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Caravan electrics guide
For as long as caravans have been a thing, they have aimed to bring the comforts and luxuries of home life to the great outdoors.
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11 min read
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9 min readDrive
For as long as caravans have been a thing, they have aimed to bring the comforts and luxuries of home life to the great outdoors.
Published
11 min read
Text size
Published
Text size
Even the very earliest caravans contained some little luxuries such as interior lighting powered by kerosene. Today we want caravans with WiFi, NutriBullets, Netflix and espresso machines.
As home life has become more connected and dependent on electrical appliances and devices, so too has caravanning. There's no reason to suggest that trend won't continue.
So, as we look at modern caravanning, how can we make sure that their electrical systems are up to the job of powering modern travel? How much power do you need, and what are the best ways to get it?
Of course, the power needs of a modern caravan vary considerably with use, occupants and the level of mod cons. Let’s assume you want to spend significant time camped off grid and unplugged from mains or caravan park power. In that scenario, how much power does your caravan need? The answer is obviously different for every caravan, but you can work it out by doing some rough calculations and adding up the power usage of your electrical equipment.
To do that, you need to find out how many watts each piece of equipment uses. That information is usually written on the device or easily searched for online. Once you know the wattage, multiply that by the hours (or fraction thereof) of use per day, and you'll know how many watt-hours (Wh) it'll use.
Add up all the watt hours – you might get to kilowatt hours (kWh) by this stage – and you'll have a rough value for how much power you'll use in a day. Here are some examples.
Refrigeration
Your fridge is probably the heaviest continuous power user. For example, a 115L dometic compressor fridge uses around 0.5kWh per day (about 40 amp-hours). A 216L version uses about double that (around 80 amp-hours).
Lighting
Although modern LED lighting is very efficient, the sheer amount of it in modern caravans can quickly add up. Small LED downlights can use anywhere between 2 and 4 watts each. Strip lights somewhere around 8 to 15, depending on length and LED density. Although it doesn't sound like much, 10 downlights and a few strips outside in the awning could use 50 to 100 watts an hour.
Devices
They don't seem like much, but the average phone battery is around 10 to 15Wh. A laptop or tablet battery between 50 and 100Wh. As such, keeping them all charged can eat up a lot of your daily energy.
230-volt appliances
We all want to power modern home appliances like blenders, coffee machines, and other 230-volt appliances in our caravans, but they are often power-hungry. For example, a simple Nespresso machine uses around 1300 watts for its heating element and pump. Even if it's only for five minutes to make coffee, that's still using around 100Wh.
Entertainment
Although stereos use a miserly amount of power, a few hours of TV each night can really add up. 32-inch, full HD smart TVs use around 40-50 watts.
Water pump
Pumps use a lot of power, but only for a small amount of time. Even if you are using 50 or more litres a day, there's a good chance the pump runs for less than half an hour in total. Total daily consumption is probably less than 50Wh.
Starlink
If you’re using Starlink to stay connected, the dish and router can be quite power hungry - often as much as running a fridge. Starlink Mini uses around 20 to 30 watts, while the Gen 2 dish can use in excess of 40 to 50 watts an hour.
Washing machine
There are many options for caravan-friendly washing machines these days. Many have a heating cycle, but if you can run cold cycles, they're much more efficient. Still, cycles often take over an hour, so you might end up using 0.5 kWh per wash.
Air conditioners and induction cooktops
It's less common to run either of these off grid because, in many traditionally wired caravans, you need either caravan park power or a large generator to keep them running. In most cases, both appliances can draw over 2000 watts (around 150amps at max) under full load. Most air cons will settle between 700ish and 1500ish watts once they're only maintaining temperature, rather than actively cooling. Even so, even the most sophisticated off-grid setups can usually only run air con for a few hours.
Once you’ve worked out how much power your caravan consumes, you now need to provide it, and for that, we obviously need batteries. It's safe to say you want to store more power than you can use in a day. For starters, on cloudy days you may get next to no charge from solar panels, and you at least want to keep the fridge running overnight until the sun comes up again.
From there, you need to decide how long you'd like to be self-sufficient in the scenario where you can't get any charge. Some people's risk tolerance is higher than others, or your constraints might be budgetary.
Having a buffer of at least 50 per cent is prudent, but many people have two or three days of capacity. Also, consider that your needs will grow as you decide you need another fridge or a few extra devices for growing kids, so give yourself room to expand.
