I’ve been camping for three decades now, and I understand food storage is usually a big nightmare for most campers.
Personally, I’ve been using camping fridges to extend the lifespan of my camp meals. The Dometic CFX3 75DZ Portable Camping Refrigerator is usually my go-to option and has served me well.
I’ve also used a couple of other camping fridges, and if you’re looking to learn how mini-fridges work, I’m your guy.
Generally, camping fridges have different operating mechanisms. The most popular camp fridge, however, the compressor fridge, works by pressurizing the refrigerant fluid.
Pressurization heats the fluid, which is then redirected to a low-pressure compartment where it expands and decompresses.
The decompressed refrigerant turns cold and is passed through the fridge for cooling. The cycle repeats itself.
But this is just but an oversimplified model.
In the section below, I’ll go into detail and share everything you need to know about the working of camping refrigerators.
Classification of Camp Refrigerators and How They Work
To understand how camping fridges work, it’s crucial that we first look at the different types of camping refrigerators.
The three popular categories of camp fridges are:
- Thermoelectric portable fridges
- Compressor fridges
- Absorption fridges
Thermoelectric fridges are a popular option because of their low price. They’re stupid cheap compared to other camping fridges.
Another great draw with the thermoelectric fridges is their super-compact design. It’s one of the great benefits for RV campers because the fridge doesn’t consume real estate in their camper van.
Plus, they’re tough and have fewer moving parts, thus reducing the chance of sliding or breakdown.
Unfortunately, thermoelectric fridges don’t get as cool as your typical refrigerator and will hardly form ice.
They’re more of an advanced cooler and less of a fridge since they cool below the ambient temperatures. So, it can only cool to a certain level, below the outside temperature of its location.
In short, they use the outside temperatures of their location to determine the inside temperature.
But that’s fine if you’re in a cool climate or need to bring them on a road trip or weekend trip where you won’t need to keep your food cold for long.
However, inside a van on a 40-degree day, your food will start getting warm, and they’ll constantly be running.
I own one for use around the home because of its lightness. Still, I wouldn’t recommend it for daily living because of its inability to cool to a set temperature and less energy efficiency.
How a Thermoelectric Fridge Works
Thermoelectric fridges work on a physical phenomenon called the Peltier Effect. It’s the reason these portable models are also known as Peltier fridges.
The phenomenon is based on different conductors/ two dissimilar metals.
If you take two conductors made of different materials and connect them in a loop, then the current will flow if there’s a temperature difference between the two junctions.
The reverse is also true.
If you force current through the wire junctions, one junction gets hot and the other cold.
When you power a thermoelectric cooler, heat moves from one plate on the inside (cooling) to the plate on the outside (warming).
And as the ambient temperature moves across the outside plate, it draws more heat, and the cycle continues.
In short, the thermoelectric works by moving the heat from the cool side to the hot side. But once the hot side is too hot for the ambient temperature to draw more heat, the TEC can no longer cool your food.
And this explains why the thermoelectric coolers will only work when the ambient temperatures are low.
Of course, our explanation is an oversimplified version of the thermoelectric effects, but it should give you some idea of how these portable fridges work.
Most traditional RVs utilize absorption refrigerators, primarily because you can power them with propane gas or electricity DC power.
I’m a big fan of their power supply versatility because I always run out of my RV battery power. But with the absorption fridges, I use alternative power methods and save my car battery for coffee making or phone charging.
While they’re not the most efficient options, the good thing is the absorption refrigerators are not temperature controlled as the TEC. But they can only go as low as 30 degrees of the ambient temperatures.
The biggest plus with this mini fridge is it lacks a motor, no moving parts, and therefore runs almost entirely silent.
Now, in a home, your fridge noise is likely to get drowned by other appliances. But while boondocking in the wilderness alone, the sounds could eventually become annoying, especially when you need to catch some sleep.
Remember that these portable fridges are gutless when not on a completely level surface. They won’t work properly if they’re not upright.
How an Absorption Fridge Works
An absorption fridge uses a special fluid known as a “refrigerant,” boiling in a low-pressure chamber.
