Our first trip away in Penny back in 2023 was fun, but something of an adventure. We took her away to see what worked and what didn’t. It didn’t take long. Pretty much nothing worked. But we were at a music festival so we didn’t much mind; it helped us build a list of what needed doing.
We gradually worked through the dodgy handbrake, non-existent plumbing, lack of towing electrics and all sorts of other issues, while also making other improvements in the shape of installing some caravan Wi-Fi.
One thing that really makes sense when heading to a music festival (or you’re going anywhere off-grid in a caravan) is solar power. You can head off to the main stage all day, then come back to a battery that’s full and ready to charge your phone for day two. Installing solar panels on our caravan would be a smart upgrade.
These days they aren’t too expensive, and they keep the best leisure battery for a caravan topped up so your van can function without needing electric hook-up, which is rarely available at a festival.
Over the past year, we have upgraded Penny’s wiring to make sure she was ready for solar. We added bus bars, a battery monitor, a brand-new battery and fresh cables to make sure the basic electrics were sound. All she needed now was a panel.
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Getting started with installing the caravan solar panels
To start off, we needed to choose what size of caravan solar panel to opt for.
I’m no expert in solar, so I spoke to people who are. Bimble Solar in East Sussex supply solar kits for all sorts of set-ups. I got in touch to ask what I should consider. They had a deal on 90W Victron panels, which I thought might be a good fit, but their team recommended going bigger. Since we had a 100Ah battery and lots of roof space, they pointed me to a 150W panel.
It cost less than £100 and would easily fit. I also asked about cheaper PWM (Pulse Width Modulation) charge controllers, but they were clear: spend extra on an MPPT (Maximum Power Point Tracking) controller. These smart controllers get more power out of weak sunshine, which we get plenty of in the UK. They cost more, but if you want to get the most from your panel, it’s worth it.
The last thing we asked was whether we needed a way to isolate the panel from the charger. For larger set-ups this is essential, but for a single 150W panel it’s just a nice extra. Bimble offered a 15A fuse, switch and mounting rail for £17. We thought that was good value and went for it.
We had already measured the roof space and knew the 1500mm by 700mm panel would fit, but we also needed to plan how to get the cable through the roof. Penny had a dead TV aerial (see: the best caravan TV aerial if you need one) with a cable running into the wardrobe. We decided to reuse that hole instead of drilling a new one, so job one was removing the aerial.
These old omni-directional aerials are simple enough but not always easy to remove. Ours was already missing the top antenna, so we could skip that step. Next, the saucer part comes off by loosening a grub screw. Ours was so loose I could simply lift it off. The base was held on by four screws and a lot of silicone sealant. The screws came out easily, but removing the base and cleaning up the sealant took the best part of an hour.
Up on the roof to install the solar panel to our caravan
With the cable route sorted, we carried out the task of cleaning the caravan roof where the panel was to go. Bimble supplied ABS plastic corner and side brackets for the Victron panel. We decided to fix the brackets to the panel first, then lift the whole thing onto the roof.
The patio table made a good workbench with space to move around. We used self-cutting hex-head bolts to attach the brackets to the panel frame, and added CT-1 sealant between the frame and brackets for extra grip. We drilled pilot holes, fitted the bolts, then backed them off to add sealant before tightening them back up.
For the roof, we used Sikaflex 522. Some people use CT-1 for this too, but Sikaflex is better suited for roof jobs. It has the right mix of strength and flexibility, resists UV and weathering, and works with all the materials on Penny, including her aluminium roof panels.
The sealant is only as good as the surface, so we spent time getting the roof clean. Years of grime meant this took some work. We started with a diluted traffic-film remover, scrubbed and rinsed, then finished with isopropyl alcohol. Once we were happy with the surface, we lifted the panel up, marked the bracket positions, and got ready for the final fix.
