Adding a semi-flexible or a portable solar panel to your caravan will enhance your holiday experience by making you independent of the mains hook up. Enjoy more freedom to roam the countryside and park up wherever suits you. Stop worrying about flat batteries!
Solar panels are easy to fit and to use. But what is the best type of panel to use and how do you go about installing one? We will explain which panels to use, how to go about the installation, and how to avoid the hazards and pitfalls.
Two easy ways to fit a solar panel to your caravan
By far the easiest type of solar panel to use on your caravan is a portable panel. These come in a variety of shapes and sizes. But don’t choose a panel that’s too small as it will not charge your battery. On the other hand too large a panel will be cumbersome and difficult to store. We recommend using a 50 watt solar panel. This is a good compromise between power, size and weight.
The panel will be taken in and out of your caravan on a daily basis. So make sure the panel is robustly constructed. There are many lightweight fabric based solar panels available which do a reasonable job while they are working. But by folding and unfolding the contacts and connections are easily damaged. Use a panel that is constructed from aluminium. This will last much longer than one built from plastic or nylon fabric.
The portable panel advantage
One major advantage of the portable solar panel is that it can be set up to face the Sun directly. A solar panel tilted upwards in this way will produce much more electricity than one laying horizontally on the ground. A fully adjustable stand is a big advantage. Set the panel up so that it is fully exposed to direct sunlight. Tilt it up or down to face the Sun, and your batteries will charge up much faster.
It is often said that a solar panel will work with low light levels. Light that’s reflected from other surfaces does contain some energy and a solar panel can use this energy to make electricity. But the amount of power available from reflected light is much less than that from direct sunlight. Setting the panel up to face the Sun directly is a real bonus.
Make sure that your solar panel has some kind of indicator to tell you that it’s working. An LED that gives you an indication of the battery charge state, and another that indicates that power is coming from the solar panel, are very helpful.
Finally, the portable solar panel does not need any work to install it. Simply take it out of it’s
bag, fold out the stand, set it up on the ground and clip the lead to your battery. That’s it!
Permanent installation of a semi-flexible solar panel
The portable solar panel is great. But if you do not want to set it up each day then a permanent installation might be better for you. However, be careful about what you fit to the roof of your caravan, you might cause more harm than good!
A caravan roof is quite lightly built and usually does not have the strength of a motorhome or campervan roof. For this reason you must not fit a standard solar panel to a caravan roof. The standard aluminium framed solar panel is too heavy and will cause too much windage for the caravan roof to support. It could cause the caravan roof to distort permanently.
The only type of panel suitable for fitting to caravan roof is a lightweight semi-flexible solar panel. Because it is built with special UV resistant plastics, a semi-flexible panel weighs a fraction of its traditional glass/aluminium cousin. For example, a traditional 100 watt solar panel weighs in at 7.75 kgs, while a 110 watt semi-flexible solar panel weighs only 2.4 kgs. The semi-flexible panel is only 3 mm thick and so does not cause any windage when the caravan is moving. Much better for your caravans roof!
The efficiency of a modern semi-flexible solar panel is at least as high as a standard solar panel. When choosing a panel make sure it is built with ‘monocrystalline’ technology. This is by far the most efficient construction commonly available. And make certain that it uses ‘back-contact’ technology, for the best efficiency.
Do not buy a polycrystalline, thin-film, or amorphous crystalline panel. These are outdated technologies and will take up far too much room on the roof of your van.
How the semi-flexible panel is fitted.
The semi-flexible panel is glued to the roof of the van using a special adhesive. The cable from the panel is taken through a watertight gland to the interior of the van and is then connected to the battery via a charge controller. That’s essentially it. Very straightforward for the average DIY fan. More details can be found on our website, and our solar panel kits contain step-by-step illustrated instructions.
So what size of solar panel do I need?
If you are fitting a solar panel to the roof of your van and you just want to ensure that your battery is charged up ready for weekend use, then a 50 watt panel should do the job.
If you are looking for some independence of the mains hook-up, then go for a 100 watt panel. This will provide a good quantity of power for the average caravan user. In addition, a 100 watt semi-flexible panel is the best compromise between size and ease of fitting.
For complete independence of the mains hook-up you should consider using 150-240 watts of solar power. The best way to fit this size of solar panel is to use two or more smaller panels connected together. So a 100 watt panel connected to a 50 watt panel will give you 150 watts of power. Fitting two panels together is usually much easier than fitting one large panel.
A panel larger than 120 watts can be very unwieldy to handle. Panels of 100 watts or less can be fitted around the other equipment on the roof.
What do I need to fit a solar panel to the roof of my caravan?
We have briefly mentioned connecting the solar panel to the battery via a charge controller. The charge controller is essential. It protects the battery from overcharging while making sure that the battery is charged to it’s maximum capacity.
You will also need suitable cable, adhesive, fuse and a roof connection gland. We have listed suitable examples of these items below.
Remember that we are here to help. If you have any questions about the above or any other aspect of using a solar panel on your caravan, please let us know.
Our recommendations for your semi-flexible solar panel installation
Solar panel kits: Our kits provide you with the solar panel, the correct charge controller and appropriate cables. See our semi-flexible kits and read more about fitting your solar panel.
Semi-flexible solar panels: The SunWorks range includes panels from 20 watts to 120 watts. These can be combined to generate more power.
Charge controllers: Our most popular charge controller is the SunWorks SB1C. This has a useful LCD display and can be fitted so that the cables are hidden from view. It can handle any solar panel from our range up to 170 watts.
Our budget controller is the SunWorks SB0 which can handle solar panels up to 125 watts.
Cables: Use 2.5 mm square 2-core cable.
Cable with red and black cores is recommended for caravan use. The cable must have suitable connectors fitted to match the solar panel. Our cables are pre-fitted with these connectors for ease of use.
Fuse: The connection from the charge controller to the battery must be fused. Use a fused battery harness.
Adhesive: We fully recommend for reasons of safety that you use Sikaflex 252i to secure the solar panel to the roof of your caravan.
Roof connection gland: This must be watertight and streamlined to reduce windage.