When the fluid is released into the air inside the refrigerator, it absorbs all the heat.
During the cooling process, the fluid boils from the heat it absorbs. The boiling results in evaporating the refrigerant into a gas (like steam after water boils).
The gas refrigerant is then passed through a salt solution, which is colder than the gas. It causes the gas to condense and mix with a salt solution.
Or rather, the salt absorbs the now liquified gas (refrigerant), and this “absorption” gives this camp fridge its name.
The salt solution is then heated again, causing the gas to bubble out of the salt solution. The refrigerant gas is cooled again, just a little enough to turn into liquid.
It’s then channeled through metal pipes to the refrigerator air for cooling the inside air again, and the cycle continues.
The process repeats itself, again and again, provided the heating col is heated.
Remember that the fridge will work optimally if there’s constant air flow, especially over the heating coils.
A compressor camping fridge is the closest to your home fridge, except probably a bit smaller.
The energy-efficient compressors are superior to all other camping fridge categories, including longevity, cooling efficiency, and power consumption.
Unlike the typical coolers that die much faster and do a shitty job all the while, a compressor will last for quite a long time, all while providing you with superior performance.
It’ll keep your food cool even on the hottest days.
We’ve an energy-efficient Novacool 3800 compressor refrigerator that we use mostly for boondocking. We’ve had it for three years now, and it is still going strong.
We made a three-month summer trip through Central America before Covid, and the fridge made ice every day without a problem.
We also don’t eat out that often, so we bought a lot of food requiring refrigeration on our trip, and the Novacool served us well. It never failed and continues to run.
Plus, we never had to worry about our RV battery power dying because it’s extremely efficient. While it drains more energy than a thermoelectric fridge, it’s more efficient than an absorption fridge.
The compressor fridges will even work when they’re not at ground level, and this is a huge plus for camping enthusiasts.
I usually bring mine anywhere, especially when I need to take on the bumpy off-roading.
But the greatest benefit is they allow for cold freezing of your food. While they’re temperature-controlled like our other options, their internal temperature fluctuates by a measly 6 degrees, so I can always keep my beer cold.
It means if the external temperatures are hot, the fridge is likely to get 6 degrees higher than what you’ve set it. On the other hand, if it’s freezing outside, the internal temperature will be 6 degrees lower than the set temperature.
How a Compressor Fridge Works
A compressor refrigerator usually has a closed loop of fluid or refrigerant.
The fluid is compressed in a high-pressure condenser chamber outside the refrigeration compartment. The compression makes the fluid hotter.
Next, the compressed fluid is directed to a low-pressure evaporator inside the fridge, where it then decompresses (expands).
The decompression cools the fluid, which is then passed to the fridge, and the cycle continues again.
Now, if you’re yet to understand how the cooling works, open your mouth wide and blow your hand. Next, press your lips together to form a tiny hole and blow on the palm again.
You’ll notice that your hand will feel warmer with the open mouth, but with the lips tight, you feel cooler.
The reason is when gas or liquid expands; it absorbs energy. The same applies to your fridge.
When the coolant is compressed, it cools the outside of your compressor fridge and results in heat loss. But when it decompresses when re-entering the fridge, it absorbs the warmth and thus cools the internal refrigerator.
One key thing to understand is you’re making the air colder while making the refrigerant warmer.
How to Use a Camping Refrigerator
Now that we know the different types of mini-fridges and how they work, let’s move to the next section and look at some o the handy tips for using a refrigerator.
1) Set the temperatures correctly
Setting proper fridge temperatures is key to preventing your food from spoiling. Generally, meat, milk, veggies, fruits, and other perishables will go bad if stored improperly.
Generally, a safe refrigeration temperature is below 40 degrees Fahrenheit; 38 is ideal.
But the lower, the better.
See, temperatures play a huge role in bacterial growth, which ultimately results in food spoilage.
Now, many campers think that keeping their fridge temperatures higher than the 40 to 50 degrees Fahrenheit range offers a nice balance between keeping their food cold and saving on power.
