRD2 V2 43 + Battery* 310](https://portablefridgeguide.com/fridges/bougerv-crd2-v2-43-battery/)[CFX5 55IM* 310](https://portablefridgeguide.com/fridges/dometic-cfx5-55im/)[Euhomy 59 qt* 310](https://portablefridgeguide.com/fridges/euhomy-59qt/)[VL60 Dual Zone* 400](https://portablefridgeguide.com/fridges/iceco-vl60-dual-zone/)[CFX5 75DZ* 460](https://portablefridgeguide.com/fridges/dometic-cfx5-75dz/)[VL75 ProD* 460](https://portablefridgeguide.com/fridges/iceco-vl75-prod/) 0200400600 * No published fridge-mode draw: estimated from capacity, calibrated on fridges that publish one, so treat it as rough. Freezer settings, lid opening and warm food all add to these figures. Run your own numbers in the [battery runtime calculator](https://portablefridgeguide.com/tools/battery-runtime-calculator/). The bars are estimates for steady running with the lid mostly closed. Freezer settings, hot sun on the fridge and warm food going in all push the real number up. In real camping, Gnomad Home measured an ICECO VL35 ProS averaging about 508 Wh a day. If you can measure your own fridge with a battery monitor, use that number instead. ## Step 2: How many peak sun hours will you get? This varies more than people expect. The [US Department of Energy](https://www.energy.gov/eere/solar/solar-radiation-basics) points out that solar radiation depends on location, season, time of day, landscape and weather. Its example: Denver gets nearly three times more solar energy in June than in December. Thick clouds can block direct sunlight entirely. Rules of thumb we use: - **Summer, open sky, panel aimed at the sun:** 5–6 hours. Dometic tells CFX owners to plan on roughly 6. - **Spring or fall, or a panel lying flat:** about 4. - **Winter, cloudy forecasts, or a campsite under trees:** 3 or less. Shade is the big one. A panel in partial shade can lose much of its output, so a portable panel you can move into the sun often beats a bigger panel fixed to a roof in a shaded campsite. ## Worked examples All examples use the formula above. Daily figures are our estimates unless noted. | Fridge and conditions | Daily use | 5 sun hours | 4 sun hours | 3 sun hours | | --- | --- | --- | --- | --- | | GLACIER Classic 35L, 77°F (EcoFlow’s published figure) | 165 Wh | 44 W | 55 W | 73 W | | BougeRV 23 Quart, 90°F | about 194 Wh | 52 W | 65 W | 86 W | | 45-qt fridge (Dometic CFX3 45 figure), 85°F | about 283 Wh | 75 W | 94 W | 126 W | | 45-qt fridge (Dometic CFX3 45 figure), 90°F | about 312 Wh | 83 W | 104 W | 139 W | | ICECO VL60 Dual Zone, both sides fridge, 90°F | about 396 Wh | 106 W | 132 W | 176 W | | ICECO VL35 ProS, real camping (Gnomad Home) | about 508 Wh | 135 W | 169 W | 226 W | | Dometic CFX5 75DZ, one zone freezing, 90°F (Dometic’s 2.76 Ah/h) | about 795 Wh | 212 W | 265 W | 353 W | How to read it: for a typical 45-quart fridge in summer, a 100 W panel breaks even in good sun with a little margin. It falls behind on a cloudy day, so your battery covers the gap. For a dual zone running a freezer, plan on 200 W or more. The [Renogy 200W solar suitcase](https://www.amazon.com/dp/B07RFQVB9M?tag=portablefridgeguide.com-20) and the [EcoFlow 220W bifacial panel](https://www.amazon.com/dp/B09TKM8PBQ?tag=portablefridgeguide.com-20) are on our list. ## Step 3: Size the battery to cover the gaps Solar only works in daylight. Your battery has to carry the fridge through the night and through any day when the panel falls short. Dometic’s own recommendation is a 100 W or larger panel with at least a 40 Ah battery. For multi-day trips, we’d size the battery to cover at least a night plus one poor solar day. For a 45-quart fridge that’s roughly 300–600 Wh of usable capacity, which a 100 Ah LiFePO4 covers comfortably. Our [battery runtime guide](https://portablefridgeguide.com/posts/how-long-will-a-battery-run-a-12v-fridge/) has the math. ## How do you connect the panel? There are three common ways: - **A fridge with a built-in battery and solar input.