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 CAMPING
REFRIGERATION BASICS
No-one travels without a fridge these days.

  

Tough and efficient mobile refrigeration gives bush travel a five-star touch, but you have to get the basics right.

There are few things in life better than icy cold beer and crisp, fresh tucker when you’re eight days from anywhere. That’s why most 4WD trekkers have a fridge near the top of their equipment wish-list. And with durable, effective 12V fridges for sale at under $1000 – less for second-hand – the touch of luxury provided by a fridge in your 4WD isn’t just a dream for rich players any more.

But as with most 4WD equipment, some bush smarts are required to get the best performance from your fridge and help prevent disaster. None of it is difficult and it’s all to help you have a great time in the bush!

 

Strap It Down

Portable FridgeMost mid-to-large sized 4WDs have enough space for a fridge to be carried and used in the cargo area. This is the safest, most sensible location for the fridge – even smarter is its installation behind a cargo barrier.

For occasional fridge use – such as if you’ve borrowed one for a short trek - the expense of a top-technology installation system may not be justified. But you shouldn’t cut corners. The fridge must be properly secured in the cargo area: wobbly fridges smash up whatever is inside them and are a general pain in the derriere at best, and a danger to you and your vehicle at worst.

Even if you can’t tie your own shoelaces, cam-action tie-down straps cost as little as $10pr so there’s no excuse for a loose fridge.

Some vehicles will require stronger tie-down hooks; the factory-fit stuff is sometimes little more than shiny decoration. Possibly, there are no tie-downs fitted or they aren’t suitably sited. Captive nuts suitable for tie-down installation may be provided in the vehicle floorpan: lift the carpet and take a look (they may be hidden under dust-sealing patches). If not, tie-downs should be installed by drilling and through-bolting. Self-tapping sheet metal screws are not good enough.

Fridge slides are the foundation for many long-term/semi-permanent fridge installations, usually as part of a cargo area fit-out including storage drawers. Most fridge manufacturers make or recommend a slide suitable for their product range. There are few vehicles to which an off-the-peg fridge slide can’t be fitted. However, some vehicles – and camper trailers - may need a set of long-extension roller drawer runners as the foundation for a custom-built fridge slide.

When the fridge is to be carried in, but used away from the vehicle – or the expense of a fridge slide isn’t justified - a less sophisticated permanent mount system might be a better option.

Engel, for instance, offers its transit slide lock that secures the fridge in the vehicle by sliding its feet into a frame.

This base is ideal for camper trailer installation where top access to the fridge means a slide isn’t required.

Speaking of camper trailers, most fridges will cop a little bit of dust but it’s best to minimise this as far as possible with installation in a dust-resistant vented box. It’s the same for fridges carried in the rear of utes.

Finally, fridges rely on airflow to rid them of heat so ensure the fridge has plenty of ventilation. Most have grilles that must be kept clear of clutter but it’s a good rule of thumb to keep 15cm clearance around all sides.

Sure, hot air rises but cool air must easily find its way to the fridge too: otherwise your fridge will struggle.

 

Power Requirements

Your 4WD may have a 12V outlet fitted as standard in the cargo area. As handy as this might at first seem, it’s not ideal for powering your fridge. Firstly, it’s ignition-switched: that means inoperative when the vehicle is switched off (from the ‘Accessories’ position with the ignition key). Secondly, the general flimsiness of these sockets allows the plug to be easily knocked out.

There is often significant voltage drop through the factory wiring harness which means the fridge may not be getting all the juice it wants.

For now we’ll disregard dual/second battery installations: that’s a topic for another day. Voltage drop in the circuit robs the fridge of its ability to operate to full potential. Measure the voltages first at the battery terminals, then at the fridge in ‘real world’ conditions: with the engine turning the alternator at above-idle speed and with the fridge compressor running. Get the fridge working hard – and therefore demanding lots of power - by setting its thermostat to ‘max’. Alternators charge at around 13.8-14V so that is what you should see at the battery. Any more than 0.5V difference at the rear of the vehicle means you should work to find the power ‘clogs’ due to bad connections, corrosion or inadequate wire size.

It’s a great idea to feed your fridge independently of the vehicle’s ignition switch by installing a dedicated power cable running straight from the battery to a positively locking plug and socket adjacent to the fridge. It’s easy enough DIY, or have a 4WD specialist or auto electrician do it for you.

There is no such thing as a wire too big - only too little – so although a cable with a conductor area of around 4mm2 may be considered adequate, a fat biro-sized red cable is better, especially if you want to install other accessories (lights, trailer brakes, amplifiers) later.

