Flexible Solar Panels: History, Use Cases, Sizes, and the Tech Under the Skin

Flexible (aka flexi or semi-flexi) solar panels started as thin-film experiments, matured with better plastics and adhesives, and today come in two main flavours: crystalline-silicon laminates on ultra-thin composites and thin-film CIGS sheets. They win where weight, curves, and quick installs matter (vans, boats, balconies, lightweight roofs) but generally have lower efficiency, and more heat than rigid glass modules. For a 1–2 bed flat, flexi panels are brilliant for balcony solar.

A short history of flexible PV

• The thin-film eraIn the 1990s–2000s, flexible PV meant amorphous silicon on plastic or metal foil: bendy, lightweight, and easy to roll up, but modest efficiency and stability.
  
• CIGS arrives: Copper-indium-gallium-selenide (CIGS) thin-film improved efficiency and temperature behaviour, enabling flexible laminates for vehicles, tents, and lightweight roofs.
  
• Crystalline goes on a diet: As conventional mono-silicon cells got thinner and tougher, manufacturers began laminating crystalline cells onto composite backers with ETFE front sheets. Add better interconnects and adhesives, and you get today’s marine-grade and camper-van friendly flexi panels.
  
• Today: Two mature paths coexist: CIGS thin-film sheets and ultra-thin crystalline-silicon laminates. Both ditch the heavy glass and aluminium frame to save kilos and allow gentle curves.

Where flexible panels make the most sense

Balconies and terraces

The standout use case for renters and flat-dwellers. Flexi panels are light, slim, and easy to mount on railings or a lightweight frame. Pair with a plug-in microinverter for instant savings.Reality check: they run warmer than framed panels, so expect fewer watt-hours per day per square metre than rigid glass modules.

Campervans and motorhomes

Curved roof? Weight budget tight? Flexi panels bond or strap without drilling rails, keep your centre of gravity low, and hide nicely.

Boats and marine covers

Walkable laminates on hard decks or stitched into canvas biminis and sprayhoods. The low profile resists snagging and wind.

Lightweight roofs and awnings

Sheds, pergolas, garden rooms, and outbuildings that cannot handle 18–25 kg per module. Flexi keeps structure costs down.

Pop-up, off-grid, and event power

Roll out, clip in, and you have portable watts for stalls, festivals, and emergency kits.

If you have a pitched roof with decent access or garden space for a ground-mount, choose rigid panels: higher efficiency, better airflow, stronger warranties, lower cost per watt, and more energy across the year.

How big and how heavy are they?

Below are typical real-world sizes to help you sketch a layout. Models vary, but these figures are a good rule of thumb.

• 100 W flexible crystalline: About 1.09 m × 0.58 m × 3 mm, roughly 2.4 kgGreat for small balconies, camper roof infill, or topping up leisure batteries.
  
• 200 W flexible crystalline: About 1.60 m × 0.75 m × 3 mm, roughly 4.5–5.0 kgThe sweet spot for most balconies and vans. Two in portrait will fit many railings or roof bays.
  
• Premium marine flexible (120–180 W range): Typical 1.3–1.6 m length, 0.45–0.55 m width, ~2 mm thick, often ~2–3 kgBuilt to take foot traffic and salt air with superior encapsulation.
  
• Lightweight glass-free “rigid-ish” (reference point): Around 430 W at ~2.05 m × 1.08 m × ~2 mm, roughly 6–8 kg Not a flexi, but useful for comparison: extreme weight savings without the bend.
  

Remember: flexible panels are area-limited. For a given balcony or roof footprint, a rigid glass module usually delivers more watts and more watt-hours.

The technology inside a flexi panel

1) The cells

• Crystalline-silicon flexi uses very thin mono-Si cells, often PERC or shingled / back-contact layouts to tolerate bending and reduce busbar shading.
  
• CIGS thin-film deposits the active layers directly on a flexible substrate, creating a naturally bendable module with good low-light response.
  

2) The sandwich

• Front sheet: usually ETFE (a tough fluoropolymer) for UV resistance and a slightly textured, anti-soiling finish.
  
• Encapsulant: EVA or ionomer adhesives lock cells or films in place.
  
• Backsheet / substrate: fibreglass-reinforced polymer or aluminium-polymer composites for stiffness without weight.
  

3) The wiring

• Interconnects use copper meshes, ribbons, or conductive adhesives designed to flex.
  
• Bypass diodes protect against hotspots when part of the panel is shaded.
  
• Leads are typically MC4 compatible with strain relief pads to avoid peel forces.
  

4) The performance bits

• Temperature coefficient
  

Silicon power typically drops about 0.3–0.45% per °C above 25 °C. Bonded flexi panels run warmer than framed modules because there is less airflow, so they give fewer watt-hours per day unless you build in a small air gap. CIGS thin-film often has a gentler temperature penalty.

• Bend radius
  

Think gentle curves, not origami. A common rule is a minimum radius near one metre for crystalline laminates. Bend once at install and avoid repeated flexing from vibration.

Installing flexible panels the right way

1. Substrate prep: Clean, dry, and smooth. For bonding, use approved tapes or adhesives and roll out even pressure. Edge-seal where the maker specifies.

2. Cooling gap: Even 10–20 mm of airflow behind the panel can boost yield and lifespan.

3. Cable management: Strain relief near the junction box, gentle cable loops, and tidy routing to avoid peel forces at speed or at sea.

4. Shading discipline: Rails, masts, aerials, roof boxes, balcony uprights, all create shadows. Position panels to minimise partial shading.

Certification matters... For buildings, look for modules tested to IEC 61215/61730 or marine equivalents. Cheap flexi sheets without proper certification are a false economy.

Pros and cons in one breath

Pros

• Featherweight
  
• Low profile and good looking
  
• Mount almost anywhere
  
• Fast, drill-light install
  
• Genuinely portable for renters and travellers
  

Cons

• Lower efficiency and lower watt-hours per day per square metre
  
• Runs warmer unless you provide airflow
  
• Shorter warranties and potentially shorter service life
  
• Needs careful handling and bend-radius discipline
  

Flexible solar panels are a brilliant tool when mass and shape are the limiting factors. They shine on balconies, vans, boats, and lightweight roofs.