Flexible solar module motorhome: lightweight energy solutions for camping & vanlife
Self-sufficient power supply in a motorhome is becoming increasingly important – and flexible solar modules are the first choice for many campers. They are extremely light, adapt to curved roofs and can be mounted almost invisibly. But what advantages and disadvantages do bendable solar panels actually have? In this guide you will learn everything you need to know before buying: from the technical differences to installation and charge controllers through to the popular brands of 2026.
Advantages of flexible solar modules in a motorhome
Minimal weight for maximum payload
A 100 watt module often weighs only 2.2 to 3.5 kg – rigid equivalents with aluminium frames quickly weigh 8–12 kg. If several modules are installed, several kilograms of roof load are saved and you stay within the permissible roof rack capacity. This is easier on the vehicle structure and reduces consumption.
Seamless integration on any roof
Flexible modules are only 2 mm flat and can be bent to a radius of up to 2 metres. This allows them to adapt to aerodynamically shaped motorhome and panel van roofs without a bulky frame disturbing the airflow. Wind noise is lower than with raised rigid modules.
Easy installation without drilling
Thanks to the low profile and the flexible material, flexible solar panels can be bonded directly to the roof using special adhesive tapes or Sikaflex. Cables can usually be routed through existing cable ducts or a thin flat cable – without drilling any holes in the bodywork. This preserves the vehicle's watertightness and value.
High efficiency thanks to modern cell technology
Current flexible modules use monocrystalline PERC cells or even SunPower cells with efficiencies of 20 to 23 %. This means they deliver more power for the same area than older polycrystalline technology and also perform well in diffuse light. A 150 W panel generates up to 900 Wh on sunny days – enough to noticeably charge a 100 Ah AGM battery (AGM battery 100Ah).
Disadvantages and limitations of flexible solar panels
- Heat sensitivity: Because flexible modules lie directly on the roof skin, the temperature can rise to 70 °C, which reduces output by around 0.3 % per degree above 25 °C. There is no rear ventilation, so yields on hot days are lower than with raised modules.
- Lower mechanical robustness: The ETFE or PET surface is hail-resistant, but less scratch-resistant than toughened solar glass. Branches or coarse cleaning brushes can damage the surface.
- Limited replaceability: Many manufacturers use proprietary connectors and integrated bypass diodes – if a fault occurs, not every cell can be replaced individually. A complete replacement can be more expensive than with rigid systems.
- The price difference per watt is around 50 to 100 % – with large systems this is clearly noticeable.
Flexible vs. rigid: when a motorhome solar module is worthwhile
The decision between flexible and framed depends heavily on the vehicle type and usage profile. For panel vans, vans with a curved roof or high-quality motorhomes where appearance matters, flexible modules are almost without competition. On flat, unused roofs – for example on an alcove – a rigid module can be the more economical solution. The following table compares three typical flexible modules, which you can also find in the Electronicx range:
| Model | Nominal output | Weight | Dimensions (L×W×H) | Cell type | Efficiency |
|---|---|---|---|---|---|
| Sunman eArc 100W | 100 W | 2.5 kg | 1,060 × 540 × 2 mm | Monocrystalline | 19,5 % |
| – | 120 W | 3.2 kg | 1,190 × 540 × 2 mm | Monocrystalline PERC | 20,3 % |
| Solara Power M 150 | 150 W | 4.5 kg | 1,490 × 670 × 2 mm | Monocrystalline | 21,0 % |
All three use modern cell technology with bypass diodes and a weather-resistant ETFE coating. When choosing, you should measure the available roof area precisely – bear in mind that the modules need some distance from roof edges and superstructures.
Installation on the motorhome roof – step by step
Prepare the surface
Clean the roof surface thoroughly with isopropanol. Even slight traces of grease or wax impair adhesion. On an aluminium or GRP roof, a primer can increase long-term stability.
Plan positioning and cable routing
First place the module loosely and mark the position. The junction box should point as far to the rear in the direction of travel as possible so that the cable does not come under tension. Flexible solar cable (4–6 mm²) is best routed through a cable duct or a roof gland.
Bonding instead of screwing
High-quality MS polymer adhesive or Sikaflex 252i is suitable for bonding. Apply a continuous bead at a distance of around 2 cm from the edge and leave small air channels for moisture drainage. Press the module on carefully and weigh it down. Depending on temperature, curing takes 24–48 hours. Never bond directly onto butted edges or joints.
Charge controller and battery: the right match
Flexible solar modules usually work with an open-circuit voltage of around 22 V (100 W panel). An MPPT charge controller efficiently converts the excess voltage into higher charging current – particularly valuable in shaded conditions. For small systems up to 200 W, PWM controllers are sufficient, but they lose around 20 % of the possible output. Which battery is the right one is explained in the 12-volt battery guide. AGM and gel batteries (AGM batteries) are proven partners for solar systems, while LiFePO4 batteries stand out with their high cycle stability. Set the appropriate charging curve on the controller. Everything about correct charging can be found in our 12V battery charging instructions.
Dimensioning with a safety margin
Plan the solar output so that the charge controller is not operated above its nominal voltage at full load. A 100/30 MPPT controller handles up to 100 V input voltage at 30 A output. Two 100 W modules in series give just under 44 V – absolutely within the safe range. Pay attention to the maximum short-circuit current capability.
Leading brands 2026 for flexible motorhome solar modules
Popular brands include:
- Sunman eArc: pioneer of direct-glazed technology, extremely light and designed for a 25-year service life. The 100 W module weighs only 2.5 kg.
- Particularly suitable for maritime conditions, but also a reliable choice in a camper.
Each of these modules reliably supplies power for lighting, cool box, water pump and on-board electronics – quiet, emission-free and independent of shore power.
FAQ – Frequently asked questions about flexible solar modules
Are flexible solar modules waterproof?
Yes, reputable modules have an ETFE or multi-layer PET cover and are protected against spray water to IP67. The junction box is potted, so even heavy rain or melting snow causes no damage.
Can you walk on flexible solar panels?
No manufacturer recommends walking on them. A one-off load of 50–60 kg may be tolerated by a module, but point pressure can cause microcracks in the cells that reduce output unnoticed.
Do flexible modules withstand strong wind?
With professional bonding using MS polymer and good surface preparation, wind speeds of over 150 km/h are no problem. The aerodynamically smooth surface further reduces the area exposed to the wind.
Do I need a special charge controller?
Not necessarily a special one, but a high-quality MPPT controller that efficiently handles the voltage of flexible panels. For small systems a PWM controller is sufficient, but you achieve better energy yield with MPPT.
How long do flexible solar modules last?
High-quality modules can reach 15–20 years, during which the rated output falls to around 80 %. What matters is the UV stability of the film and correct installation without localised stress points.
Is a flexible solar module worthwhile under cloudy skies?
Monocrystalline cells still work at around 20–30 % of their rated output even in diffuse light. A 200 W module still delivers around 40–60 W on an overcast day – enough to cover standby consumption.
How do I attach a flexible solar module to a motorhome roof?
The professional method is bonding with Sikaflex or a comparable adhesive. Never drill through the roof! Allow the adhesive to cure for a few days and route the cables into the vehicle interior using flat roof glands. A step-by-step guide is available in our installation section.
Can I combine several flexible modules?
Yes, as long as you observe the voltage and current limits of the charge controller. Connecting in series increases the voltage, connecting in parallel increases the current. Where possible, combine modules of the same output and tilt to avoid yield losses.