With sealants such as Sikaflex, you only get one shot, so we had a cuppa, took a deep breath, and went for it. We needed the cables to exit towards the centre of the van, so we ran them where they needed to go, applied sealant to the bracket feet, and set the panel down. Penny has a loose-laid roof, so we added some weight to the panel while the sealant cured – first one side, then the other.
As mentioned, the cables ran through the old aerial hole. To keep things watertight, we used a gland box from Bimble. It lifts the cables off the roof and seals the opening properly. We mounted the gland box over the old hole and fed the cables through with a bit of slack. Once the gland is sealed down, you can’t adjust the cables easily, so it’s important to get the length of cable you need roughly right before you tighten everything down.
With the panel now stuck on the roof and the cables neatly clipped down, it was time to start getting technical and connect things up inside the van. The panel was already generating power but with nothing connected, it wasn’t going anywhere useful. We still needed to cut and run the solar cable, so we covered the panel while we worked, to keep things safe. As an added safety precaution, we used rubber gloves while we worked on the panel cables.
The wiring is very simple. There is a positive and a negative cable coming from the panel. They need to be routed to the charge controller, with the positive cable going through a fuse to protect the circuit.
From the charge controller, a new cable is run to the battery, or in our case to the positive and negative bus bars. This would allow the power generated by the panel to charge the battery as long as the sun were shining.
Final fixings
Bimble supplied us with a Victron 75/15 charge controller for our set-up and we mounted it at the back of the wardrobe, keeping the cable run from the roof nice and short. We also made a little mounting plate to hold the fuse holder and the charge controller neatly next to each other.
With that secured, we were able to run the cables into place – for the final time. Once we had ensured the connections were nice and tight, and connected the right way round, we were ready to test.
For one last time, we clambered up the ladder, removed our cardboard panel cover and whooped with delight as the solid green light on the controller confirmed that the sun was charging the battery. The controller has Bluetooth, allowing us to download the VictronConnect app to see what the panel was up to. We’re pretty sure this is the first time in her life that Penny has had her own app. So that’s a result in more ways than one.
How we went about installing solar panels to our caravan: a step-by-step guide
1. The bracket kit comprised four corners and two sides.
2. Lay the panel on a flat surface to fit the brackets.
3. We trial-fitted everything.
4. We pilot-drilled the brackets.
5. After pilot-drilling, the bolts were fitted.
6. We took them all out again to add a polymer sealant to the brackets.
7. Bottom surfaces were keyed with sandpaper to help sealant adhesion to the roof .
8. Ensure the roof is spotlessly clean before fitting the panel. We used traffic-film remover and brake cleaner to ensure a dry, clean surface.
9. We applied Sikaflex 522 to bond the panel to the roof. The datasheet says allow 48 hours’ curing time.
10. We binned the crusty old TV aerial and used the existing hole to route the cables into the van.
11. The cables attach to the panel using the preattached weatherproof plugs. We clipped them under the panel to further protect them from the elements.
12. A lot of cleaning, and plugging of the aerial mounting holes was completed before the cable gland was bonded into place with Sikaflex.
13. Make sure you mark the positive and negative cables – it makes life much easier!
14. The whole assembly was then mounted on the back wall of the wardrobe. Cables were tidied later.
16. Once this was all done, we were ready to remove the cardboard cover from the panel and see if it all worked.
This isn’t the only bit of DIY I’ve done to my tourer either, as I refurbished the kitchen cabinet doors in my caravan to create a more stylish look, and also went about fixing the leaking cassette toilet too.
Future Publishing Limited, the publisher of Practical Caravan, provides the information in this article in good faith and makes no representation as to its completeness or accuracy. Individuals carrying out the instructions do so at their own risk and must exercise their independent judgement in determining the appropriateness of the advice to their circumstances and skill level. Individuals should take appropriate safety precautions and be aware of the risk of electrocution when dealing with electrical products. To the fullest extent permitted by law, neither Future nor its employees or agents shall have any liability in connection with the use of this information. You should check that any van warranty will not be affected before proceeding with DIY projects.
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