However, you can go too far in the other direction. It may seem tempting to build in a lot of battery capacity, so you'll have autonomy for days and days. However, assuming you can build a reliable charging system with some redundancy, you're unlikely to need more than a couple of days' capacity (on average, it's sunny well over half of the daylight hours every year in most of Australia). Plus, at a certain point, you won't be able to keep a large battery bank charged, or you'll only be using a small percentage of its capacity, and therefore, you've wasted money and resources on making it so big. You are far better off being able to charge quickly and reliably than having a large battery bank.
The obvious answer is solar panels, but it's not a complete answer. Once you've worked out how many kilowatt hours a day you'll consume on average, you need to be able to produce that much power.
Let's say your caravan consumes 2kWh of energy per day. You need power generation that can match that. If that's with solar panels, they need to be able to do that during daylight hours. Results will vary depending on location, season, and individual panels, but in that example, you probably need around 600W of solar panels pointed at the sky.
A simple rule of thumb often mentioned is to have twice as much solar power in watts as you have usable battery capacity in amp-hours. So, if you have 200 usable amp hours of batteries, 400 watts of solar capacity will keep you charged in most scenarios. But more is always better.
Of course, there are some limiting factors for caravans and campers when it comes to solar. For one, we often like to (or have to) camp in the shade. Particularly if your panels are roof-mounted, that can severely limit their potential.
Secondly, there's only so much real estate available on a caravan or camper's roof. Although solar panels are getting better and produce more power per square meter than ever before, most people would struggle to fit more than 800 watts to the roof if they have to fit them around hatches, an air conditioner or other roof-mounted fittings.
For both reasons, having some solar capacity that you can move around is a good idea, so folding panels or solar blankets are good options as they can boost capacity when needed, and be moved with the sun in shady campsites.
In almost every scenario, modern LiFePO2 batteries are the superior choice for caravan and camper power storage. They are energy-dense, fast to charge, and can handle high loads. They're also lighter and can be safely discharged further than AGMs, so you need much less battery for an equivalent amount of storage. However, they are currently much more expensive.
It can be tempting to search for the cheapest batteries, but buying from reputable sellers is wise with lithium batteries, as other non-LiFePO2 lithium batteries are often less stable.
On the other hand, Absorbed Glass Matt (AGM) batteries, the most commonly fitted battery to caravans, still do a great job. Unless you have a lot of high-load appliances you want to run from battery power (like air con or an induction cooker) or you need to save a lot of weight, AGMs work great, and they are also a little simpler to install. There's no need to rush out and upgrade just for the sake of it.
Undoubtedly, you will want to use a few appliances that require 230-volt electricity. For that, you will need to install an inverter, which is a device that converts DC power to AC power.
Inverters are rated in watts, so you'll need to match yours to the expected maximum watts your most power-hungry appliances use. Typically, anything that heats food uses between 1000 and 2000 watts (a microwave, toaster, coffee machine, or air fryer, for example), while an air conditioner or induction stove might spike over 2000 watts. If that's what you want to run, you may also need to invest in lithium batteries, which can handle higher amperage loads for longer than AGMs
If you only need to charge simple devices like a laptop, camera, or the battery for your cordless drill that winds down your stabiliser legs, a much smaller inverter will be suitable. Some are as small as 150 watts and well-suited to simple charging duties.
Undoubtedly, there will be some days when you just can't keep up. Depending on how often you camp, that could be a big or small problem. Full-time travellers will probably need more energy security than travellers who take shorter trips through the year.
As most of us have an engine in our cars, that's backup number one. If you're low on power, it's usually easy to start the engine and let it run some charge into the batteries, ideally through a high-capacity DC-DC charger. Most of us will have fitted something like it to charge while we drive, and if we only need the backup a few times a camping year, it's a cost-effective way to stay charged.
If you camp more often or have high-draw appliances, you may need to invest in a petrol generator. In the past, many people needed generators to power air conditioners, so large, 3kW or more generators were needed. However, increasingly, air conditioners (and induction cooktops) are run from the caravan's inverter, which is powered by the batteries. In this case, a smaller generator, around 2kW, might be enough to keep the batteries in check while these appliances are running.
There are distinct advantages to running a higher-voltage system in your caravan, but also significant hurdles to overcome. The main one being, most electrical devices don't run on 24 or 48 volts, so even if you set up either of them, you'll probably still need a 12-volt circuit or battery bank.
However, those higher voltages excel when you need to run high-powered appliances often. Case in point is Jayco's new 48V off-grid caravan, which boasts the ability to run an air conditioner and induction stove reliably from its battery bank. When systems run at higher voltages, they are generally more efficient, and overall amperage is lower, making them safer. Most off-grid homes are set up with 48-volt systems, for example.
In general, unless you have very specific needs, a 12-volt system is probably right for your caravan.
