ETFE Solar Panels [Everything to know about]

In determining the mechanical properties of solar modules, the type of coating material used is crucial.

For flexible solar panels, ETFE is one of the most popular coating systems. It is a very flexible material with exceptional mechanical properties.

ETFE flexible rubberized solar panels are incredibly good-looking, thin, and lightweight and work perfectly for outdoor applications. This cutting-edge technology is no doubt an improvement of the old and cheaper PET solar cells coating system.

Unlike traditional solar panels that need frequent cleaning, ETFE PVs have a non-adhesive surface, so dirt is easily washed away by rainwater.

For a solar power user, this means that ETFE solar panels are hassle-free to maintain.

ETFE PV modules are usually flexible, semi-flexible, or foldable. These designs enable easy installation to surfaces of all shapes and designs, which translates to more applications compared to conventional, rigid solar panels.

In this article, you’ll learn all there is about ETFE solar panels and get answers to some of these questions:

• What exactly are ETFE solar panels?
• How do ETFE solar panels compare to PET and conventional solar modules?
• How are the components of ETFE modules, and how are they installed?
• What is the efficiency of ETFE PVs?
• Are ETFE flexible solar panels any good?

Are you ready to learn the ins and outs of ETFE solar panels? Then this comprehensive guide is perfect for you.

What is ETFE, and what is its Role in Solar Panels?

ETFE (ethylene tetrafluoroethylene) is a fluoro-polymer or plastic used as a protective coating on solar panels.

ETFE is currently the most popular polymer for solar panels backsheet and front sheet due to its excellent features such as high fire resistance, excellent solar transmittance, and self-cleaning nature.

The most crucial component of EFTE is the ethane molecule. This molecule is so stable that it’s able to tolerate thermal and chemical stresses.

There’re also chlorine atoms in the polymer, which prevent discoloration of the solar panel after continued exposure to UV rays.

ETFE is almost totally permeable to UV rays which means that maximum solar energy penetrates the solar cells for power production.

All these perks lead to one thing– improved efficiency of ETFE solar panels.

The primary role of this outer plastic on solar panels is to protect the inner solar panel components, including the power-producing solar cells, from:

• Harsh weather
• Mechanical stress
• Dust and dirt
• UV radiation
• Thermal stresses

Additionally, ETFE fabric laminated solar panels are shielded from electric conductivity between the solar cells and the surroundings.

In line with these roles, we can say that ETFE is an insulating layer for flexible solar panels and a must-have for modules used for outdoor applications.

The benefits of ETFE go beyond improving solar power production. This polymer is made from sustainable materials that are totally recyclable. The lightweight and compact design of transparent solar panels translate into low carbon emissions, especially during transportation.

In a nutshell, ETFE is, at least for now, the ideal coating material for flexible solar panels.

ETFE Solar Panels Components

ETFE film- The outer protective layer installed on the face of an ETFE solar panel. This material is an upgrade to the old PET coating material.

EVA (Ethyl-Vinyl Acetate) – An encapsulating material used to provide mechanical support and extra environmental sealing for the solar cells. EVA allows easier penetration of sunlight without being degraded.

Rubber strip- Protects the edges of the solar panels from the problem of delamination. To offer proper protection, the rubber strip should be highly heat-resistant.

Backing board- Usually fiberglass or aluminum and the main component that gives the solar panel the ‘flexibility’ feature. Fiberglass is a superior backing for solar panels than aluminum, and it is considerably more expensive.

Solar cells- Solar cells convert solar energy into an electric current. The solar cells can be a monocrystalline, polycrystalline, or thin film.

PV grommets- Holes cut into corners of flexible solar panels that are used for mounting. Most ETFE solar panels have 4 grommets.

PV connectors- These are usually MC4 connectors that are used to connect all your ETFE solar panels together. Some flexible solar panels don’t come with MC4 connectors, so you may be required to buy them separately.

ETFE Solar Panels vs. Non-ETFE Solar Panels

In the following table, we will compare ETFE and conventional (non-ETFE) solar panels so you can determine which is the best option for you:

Note: While each of these types of solar panels comes with its pros and cons, they’re meant for completely distinct purposes.

ETFE solar panels are suitable for outdoor applications since they’re lightweight and can be installed on complex surfaces with unconventional shapes.

On the other hand, conventional rigid are perfect for roof and ground mounts for a more permanent power solution.

ETFE VS. PET Solar Panels

Other than ETFE, the other common coating film for flexible solar panels is PET.

