When I first started putting solar on my RV, I was really excited about the flexible solar panel option. Understanding that many say rigid panels are better, four years later I am still satisfied with my decision to go "Flexible" with solar.
The choices were very limited back when I purchased my first Unisolar thin-film panels off of eBay. I have since expanded my solar array and upgraded my charge controller three times, but the original Unisolar panels still produce half of the solar power generated on my roof.
The flexible solar panels available today are much more efficient than they were four years ago. This could be due to the cost of monocrystalline solar cells dropping. Or perhaps advances in the manufacturing process and encapsulation materials could have something to do with it. Regardless of how it happened, as consumers we now benefit by having more choices at a lower cost.
Gone are large thin-film solar panels. Lightweight thin high-efficiency panels are now the norm in today’s flexible solar panel market. They are also affordably priced just above their rigid counterparts. RVs, campers, boats and vans can certainly benefit from solar panels that offer light-weight, high-power, versatility and great asthetics.
What Are The Options?
If you’ve purchased or have been shopping for flexible solar panels on sites like Amazon, you may have noticed that the flex panels that come up in the search results look strikingly similar. You might be asking “Which one should I buy?” I always start with customer reviews focusing primarily on those flagged as “Verified Purchase”. This helps weed out the fake reviews. Once you’ve narrowed it down to a few quality panels, you can start comparing features.
Where to find flexible solar panels
Buying flexible solar panels on Amazon is a start. Even if you don't buy, it's a great place to start shopping and checking reviews.The list of flexible solar panels keeps growing each month. Take a look at what flexible solar panels available on Amazon right now. If you're looking for a bargain, you may also check eBay.
Purchasing directly from a reseller is also a good option. Resellers will be more familiar with the product and can provide better support in the long run. They might even let you know about any discounts available that will save you money.
Many folks ask "What kind of flexible solar panels do you have?" Here's a complete write-up of our entire RV off-grid system if you're interested. The short answer is that I've installed high-efficiency SUNPOWER branded flexible solar panels on our RV. I purchased through a SUNPOWER solar reseller, Sun Powered Yachts.
I've continued going back to them for more SUNPOWER panels as I've expanded my system and they've been very helpful. They have even offered to give you this discount.
Features to look for in a flexible solar panel
You'll find that most flexible solar panels look very similar. Don't base your decision solely on price. Here are some characteristics to consider.
Type Of Solar Cells
I should mention that the cells in modern flexible solar panels are actually not flexible. In fact, they are very fragile. Keep in mind that the overall thickness of a typical flexible solar panel is about 1/8" thick. Most flex panels use high-efficiency monocrystalline solar cells, but not all mono cells are the same. They can vary significantly in quality, efficiency, durability, and price.
Flex panels with higher quality cells often have a copper backing that helps protect the cell. Cheaper panels may not. Unfortunately, you won't be able to tell the difference just by looking at the panel.
Poorly made flexible solar panels can be easily broken if handled poorly or over-flexed. They can be bent slightly to fit curved surfaces, but should not be bent more than 20 degrees or so. If bent too far, you could damage the solar cells or connections inside the panel. Once that happens, the panel will have to replaced.
Each panel has its specifications printed on the back of the panel. The panel’s maximum output (watts, amps and volts) are all listed there on the back. Reputable manufacturers will test each panel under Standard Test Conditions (STC) prior to packaging to ensure it measures up to its specifications. Nevertheless, I recommend doing your own basic tests with a multimeter to verify proper operation prior to installing.
Front and Backing Material
The two most commonly used materials used for the front layer of flexible solar panels are PET and ETFE. The names are acronyms for their chemical names. PET panels have a glossy appearance, while ETFE panels have a bumpy, matted texture to them. PET panels are more prone to scratching and weathering while ETFE is a stronger material with better UV protection. Plan to spend more for an ETFE coated flex panel.
There are other materials used, but PET and ETFE are the ones most commonly used. Here's a photo of what the surface of an ETFE coated panel looks like.
The backing layer of a flex panel is typically made of a thicker white laminate material. Some have an aluminum backing to help dissipate the heat generated by the solar cells. There are also flexible solar panels with a peel-and-stick backing for easy installation.
The length of the cable and type of connectors provided can vary from one manufacturer to another. Many are DIY modules, so the come pre-wired with standard MC4 connectors.
Some flex panels come with short cables while others may have up to five feet of cable. When planning your system, count on having to order solar extension cables like these from Amazon to connect your panels together and run the ouputs to a solar charge controller.
Also consider making your own solar cables to save money and have fewer connections. I wrote and article with a video that will show you how. Check it out the article here.
Price and Warranty
100 watt panels are the most common size for flexible solar panels. You’ll see prices ranging from $160 to $500. So what is the difference between a $500 panel and a $160 panel?
You may be paying for higher quality materials and components or the reputation of the manufacturer. The bottom line is that it is really hard to tell the difference. If you are looking for assurances, many manufacturers offer a multi-year warranty. Be warned that there may be hidden terms that make it difficult to return or get a refund. So be sure to read the “fine print” and understand the limitations of the warranty.
Test Before Installation
Prior to installing the panels I recommend taking some basic measurements to ensure your solar panels are performing at the expected levels (as indicated on the back of the panel). I also recommend testing them routinely every few months to make sure they are still performing to spec. You may find that inexpensive panels will perform just as well as expensive ones when you first install them, but start degrading after a couple years. This is why a good warrantee is important.
Once tested, mount the panels in such a way that you can removed them needed. If panels wear out prematurely or fail, then it's simple process to remove and replace it. Here's the best way I've come up with to install flexible solar panels.
Hope This Helps
I hope this gives you a few things to think about when shopping for flexible solar panels for your RV. If you have any comments or questions feel free to post them below.
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