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The Best Flexible Solar Panels: Our UK Buying Guide (Updated for 2025)
- Chris Wallace-Tarry
- 4 days ago
- 13 min read
Updated: 3 days ago
If you've got a pop-top roof, if stealth is important, or if you're going for a drill-free install, flexible solar panels can be a neat, low-profile alternative to rigid solar panels. They’re wafer-thin, feather-light, mount with adhesive rather than screws, and they mould to the form of curved roofs. The trade-off is that flexible solar panels don’t match rigid panels for outright efficiency or longevity, and they're more affected by heat. That doesn’t make them a compromise too far; it simply means choosing them for the right reasons and installing them the right way.
In this guide, we’ll demystify what “flexible” really means, how today’s panels are built, and where the market sits on efficiency, weight-per-watt, and warranties. We’ll explain why heat matters, how to manage it, and how to size and wire a system that suits weekenders through to long summer tours. Finally, we'll go over the step-by-step process that Shane used to mount flexible panels to his first van.
Index
Shane, the founder of The Van Conversion, is a campervan professional and NCC-certified electrical installer. Since 2020, he’s lived on the road full-time, completing several van builds along the way. He’s the author of Roaming Home and the creator of The Van Conversion Course, which have helped thousands build their own vans. Shane also writes The Van Conversion Newsletter, where he shares hands-on tips and practical insights. He’s passionate about empowering others to make their vanlife dreams reality.
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The Best Flexible Solar Panels: Our Top Pick
Based on a balance between cost, published module-level efficiency ratings, and warranty length, we believe that Renogy flexible solar panels are the best overall buy. They make ultra-thin, ultra-light flexible panels using the most up-to-date materials and cell technology. They make 50W, 100W, 150W, and 200W panels, which should be sufficient to put together arrays that suit most conversions.
What is a Flexible Solar Panel?
Flexible solar panels are thin, bendy solar panels that can flex to match gentle curves. They're very thin, typically only 2-4mm, and are thus also very light. They don't incorporate a bulky structural frame like rigid panels do, and the junction box is generally very low-profile.
Due to their lightness and minimal design, flexible solar panels are designed to be mounted flush to your roof with adhesive. This means that installation is completely drill-free, and also that a flexible panel is very low-profile. They're therefore perfect for mounting on pop-top roofs, and for stealth campers where protruding rigid panels would be a dead giveaway.
The State of the Market: Are Flexible Solar Panels any Good?
These days, the best flexible solar panels have a tough ETFE topsheet, which is very durable and doesn't crack or scratch, unlike rigid panels. It's a textured coating that resists UV much better than the PET alternative and is 'self-cleaning', meaning it doesn't collect algae or dirt.
The Effiency of Flexible Solar Panels
Modern, high-quality flexible solar panels are all high-efficiency monocrystalline (read about why this matters here) and are made of either back-contact or PERC cells. However, it's important to realise that flexible panels still aren't as efficient as rigid ones. Most manufacturers quote cell efficiency figures, but the efficiency of the whole panel, or module efficiency, is what really matters.
Renogy's 100W flexible solar panel offers a module efficiency figure of 15.7%. EcoFlow's 100W offering sits at 15.5%, and Bluetti's ultra-efficient FX series gets up to 17%. This is in comparison to module-level efficiency figures of around 20% for rigid panels. Market leading efficiency ratings can be found in high-end marine panels like those from Solbian, which get up to 17-18%, and Solara Power-M at 18.8%. Note that those extra percentage points in efficiency will cost you hundreds of pounds over more affordable panels.
Weight-Per-Watt
Weight-per-watt is where flexible panels shine, rather than in efficiency. Those Renogy, EcoFlow, and Bluetti panels all weigh 2.2-2.4kg, giving them weight-per-watt figures of 0.022-0.024kg/watt. High-end marine panels are even lighter; the above Solbian panel weighs only 1.4kg. By contrast, rigid panels sit at more like 0.05-0.06kg/watt: about triple the weight for the same wattage. This is usually the only kind of panel that will work on a pop-top roof, as rigid panels would make the roof too heavy to raise by hand.
