The step-by-step guide to fitting a caravan solar panel
Caravan's crack team of Young Tourers get to grips with fitting a caravan solar panel to a Swift Conqueror, for enhanced off-grid touring
Step 1 Choosing a suitable caravan solar panel kit
There are various caravan solar panels on the market, so think about your requirements before making a purchase.
The main factor to consider is the capacity (watts) of the panel. A 100W panel is an excellent all-around solution, although those with greater requirements can opt for a larger capacity. Take a look at Caravan magazine's guide to solar to find out more.
For various solar products, take a look at the Solar Technology International website (solartechnology.co.uk).
This British firm supplies rooftop kits in both flexible and rigid panel designs, as well as freestanding, fold-up systems.
Made by PV Logic, these are high-efficiency, crystalline panels, which boast a 20-year warranty on the panel and a 10-year warranty on the charge controller. The panel warranty states after 20 years the cell output will be no less than 80% of its performance when new.
Our kit contained everything we needed to get the panel up and running. Check your equipment's the same before starting the job.
Step 2 What do I need to fit a caravan solar panel?
DIY fitting doesn't require any tools you won't find in the average DIYers tool kit: a selection of screwdrivers, a drill (with two bits suitable for metal), snips, wire strippers, electrical tape… oh, and a mastic gun.
Step 3 Check your Kit
We opted for a mono-crystalline solar kit.
These panels have a higher purity of silicon than poly-crystalline ones, so you need less panel area to create the same charge.
You can expect the following efficiency ratings from the three main types of photovoltaic solar panels:
- Mono: 15-20% (The record is 21.5%)
- Poly: 13-16%
- Thin-film solar cells: 7-13%
Our kit came with everything you need, including panel, two-core cable, Sika/bonding adhesive, cable entry gland for the roof, solar controller and an inline fuse.
Step 4 Where do I fit my caravan solar panel?
Choosing where to fit the panel can seem like the hardest decision — where does it go? There is no right or wrong answer, but there are some things to consider.
Firstly, think about the cable route. Where is your battery kept? Minimising the number of internal works and cable routing inside the van is a bonus. Find a location where you can access a top locker and some vertical cable trunking.
In the Swift Conqueror, we found great access into a top locker, behind the 12V electrical system.
The best routes are not always easy to find. We'd recommend having a screwdriver handy. You might need to remove pieces of trim to see clear paths. The benefit of using the 12V locker as access is the cable trunking running down towards the floor.
Most caravans have one or two of these to run the factory cables. And there's usually a bit of spare space for additional cabling.
Be sure to properly plan your route, junctions, connections and fuse location. Consider creating a diagram before you start the installation process as this will reduce the risk of error!
Step 5 Measure twice, Cut Once!
Check and double-check everything before starting work. We unboxed the panel and lifted it onto the roof. As well as the internal considerations, it's crucial that you think about the outside, too.
The location of the entry point is crucial, though you can run trunking across the roof if required. Consider any obstructions including roof vents or aerials and possible future installations like satellite systems or air-conditioning. You need to get this part right!
Step 6 Stick the caravan solar panel down
With the caravan solar panel in position and measurements double-checked, we carefully marked the edge the panel using a non-permanent marker.
The markings showed us where to apply the glue. Once completed, we cleaned the roof with soap and water, dried it off, then used the solvent cleaner (also supplied).
Then we cracked open the can of Sika adhesive. If your kit doesn't contain adhesive, check the manufacturer's recommendations or ask your dealer.
Now it's time to fix the panel. Apply a generous amount of adhesive within the marked area. Then, remembering to check the orientation of the panel, carefully place the panel onto the adhesive, and bed it down.
Once you're happy with the position, carefully remove any extra sealant with a paper towel. Then shape it with a wet finger, ensuring an excellent, consistent seal all around.
Be sure that once it's in the correct position, you don't move it.
Step 7 Drilling!
With the panel bonded in place, it's time for the scary part — drilling the roof!
Double-check where you drill. This stage may require a bit of 'toing-and-froing' inside the van and outside. Once you're sure you've got the mark in the right place, you're ready to drill.
We needed two drill bits. The cable measured 11 mm, so we opted to start with a pilot bit at 4 mm, before drilling with a 12 mm bit.
It's a good idea to have a second pair of hands to hold and support a piece of timber or similar inside the caravan when you drill into the caravan. It will prevent damage to the internal ceiling boards! Drill steady and slow!
Step 8 Insert the cable
Now that there's a hole in the caravan roof, it's a good idea to fill it. You'll need a cable entry gland, which may come with your kit.
Fit the watertight seal and pass all the cable through the opening. From here, providing you have drilled the hole big enough, insert the wire into the caravan through the hole. The second pair of hands to receive the cable is useful.
