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Find out if you can power your motorhome using solar panels, including how much energy is required and how much they cost
Installing solar panels on a caravan or motorhome requires an initial investment, which will take a while to recover, but not as long as solar panels on a residential rooftop. This is a long-term investment, but it’ll be worth the money for many reasons, such as increasing your ability to travel without relying on chargers in urban areas or holiday parks to charge your leisure battery. The best solar panels will also extend the life of your battery and ensure that it never runs out of stored power while the vehicle is not being used.
It’s always better to buy more expensive solar panels if you can afford to, as the quality will be much better and they’ll last longer. As with residential rooftop solar panels, monocrystalline solar panels are much more efficient than polycrystalline or thin-film solar panels, although the latter may be a better fit for vehicles with curved roofs.
Solar panels on caravans and motorhomes work in the same way as solar panels on the roof of a house. Light from the Sun interacts with silicon crystals to generate electricity. This is then fed into the caravan’s battery so that the electricity can be used for appliances.
Solar panels on caravans tend to be smaller than those on residential rooftops. Thin-film solar panels are sometimes more appropriate, especially for vehicles with curved or shaped roofs, as thin film is flexible and can be bent into shape; however, they are not as efficient as monocrystalline panels.
Solar panels are attached to the roof of a caravan either using adhesive or attaching to mounts that are either drilled into or glued onto the caravan roof. The solar panels are then connected to an inverter and charge controller, which are in turn connected to the caravan’s battery with wiring.
As with solar panels on residential roofs, the inverter changes direct current (DC) into alternating current (AC) so that appliances can use the electricity. The flow of electricity is regulated by the charge controller.
The number of solar panels you’ll need depends on how many watts (W) the appliances in your vehicle use and how often you’ll be using each appliance. You’ll also need to account for use during different seasons of the year. The wattage information for each product is usually clearly visible on the label on the underside of the appliance, but you can also find it online.
The higher the wattage of a solar panel, the more power it can generate. A 60W system is enough to power the lights, TV, water pump and radio in a small motorhome for about two hours per day, but larger items, such as fridges, will need a higher-rated panel.
A large leisure battery in your motorhome ensures plenty of power during periods of lower solar energy generation, such as very cloudy days.
Once you know the total wattage of your appliances, you can choose the size and number of solar panels you need. As solar panels are also rated in watts, you can use a formula to determine the total wattage you need from the solar panels:
Watts (Solar Panel Rating) x Hours (Daylight/Sunlight Exposure) = Total Watts Per Day
You can plot this information in a table:
| Appliance | Energy required each day (Watt-hours) | Number of 100W solar panels required |
|---|---|---|
| Living room light | 48 | 1 |
| Halogen light | 20 | 1 |
| Kitchen fan | 10 | 1 |
| Kettle | 200 | 2-3 |
| Water pump | 8 | 1 |
| 14-inch 12-volt (V) TV | 90 | 1-2 |
You can also use a ready reckoner:
| Vehicle | Campervan, caravan, small motorhome with 110-amp hour (Ah) battery | Campervan, caravan, small motorhome with 110Ah battery | Large motorhome with 200Ah battery | Large motorhome with 200Ah battery |
|---|---|---|---|---|
| Time of year | Spring-Autumn | All year round | Spring-Autumn | All year round |
| 60W solar panel | Lights, water pump, radio and TV 2 hours per day | Lights, water pump, radio and CD | Lights, water pump, radio and CD | Lights, water pump, radio and CD |
| 85W solar panel | Lights, water pump, radio and TV 3 hours per day and 240V appliances | Lights, water pump, radio and TV 2 hours per day | Lights, water pump, radio and TV 2 hours per day | Lights, water pump, radio and CD |
| 130W solar panel | Lights, water pump, radio and TV 5 hours per day and 240V appliances | Lights, water pump, radio and TV 3 hours per day and 240V appliances | Lights, water pump, radio and TV 3 hours per day and 240V appliances | Lights, water pump, radio and TV 2 hours per day |
To generate 224W of solar power over four hours – 224W being the minimum needed to keep your caravan’s lights and appliances running in winter – you’ll need at least a 56W solar panel. However, if you don’t use the vehicle in winter, you can probably choose a lower-rated solar panel instead.