Cost
Cost used to be a major point in favour of flexible solar panels, as they were often cheaper than rigid ones. However, the price of solar cells has dropped precipitously in recent years, and this is no longer the case. In fact, flexible solar panels from reputable manufacturers typically cost a bit more than their rigid counterparts.
Whether you're going for flexible or rigid, it's important to not skimp on quality and buy your panels from a reputable manufacturer. On Shane's last van, he installed four 100W flexible solar panels he’d bought from Amazon; not the absolute cheapest, but still budget models. Over seven years, he watched their output steadily decline until they were producing less than half of their original rating.
We recently helped another customer who’d bought a bargain-bin solar kit from Amazon; the panels were literally wired backwards out of the box. It took a full rewire just to get them working. Cheap flexible panels might look like a shortcut, but in reality, they’re a false economy.
How Long do Flexible Solar Panels Last?
It's also worth mentioning lifespans, and comparing warranties across flexible and rigid panels tells the story. The panels discussed above all come with warranties of up to five years, with no distinction made between a materials and performance warranty. By contrast, you can expect 5-10 year materials warranties on rigid panels from marques like Renogy and Victron, with a 25-year guarantee that the panel won't drop below 80% of its original output. This demonstrates the fact that even the best flexible panels aren't as long-lasting as rigid ones. A lot of this can be attributed to how flexible panels handle heat.
We've summarised the differences between rigid vs. flexible solar panels in the table below:
The Effect of Heat on Flexible Solar Panels and How to Deal With It
Flexible panels don’t usually have dramatically worse temperature coefficients than rigid glass modules, but they operate hotter because they’re bonded flat to a roof with little or no airflow. This disrupts convective cooling: a framed panel rides above the roof in moving air, so for any given sunny day its cell temperature is lower. Flexible panels soak heat into the laminate and the roof beneath, which cuts solar output and, over time, accelerates polymer ageing. This is why flexible panels typically deliver a little less on hot days and age faster.
You can mitigate this effect to an extent with proper heat management during your installation. Wherever the roof layout allows, mount your flexible solar panels on narrow spacers to create a micro-air-gap. Avoid sticking them down with a continuous adhesive bed that traps heat, don’t seal every edge airtight, and use a lighter-coloured sealant-adhesive. These simple choices measurably lower cell temperature and ease the long-term stress on the laminate and the roof. At the end of the day, however, long-term durability is the price one pays for the minimal contruction of a flexible solar panel.
Who Are Flexible Solar Panels For?
The benefits of flexible solar panels lie in their form factor and ease of installation, rather than in their performance. Flexible solar panels are extremely lightweight, and fit flush to your roof without any drilling. Therefore, they're ideal for:
Pop-top roofs: a pop top can't be drilled into, and can't take the weight of rigid panels. Flexible solar panels are the only way to get a permanent, full-sized solar array on a pop-top camper.
Stealth builds: rigid panels sticking up out of your roof is a dead giveaway that your otherwise unassuming panel van has someone living in it. In countries that are strict on vanlife like the UK, flexible solar panels are often the only viable option for full-timers.
Drill-free installations: many entry-level, summer, or weekend vanlifers go for simpler builds with less permanently installed hardware. If you've no fixed kitchen, no exterior metalwork, and a stripped-back electrical system, it's very reasonable to just want to stick a flexible panel to your roof rather than drilling and bolting a framed array.
Flexible solar panels don't match rigid ones in terms of performance and lifespan, but for less hardcore vanlifers, that's just fine. If that sounds like you, read on for our recommendations on the best flexible solar panels currently on the market.
The Best Flexible Solar Panels: Our Top Picks
If you've decided that flexible solar panels are right for you, we've collected the models that we'd be happiest installing on our own vans. We've prioritised price and efficiency, with warranty length also an important factor.
