Keeping Your Cool: Mobile Fridges

Keeping Your Cool: Mobile Fridges

by Stephan Edwards

In the overland sphere, after roof top tents, there is hardly any accessory that is more discussed and debated than the 12 volt portable refrigerator/freezer. Allow me to declare my bias up front. I believe it is - no joke here - the greatest innovation in adventure travel of the twentieth century, and having owned one for three years now, it would be the very last of my vehicle’s modifications I would give up. I’d give up overlanding first.

So, why am I so over the moon for this accessory that on the surface of things seems like a luxury? They are expensive and bulky. They demand a whole host of additional equipment and accessories installed in your rig to run them effectively. They suck power from your battery. Why a fridge, when the new generation of roto-molded coolers now on the market are so thermally efficient, especially when even the most expensive ones are half the price of a fridge of less capacity? 

Let’s open the lid on all these questions and more.

How does it work?

Just like your refrigerator at home, the portable 12v fridge runs on a compressor that circulates refrigerant, which, alternating between its liquid and gaseous states, creates a cooling effect inside the fridge through an evaporator. Though there are a handful of these fridges offered with a vertical door design, almost all of them have a sealed and latched lid on top of the unit. Some models come with dual compartments whose temperatures can be adjusted individually. All of them can be cranked low enough to be used as a freezer. They usually feature a cigarette-style 12v plug for DC power on the road, along with a 110v AC input for when you want to bring it into the house. Heavy duty handles are used for strapping it securely in place in a vehicle and for portability.

Many of the newer models have advanced electronics and Bluetooth connected apps for monitoring battery life and keeping temperatures in the sweet zone. Accessories like insulated covers protect your investment and improve performance. But the history of the portable fridge is a long one, and overland travelers in Africa, Australia, and Europe have availed themselves of the benefits of mobile refrigeration for many, many years. Only in the last decade or so has the market opened up in North America for venerable brands like ARB, Dometic, and National Luna

Why should I get one?

The advantages of carrying an honest-to-goodness refrigerator in your overland vehicle are legion. 

The first is the sheer convenience of the thing. After you switch it on, a typical fridge will reach operating temperatures in less than 15 minutes. Load it up with your favorite beverages and fresh foods from your home or the store, and you’re ready to hit the road. In contrast with a cooler, you never have to worry about draining it, or tracking down ice to refill it, or suffer anxiety as your cubes and blocks slowly turn to water. Mounted in your vehicle, you save your back by rarely having to lug it around

From a food safety standpoint, the fridge also maintains a constant temperature within the whole of the food compartment, regardless of the environment. There are no temperature gradations like we see in coolers, where items at the bottom stay colder than those closer to the lid. Your steaks aren’t floating around in an ice water bath, and the fridge is easy to clean. 

It will, quite literally, save your bacon.

As noted earlier, you can drop temperatures low enough to turn the fridge into a freezer, and dual-compartment models offer a fridge/freezer combination that’s hard to beat. Especially for longer adventures, the advantage of making meals ahead of time, freezing them, and then thawing them out for a fast dinner in camp is a great convenience. When your frozen foods are finished, raise the temps in the freezer compartment, and it offers its extra storage space as a fridge again. (Or, just keep it that way for ice cream and ice cubes…). The National Luna NL 72 Legacy Double Door fridge is a great example of what a dual-compartment fridge can do.

Finally, it’s often a challenge to eat balanced meals on the road. The fridge offers refuge for your fruits, vegetables, greens, and other produce that benefit from refrigeration, as well as fresh meats and dairy products. Those items stay fresher longer, too. You can plan for real meals on the road with a lot more flexibility.

As a couple of bonuses - if your adventure rig is also your daily driver, the fridge makes runs to the grocery store a little easier on hot days by ferrying your cold items home in temperature controlled comfort. And, if you need the space instead, simply remove the fridge from your vehicle, plug it into a wall outlet with the 110 volt AC adapter, and voila - instant garage fridge!