** Per the makers, the [Anker EverFrost 2 40L](https://portablefridgeguide.com/fridges/anker-everfrost-2-40/) takes up to 100 W at 12–30 V, the GLACIER Classic up to 110 W at 11–30 V, and the [BougeRV CRD2 V2.0 + 240Wh](https://portablefridgeguide.com/fridges/bougerv-crd2-v2-43-battery/) up to 150 W at 12–32 V. Anker notes that solar charging only works with a battery inside the cooler. A [100 W folding panel](https://www.amazon.com/dp/B0DPFK9YMX?tag=portablefridgeguide.com-20) matches these inputs. Check that the connector fits first. - **A power station.** Plug the panel into the power station’s solar input and the fridge into its 12 V outlet. Gear Diary topped up a power station running an ICECO VL60 by setting up a 350 W panel array for about six hours. - **A 12 V house battery.** You need a solar charge controller between the panel and the battery. A suitcase panel with a built-in controller is the simplest way. Whichever you use, don’t exceed the input’s voltage or wattage limit. Too high a voltage can damage the electronics. Too much wattage is usually just wasted. ## Mistakes that leave you with a flat battery - **Sizing from the panel’s label, not real output.** That’s why the formula divides by 0.75. - **Planning around summer sun on a fall trip.** Shorter days and a lower sun cut output a lot. - **Parking in shade to keep the fridge cool,** then putting the panel in the same shade. Run a longer cable and put the panel in the sun. - **Forgetting the freezer.** EcoFlow’s own figures for the GLACIER Classic show freezer mode using about three times the energy of fridge mode (520 vs 165 Wh a day at 77°F). Size for the setting you’ll actually use. - **No battery buffer.** One cloudy day shouldn’t end your trip. ## Bottom line For a single-zone fridge of 45 quarts or less, 100 W of solar plus a decent battery keeps up in summer. Smaller and more efficient fridges can get by with less. For a dual zone with a freezer, or for winter and shady sites, plan on 200 W or more. Start from your fridge’s real daily energy, divide by honest sun hours and 0.75, then round up. The [battery runtime calculator](https://portablefridgeguide.com/tools/battery-runtime-calculator/) shows the solar break-even for your fridge and temperatures. ## Don't guess. Calculate. - [🎯 Fridge Matcher](https://portablefridgeguide.com/tools/fridge-matcher/): which fridges fit your trip - [🔋 Battery Runtime](https://portablefridgeguide.com/tools/battery-runtime-calculator/): hours per charge and solar needed - [🧊 Fridge vs Ice](https://portablefridgeguide.com/tools/fridge-vs-ice-cost/): how fast it pays back - [📊 Compare every fridge](https://portablefridgeguide.com/fridges/): sortable spec table ## Frequently asked questions ### Will a 100W solar panel run a 12V fridge? It can keep a battery topped up for a small or efficient mid-size fridge in good sun. By our math, a 45-quart fridge at 85°F needs about 75 W with 5 peak sun hours, so 100 W gives some margin. It won't keep up in cloudy weather, short winter days or with a dual zone running a freezer. ### Can I run a portable fridge directly from a solar panel? Not reliably. Panel output changes with every cloud and stops at night. You need a battery between the panel and the fridge: a house battery with a charge controller, a power station, or a fridge with a built-in battery and solar input. ### How many peak sun hours should I plan for? It depends on where and when you camp. Dometic tells CFX owners to plan on roughly 6 hours of sun a day; we use 5 in our examples and suggest 3 for winter or cloudy trips. The US Department of Energy notes that Denver gets nearly three times more solar energy in June than in December. ### What size battery do I need with