Solar Panels are a crucial component of the RV solar power system geared for the off-the-grid van life; if you say freedom, we say solar power! Flexible solar panels are lighter, usually easier to install, and don’t reduce your car’s aerodynamic.
Flexible solar panels, being frameless, require adhesives to affix them to the roof of an RV. This type of solar panel requires an additional moisture barrier called a side or edge seal. Sealants are also used to reinforce and strengthen weak spots like edges and corner junctions, making the solar panel array more structural stable and weather resistant.
What’s the best adhesive you can use to fix flexible solar panels on your van or RV’s roof?
3M and Sika are the brands that pop up a lot when searching for the right adhesive for flexible panels. These two brands have excellent products, such as weather-resistant, fast curing, and long-lasting adherence to diverse surfaces (abstracts). These two brands are well-known by professionals and regular customers not only because they’ve been in the business of sealants and glues for ages but also because their products are ahead of the competition.
Let’s talk about the Sika adhesive first. This is a Swiss brand diehard van-lifers vouch for with their lives. I personally recommend the Sika flex 252 for numerous different situations, and securing your flexible solar panels to your RV’s roof is one of them. I also recommend using the Sika flex 212 product range as it is specifically formulated and advertised as a flexible solar panel adhesive.
Secondly, you also have another American brand, 3M, that produces excellent adhesive tapes widely used in van conversion and RV repairs. They have a lot of different types of tape models. You want to have a high-strength tape that has a double-sided acrylic foam coating. It needs to stand harsh environments, high/low temperatures and offer an insulation backing to the solar panels.
My personal favorite is the 3M VHB adhesive tape. You can choose between different thicknesses, and it’s good to leave a certain space between the panels and the roof to let a small airflow pass under and, therefore, allow the moisture to get out.
3M also has an adhesive spray that works well for fixing flexible solar panels. It’s the 3M Hi-Strength 90 Spray, which can bond metal and flexible panels. It’s advertised as extremely strong, and it’s easy to use as a spray. Remember that it is crucial to have both surfaces perfectly cleaned before applying any glue or adhesive to them. You don’t want to have your solar panels ripped off by the wind on a highway because your surfaces weren’t clean when you applied your adhesive.
Important Points when installing your flexible solar panels to your campervan with any adhesive
- ALWAYS clean your roof first. You can use soapy water to have a clean surface but using alcohol or benzine is even better.
- Do the same with your solar panel (only the part that will be glued to your van. Don’t use any chemical other than soapy water directly on the surface of your solar panel). You want the areas that will be in contact with your RV’s roof perfectly clean as well.
- Mark-up the areas where you will fix your flexible solar panels. You won’t have a second chance, so you’ll want to be as precise and preventive as possible. It allows you to plan the space and different tools you’ll need.
- Apply your adhesive on either the solar panels or the van surface (or both, depending on your adhesive characteristics).
- Place your solar panels following the guides you marked previously. Important: try to stick it correctly from the first time, especially if you’re using tape. Indeed, it will be complicated to change its position afterward.
- Apply pressure all-round the panel such that the tape/glue gets in contact with both panel and roof. Double-check you did this correctly. You don’t want to discover some parts where the adhesive has unnecessarily dried because it wasn’t in contact with your roof.
When installing your flexible solar panels, you want to keep in mind that their performance will depreciate as their temperature increases. That’s why most of the time you’ll see traditional solar panels (not flexible) mounted with a gap under them, allowing air to flow and therefore cooling the installation.
It’s different with flexible panels. There are generally glued directly to their support and don’t have any air flow going under them. Thus the heat produced is directly transferred to the structure they are glued to.
Even though it’s not always easy or even possible to do, try to have a small airflow passing under your solar panels. It will increase their performance by keeping them cooler.
An excellent way to do this is to mount each panel on top of a sheet of 3mm aluminum composite sandwich (i.e., typically thin aluminum sheets with a layer of polyethylene or similar between them). The polyethylene will help to diffuse the heat.