The easiest and safest way to run this cable to the rear of the vehicle is under the carpet. This will generally require popping-off some interior trim panels, and if there are no factor-provided blanked-off holes, drilling through the firewall in a location clear of components or direct water splash zones. This power feed wire must – must, MUST - be fused adjacent to the battery. Some enthusiasts and installers prefer circuit breakers.

Some have built-in digital volt meters to help you determine battery condition.

It’s best to have a single run of cable – no joins - all the way to the fridge plug. The cable must be physically protected from damage and abrasion for its entire length. If possible, have it follow (or tape it to) the factory wiring harness. All holes must be grommeted; any runs over bodyshell interior edges must be shielded with convolute wiring tube or similar.

Failing any one of these physical and electrical protection procedures may end in disaster: a toxic interior fire started - then maintained, despite the use of a fire extinguisher - by the vehicle battery.

Several types of fridge plugs exist: some are ‘off the shelf’ while others are specific to brands of fridges. Choose one with a tight fit or a positive latching mechanism to prevent the plug/socket being accidentally knocked off.

 


These camper trailer fridge plugs shorted out and failed...

Ideally, sockets should be mounted above floor level to – or through – a sturdy interior trim panel but flying leads work okay, too.

When installing plugs onto power cables make sure all joints are strongly crimped and soldered: crimping can corrode and solder can fatigue, but together they’re forever.

Don’t skimp on the earth connection. If wiring 12V power cable to a camper trailer, do not rely on the vehicle trailer socket and plug: install a dedicated power feed/earth through a sturdy socket - such as an Anderson plug – on top of your drawbar.

Packing and Stacking

Rough roads and ruts create havoc with whatever is in your fridge so it should be packed using a bit of Murphy’s bush wisdom: if it can spill, break, pop, splash or crack, it will. Your fridge’s diminutive size means you need to be far more ruthless not just with how, but with what goes into it, too.

Hundreds of kilometres of corrugations can damage some fridges’ internals – or wear through the base of your precious cans of beer. Don’t laugh, but pre-packing your cans (and other products) in stubby holders prevents this happening. The 24 cans of beer in a slab/carton/case sometimes come packed as six-packs with polythene retainers: not only are these great for tying tinnies in a cold creek, they’re good for reducing rattles, too.

Many foods that you usually store in the fridge at home (tomato sauce, marmalade etc) can often survive without refrigeration, freeing up valuable cool space. Due to the risk of breakage and personal injury glass is a general no-no in the bush, so tip your special sauces into plastic squeeze bottles, whether they are for the fridge or not. Takeaway food containers may be handy for leftovers at home, but better-quality items with tight fitting lids are less likely to leak when travelling. Looking in a homewares shop for these and other containers will probably give you a few more good food storage ideas, too.

One or two wire baskets are a boon in the fridge. They allow quick access to the food underneath and packing the basket with your lunchtime stuff (butter, sliced cheese, ham – or sandwiches made at breakfast time) minimises rummaging around in your fridge.

Fresh meat should be ‘cryovacced’: single-meal portions of meat are vacuum-sealed into plastic bags. Cryo meat remains fresh in the fridge for weeks, takes up very little room and is just about spill-proof – especially if you also pack the steaks in a plastic container.

Butcher-shop cryo is not widely available so you may have to ask around. If you plan to travel a lot, you can buy the equipment for home DIY vacuum packing, too.

For single-zone fridges, there’s no real benefit to freezing meat before your trek. It was a good idea before fridges were invented; pre-freezing tucker gave you four days’ fresh steaks rather than three. In the tight confines of a mobile fridge, frozen food can provide a ‘false stability’ and as it thaws, allow everything else to topple over.

Spilt milk is big problem when travelling: Take a good look at the spout on your UHT milk to make sure it doesn’t leak. Buy a couple and test: Quite often the $1.80 milk has a far stronger spout (or a screw lid) than the $1.25 stuff but the 1-litre plastic bottles and can be suspect, too.

To eliminate the risk, consider not carrying milk in the fridge at all: Buy heat-treated milk in breakfast-sized (250ml) packs and use tubed sweetened condensed milk for tea breaks.

Lastly, no-one wants a whiffy fridge. A small sponge and some cleaner (your 4WD’s window cleaner is ideal) is handy to deal with any minor spills.

At the end of every trip – or when you’re in a town for a few days - empty your fridge and give it a thorough clean, before you stock up again for the next adventure.

 

 

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