A Guide to Caravan Solar Panels 2020

By 16 min read

Caravan solar panels bring you one step closer to total freedom

Solar panels will keep your caravan's battery topped up and your appliances powered

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The most wonderful thing that a caravan or motorhome offers you is freedom – to go wherever you like, whenever you like, for as long as you like. Until you need to charge your battery.

With your own electricity supply, you can go completely off the beaten track, exploring wild and remote beauty spots, camping in the grounds of stately homes and on farms or raving at music festivals, all without having to worry that you’ll run out of power. And it won’t be costing you a penny.

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What's in This Guide to Caravan and Motorhome Solar Panels?

How Do Solar Panels for Caravans and Motorhomes Work?

caravan solar panels

The type of solar panels that we’re talking about in this article are called photovoltaic panels; this means they convert sunlight into electricity. They are made of 2 layers of silicon which produce electricity when they are exposed to sunlight, as the sunlight causes electrons in the silicon to move.

The electricity is fed into your caravan or motorhome’s leisure battery, where it is stored temporarily. When you use an electrical appliance, it draws on that store of electricity.

It’s light – not heat – that makes solar panels work, so they only need daylight to function. They will work most efficiently in strong sunlight, especially in summer, and the British climate is more than adequate for them. In fact, solar panels actually work best at temperatures around 25ºC.

Benefits of Caravan and Motorhome Solar Panels

Free electricity. Once you’ve paid for the panels, all the electricity they generate is free. Whether or not the panels provide all the electricity you need, at the very least you’ll be paying less for electric hook-ups or generator fuel.

Freedom. You’re not tied to campsites with electricity or worrying about having enough generator fuel – sunlight doesn’t run out.

Reliability. The sun is there every day and the panels will work anywhere in the world.

Eco-friendliness. Instead of burning fossil fuels, you’re using a renewable source of energy which doesn’t generate pollution or carbon emissions.

No flat batteries. A fixed solar panel will keep your battery charged even when the caravan’s not in use – and keep any alarms and security systems powered too.

Longer battery life. Keeping your battery fully charged will prolong its life. In a lead acid battery, the lead dioxide plates get covered with lead sulphate as the battery discharges, and if these deposits have time to crystallise, your battery’s efficiency will suffer. This is particularly important if your caravan isn’t in use for a while, as your battery will lose charge at about 4% a week.

Silence. Generators are noisy, heavy, produce exhaust fumes and are banned in some places. Solar panels are clean, silent and welcome everywhere.

Durability. You can expect a good quality solar panel to last for 25 years – plus you'll benefit financially from your longer battery life too.

Low maintenance. Solar panels have few moving parts, so there's little to go wrong. You just need to keep them clean.

Disadvantages of Caravan and Motorhome Solar Panels

They’re expensive to buy. We’ll come onto costs later, but you’ll obviously need to be able to afford to pay for the panels – plus if your battery is a bit old and rubbish, you might want to buy a new battery too. Weighed against the long-term savings you’ll make, however, solar panels are a sound investment.

They don’t work at night and are much less efficient in winter – when, ironically, you’re likely to need more electricity for things like heating and lighting. You’ll have to buy quite a powerful panel if you want it to provide all your electricity all year round. Even a small amount of shade on a little bit of the panel can inhibit its performance.

Types of Solar Panels for Motorhomes and Caravans

Monocrystalline solar panels are the most effective and space-efficient type of solar panel and consequently the most popular. They’re also the most expensive, as the process used to make them is not particularly efficient.

Polycrystalline solar panels are made from large numbers of small crystals, so are less efficient than monocrystalline panels, which are made from 1 single crystal. So a polycrystalline panel will be larger than a monocrystalline panel of equivalent power.

The difference is not very significant, however, when it comes to caravan and motorhome panels; it only really matters if you are buying solar panels for your house. And a good quality polycrystalline panel will probably perform better than a low-quality monocrystalline one.

Thin-film solar panels, also called amorphous solar panels, are thin, flexible and lightweight. They are generally cheaper than crystalline panels, as they are less expensive to make, but they are also less efficient. A thin-film panel will be larger than a crystalline panel of equivalent output. However, thin-film panels are slightly less adversely affected by higher temperatures (solar panels become less effective in temperatures over 25ºC).

Flexible and semi-flexible solar panels will bend (within reason!) so can be fitted flush with your caravan roof even if it’s not flat. Some people prefer them for this reason, as they are less conspicuous and more aerodynamic – some are just 3mm thick. You can glue or screw them in place.

Rigid panels are covered by a glass front and are consequently more breakable than flexible panels, but they tend to be more efficient, so will provide more power from the same area.

Fixed or Portable Solar Panels?

