How to Install a Fixed Solar Panel to a Bundutec Bundutop Roof Top Tent
We thought it would be helpful for others to know how to install a fixed solar panel to a Bundutec Bundutop roof top tent as it is not as straightforward as you might think due to the design of the Bundutop with its internal winch.
Ian from Bundutec in Australia was extremely helpful in giving us the rundown of what needed to be done with mounting a fixed solar panel to the Bundutop as the supplied manual has limited information for this. When it came to what adhesives needed to be used, we spoke directly with Sikaflex and one of their technician’s gave us a lot of great additional information which we have included in this post below.
Roof Weight Load Limitations
When considering fitting a fixed solar panel to the Bundutop be aware that the roof can only support an additional 25kgs before you will run into problems with the internal winch. Make sure the total weight of the solar panel and additional aluminium supports that are required to fit the solar panel weigh less than this maximum load rating.
Angled Aluminium Supports
A fixed solar panel mounted on top of the Bundutop will need to be supported by two angled aluminium pieces. These angled aluminium supports will need to run the full length of the roof to distribute the weight evenly across Bundutop roof. The fixed solar panel is then secured to the angled aluminium ensuring you leave a gap underneath the panel of at least 15mm for the heat to escape and provide some airflow, ensuring maximum solar efficiency.
We used 40mm x 40mm x 3mm angled aluminium. We could have probably got away with using 2mm aluminium, but we opted for something slightly stronger just in case. We purchased two lengths of 2-metres from our local aluminium supplier. We cut both pieces down to approximately 1953mm. This is the approximate length of the raw aluminium roof sheet, but we would recommend you measure this for yourself. We then added a radius to each end of the 40mm aluminium sections that would sit vertically on the roof for aesthetics. Once we had the aluminium sections cut and ready, we then double checked these fitted on the roof perfectly. Then we lay these down on the ground and mounted our Enerdrive 180W solar panel to them using pop rivets. We should have used self-tapping screws as this would have made it far easier than pop rivets as we do not have a battery-powered rivet gun.
Remember to leave around a 15mm gap underneath the solar panel. You need a decent size gap to allow any heat to escape and stop the solar panel from getting too hot. If a solar panel gets too hot, you lose efficiency in the panel. This gap also helps with airflow when driving.
Once the solar panel was mounted to the two angled aluminium pieces, we then drilled two holes in each end of the aluminium, eight in total. These holes are where we would add pop rivets to the Bundutop roof for additional security.
Adhesive Required to Mount the Solar Panel
Due to the internal winch and all the running cables and pulleys inside the Bundutop to lift the tent up and down, you are unable to pop rivet the full length of the aluminium sections. You can only pop rivet the end sections which are out of the way of the internal lifting mechanisms. As a result, you need to use an adhesive between the aluminium sections and the raw roof sheet. Ian at Bundutec advised us to use Sikaflex, but when it came to what Sikaflex we were a little unsure. We really wanted to be sure that whatever we used was fit for purposes as we did not want to have any issues with the solar panel flying off the roof when driving.
We called Sikaflex head office and spoke with one of their technicians. Sikaflex was extremely helpful. We advised them what we were trying to achieve and the materials we were using. Sikaflex advised us to use the following to ensure a strong bond between the solar panel aluminium mounts and the Bundutop roof.
- Clean all surfaces with acetone.
- Then apply Sika Primer 210 to both surfaces.
- Let the Sika Primer 210 dry for at least 30 minutes.
- Then apply Sika 252 adhesive.
Trying to find Sika Primer 210 was quite difficult. We finally found some online, be aware that it is expensive. However, we wanted to make sure we did this part of the installation correctly. First, we cleaned both the roof and the aluminium pieces with acetone. Then we marked exactly where the solar panel was going to sit on the roof, removed the solar panel, and then added masking tape. We then painted on the Sika Primer 210 to the Bundutop roof and then to the aluminium sections secured to the solar panel. After 30 minutes, we removed the masking tape from the roof and then applied the Sika 252 adhesive. Once the adhesive had been applied, we picked up the solar panel and placed it on the roof. We then carefully drilled through the pre-drilled holes in the aluminium into the roof, making sure we didn’t drill through the roof lining. Then we added silicon, and then eight pop rivets, two on each end for additional security.
As we used 3mm aluminium we had to then use a ratchet strap to pull the solar panel down on to the roof as tightly as possible ensuring the aluminium had a nice tight fit. Once the adhesive had time to cure, we then added another strip of Sika 252 to the side of the aluminium pieces to seal any gaps.
Wiring the Solar Panel
As the Bundutop comes already prewired, wiring in the solar panel is rather straightforward. You will need to purchase at least two red anderson plugs to work with the red anderson plugs already fitted to the Bundutop.
All you need to do is connect a red anderson plug to the solar panel cables and then connect the solar panel to the red anderson plug on the top section of the Bundutop. We added split tubing to this cable to provide additional protection. As per our post on how we fitted our Bundutop to our camper trailer, you will then need to run a cable from the second red anderson plug on the side of the Bundutop to your battery. As we have a Redarc BMS Manager30 which already has a solar regulator, we only need to run the positive cable to the Redarc. Most DCDC chargers should have a solar regulator for you to connect to. If not, you will need to install a solar regulator between the solar panel and battery.
We pulled the trailer out of the shed and into the sun and checked the Redarc Manager30 to see if the solar was providing any amps into the battery. It worked straight away which is always a relief. When we did plug in the solar panel to the Redarc Manager30, even in the shed, the solar input does appear instantly, so you do know if there is an active solar connection with the Redarc BMS.
12-Months On
12-months on how has everything worked? Having the fixed solar panel has been a real comfort for us, especially when camping in one location for more than a few days and we have our freezer running. Our camper trailer battery has not dropped below 60% since we have had our Enerdrive 180W solar panel fitted to our Bundutop roof top tent. A great example of how well this has worked for us, was when we did our last Simpson Desert trip. We stored our camper trailer in Birdsville for five days and left our freezer running with all our meat. When we returned to pick up the trailer our battery was sitting at around 70% in the late morning. There had also been a few cloudy and rainy days while we had been in the desert and the battery did not go any lower than 60%. The Redarc Manager30 provided us with plenty of data for the days we had been away, and it was obvious when it was cloudy and rainy from the charge logs. All our meat was still perfectly frozen.
One of the big concerns we had with mounting a fixed solar panel on our Bundutop roof top tent was the limited number of pop rivets and the heavy reliance on adhesive to secure the solar panel. If we had no pop rivets, we probably would have not fitted the solar panel at all. We have read enough stories online about solar panels only being stuck to the roof and flying off. We do not know how those people mounted the panels, so I am sure that has something to do with it, but it is a little disconcerting if your solar panel is only secured by adhesive. As we followed the Sikaflex requirements to the letter, we are certain we will have no issues with how it is mounted. We regularly check the solar panel to ensure it is well secured and we have not seen any issues with movement or any breaks in the adhesive. Having the four pop rivets on each aluminium angled section does provide us with enough comfort that the solar panel will not go anywhere.
If you would like to read our review on the Bundutop roof top tent you can read it here. We have also added a post on how we fitted our Bundutop King roof top tent to our camper trailer here. For more gear stories, you can find them here.
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The thoughts of Peter.