The Best Flexible Solar Panels: 75-125W
Our top pick is Renogy's 100W Flexible Solar Panel. Renogy are unusal in that they're upfront about the module efficiency of their panels, which we appreciate. It stands at 15.7% for this model, which is very respectable within this price range. The Renogy panel is very light, at 2.4kg, and comes with a 5-year material and 90% performance warranty.
As a runner-up in this category, we selected Bluetti's PV100 FX flexible solar panel for its unusually high module-level efficiency rating: 17% for the 100W panel.
The Best Flexible Solar Panel: 175-225W
We found Renogy's 200W flexible solar panel to stand out among its competitors, mainly due to its published module efficiency of 16.7%. This is achieved with half-cut PERC cells, which reduce the effect of partial shading and trap additional sunlight in a multi-layered design. The 25-year 80% performance warranty is also very impressive, backing up the manufacturer's confidence in their construction and heat resistance.
The Best Flexible Solar Panel for Maximum Efficiency
If flexible is your only option and you can't skimp on efficiency, high-grade marine panels are your best bet. Solara's Power M-series top out the flexible market with 19% module efficiency, which is almost what you get from rigid panels. These panels are designed for the exigencies of marine use, so they'll withstand extreme heat, humidity, cold, and salt water, and can be walked on without issue.
The Best Flexible Solar Panel Kit
Buying your flexible solar panel in a kit saves you having to figure out which charge controller you'll need and sizing your wires and fuses. Instead, buy everything you need pre-specced and ready to install. Sunstore Solar bundle their 150W flexible solar panel with the excellent Victron SmartSolar Bluetooth MPPT charge controller, a roof fixing kit, and all the wires and fuses you need for your installation.
Sizing Your Flexible Solar Panels
As we discuss in detail in our campervan solar systems guide, sizing your solar array involves figuring out your daily electricity usage, the number of hours of sunshine you'll get each day, and the efficiency of your panels. Our energy consumption calculator is a simple way of calculating your daily electricity usage, which is also used to work out the size of your leisure batteries. Once you have this number, use our solar panel calculator to size your solar panels.
Average sunshine hours vary depending on location and can be found online. Wikipedia has a useful list of cities around the world and their sunshine hours - to find the daily average across the year, take the annual total sunshine hours and divide by 365. If you'll only be using your van for part of the year, add up the number of sunshine hours for your chosen months and divide the total by the total number of days across that period. For example:
Daily sunshine hours for London, England for all-year use =
Annual sunshine hours (1,633) / 365 = 4.47
Daily sunshine hours for London, England for 3-season use =
Sum of monthly sunshine hours for months March - October =
155 + 169 + 199 + 204 + 212 + 205 + 149 + 117 = 1,410
Sum of days per month for months March - October =
31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 = 245
Average daily sunshine hours = 1,410 / 245 = 5.76
Solar panel efficiency is the amount of solar power that your panels are able to convert into electricity. Note that the important number is module efficiency, rather than the cell efficiency that's often quoted by manufacturers. The equation for calculating module efficiency is:
Module efficiency = Rated Power (W) / (Area (m²) x 1000
This equation won't give you as precise a figure as a published module efficiency figure, but it's accurate enough for use in solar panel sizing calculations.
Solar Charge Controllers for Your Flexible Solar Panels
We go over charge controllers in much more detail in our 2025 Buying Guide, so be sure to check that out. In brief, a solar charge controller sits between your solar panels and your leisure batteries, ensuring that your panels work efficiently and your batteries charge safely. Charge controllers come in two types; PWM and MPPT, and we always recommend MPPT. They're a bit more expensive, but they give you significant gains in terms of solar efficiency and power generation.
Charge controllers come in different capacities, and must be sized depending on the size of your solar array. Use our handy MPPT sizing calculator to figure out the size you need.