PET stands for Polyethylene Terephthalate, which is clear, sturdy, and shatterproof plastic. ETFE is gradually replacing this material as the outer covering system of flexible solar panels.

Below is a table highlighting the main differences between ETFE and PET solar panels:

Summary: Solar panels should be coated with ETFE as it is the best alternative to PET. Although ETFE is more expensive, it’s superior to PET in all other aspects.

ETFE Solar Panels: How Sturdy Are They?

ETFE PVs are an extremely sturdy material that can withstand outdoor elements such as hail, extreme wind, and snow, as well as other physical stresses.

These solar panels are less prone to cracks and fractures. In fact, you can walk on them and cause no damage to the inner power-generating components and interconnection points.

Thanks to their sturdiness, ETFE laminated solar panels have been used to charge devices for outdoor activities such as camping, hiking, and hunting.

And it’s not just about physical sturdiness. ETFE solar panels are also impressively resistant to dirt corrosion and extreme temperatures.

Let’s briefly delve into each of these properties.

Dirt resistance

ETFE solar modules have a non-adhesive surface, so dirt and dust cannot adhere to them.

Dirt blocks sunlight off the solar cells and reduces overall efficiency. Due to dirt resistance, this problem is eliminated, and these flexible PVs operate at the best efficiency possible at all times.

Corrosion resistance

Corrosion in solar panels is caused by chemical reactions between the outer material and environmental conditions such as moisture. ETFE is resistant to these chemical reactions, protecting the other components of the module from deterioration.

Extreme temperature resistance

The operating temperature range for ETFE solar panels is around -40◦C to 150◦C

As you can tell from the range above, ETFE solar panels can tolerate extreme temperature fluctuations and also produce power over a wide range of temperatures.

The wide operating temperature range indicates that ETFE PVs perform better than other solar panels.

What is the optimum temperature for ETFE solar panels?

ETFE solar modules are more efficient when the temperature goes up. However, most ETFE modules will have peak efficiency at standard temperature (77◦ F/25◦ C)

A combination of these intrinsic and extrinsic features makes ETFE the best backsheet material for flexible PVs.

Because of these valuable properties, ETFE is also a common polymer in the chemical and mechanical industries.

Semi-Flexible Vs. Flexible Vs. Foldable ETFE Solar Panels

Any solar panel which can be bent falls under the flexible category. Flexible ETFE solar panels usually don’t have a metal aluminum framing and a glass build. They’re the exact opposite of rigid solar panels.

Semi-flexible solar panels are under the broad ‘flexible' category and come between foldable and rigid solar panels.

Most semi-flexible ETFE solar panels can only be bent to a certain degree, say 10◦ or 30◦ , in a curved manner. Anything beyond that maximum angle will definitely break the solar panel.

Foldable in the solar panel's scope refers to the super flexible modules. These are the kind of solar panels you can easily fold, insert into your bag, and carry wherever you go.

When referring to foldable solar panels we mean the kind that can be wrapped around light poles for power production.

ETFE Solar Panels: A Size, Wattage Rating, Voltage Rating, and Weight Breakdown

Size

ETFE solar panels have a thin and compact design and are definitely smaller than conventional solar panels.

In terms of thickness, these panels usually measure around 0.1″. To get the exact dimensions of your flexible solar panels, you should check the manufacturer's information sheet.

Wattage rating

This is a measure of the power an ETFE solar panel can produce. The higher the wattage rating, the more power the solar panel produces.

There’re a ton of ETFE solar PV types with regards to wattage ratings. Some examples are: 18W, 20W, 50W, 55W, 75W, 90W, 100W, 110W, 120W, 150W, and 300W.

Voltage rating

Voltage is the amount of potential energy that a solar panel produces. Most ETFE PVs come in the following voltage ratings: 12V, 18V 24V.

Weight

ETFE solar panels are very lightweight. Many weigh around 5 pounds. Compared to conventional solar panels, which weigh on average 40 pounds, ETFE panels are incredibly light.

Here are 3 examples of ETFE solar panels indicating some of these parameters:

• A Lensun 50W solar panel has the following dimensions 755mm × 530mm× 2.5mm (29.72″ × 20.86″ × 0.09″) and weighs about 4.475 pounds (2.03 kg)
• A JK 100W ETFE solar panel measures 1245mm × 550mm × 2.5mm (49.05″ × 21.65″ × 0.09″) and weighs 6 pounds (2.71 kg)
• A Solar Marine 300W ETFE solar panel measures 1810mm × 920mm × 3mm (71.25″× 36.25″ × 0.12″) and weighs 5.5 pounds (2.5 kgs)

Cost of ETFE Solar Panels/ Buying Guide

The cost of ETFE solar panels varies depending on 2 main factors: Power rating and backing material.

