What Size Solar Panel Do I Need to Run a 40l Engel?

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What solar panel size do you need to run a 40l Engel? That is the question campers, travelers and outdoor enthusiasts are asking. It is one of the most popular portable fridge models around, but how many should you have? And do you need batteries to use it?

A 50 watt solar panel can run a 40L Engel for 5 hours. To keep the fridge going for 24 hours the solar panel must be connected to a 150ah deep cycle battery which will power the fridge when the sun goes down.

40L Engel Solar Power Requirements

Engel fridge power consumption is measured in amps while solar panels are in watts. So the first thing you have to do is figure out how to convert watts and amps back and forth.

Watts / volts = amps
Amps x volts = watts
Watts / amps = volts

A 12V 40l Engel fridge uses 0.7 to 3 amps or 36 watts an hour. Add 20% to the required watts and you have 43 watts, which you can round off to a 50 watt solar panel

3 amps x 12 volts = 36 watts + 20% = 43 watts, or a 50 watt solar panel

A 50 watt solar panel can run the fridge for 5 to 6 hours depending on how much sun is available. It is possible to use a smaller solar panel. You can connect two 20W modules for instance, but having reserve power is ideal in case solar production is low.

Engel fridges can run on different power sources – AC, DC, 120V, 12V etc., – but we use 12 volts because that what most will have when camping. However the formula remains the same: Engel fridge total watts + 20% = solar panel size.

A 50 watt solar panel such as the Newpowa PV Module will be sufficient for the Engel. If you want to be safe, you can go with an 80 watt or 100 watt solar panel or connect two 50 watt panels together.

Engel Fridge Solar Panel Chart Guide

Engel has several portable fridge models available in various sizes and capacities. Below are some of the more popular capacities along with recommended solar panel sizes. Keep in mind that the amps drawn by the fridge may vary, so check your product documentation for details.

The solar panel recommendations given below are the ideal, not the minimum. 40 watts is the absolute lowest you can use, but you would need the panels to produce 40 watts an hour for the entire day to power an Engel fridge.

Engel Fridge SizeAmps Drawn Per HourSolar Panel Size
15L / 16 quarts 0.6-2.550W
20L / 22 quarts 0.66-2.75 50W
40L / 42 quarts 0.7-3.0 50W
60L / 64 quarts 0.7-4.2 60W
79L / 84 quarts 0.7-4.2 60W

A 50 watt solar panel can produce 50 watts only in ideal circumstances. Cloudy skies and other weather factors lead to a drop in performance. But even in less ideal situations the solar panel should still run a 40l Engel easily.

These figures assume you are camping during summer or in a sunny location. If you are camping in the Pacific Northwest during fall, you may need an 80 watt solar panel to make up for lack of sunlight. Check the weather in your area before deciding what solar panel to get.

No matter where you are there will always be variables that affect solar power performance. In an ideal world solar panels will always run at peak power but in reality that is not the case.

If your Engel needs 35 watts and you use a 35 watt solar panel, you have to hope the panel never falls below 35 watts while you are running the fridge. In case it does the fridge will stop running and if it is filed with food and rinks they could be spoiled.

But if you have a 50 watt panel on the other hand, you can relax. Even if the panel drops below 50 watts there should be enough power left to run the fridge. So the more power you have, the better for your fridge.

How Long Can Solar Panels Run an Engel Fridge?

Solar panels can provide power for as long as there is sunlight. The number of sun hours available determines how long you can keep an Engel fridge running on solar.

If your Engel fridge draws 2.5 amps an hour, that is 30 watts. Assuming it is summer with 6 hours of sunlight you can use a 50 watt solar panel to power the fridge.

With enough sunshine you could get away with just 40 watts. But a 50 watt panel is still the better option so you don’t have to worry in case the sky clouds for a bit. Even if the panel drops 5 to 8 watts during summer, there is enough power left.

With 50 watts of power that fridge can run for several hours. Peak performance will be at noon and drop during the afternoon. If you keep an eye on the panel, you will see the charge at around 40 watts in the morning and reach 45 to 50 watts at noon before dropping off again.

The watts drop will vary depending on the temperature. As the day gets hotter the voltage drops and so does solar power performance. It is the energy of sun, not the heat, that PV modules require. Solar panels do not need heat to function. As long as the sun is out there, the cells will be able to convert it to current.

So it’s pretty simple, you can power a 12V fridge for as long as there is sunlight. That is fine if you plan to camp for a few hours or half day. But what if you want to camp for a day or two?

In that case you will need a battery, one that is large enough to run the fridge for as long as you like. Having enough batteries to run the fridge for a day or more requires a bit more math.

How Many Batteries Do I Need to Run a 40L Engel?

You can connect an Engel fridge to a solar panel directly and run it without a battery. That is well and good if you will use the fridge for 5 to 6 hours a day. But if you want to run the fridge overnight you have to use a battery.

A 12V 150ah deep cycle battery can run a 40l Engel fridge for 24 hours, provided the fridge uses 3 amps an hour or 72 amps a day. Even if the battery has a 50% depth discharge, that still leaves 75 amps available.

To put it another way: 72 amps is 864 watts, so the battery must supply that power for 24 hours. A 12V 150ah battery has 1800 watts with 900 watts available per charge.

By connecting a solar panel to a battery you can charge the battery and store energy for use later. 150ah is the minimum requirement to run the fridge for a day. If you plan on going on a 3 day trip and want the fridge on 24/7, you should get a 500ah battery bank.

A battery bank that size will run a 20 to 40 liter Engel fridge for 3 days or a 60 to 80 liter Engel for 2 days. This battery bank is only for the fridge and you cannot use it to run other devices. if you pack a lot of other gear, add the total watts to get an idea of what battery bank size is required.

If you want to pair a battery with the solar panel, a good choice is the ECO WORTHY 150ah LiFePO4 as it is designed for freezers and other appliances.

Tips For Using Solar Power with an Engel Fridge

You can run an Engel fridge solely from a solar panel or a battery, but the best option is to use them both. This gives you more options and greater flexibility in the long run.

With just solar panels you are limited to 5 or 6 hours a day. If you use the battery to run the fridge for 24 hours, power gets quickly depleted. By using solar panels during the day and the battery at night, you can keep the fridge going without depleting your power source.

A 50 watt solar panel and a 150ah battery is enough for an Engel. For a 3 day camping trip, get a 500ah battery and a 250 watt solar panel. Again you should add your total power consumption, not just the fridge.

If you are on an RV or in a solar powered mobile home, you probably have a generator to run other appliances. RV campgrounds have power so you can use the solar panels and batteries on the fridge. But if you only depend on the batteries, make sure you have enough power for all your needs.

Use the cigarette lighter socket on your vehicle if possible. Connect the fridge to it and as long as your vehicle runs, the fridge receives power. When you pull over and stop, the fridge switches over to the battery automatically. With these, plus solar panels, you have more options on how to run an Engel fridge.


No matter what Engel fridge size you go for, you should always have some extra power on tap. Planning ahead for your next trip will make it easier to determine how much energy you need.