Fixed Solar Panels

As the name suggests, these are permanently fixed to your caravan or motorhome, usually on the roof. This means that, unlike portable panels, they can’t be constantly repositioned to catch maximum sunlight as the sun moves through the sky.

Their efficiency is therefore dependent on where your caravan is – if you park in the shade, be prepared for your panels to take a tea break. But they’re also much less faff than a portable panel: once they’re installed, you never have to move them, get them out, put them away or worry about leaving them unattended. They can be charging your battery before you’ve even got up in the morning, and they’ll also keep your battery charged and your alarm working when you’re not using the caravan.

Portable Solar Panels

Portable solar panels have 2 main advantages. You can move them throughout the day so they catch as much sunlight as possible as the sun moves through the sky. And on a hot day, you can park in the shade and have your panels still in the sunlight.

However, you have to set portable panels up and you’ll have to keep moving them throughout the day if you want to get the benefit of them. You need somewhere to store them, somewhere to set them up (they may come with a stand) and you also either need to secure them, for example with a bike lock, or be prepared to leave them unattended.

What Size Solar Panels Do You Need for Your Caravan or Motorhome?

It’s important to choose the right size panel for your caravan or motorhome. If the panel isn’t powerful enough, you’ll run out of electricity regularly; if it’s too big, you’ll have spent too much and will feel you haven’t got value for money. Here are 3 steps that’ll help you to work this out.

1. Make a List of All Your Appliances’ Wattages

First, you need to work out how much power you need. Write down the power ratings, in watts, of every piece of electrical equipment you use in your caravan. The wattage (or an estimate) should be on a label on the back or bottom of the appliance. If you can’t find it, you might be able to find the rating online.

As a guide, these are estimated wattages for some common caravan and mobile home appliances:

Alarm clock
Coffee maker
Electric kettle
Phone charger
Electric fan
Electric heater
Water pressure pump
Satellite dish
LED light

2. Work Out Your Daily Appliance Usage

Next, work out how long you use each appliance for each day. So if you use an 8-watt lightbulb for 3 hours a day, you will need 8 watts x 3 hours = 24 watt hours per day for that light. Do this for every electrical item, then add all the results together to find out how many watt hours, in total, you’ll need your solar panels to generate.

So, in this example below, you need to work out what size solar panels will give you 224-watt hours of electricity each day.

Number of Hours Used Each Day
Energy Needed Each Day in Watt Hours
Living room light
Halogen downlight
Kitchen fan
Water pump
14-inch 12-volt TV
12-volt radio

All solar panels have a power rating in watts. However, the panel will not produce this much power all the time; the rating is the maximum amount of power the panel can produce. You will only get this when the sun is very bright.

3. Work Out How Much Power You’ll Need Through the Seasons

In summer you’ll get bright sunshine for anywhere between 4 and 7 hours a day. To produce 224 watts over 4 hours you’ll need a 224 / 4 = 56-watt panel. But in the winter, you can only expect around 1 hour of peak performance from your panels. So if you wanted your solar panel to provide all your electricity in winter too, you would need a 224-watt panel. In spring and autumn, the sunshine hours will be somewhere in the middle.

Here’s the amount of power you can expect from various sizes of panel on an average summer and winter day:

Solar Panel Rating
Power Generated on a Summer's Day
Power Generated on a Winter's Day
4 watts
24 to 28 watt hours
3.2 watt hours
10 watts
60 to 70 watt hours
8 watt hours
20 watts
120 to 140 watt hours
16 watt hours
25 watts
150 to 175 watt hours
20 watt hours
50 watts
300 to 350 watt hours
40 watt hours
80 watts
480 to 560 watt hours
64 watt hours
100 watts
600 to 700 watt hours
80 watt hours
150 watts
900 to 1,050 watt hours
120 watt hours

While the ratings might not be that useful as an indicator of how much power your panels will generate per se, they do enable you to compare panels. You know an 80-watt panel is always going to be twice as powerful as a 40-watt panel under the same conditions, for example.

In practice, once you’ve worked out how much solar power you need, our advice is always to add an extra 20% to compensate for things like cloudy days and shade. In relation to the example above, we’d generally advise:

• Around a 70-watt panel if you’re only using the caravan in summer

• A 270-watt panel if you want it to supply all your electricity in winter too

• If you only want the panel to keep the battery charged when you’re not using the caravan, a 20 to 50-watt unit should be enough

Here are some estimates for what different sizes of panel would provide in different types of motorhome:

Campervan or Small Caravan: 110 amp Hour Battery
Large Motorhome: 200 amp Hour Battery
60 watts
Lights, water pump, radio, TV for 2 hours a day
Lights, water pump, radio, CD player
85 watts
Lights, water pump, radio, TV for 3 hours a day, 240-volt appliances
Lights, water pump, radio, TV for 2 hours a day, 240-volt appliances
130 watts
Lights, water pump, radio, TV for 5 hours a day, 240-volt appliances
Lights, water pump, radio, TV for 3 hour a day, 240-volt appliances

How Much Do Solar Panels for Caravans and Motorhomes Cost?

