How Much Power Do I Need for a Camping Fridge?

Jun 08, 2025

Think your camping fridge just sips power? Think again. Most camping refrigerators need 30–50 watts to run, but trip length, fridge size, and weather all change the game. Want cold beers and a battery that lasts the weekend? Stick around—we’ll make your fridge smarter than your tent.

Understanding Your Fridge's Power Needs: Watts vs. Watt-Hours

The Quick Answer: Typical Power Consumption

A camping fridge is essential if you want your food and drinks to stay fresh while you're out in nature. Most camping refrigerators typically use between 30 to 50 watts while running. However, actual power needs can vary depending on size, design, insulation, and outdoor conditions.

Knowing your fridge’s power draw helps you choose the right setup. It can save you from warm drinks and spoiled sausages halfway through the weekend.

Thetford black caravan fridge with chrome trim on a white background.

Average Running Watts of a 12V Compressor Fridge

Most camping fridges operate on 12V DC systems. A mid-sized compressor fridge may run around 40 watts, which means it draws roughly 3.33 amps while operating.

This figure reflects the average running load—not the peak demand. It gives you a good baseline for estimating total energy use over time.

Why You Must Also Consider "Startup" Watts (Surge Power)

Some fridges, especially older or budget models, need a bit of a jolt to start up. Their startup or surge power can be 2–3 times their running wattage.

That means a 40-watt fridge might briefly draw 80 to 120 watts when switching on. It's crucial to factor this in if you're using an inverter or a low-powered battery system.

Why Watt-Hours (Wh) Are the Most Important Number

Instant power (watts) matters, but watt-hours are the real star. This figure tells you how much energy your fridge consumes over a day. It’s what truly affects battery drain and solar panel sizing.

From Instant Power (Watts) to Daily Energy Use (Watt-Hours)

To calculate watt-hours, multiply the fridge's wattage by the number of hours it runs. If a 40W fridge runs for 8 hours, it uses 320 Wh per day.

This helps you plan your power setup, whether you're using a battery, solar panels, or a generator.

The Critical Role of the "Duty Cycle"

Fridges don’t run all day non-stop. The duty cycle refers to the percentage of time your fridge's compressor actually operates.

A 50% duty cycle means your fridge runs half the time. Good insulation and mild temperatures can reduce runtime, saving you power.

Factors That Dramatically Change Your Power Needs

Ambient Temperature: The Biggest Power Drain

When the weather heats up, so does your fridge’s energy demand. High ambient temperatures force your fridge to work harder, cycling on more often.

Even a well-insulated fridge can struggle if left in direct sun all day. Shade helps, as does pre-cooling it before your trip.

Your Fridge's Temperature Setting and Insulation

Lower temperature settings require more energy. Likewise, fridges with poor insulation leak cold air and need to run more often.

Look for fridges with high-efficiency ratings and proper sealing. They help keep food cold without draining your power supply.

How You Use It: Fridge Contents and Opening Frequency

A full fridge holds its temperature better than an empty one. Cold items help each other stay cool.

Opening the fridge often or keeping it open too long makes the compressor kick in more frequently. Be quick with the door—and don’t stare in hoping a snack appears.

Dometic tall absorption caravan fridge freezer open with contents inside on a white background.

How to Calculate Your Total Power System Needs

A Simple Step-by-Step Calculation

To avoid dead batteries or warm drinks, do a quick power audit. Here’s how to work it out.

Step 1: Find Your Fridge's Daily Watt-Hour (Wh) Consumption

Take the wattage of your fridge and multiply it by its daily runtime. For example, a 40W fridge running for 8 hours uses 320 Wh/day.

Step 2: Decide How Many Days You Need to Run "Off-Grid"

Multiply your daily Wh usage by how many days you plan to camp. For a 3-day trip at 320 Wh/day, you’ll need 960 Wh total.

Step 3: Add a Safety Buffer (Why You Need 20–30% Extra)

Conditions change. You might run the fridge longer than expected or use it more intensively.

Add 20–30% extra to your total to cover unexpected demand. In this case, 960 Wh + 25% = 1,200 Wh.

Step 4: Putting It All Together for Your Total Power Requirement

Once you know your total Wh requirement, you can plan your power sources. It’s your blueprint for battery and solar sizing.

Sizing Your Battery and Solar Setup

Matching Battery Capacity (Ah/Wh) to Your Calculated Needs

Batteries are usually rated in amp-hours (Ah). To convert watt-hours into amp-hours, divide by the voltage.

For a 12V system: 1,200 Wh ÷ 12V = 100 Ah. Always round up and include your buffer for longer reliability.

EcoFlow portable fridge powered by solar panels in a grassy outdoor field with green trees in the background.

How to Choose the Right Size Solar Panel to Keep Your Battery Charged

A 100W solar panel typically generates around 300–500 Wh/day, depending on sunlight and conditions.

If your fridge uses 320 Wh/day, a 120W to 160W panel gives you a safe margin. It's always better to overestimate solar input than fall short in the middle of nowhere.

Other content you might like:

Back to Camping Refrigerators Blog