Here are some examples to illustrate this:

• A typical 100W, 12V ETFE solar panel should cost you around $180-$190.
• A 20W, 12V ETFE aluminum back sheet solar panel goes for around $50-$60.
• A 50W, 18V ETFE fiberglass back sheet module costs around $140-$150.
• A 300W monocrystalline solar cells panel costs approximately $750.

Are ETFE PVs cheap?

ETFE solar panels are pricier than PET flexible solar panels and conventional rigid solar panels. The superior characteristics of ETFE raise the price of these panels, but you'll at least get value for your money when you invest in them.

Where to buy ETFE solar panels?

The best place to get ETFE solar modules is right from manufacturers.

Some leading ETFE solar panels manufacturers/brands to consider when you want to buy your flexible solar panels include: Sunpower, Lensun, Chanve, Giaride, Tesla, LG, GC, Kingsolar, WindyNation, AllPowers, Renogy, Sunbeam, RichSolar, Solbian, LinkSolar, Gioco, Bimini and Fly Solartech.

Most of these brands have online shops where you can order your ETFE solar from wherever you are worldwide.

ETFE solar panels buying tips

• Buy your ETFE solar panels from reputable manufacturers so that you're assured of their quality. Cheap, low-quality ETFE modules from untrustworthy companies will die off after a few months of operation and make your investment worthless.
• Consider the maximum surface area where your solar panels will go to know the number, size, and power rating of flexible solar panels to buy.
• Evaluate your power needs to know the right kind of ETFE PVs to buy. If you’re outdoorsy, determine the means of transport you commonly use and the kind of devices you carry around. This will give you an idea of what will be suitable to meet your power needs.

Installing ETFE Solar Panels

ETFE solar panels kit

Here are the basic items you’ll get in a basic ETFE solar panels kit:

• ETFE coated flexible solar panels
• Cables
• Cable glands
• MC4 connectors
• MPPT charge controller
• Circuit breaker

For such a standard ETFE solar panels kit with at least 3, 100W flexible modules expect to spend around $1,500-$2,000.

For a DIY ETFE flexible solar panel mounting, you need to have the following:

• Basic tools such as a tape measure, wire stripper, screwdrivers, drill, etc.
• Glue or adhesive tape for a direct mount
• Mounting bracket for a rack mount

Side note: Since most of these components are used outdoors, they should be waterproof and resistant to weather conditions.

The installation process

ETFE flexible solar panel mounting should be done on a racking system. This creates an air gap between the module and the solar panel that eliminates overheating problems.

We all know how overheating can be detrimental to a solar panel’s efficiency.

The only time you’d want to go with the direct mount is when you’re installing a flexible solar panel on a streamlined surface such as on top of an airstream. A rack mount in such an application may bring air turbulence issues.

Regarding the actual mounting, you should first understand that it will depend on the structure of the area you want to install the ETFE solar panels.

The installation can be as simple as placing a rack on flat ground then your solar panels on top.

This would work in a camping situation, where you just want temporary power to charge your devices off-grid.

If you’re looking for a more permanent installation (example: on a golf cart roof), you should follow the following procedure:

• Prepare the surface by cleaning it up with rubbing alcohol and a soft cloth
• Fix the rack on the surface (you can screw it in). PVC tubes can also serve as an excellent substitute for metal racks.
• Install the solar panels to the racking (use the grommets at the edges of the panel as the fixing points)
• Connect the solar panels together using the MC4 connectors
• Channel the output of all the solar panels to a load or energy harvesting system.
• Expose the flexible solar panels to the sun, and you will get electricity to charge your device.

Here’s an article that explains in detail how you can power your golf cart with flexible solar panels.

Bonus tip: If you're an outdoorsy person, it's good to invest in an extra ETFE flexible PV to supplement your permanently installed ones.

Efficiency and Applications of ETFE Solar Panels

ETFE modules are high-efficiency solar panels boasting around 15-25% efficiency at peak performance.

This makes them as good as conventional solar panels, not to mention that they offer a ton of other benefits.

ETFE solar panels are the perfect power solution if you can answer ‘YES' to these questions.

• Does the application require weight savings?
• Do I need a portable configuration for a power solution?
• Is the installation needed on a curved surface?
• Do I need a power solution for outdoor projects?