Here’s a perfect video by RV with Tito that will walk you through this type of installation:
Best adhesives for installing flexible solar panels
The below-listed products are some of the most recommended products for installing your flexible solar panel onto the roof of your camper van.
This tape conforms to rough, textured surfaces and has a wide range of applications for joining, sealing, waterproofing, and vibration absorption.
3M is a renowned and trusted brand in the adhesive world. You can use this type of tape to install your flexible solar panels. Don’t forget to correctly clean both surfaces before applying the tape. Otherwise, you can be sure it won’t stick as well as it’s supposed to.
- A very effective and super strong double-sided mounting tape.
- An added insulation layer to the flexible solar panel.
- Adheres on a variety of plain or painted surfaces, including glass, metals, plastic, wood, and concrete.
- Highly resistant to any van life-related environments. It can stand high and cold temperatures, as well as UV light, solvent, and chemicals. It ensures perfectly sealed bonds against water and moisture, even in harsh environments.
- Not paintable
- Difficult to remove/scrape off if you didn’t apply it correctly from the first time.
You’ll usually want to use this EternaBond Roof Repair on the panels fixations rather than directly on your panel. You can check this video for more details: https://www.youtube.com/watch?v=nShLdvEQyZI – You won’t be able to use it directly under your panels since it’s one side only tape. It’s used to repair RV roof leaks, and therefore it is incredibly sticky and 100% waterproof.
- Strong adhesive that can last many years.
- 100% weather resistant.
- Hard to take off. Be extremely cautious if you need to take it off. Do it slowly in order not to rip off the surface.
It offers permanent and elastic seals for your flexible solar panels. Many vanlifers chose this option to fix their panels as it has a very high adhesive strength. Keep in mind that this will be hard to take off if you need to do something with your solar panels (if you bought a new vehicle and want to keep your solar panels, for example).
- High adhesive strength
- UV and water-resistant
- Can be painted
- Fast curing
- Difficult to remove once applied
- No insulation properties
Sika is a Swiss brand providing different bonding and sealing solutions for professionals in diverse sectors. It has over 100 years of experience in the business and made the best overall products available over the years. Therefore, I can strongly recommend it as the best adhesive for your solar panels.
Sikaflex 252 is a super-strong solution, and we have many people reporting no issue at all after five years or more of usage. Keep in mind that the product itself (even not opened) as an expiration date and that you want to use it before it hardens. If you are using solar panel mounts/fixations on the roof of your motorhome, I would strongly recommend you to use this over the EternaBond Tape.
It is completely resistant to salt water and can withstand the harshest conditions experienced at sea.
It is also the most suitable and secure adhesive for attaching flexible solar panels to a caravan roof since it can withstand the most extreme weather conditions.
- Withstands extreme weather conditions.
- They are specifically designed for mounting flexible solar panels.
- Available in white and black
- Renowned and trustworthy brand
- Does not have insulation properties.
- Difficult to remove
Spray adhesives are convenient, and with their fast-drying ability and easy application, they can be the perfect fit for your installation.
It comes with a variable-width spray nose pattern that allows you to apply it correctly on the desired surfaces (which you previously cleaned).
- Discolours when exposed to weather elements.
- Impossible to remove
I never used it personally but heard many people saying that it was the only spray adhesive that worked in their situation. You can see it’s a good product by its popularity on Amazon and by reading the dozens of positive feedback and reviews.
- Does not discolor
- Slow curing
- Permanent adhesive-Impossible to remove
This range of adhesives and sealants will likely reduce the installation cost of your solar array on your campervan. These different solutions are readily available online and from various specialists, hardware stores make. It shouldn’t take you more than a day to install your flexible solar panels (unless you have many).
Once more, don’t forget to correctly clean the area you want your panels to be; otherwise, it won’t stick correctly no matter the adhesive you chose.
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