solar? Enough to cover the night plus at least one bad-weather day. Dometic suggests a 100 W or larger panel with a battery of at least 40 Ah. For a 45-quart fridge on multi-day trips, a 100 Ah LiFePO4 battery gives you a comfortable buffer. ## Sources - [Dometic CFX3 45 product page and FAQ](https://www.dometic.com/en/product/dometic-cfx3-45-9600025318) · checked 2026-10-30 — Recommends a 100 W or larger panel and a minimum 40 Ah battery; a battery is needed to store solar energy; plan on roughly 6 hours of sun per day; 1.03 Ah/h published draw - [US Department of Energy: Solar Radiation Basics](https://www.energy.gov/eere/solar/solar-radiation-basics) · checked 2026-10-30 — Solar radiation varies by location, season, time of day and weather; Denver receives nearly three times more solar energy in June than in December; clouds can cut direct-beam radiation by up to 100% - [EcoFlow GLACIER Classic product page and spec table](https://us.ecoflow.com/products/glacier-classic-portable-refrigerator) · checked 2026-10-30 — Solar charging 11–30 V, 8 A/110 W max; refrigeration 165 Wh/24 h (0.57 Ah/h) and freezing 520 Wh/24 h (1.8 Ah/h) at 25°C/77°F in Eco mode - [Anker SOLIX EverFrost 2 40L product page](https://www.ankersolix.com/products/everfrost-2-40l-electric-cooler) · checked 2026-10-30 — Recharges from a 100 W solar panel (12–30 V input); solar recharging only works with a battery inside the cooler ## Get new guides by e-mail One short e-mail when Portable Fridge Guide publishes a new guide. No spam, no sharing your address, and you can unsubscribe in one click. E-mail address New posts only · Unsubscribe anytime · [Privacy](https://portablefridgeguide.com/privacy/) Our #1 pick Built-in 110 W solar input and a published 165 Wh/day draw ![EcoFlow GLACIER Classic 35L](https://portablefridgeguide.com/_astro/ecoflow-glacier-classic-35.BOvSiZZQ_1BQs2x.webp) ### [EcoFlow GLACIER Classic 35L](https://portablefridgeguide.com/fridges/ecoflow-glacier-classic-35/) 7.6 - 37 qt - Single zone - Down to -4°F - Battery included EcoFlow power-station owners who want a cordless fridge with a published, low average draw and IPX4 weather resistance. [Check price on Amazon](https://www.amazon.com/dp/B0F62HMKBX?tag=portablefridgeguide.com-20)[Read the full review](https://portablefridgeguide.com/fridges/ecoflow-glacier-classic-35/) [🔋 Will your battery last? Runtime and solar needs for your fridge, battery and weather.](https://portablefridgeguide.com/tools/battery-runtime-calculator/)[📊 Compare every fridge Sortable chart of every fridge we track.](https://portablefridgeguide.com/fridges/) ## Keep reading [Power ### How to Power a Portable Fridge: Car Socket, Second Battery, Power Station or Solar Five ways to power a 12V fridge: car socket, starter battery with battery protection, second battery and DC-DC charger, power station, and solar, compared. Updated Oct 30, 2026](https://portablefridgeguide.com/posts/how-to-power-a-portable-fridge/)[Power ### How Long Will a Battery Run a 12V Fridge? The Math, With Worked Examples How long a battery runs a 12V fridge: usable Ah divided by average draw, adjusted for heat. Worked examples for AGM, LiFePO4, power stations and built-in packs. Updated Oct 30, 2026](https://portablefridgeguide.com/posts/how-long-will-a-battery-run-a-12v-fridge/)[Explainer ### Portable Fridge Power Consumption Explained: Watts, Ah/h and Wh per Day Why a 60 W fridge doesn't use 60 W: rated input vs average draw, Ah/h vs Wh, duty cycle, what independent tests measured, and why our chart is estimated. Updated Oct 30, 2026](https://portablefridgeguide.com/posts/portable-fridge-power-consumption-explained/) Built-in 110 W solar input and a published 165 Wh/day draw Glacier Classic 35L $$$$ Premium Price tier: Premium [Check price](https://www.amazon.com/dp/B0F62HMKBX?tag=portablefridgeguide.com-20)