Camping Fridge Wattage: What You Need to Know

Jun 08, 2025

Camping refrigerators don’t run on fairy dust—most use 20–100 watts, depending on type and size. So before your milk turns into yoghurt mid-hike, read on. We’ll break down fridge types, power hacks, and how to keep things cool without blowing your battery—or your trip.

Understanding Camping Fridge Wattage: The Simple Answer and the Full Story

The Quick Answer: Typical Wattage of a Camping Fridge

Camping refrigerators typically use between 20 and 100 watts, depending on their design and size.

Compressor fridges are generally more efficient, while absorption fridges tend to draw more power. Knowing which type you have helps plan your power setup accurately—vital if you’re relying on batteries or solar panels.

Dometic black single-door fridge with partially open door displaying food items on a white background.

Average Wattage for 12V Compressor Fridges (by Size)

Compressor fridges are common for campers due to their efficiency.

Typical running wattage by size:

Small (15–30L): 20–35 watts
Medium (30–50L): 35–45 watts
Large (50L+): 45–50 watts

These fridges cycle on and off, so their average energy use is often lower than their rated wattage suggests.

Wattage of 3-Way (Absorption) Fridges

Absorption fridges, also known as 3-way fridges, use more energy—typically around 70 to 100 watts when running on 12V power.

They’re silent and have no moving parts but are much less efficient compared to compressor models.

Tall Thetford fridge freezer with both doors open, revealing neatly arranged groceries, on a white background.

Running vs. Startup Wattage: Why There Are Two Numbers

Some fridges have a startup surge that briefly draws more power than their running wattage.

This is common with compressor fridges, which might spike at 100W but settle at 40W during regular use.

For trip planning, always focus on average running wattage, not the peak.

Beyond Watts: Why Watt-Hours (Wh) Are More Important for Camping

Watts tell you how much power your fridge needs at a moment in time.

But watt-hours (Wh) tell you how much energy it uses over time, which is what really matters for camping.

What is a Watt-Hour (Wh)?

A watt-hour is simply one watt of power used for one hour.

For example, a 30W fridge running for 10 hours consumes 300Wh per day. That’s the number you’ll need when sizing batteries or solar setups.

Understanding Duty Cycle: Why Your Fridge Isn't Always Running

Camping fridges don’t run non-stop.

They typically cycle on and off. A 40W fridge might only run 30–50% of the time, depending on external temperature, how full it is, and how often it’s opened.

This means actual power usage can be much lower than the rated wattage suggests.

Calculating Your Fridge's Daily Power Needs in Watt-Hours

To estimate daily usage:

Multiply your fridge’s average running wattage by how many hours it runs each day.

Example: 30W × 10 hours = 300Wh. This figure helps you choose the right battery or solar panel setup.

Key Factors That Influence Your Fridge's Actual Wattage Use

The #1 Factor: Ambient Temperature

Hot weather makes your fridge work harder.

If it’s exposed to sunlight or high temperatures, it will draw more power to stay cool. Shading your fridge is a simple but effective way to reduce energy use.

Fridge Contents: A Full Fridge is an Efficient Fridge

A fridge that’s packed (but not overfilled) retains cold better.

Cold items help stabilise internal temperature, reducing the need for the compressor to cycle on frequently. Just be careful not to block airflow inside.

Thetford fridge with door open showing shelves stocked with drinks, dairy, and fruit on a white background.

Ventilation and Placement

Fridges need space to release heat. Poor ventilation around the vents or compressor increases power usage.

Avoid placing the fridge near heat sources or in enclosed spaces without airflow. Outdoors, a shaded and breezy spot works best.

Your Fridge's Temperature Setting

Setting your fridge too cold increases energy consumption.

Stick to around 3–5°C for chilled food. Colder settings aren’t usually needed for short camping trips and only drain your battery faster.

How to Use Wattage to Plan Your Power Setup

Translating Watts into Battery and Solar Needs

Once you’ve calculated your fridge’s daily watt-hour usage, you can begin planning your battery or solar setup.

How to Size Your Battery (Ah) Based on Daily Watt-Hours

Use this formula:

Watt-hours ÷ Battery Voltage = Amp-hours (Ah)

Example: 300Wh ÷ 12V = 25Ah per day.

For longer trips or to protect your battery, aim for a battery bank that’s twice your daily usage, especially for lead-acid batteries that shouldn’t be discharged fully.

How to Choose the Right Size Solar Panel to Keep Up

A 100W solar panel generates about 300–500Wh/day in the UK summer, depending on sun exposure.

That’s enough to power a small to medium camping fridge with a suitable battery setup. Always oversize a little to account for cloudy days or inefficiencies.

Common Mistakes to Avoid When Calculating Power

Forgetting About Powering Other Devices

It’s easy to overlook other gear—like lights, fans, or phone chargers.

Add these into your daily consumption when sizing your power system. Your fridge might only be part of your overall energy usage.

Not Accounting for a "Safety Buffer"

Unexpected weather, heavy use, or longer fridge runtimes can increase power needs.

Always add 20–30% buffer to your calculations. This prevents power outages and protects your food—and your sanity.

Using the Wrong Gauge Wiring (Voltage Drop)

Thin wires can cause voltage drop, especially over long cable runs.

This reduces efficiency and may even cause your fridge to shut down. Always use cables rated appropriately for the current and distance involved.

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