9 Tips for Using 12V Power

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To paraphrase Queen’s 1989 lyrics: ‘we want it all and we want it now’ when it comes to connectivity when we travel: our phones and tablets, our music, our cold drinks and frozen steaks, our cool air, our light and, for some, our coffee! But if you are under a million stars and miles from mains power, there are only three ways you are going to get what you want: a portable generator, solar, or battery power.

Let’s dispense with the generator first. If you want enough power to run a normal caravan air-conditioner, you’ll need an output of at least 2000W – more likely close to 3000W – as its required start-up power can be three or four times its running needs. That means a heavy, space-consuming gennie that will require you to carry a petrol fuel supply. Then there is the noise to consider…

That leaves solar and battery power, both usually operating in tandem. And, unless you are carrying a bank of AGM deep-cycle batteries – or have installed the latest state-of-the-art  lithium power pack and a large inverter – to run your 240V appliances, you’ll be looking to 12V. So here are some simple tips to make the most of it.


If you’re not running an air-conditioner in your van, you’ll need another way to stay cool. My preference is for a pair of Caframo 807 Sirocco 12V fans, mounted so they cover the lounge and bedroom. Apart from being impressively quiet, they have four pre-set timer settings so they can switch off once you’re asleep. However, as they draw just 0.34A at high speeds, they won’t flatten your batteries overnight, even if they do run all night.

The fans measure 180mm in diameter so they don’t take up much space, can be folded flat against the wall when not in use and their flexible blades won’t amputate (or even hurt) your hand or foot if engaged accidentally.


General solar installation

It’s hard to buy a caravan without a TV these days and, inevitably, it will be a 12V one. This means it will be powered off a 12V socket and you’ll need to run it through a small (supplied) transformer if you want it to run on 240V. But with such a small current draw, why would you?

Look for a good, built-in antenna, as you may have to re-tune your TV each night and you want this to be quick and easy. Some caravans have outside ports and arms to relocate your TV for external viewing, but, if not, ensure that it at least has an antenna socket and a 12V plug.



Keeping all your 12V appliances charged can be a challenge. Between us, my wife and I have two iPhones, two iPads and my laptop, and then there are the chargers for our Victa electric chainsaw and AEG impact wrench.

A starting point is to ensure that you have enough 12V outlets in the right places. One on each side of the bed is a good start, then at least one (preferably two) under the dining table, or adjacent, another in the kitchen and one in the bathroom, plus an external point on the nearside. Some of the latest ones also come as a combo with one or two USB slots, so opt for these as well.

Another charging option is portable solar power and we throw a Power Film 60W solar charger in our backpack when we go exploring. Weighing just 1.45kg, the charger measures just 279x241x51mm folded, then unfolds into a solar panel measuring 1499x1092mm. The unit’s rechargeable batteries can be topped up by the sun and used to power a wide range of electronic devices. Alternatively, when unfolded, ours can even run our Engel 40L fridge direct from the panel when laid out in full sunlight, without the need for a battery.

Back in the caravan, we have a Kogan Rapid Travel Charger that has four USB outlets – two 6A ones for mobile phones and two 8A outlets for our iPads. It comes with a variety of mains power travel plugs, but we run it through our portable Engel 150W inverter and this means everything can be charged simultaneously overnight via the one 12V power socket.



Ensure that your caravan has an inverter, either a built-in or portable unit. This will allow you to run or charge a range of devices, drawing on your van’s battery. The current median size for built-in inverters is 300W, but units up to 3000W are available.

We have got by for years with a portable Engel 150W inverter but, since the advent of coffee pod machines, I’ve been a bit envious of 1000-1500Ah systems. The problem is that these need bigger and more batteries that, in turn, need to be fed by higher output chargers and larger solar panels, and this spiralling cycle inevitably adds weight and cost. My more pragmatic coffee solution is to use a plunger and to pack the next ‘must have’ 12V item below…


The Lavazza EspressGo espresso maker is a true 12V solution for tragics like me who crave a proper caffeine fix to kick-start their day.