How to Install Flexible Solar Panels on Your Van
Having decided on your flexible solar panels and the size of your array, let's take a look at how to install them on your van.
Dry-fit and mark: choose where you'll install your panels, staying as clear as possible from anything that will cast shade on them. Plan where you'll install the gland that holds the cables as they enter the roof, and make sure you've got enough cable to reach this and extend at least 30cm inside. When you're happy with your mounting location, mark it with painter's tape.
Prepare the roof surface. Wash and degrease the footprint where you'll mount the panels with isopropyl alcohol.
Place the cable gland. Pick a high, draining spot close to the panel junction box and away from places water can pond. Drill and saw the hole, file the cut metal edge, paint the bare metal with anti-rust paint, and fit the gland. Check out our article on solar cable entry glands for more detailed fitting instructions.
Choose your ventilation strategy. Because flexible solar panels run hot when bonded flat, we need to incorporate cooling from the start. If you're mounting to a ribbed panel van roof, ventilation is already in place; simply stick the panels to the ribs, and leave the channels in between free for air flow. If you're mounting to a flat pop-top roof, we need to create these air gaps ourselves. We recommend a micro-air gap using narrow spacer ribs (cut lengths of 3-5mm plastic batten do the job well) so air can travel under most of the laminate. Plan to leave breather breaks in the perimeter sealant bead so the panel isn’t sealed airtight.
Lay out the adhesive. Our favourite sealant adhesive for this kind of job is either Sikaflex 522 or 3M VHB tape. If you're going with Sikaflex on a flat roof, run a perimeter bead 10-12 mm in from the panel edge and add longitudinal rib beads every 80-120 mm across the footprint. Remember to leave small gaps in the perimiter bead for cooling, and don't spread out a continuous bed of sealant. If you go with 3M VHB tape, follow a similar pattern, with a continuous perimiter strip punctuated by breather breaks and longditudinal support strips in the middle.
If you're installing your panels on a ribbed roof, the easiest method is to apply your adhesive along the ribs. Make sure the lateral edges of your panel are supported to prevent flapping or peeling: if you can't get both edges to sit on a rib, you might need to create an appropriate surface using layers of mastic tape.
Bond the panel. Lower the panel onto your adhesive. Starting from the centre, work outwards with a soft roller or the palm of your hand to seat the beads without squashing them flat; you’re aiming for a compressed bead height of a couple of millimetres, not a pancake. Wipe away any squeeze-out, and verify that your breather breaks have held. Leave the sealant to cure for the manufactuer-recommended time.
Wire up your panels. Feed the cables from the panels through your cable entry gland, and wire them into your solar charge controller. Check out our complete guide to campervan solar systems for detailed instructions on solar panel wiring.
Final Thoughts
You should now feel equipped to choose and install flexible solar panels for your van conversion. They're not right for everyone, but flexible solar panels might be exactly what you're looking for if you've got a pop-top roof, a stealth build, or are going for a drill-free installation. We recommend Renogy's flexible solar panels in both their smaller and larger sizes to virtually all installers. Alternatively, buy your flexible solar panels in a kit to simplify your build. If you need more information on solar systems before buying your components, our comprehensive guide should answer all your questions.
Don't forget to subscribe to The Van Conversion Newsletter for everything you need to get started with your own van conversion (we'll send you a free wiring diagram when you join).
If you're looking for some guidance with your van conversion, you might be interested in our book Roaming Home, or in our online course The Van Conversion Mastery Course. You'll learn directly from our founder Shane how to convert a van into your dream home - no prior experience needed. Shane also offers one-to-one consultations, where he'll help you with any aspect of your build in a face-to-face video call. All consultations come with a free copy of Roaming Home and our Diagram Pack.
Finally, our Van Conversion Ultimate Guide lays out the whole van conversion process in easy-to-follow sections with tools, materials, and step-by-step instructions. It's the perfect companion for your van build.
Until next time.