As such, ETFE solar panels are commonly installed on golf carts, caravans, camp trailers, RVs, camper boats, tub trailers, and airstreams.

Even though the top surfaces of some of these modes of transportation are curved, flexible ETFE solar panels are the perfect power solution.

If installed properly, flexible ETFE PVs will keep everything streamlined and won’t cause any mobility problems.

Additionally, ETFE modules can charge small devices such as cameras, smartphones, and tablets.

How do you deal with a Peeled-off ETFE Solar Panel?

Even though ETFE solar modules are superbly sturdy, the film can peel off due to aging or extreme physical stress.

Let's say the ETFE film peels on one of the solar cells. Should you leave it like that, repair or scrap it?

Leaving a flexible solar panel in a peeled state will cause a short and probably overheating, which may lead to voltage and current reduction.

It is definitely not a good idea to scrap your peeled ETFE solar panel since it means that your investment will be lost.

The best option is to attempt to repair the solar panel. You can do this by cutting around the connections of the faulty solar cell. Add clear epoxy as a temporary covering system for the solar cell to prevent any further efficiency problems.

Please note: You may never get the expected power from a peeled ETFE solar panel, but it's better off repaired.

As a precautionary measure, handle the modules with care and when it's time for storage, do it appropriately.

Pros of ETFE Solar Panels

Highly temperature tolerant

Solar panels are subjected to high temperatures, which can lead to overheating problems, particularly with thin, flexible solar panels.

Luckily, ETFE solar modules will tolerate not only high temperatures but also wide temperature fluctuations.

Space-saving

The thin and compact design of ETFE modules makes them fit for applications where free space is a problem.

What’s more, the flexible nature of these solar panels makes them suitable for unconventional installations such as around light poles.

Enhanced efficiency

Depending on the types of solar cells used, ETFE modules will have an efficiency ranging between 15-25%.

Currently, this is the standard efficiency even for conventional solar panels.

High light penetration (as high as 95%)

ETFE brings chlorine atoms to the structure of solar panels. Chlorine ensures that the laminations stay intact and that no discoloration occurs.

Thanks to this, light penetration is kept at a maximum, consequently raising the productivity of these solar panels.

Self-cleaning

Due to the textured finish on ETFE flexible solar panels, they’re dirt and dust and stain-resistant.

This means that they don’t need frequent cleaning as is the case with conventional solar panels. The non-adhesive and self-cleaning nature of ETFE solar panels keeps them in peak performance all the time.

Durable and sturdy

A solar panel made with ETFE exhibits unmatched durability and strength. The ETFE PV system will continue to produce power as expected even under harsh outdoor conditions.

Since the inner components, such as the solar cells, are perfectly protected by this coating system, the longevity of these solar panels is also assured.

Cons of ETFE Solar Panels

ETFE solar panels have many advantages, but they also present some challenges. Below are the main drawbacks of ETFE panels:

Pricier than conventional solar panels

The price of ETFE solar panels is double or thrice the cost of aluminum-framed solar panels.

This makes the initial expense a heavy one despite the excellent benefits of the modules in the long run.

To get the best out of your investment, buy quality ETFE PVs from the reputable companies we listed earlier.

Fragility problems

Even with ETFE flexible solar panels being exceptionally sturdy in their standard flat configuration, they can easily break when you over flex or bend them beyond the maximum limit.

For this reason, you should get details about the maximum bendable angle of your ETFE flexible solar panels from the manufacturers to know how you’ll handle them without breakage.

Yellowing and overheating

If ETFE solar panels are exposed to extreme temperatures, they’ll suffer from yellowing and/or overheating. Yellowing is specifically caused by extended excess exposure to UV radiations.

Both yellowing and overheating can significantly reduce ETFE modules’ efficiency and consequently the power you get from them.

Frequently Asked Questions

Conclusion

Nowadays, we carry a myriad of devices around, so we require a power source to keep these devices charged.

There’s no question that ETFE panels are the type of PV modules you'd want to have with you wherever you go, especially if you need the power to keep your devices juiced up.

The uses of ETFE PV modules are endless. In addition to charging your small devices, you can power a golf cart, RV, camp trailer, boat, etc.

ETFE solar panels are lightweight, sturdy, and durable, making them the best power solution for home or outdoor activities. ETFE solar panels are also ideal for emergencies and can be a power source where grid power isn’t accessible.

With ETFE solar panels, you can now have a device that puts out power anywhere anytime as long as there's sunshine.