This high quality and compact dedicated 12V cylinder is designed to fit into a car cup holder but, based on experience and the cost of dry cleaning, I would strongly recommend only using it when not in motion!

It’s ideally suited to a caravan, where you can also add some hot milk if required. Simply fill the 50ml water reservoir, slip your choice of Lavazza A Modo Mio capsules in the lid, activate the heating element and then watch the EspressGo brew a perfect piccolo nero at a respectable pressure of 16 bar. I use a Latte Perfecto 240V milk frother when plugged into mains, as it draws 500W, but some milk in a saucepan frothed on the gas jet is a passable substitute for a breakfast brew in the bush.

The whole process takes only a few minutes and draws 140W, making it a perfect coffee mate for our Engel 150W inverter. A full coffee pod machine would draw around 1000W during the brewing phase.


When travelling, you hear tragic stories of how the barra went off or the beer got hot. However, there are a number of simple tips you can use to extend the life of items stored in a 12V fridge.

For a start, you should turn your RV fridge on at home a couple of days before you leave, using your household power supply to bring it down to its minimum temperature. Then, pre-cool the food and drinks in your home refrigerator before placing them in your portable fridge/freezer, ideally packing appropriate food in air-tight containers and having meat vacuum-sealed by your butcher.

Portable fridges are usually stored in the back of your tow vehicle, where they get less cooling from your air-conditioner and often sit for hours in the sun. The standard insulating bag you buy is not enough to counter this, but insulating bats packed around the fridge will certainly help, ensuring you don’t block off any air vents.

Another useful tip: a full fridge will retain its temperature longer than an empty one, so if you are travelling with a lightly loaded fridge, add bottles/milk cartons full of water, along with a couple of packing towels, to stop them splitting when travelling over corrugations.


A 12V compressor fridge will cope with very high temperatures better than a three-way fridge, but it’s important to ease its workload whenever you can. If possible, position your caravan so that the wall to which the fridge and its vents back on to is either shaded or not exposed to the sun at the hottest time of the day – late afternoon. This is particularly important for gas fridges.

If this is impractical or impossible, cover the affected area of the van with shadecloth or canvas. Get your local canvas or awning manufacturer to fit a small section of sail track to the van body above the fridge and have them supply a section of shade cloth that can simply be inserted and pegged. It will make a huge different to your fridge’s ability to retain its temperature.

Another idea is to use a small solar film blanket fitted with sail track here instead of shade cloth, as it will then perform two duties – shading and charging. An external Anderson plug is the easiest way to get its charge back to your van’s battery.

Also, have a smart charger or a DC-DC charger fitted to your car or caravan to ensure your caravan’s deep-cycle batteries receive the full 13.9-14V charge from your tow vehicle when travelling. This should be mounted as close to your van’s batteries as possible to minimise the voltage drop.


The electric pump in your caravan is one of the prime energy users, so if you are planning to camp in a remote area for a week or more, consider supplementing its use with a manual foot or hand pump.

While not convenient for a shower, a manual pump is ideal for most of your other water needs and should be cheaply and quickly fitted by any caravan repair or service business.


Because cool air falls, a portable fridge will generally keep its cool better than an upright cabinet fridge as, every time you open the upright model’s door, a lot of your hard-won cool spills out the bottom. So in really hot weather, you’re better drawing your daily needs from your portable fridge than your built-in one.

The other thing you need to know is your refrigeration limitations. A typical portable 39-47L fridge/freezer features a highly efficient compressor and draws about 2.5Ah so, if you are running it flat-out in the freezer (-0°C) mode, the thermostat is bypassed and the compressor will run continuously. This means it will flatten a fully-charged 100Ah deep-cycle battery in about 40 hours, or say two days, as these batteries leave a little in reserve.

In refrigeration mode (usually 3-4°C), the thermostat will cut the compressor in and out, so the ambient temperature, the fridge’s contents, and the number of times you open the door/lid will affect how much of any given hour the compressor will run. If it’s hot and it runs for 30 minutes in every daylight hour – and less at night – to maintain that temperature, it may refrigerate its contents, but not freeze them, for up to four days.


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