Solar panel prices vary based on everything from the type of cell and flexibility to power output and manufacturer. Don’t forget that you might need more than a single panel to give you enough power for your needs, so this’ll up the price.

The smallest panels (30 watts) start at around £70, whereas solar panels of 100 watts or more could set you back between £500 and £1,000, depending on how many you require.

You’ll find that some manufacturers offer their solar panels as a kit, which might include the cables and regulator, and others you’ll need to buy these separately.

Buy the Best Solar Panels for Motorhomes and Caravans

There are a number of manufacturers producing solar panels for caravans and motorhomes. Below you can explore some of the top-rated models on Amazon, in order of their wattage/output. Just follow the link for further details and to make a purchase.

We've highlighted 3 dominant brands in the solar market:

1. HQST: Affordable solar solutions for the off-grid solar market.

2. Photonic Universe: UK brand producing solar and wind power products since 2009.

3. Renogy: Award-winning manufacturer of high-quality solar products.

Cell Type
Photonic Universe
50.5 x 44.5 x 2.5 cm
34.1 x 63 x 2.54 cm
54.1 x 63 x 3 cm
119.38 x 54.2 x 3.6 cm
104.1 x 53.3 x 0.5 cm
119.4 x 53 x 3.8 cm
Photonic Universe
84.5 x 67 x 3 cm
100.3 x 99.1 x 3.6 cm
100.3 x 99.1 x 3.6 cm
Photonic Universe
139 x 99 x 4 cm

Installing Solar Panels on Your Caravan or Motorhome

Check that fitting a solar panel does not invalidate the warranty on your caravan or motorhome, and check if it needs to be installed by the manufacturer’s own tradesmen.

You should also tell your insurance company that you are installing the panels, as they will count as a modification to your caravan.

You can expect to pay between £120 and £250 for installation, and installation should take around 2 to 3 hours.

You can install your own solar panels, but we wouldn’t recommend it; we would always recommend going to a reputable installer. A badly fitted solar panel could be a fire risk, and if you drill through the roof and you don’t know what you’re doing, you could have a wet caravan next time it rains. A professional will be able to fit the panels safely and securely and without invalidating your insurance.

Regulators and Charge Controllers

Unless you’re installing a tiny solar panel, you should get a regulator or charge controller. This stops your battery from being overcharged, which damages it, and also regulates its temperature to stop it from overheating.

Check that the regulator includes a blocking diode, which prevents power from going back into the solar panels from the battery when it is dark. If your panel is so small that you’re not using a regulator, you’ll need a blocking diode anyway.

Prices for regulators start from around £15 and go up to £70. Get a good quality regulator; it will help you get the best out of your system. You may also need an inverter, which converts the battery current (DC) to mains electricity (AC).

5 Top Tips for Getting the Most Out of Your Caravan Solar Panels

1. Position the panels horizontally unless you are moving them throughout the day. Experts differ on the best way to position your panels but we would generally say that horizontally is the best option for getting maximum sunlight. And obviously, keep them out of shade.

2. Look after your battery. For you to properly reap the benefits from your solar panels, your battery needs to be in excellent condition. There’s no point in investing in a good quality panel if your battery can't store the energy it produces efficiently. So make sure your battery is properly maintained.

3. How efficient are your appliances? Some caravanners switch to appliances which will use less battery power, such as LED lights instead of halogen bulbs, 12-volt TVs and 12-volt or gas fridges (12-volt appliances mean you don’t have to run an inverter to produce mains electricity, which always involves some wasted power). Renewable Energy Hub says that your fridge can account for 60% of the electricity you use; heating appliances also draw a lot of power.

4. Keep the panels clean. This can majorly affect their efficiency. If you notice your panels aren’t working as well as they have been, dirt is one of the most likely culprits, as grime, dust and general muck on the panel will block sunlight. Clean the panels regularly with warm water, a soft cloth and a gentle soap. Don’t use abrasive cleaners, or you’ll scratch the panel, and don’t make a polishing motion or you might create static which will attract dust! Rinse the panel with clean water and let it dry on its own.

5. Make good use of your regulator. If you can see how fast the battery is discharging, you can identify which of your appliances use the most power, and turn them off when you don’t need them or when the battery charge starts to get low.

Fran Whittaker-Wood
Fran Whittaker-Wood Editor

Fran is The Eco Experts’ resident solar panel and double glazing oracle She loves orangutans and is passionate about protecting the planet’s rainforests from the unsustainable production of palm oil. And minstrels.