But that’s further from the truth.
Fridge food, or any other food for that matter, can’t go bad on its own.
Instead, the bacteria usually break it down.
The higher the ambient temperatures, the more the bacteria multiply, and the faster they break down your food.
After all, we all know that freezing foods will extend their lifespan and even sometimes beyond their expiry date.
So, lowering your fridge temperatures to 33-35 degrees F will improve your food’s life shelf exponentially.
Of course, this translates to more energy consumption, but the electricty price isn’t comparable to that food of going bad.
If you buy foods that need refrigeration, ensure you put them in the fridge immediately. Otherwise, their extended stay outside may result in faster spoiling.
I’d also recommend you’ve an extra thermometer in your fridge. The built-in units are, at times, misleading.
- Milk should be stored at 41 degrees, while eggs should be at 45
- Lower your camping refrigerator temperatures by 3 to 4 degrees to create a buffer. Their compact size means they’re subject to fluctuating temperatures
2) Packing your Camping foods Correctly
Storing your camping food in a fridge is also necessary for their long life and maintained quality.
The ten golden rules that I use for packing food in my camping refrigerator are:
1) Always write a date on whatever you freeze so it doesn’t get frozen for long periods.
2) You should always store frozen goods at your fridge’s bottom and middle section
3) Store new food at the back and old at the front. It’ll allow you to set eyes on the old stuff before you forget or it goes bad.
4) Avoid cross-contamination by separating things. For example, meats should be stored separately from veggies & fruits, and canned beverages.
5) You’re not a restaurant. So, don’t overstock your fridge to the extent that your food goes bad or lacks space.
6) Vac seal and freeze your meat. Alternatively, wrap your meat tightly before freezing.
7) All opened foods or cut ingredients should be stored in a plastic bag free of air. Saran/plastic wrap is your friend.
8) To defrost your meat, start by thawing it, and cook when ready. If in a hurry, put the frosted meat in cold water.
9) Keep away the heavy items from your camp fridge doors, or otherwise, it will break. Don’t place the perishable foods on the fridge door because temperatures fluctuate significantly.
10) A freezer is suitable for extended storage. Eggs, dairy (except butter), veggies, and fruits shouldn’t be stored in the freezer.
3) Positioning your fridge
Properly positioning a fridge in a camper is critical for its stability and long life.
When positioning your fridge in a camper, start by securing it. It should help prevent the fridge from falling and breaking down.
The good news is that most campers usually come with a designated section for installing the fridge.
However, if you need to get creative, you can utilize some wood boards to secure the fridge.
The ideal location should be out of the way to avoid accidents.
Plus, the location should be free from direct sunlight. While the sunlight may not seem as much, the extra heat forces your camper to work harder than it should.
4) Keeping your Camping Fridge Cold
Getting a camping refrigerator cold is super easy. You must play to the temperature settings to go as low as you’d prefer.
However, there’s another trick I use to keep my fridge cold. Using frozen water bottles.
So, the thing is what I do; I usually buy a bunch of empty water bottles, then fill them with water.
Next, I put them in a freezer a day before heading out for my camping trip.
And when stocking my refrigerator, I pack a bunch of frozen bottles.
While the tip isn’t the most bullet-proof, it works wonders, especially when I’m with my thermoelectric fridge and not planning to stay outside for long.
My TEC isn’t affected by ambient temperatures when I’ve frozen water bottles.
Of course, as I mentioned previously, using a thermostat setting is probably the easiest way to get the refrigerator temperature to its minimum.
Using Fan and Air Vent to Maintain Low Temperatures
A thermostat is perfect for lowering and maintaining the internal fridge’s temperature.
Now, for compressor fridges, this comes easy, provided the fridge is connected to the power sources.
But not so much for the thermoelectric fridges.
The TEC depends on the external ambient temperatures to maintain cool.
Luckily, you can control the outside environment by using a fan and air vent.
Camper van fans are particularly effective, considering the space is usually small and insulated.
Using a fan lowers the ambient temperatures, which will, in turn, allow the thermoelectric fridge to lower and maintain the temperature.
