In this article you will learn the differences between flexible vs rigid solar panels for your RV.
This is a decision you will have to make before choosing your solar array.
If you head to any large campsite you will see plenty of vehicles with these types of solar panels. To be honest, both do a brilliant job in using sunlight to generate electricity and charge batteries.
But there’s pros and cons to each style. Below we will do a side-by-side comparison while going through each advantage and disadvantage of flexible and rigid solar panels for RVs.
In This Article
What’s the Difference between Flexible and Rigid Solar Panels?
Flexible and rigid solar panels both work in the same way and carry many of the same features. They use silicon solar cells to convert sunlight into electricity.
The way they are built is very different which leads to some distinct differences.
What is a Flexible Solar Panel?
A flexible solar panel is designed to be bendable. The solar cells are attached to a thin backsheet and then wrapped in thin film plastic like ETFE or PET. As there is no stiff metal frame or glass this allows the panel to flex a certain amount. Generally, they can bend upto a 30 degree arc.
What is a Rigid Solar Panel?
A rigid solar panel is what you traditionally imagine when you think of a solar panel. The solar cells are mounted inside an aluminum metal frame and covered with tempered glass. These materials are thick and rigid so there is no flexibility in the panel structure.
Flexible vs Rigid Solar Panels Comparison
Below is a comparison for a quick overview in features and performance.
|Feature||Flexible Solar Panel||Rigid Solar Panel|
|Weight||Lightweight (4lbs)||Heavier (12+ lbs)|
|Cell Type||Silicon – Monocrystalline or Polycrystalline||Silicon – Monocrystalline or Polycrystalline|
|Thickness||Low profile (Less than 1inch)||Thicker (1.5 inches)|
|Use on Vehicles||Yes||Yes|
|Electrical Output||Direct Current (DC)||Direct Current (DC)|
|Installation / Mounting||Adhesive, Hooks, Portable||Z-brackets or Corner mounts with adhesive|
|Durability||5 – 10 years||25 years|
Advantages of Flexible Solar Panels
Let’s look at the benefits of flexible solar panels.
Flexible solar panels are incredibly lightweight with popular 100 watt ones weighing around 4lbs. That’s about 75% lighter than a traditional solar panel.
This is a huge benefit for using RVs which can help save weight when driving. In addition, many RVs don’t have very strong roofs so if you want to install multiple solar panels it won’t risk overloading the structure.
Many people love how thin flexible solar panels have become. They are less than 1 inch thick! This allows you to place them on top of a campervan without anyone even knowing. If you’re building a stealth camper then flexible solar panels are essential.
Mount on Curved Surface
This is the big reason flexible solar panels have been created. The ability to gently bend them allows you to mount them on uneven surfaces. You might have a curved roof to your RV, caravan, or trailer which makes it hard to mount rigid solar panels.
The flexibility allows you to stick these types of products to fit the curvature of your surface.
Easy to Install
They are also super easy to install. Even on an RV, you can stick them down with VHB M3 tape. This adhesive tape is very high bonding and will stay secure even as you drive along and create wind resistance.
It is not just easy to make this installation but it also avoids drilling holes that may compromise the waterproofing of your rooftop.
Waterproof and Weatherproof
Of course, all solar panels are designed to be used outside. As you can use flexible solar panels to permanently mount on vehicles they are completely waterproof. You don’t need to worry about them during heavy rain. Adding to this they will stand up to high winds, snow, dust and dirt.
The best flexible solar panels have an ETFE covering which is a durable thin-film plastic that is self-cleaning!
Portable and Versatile
You don’t have to mount flexible solar panels in a single location either. Many people use them in a portable fashion. This is because they are so lightweight. Plus you can send them into fabrics like tents or simply hang them from wall hooks.
Disadvantages of Flexible Solar Panels
Flexible solar panels are awesome but they do have their downsides too.
They will last a number of years but nowhere near as long as a rigid solar panel. When mounted outdoors you can expect a PET flexible solar panel to last around 5 years and an ETFE one to last 10 years. After this amount of time the solar cell will still work well but you might notice issues like delamination or general wear and tear to the plastic coverings.