Step 9 Stick the entry gland down
Follow the same steps to seal the entry gland as with the panel. Mark it, check it, clean it and stick it with the adhesive. Be generous with the adhesive/sealant at this stage, as you want to ensure the entry gland is entirely watertight.
As with the panel, paper towel and a wet finger are perfect for removing excess sealant and shaping the seal. We found it was useful to use a bit of tape to hold it in place while the adhesive set.
Step 10 Move inside!
Other than a quick check, and the removal of the securing tape, we're all finished with works on the roof. It's time to move inside! In these next few steps, we focus on installation of the controller, routing of the cable and installing the inline fuse.
Step 11 Plan your cable route
By this point, it's important to know your cable route, factoring in practicality and space, using the existing trunking found in the Swift.
Step 12 Install your controller
Now to fit the solar charge controller. It's the brains behind the panel, giving you charge options as well as charging and battery status.
We opted to have this mounted out of sight in a cupboard, alongside all the other 12V controls for the caravan. It's also an ideal spot along the cable route to the battery.
Our kit included mounting screws, and we located the unit in a locker on the exterior wall.
Remember: double-check the length of your screws against the thickness of your wall. The last thing you want is four external coat hangers!
Step 13 Route and cut your cable
With the controller mounted, cut the length of wire from your solar panel to the controller. You will get eventually into the solar panel input.
The next job is to route the cable down towards the battery. Our cable ran from the controller, behind the 12V system, down the existing plastic trunking to beneath the front bench. It's here we installed our fuse.
Step 14 Check the inline fuse
Our panel arrived with a 10A fuse. If you get no fuse in your kit, check the required rating with your dealer or panel manufacturer.
We fitted the fuse in an easily accessible location under the bench seat. We used a safety knife to strip back the plastic sheath and cut away the live cable, as indicated by the colours and +/- stickers.
Be sure to double-check this. Once the ends are exposed and bared, we fit the fuse holder and add the fuse.
Step 15 Connections
Now here comes the fun part: connecting it all up. Once we installed the fuse, it was time to connect to the battery.
You may find that your van has pre-drilled holes into the battery box or existing ones from previously fitted equipment. If not, you'll need to drill a hole into this area to make a connection to the battery.
We removed the battery before we made this connection. Once the cables are fed into the battery box, bare the ends, attach them to your terminals and make good the connections. Do not connect the terminals to the battery at this point.
Step 16 Connections continued
Before making a final live connection, we firstly stripped and connected the cable from the battery to the controller using the supplied wiring diagram.
Afterwards, we inserted the leisure battery and connected the terminals, leaving us with the final step - connecting the cable from the panel into the solar charge controller.
Step 17 Check, Check and check again
Now is a great time to have a quick check of your work. We went through the whole system. Connections, cable routes, fuses; we checked them all. The controller usually shows a series of lights to reflect the battery and solar status.
Your user guide will help you to identify what these mean.
Step 18 Refit the trim
At this stage, we had seat cushions, trim and cupboard contents everywhere. We secured our cables using zip ties and wall clips. Then we cleaned up any mess and replaced and refitted the plastic and wooden trims.
Step 19 Remove the tape
After a few hours, depending on weather conditions, the tapes on the roof should be OK to remove. Double check the entry gland doesn't move before taking off the securing tapes. Remove any other waste, materials or tools from the roof.
Step 20 Enjoy luxury off-grid living!
Of course, it's best to give your panel a day or so before heading off into the distance. You want to ensure the panel comes with you! Now your panel is fitted, you'll experience the ultimate freedom of off-grid touring.
Solar is great for exploring sites off the beaten track and keeping the leisure battery topped up when in storage. Correctly fitted, a roof-mounted solar panel should give you years of trouble-free electricity!
Our experience & feedback on fitting a caravan solar panel
How hard was it?
Fitting this unit was our first attempt at installing a solar panel to a caravan. It seemed daunting, but once we got started, it was a piece of cake.
We found the most important thing was to make sure we had all the materials and tools we needed. Pick a good day, grab a helper and you shouldn't have any issues. Within half an hour, we noticed the battery charge level on the Conqueror was already increasing. Now, that's a result!
Links If you'd like to see our video on fitting, search 'Young tourers' on YouTube. If DIY fitting sounds a bit too much, your caravan dealer or a reputable installer will help.
Tools we used:
- Electric drill (ideally cordless)
- 4 mm drill bit 12 mm drill bit
- Adhesive gun Safety knife
- Wire strippers Platform/ladder
- Wire cutters Cleaning equipment
- Screwdriver selection
Words by Karl Wray Photos by Dan Arnold
If you're young and thinking about starting your caravanning adventure, do it! You will have so much fun.