Group your Meals
Grouping of meals can also help to keep the ambient fridge temperatures down.
For example, I usually group ingredients for meal one in bag one, meal two in bag two, and so forth.
The idea behind the food grouping is to allow you to limit the time you need to open, dig and sort the foodstuffs.
Instead, stacking them in order ensures you’ve everything in place and ready. It avoids you opening the fridge repeatedly, letting hot air in and lowering the temperature.
Also, I suggest you don’t drain off the melted water from your fridge unless you find it necessary. The water is usually cold and helps lower the temperatures and fill the spaces that would allow the entry of hot air.
I know I had mentioned this earlier, but still worth reiterating.
Keeping your fridge in the shade is necessary because it prevents the fridge from overworking itself.
You could even go the extra mile and put an insulating material such as a towel or blanket over the fridge for added insulation.
Personally, I use a damp towel, which helps with evaporative cooling.
5) Keep your Camping Fridge on Level Ground
I live in a fairly steel hilly area, and normally, when I park my camper van, it’s usually on an incline. But I usually put the togue a few inches above the ground, so I can level the trailer.
So far, I’ve not had a problem.
But it may not necessarily be true for you.
While a few degrees out of level is okay, I wouldn’t recommend running your fridge, especially if you’re out of level.
Of course, it also depends on the type of portable fridge that you’ve.
For example, thermoelectric fridges are rugged to withstand the harshness of difficult terrains, including uneven surfaces.
A TEC on the relatively uneven ground shouldn’t be a huge issue. The main concern should come from the loose connections and wires.
But that’s not the case with the compressor and absorption fridges.
The unlevel ground may lead to loose connections on the absorption fridges and makes the compressors run less efficiently because of poor heat transfer.
6) Sizing is Crucial
Sizing a portable refrigerator is crucial, especially when space is premium.
You don’t want to invest in an overly large fridge your RV can’t support or a small one that won’t fit your needs.
Of course, everyone has different demands, but I usually like to consider how many days I typically camp, the amount of food I need, the climate, and the availability of drinks storage.
Usually, I aim for a refrigerator that can support me for a week off-grid before I need to restock.
That said, here’s a general breakdown of the camping refrigerator size to consider:
- 21-quart: Weekend trips with a few spaces for drinks
- 36-quat: Can run for a whole week
- 53-quart: Can run for a whole week and has extra space for 12-pack drinks
Understand that each camp fridge is different and built for different purposes. For example, most of the angling fridges usually have more space for drinks than food.
So, it’s crucial to consider your camping needs a purpose before selecting the ideal size.
Benefits of a Portable Fridge
A portable fridge is the best single upgrade you can make to your camping experience.
Usually, most portable fridges are ultra-light and portable.
I’ve a Dometic portable fridge that I use in my RV, and one thing I love about it is the unmatched portability.
While not as easy as tossing a cooler in the back of my truck and grabbing it out, the mini-fridge is fairly lightweight and convenient to handle.
The portable fridge is also more rugged and has good handles, which is exactly what I needed to traverse the rugged conditions.
It also has superior cooling properties, which was important for me, especially when I needed to head out for the hot summer trips.
The portable fridge is also quiet and gives me peace of mind when I need to rest after a long day in the wild.
Finally, it’s a useful gear in that it can fit many environments. I don’t mind using it at home when I’m not in the wild.
Drawbacks of a Mini Fridge
Q: How do I power a camping fridge?
A: The best way to power your portable fridge is through the RV deep cycle battery power. But depending on the fridge, you can also use AC/DC power connections for the electrically assisted cooler or solar panels.
Q: How long can I run my camp fridge?
A: Generally, a fridge consumes one amp-hours, so when running on a 100 amp battery, you could run it for 100 hours before requiring a recharge.
Having a portable camping fridge is a nice way to upgrade your RV. It allows you to enjoy all the convenience and luxuries of your home, even in the wilderness.
But knowing the proper way to use the right fridge also makes a difference in your camping experience.
Fortunately, I’ve shared everything you need to know about how camping fridges work.