Ok, what do I need to set up my vehicle to run a portable fridge?

Here’s where the 12 volt fridge creates a few dilemmas for the overlander. First, fridges are bulky, even the smaller models take up a lot of space. That space should be dedicated to the fridge exclusively, as you need tie-down points to secure the unit, as well as room to open the lid, room to access the food compartment, and breathing space to allow for proper ventilation for the compressor. A fridge is heavy, likely not as heavy as a huge cooler with bags and bags of ice, but its weight needs to be taken into account as you calculate your payload capacity.

In some vehicles, the height of the fridge may be an obstacle, and shorter members of your expedition crew could find it challenging to look inside and find items without a boost. In some applications, a fridge slide (a kind of drawer that extends the fridge outside the vehicle) helps with this problem, and some of them have “drop-down” mechanisms that lower it to waist level for even easier access. The price of all this is space, and if your vehicle is on the small side, you may not be willing or able to sacrifice the real estate. 

Second, if you are going to install a fridge in a dedicated overland vehicle you will need to invest in auxiliary power and power management. This adds an extra layer of cost and complexity to your build over a cooler. A fridgecan be run via the vehicle’s main battery. All makes and models come with an adjustable and automatic low voltage cut-off that switches off the compressor when battery levels dip low. But for longer trips, and adventures where there is comparatively little driving, this is a bad strategy that could leave you stranded. While modern portable fridges draw remarkably little current, over time it will eventually affect the health of your main battery.

So, what does this dedicated power system look like? First, you need a deep cycle auxiliary battery that’s designed for long, slow drain and constant recharging. That battery could be permanently mounted in your vehicle, or it could be a portable power pack.

If you choose to mount your auxiliary battery directly in the vehicle, you need to find a space for it, and install a battery isolator or DC-to-DC battery charger that allows your engine’s alternator to charge the auxiliary battery, while at the same time protecting the main battery from the draw of the fridge. You can read more about battery chargers here. An optional extra is a fixed or portable solar panel and solar charge controller to add extra charging power to the system. For more on solar power, see Garrett's article in the Notebook.

Add in the wiring, the fuses, and a dedicated power point for plugging it in, and your investment has quickly ballooned well beyond the original cost of the fridge itself. That said, with a properly installed auxiliary power system, particularly if it’s supplemented with even modest levels of solar charging, your fridge can run almost indefinitely - not something you can say about ice. In addition, this new power grid opens up other options for upgrading your electrical system. The installation of house lights, water pumps, inverters, fans, and power points for charging electronics are all now on the table.

A final point - the fridge is a machine, and, unlike coolers, they can break. This is fairly rare, many veterans of overland travel have had fridges that have run without issue for decades. But, a broken fridge deep in the wilderness presents a problem that’s difficult to address. In all cases, tie down your fridge securely, don’t let it rattle around in the back of your rig, protect it from dust, and make sure it has plenty of ventilation.

Final thoughts?

For two years my wife and I lived and traveled overland in southern and east Africa. During that time, our most trusted companion, besides our Land Rover, was our fridge. In the rural countrysides and wilderness areas of developing nations, ice is almost non-existent. At the end of a long day on rough tracks, having fresh food and a cold beer easily at hand was the best tonic for road weariness, and as much a boost to the spirits as the incredible sunsets and the distant roar of lions. We wouldn’t travel without one again.

Overlander has a comprehensive lineup of high-quality 12 volt refrigerators to elevate your overland setup both in functionality and convenience. Fridges from National Luna, Dometic, and ARB offer a wide range of features, sizes, and price points to fit your budget. Shop for fridges here

In addition, Overlander also supports your fridge installation with batteries, battery isolators, solar panels, and solar charge controllers - not to mention fuse panels, switches and wire management

What do you love to keep cold when you're on the road? Let us know in the comments.

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