Solar panels prices for caravans can be anywhere between £70 and £1,000, depending on the size and wattage of the panels.
To give you a rough idea, here are the prices levied by one UK supplier for small, medium and large solar panel kits:
| Small | 115W | £260.99 | 160W | £448.99 |
| Medium | 230W | £388.99 | 330W | £604.99 |
| Large | 350W | £467.99 | 700W | £754.99 |
Whether it’s worth spending a lot of money on a large solar panel system depends on what you use the vehicle for and how often.
If you use the caravan or motorhome mostly in or near urban locations or in rural locations with charge points, such as on holiday and in camping and caravaning parks, then you may not need a large solar power system.
However, if you’re planning to travel through a remote landscape with large distances between charging points, then a large solar panel system may become more necessary.
With a residential solar panel system, it generally takes between six and 10 years to recover your initial investment. When it comes to solar panels for caravans and motorhomes, this payback time is reduced because the systems are much smaller. If you use your caravan or motorhome infrequently, it may not be worth the investment.
If you want to install solar panels on your motorhome, you’ll need some power tools and knowledge of wiring diagrams. Before you start, check your insurance policy with your provider and inform them of the work. It could be classed as a modification.
The first step is to fix the solar panel mounts to the solar panel, which will require drilling some holes into the frame of the panel. Some solar panels can be glued to the roof of the motorhome, but in these cases, you must ensure that the roof is clean first.
If you’re using the mounting method, you should mark where on the roof you need to drill, making sure you’re not going to drill through any wiring or fixtures. Drill another hole in the roof to feed the cable down into the vehicle so that the panels can connect to the charge controller and battery. A special cover usually comes with the solar panel kit to protect the inverter against wet weather.
If you’re bonding the panel or mounts to the roof with glue, it’s a good idea to leave it overnight to set.
Turn off the motorhome’s electricity supply before you start connecting the wiring. Multiple solar panels should be linked in a series or parallel connection.
The inverter should be installed within the vehicle in a well-ventilated location.
The charge controller regulates the charge to the battery. It should be installed in an accessible location near the motorhome’s battery to avoid lengthy wiring. It’s important to check the earth with a voltmeter. The cables from the solar panel and the battery should then be wired into the charge controller and inverter.
Check all the cabling and connections to ensure they comply with the instructions, and then test the system.
Solar panels can be used while driving the motorhome, so there’s no need for any removal, which would be very difficult if properly fixed in position anyway.
The only likely downside to installing solar panels on caravans and motorhomes is the high initial cost, as is also the case with solar panels on a residential roof. This means it’ll take a while for you to recover your initial investment.
However, solar panels are easy to use and maintain and are a very good long-term investment. They’ll significantly improve your independence while travelling around, reducing your reliance on holiday park charge points. As they’re powered by sunlight, they will also help reduce your vehicle’s carbon footprint.
Additionally, they’ll extend the life of the vehicle battery and add to the value of the caravan or motorhome if you want to resell it.
Low-cost solar panels for caravans and motorhomes, as with solar panels for residential roofs, will be of lower quality, so they’ll not be as efficient and will probably not last as long as more expensive panels.
A solar inverter is an essential component for a solar panel system in a caravan or motorhome, as it converts DC power from your vehicle battery into AC power so it can be used to power the vehicle’s appliances.
The leisure battery in a caravan or motorhome powers the appliances within the vehicle. Installing solar panels means the battery can be recharged regularly with clean solar power, which will extend its life.
The charge controller regulates the amount of power fed into the battery.
It’s advisable to buy a large solar panel system to ensure that all the appliances within the vehicle can be operated using clean solar power. Fed into the leisure battery, a solar panel system ensures that you’ll have plenty of power to run the appliances and have some remaining for use at night and on cloudy days when the panels aren’t generating as much power.
As with solar panels in any other location, it’s always best to use solar panels with monocrystalline solar cells rather than polycrystalline or thin-film options, which are less efficient and will generate less energy.
All solar panels need to be cleaned regularly so that they’re free of dirt and grime, which will reduce the amount of power the panel generates. Rain will help somewhat, but it’s a good idea to clean the panels with a hosepipe or a bucket of slightly soapy water now and then.