Don’t get me wrong, flexible solar panels still deliver astounding performance. They can include monocrystalline solar cells with a conversion efficiency of over 20%. But they can never quite match up to a thicker solar panel. This is because the silicon cells are not quite as efficient. The PV layers are thinner and spread over a wider surface area to generate the equivalent power levels. If you have a rigid and flexible solar panel of the same dimensions the flexible one will produce a lower wattage output.
As we just discussed, flexible solar panels are more likely to overheat. This is because they are usually stuck flat to a rooftop or surface. This reduces the ability for air to flow under the panel and dissipate heat. When solar cells get hot their output will temporarily reduce.
More Prone to Damage
As there is only a thin film of plastic protecting the cells there is more risk of damage. For example, some people think it is OK to walk on a flexible solar panel but this is not true. In addition, sharp points can accidentally pierce the plastic film. If this happens water and dirt can get inside and degrade the solar cells.
Flexible solar panels are more expensive than rigid solar panels. This is because the manufacturing process takes more care. They are also produced in few numbers so the manufacturing costs are not as efficient. You can pick up a decent 100 watt rigid solar panel for around $100 while a flexible solar panel costs $150+.
Advantages of Rigid Solar Panels
Rigid solar panels are still very popular and for good reason! Let’s look at their benefits:
Durable and Long Lasting
The biggest reason people love rigid solar panels is because they last decades. You can expect them to last 25 years or more and manufacturers will provide a power output warranty of this length.
The anti-rust aluminum frames will easily stand the test of time even when driving around on an RV. Adding to this, the tempered glass covering the cells is resistant to shocks, bumps, and knocks. The silicon cells are incredibly well protected.
Rigid solar panels deliver the best conversion efficiency as the silicon solar cells are laid thicker giving you more power per square inch. With monocrystalline cells in a rigid panel, you can expect 21% or more efficiency in direct sunlight.
When you mount a rigid solar panel it will be slightly raised on brackets. This helps to keep them cool during hot weather and strong sunshine. The gap allows a draft to form and air to flow underneath. As the air flows underneath it dissipates heat from the solar panel. Low temperatures help to increase solar cell performance. The performance of a hot solar panel will temporarily degrade based on its temperature coefficient.
Hard to Damage
Not only do they last for decades, they are super tough making them hard to damage accidentally. The tempered glass will not give way to a falling object, sharp end, or any bumps. Plus the way they are mounted discourages people from walking across them.
Waterproof and Weatherproof
The long durability also applies to harsh weather conditions. Rigid solar panels are completely waterproof and resistant to strong wind, snow, ice, and dirt. You might have to do some cleaning every so often to remove dirt and debris like leaves. In addition, the aluminum frames are anti-corrosive so you won’t have any issues with rust.
You can even expect them to resist hailstones upto 1 inch in diameter!
Disadvantages of Rigid Solar Panels
When looking at rigid solar panels you should be aware of the downsides, particularly for RV and similar vehicles owners.
With all the extra metal frames and glass covering comes extra weight. You might be able to mount one or two rigid solar panels on an RV but more than this can create excess weight. This is especially a problem for older vehicles with less supportive rooftops.
A rigid RV solar panel can weigh upwards of 15 lbs. This is not too bad for a single panel but can add up quickly with multiple panels. You might notice problems with overloading a structure and reducing fuel efficiency dramatically.
Tricky to Install
Rigid solar panels are not hard to install but it is trickier than a flexible solar panel. You can still carry out the job yourself by either drilling z-bracket mounts or using corner mounts and adhesive. If you have an uneven or curved surface you might run into problems too. Either way, you will need a mounting system or brackets to properly secure the frames of the panel.
Flexible vs Rigid Solar Panels for RV Summary
I hope this article helps you clearly see the difference between rigid and flexible solar panels.
The benefits of flexible solar panels often outweigh the disadvantages when you want to save weight or mount on a curved surface. That being said, if you want the highest efficiency and durability then you can’t look past a rigid solar panel for your RV.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.