Solar Blankets & Portable Solar Panels for UK Campervans: Do They Work?
A solar blanket (foldable or rollable solar panel) is a portable solar solution. Instead of mounting panels on the roof, you deploy them on the ground and angle them toward the sun. The advantage is flexibility — you can position them for maximum output, and they are not affected by the van's orientation.
I have used a 100W solar blanket for three years as a supplement to my 300W roof array. On sunny days, it adds 30–40% to my total solar harvest. In winter, it is even more valuable because I can angle it toward the low sun.
Solar Blankets vs Fixed Roof Panels
| Factor | Solar Blanket | Fixed Roof Panel |
|---|---|---|
| Output (summer, ideal conditions) | 80–95% of rated (if angled correctly) | 60–80% of rated (flat roof) |
| Output (winter, low sun) | 70–90% of rated (if angled) | 25–40% of rated (flat) |
| Setup time | 2–5 minutes | Zero (always deployed) |
| Theft risk | High (deployed and unattended) | None |
| Wind vulnerability | High (can blow away) | None |
| Storage space | Needs 30L+ when packed | None (roof mounted) |
| Cost per watt | Similar | Similar |
| Lifespan | 3–5 years | 25+ years |
Types of Solar Blankets
| Type | Folded Size | Weight | Power | Cost | Durability |
|---|---|---|---|---|---|
| Foldable (semi-rigid) | 500 × 400 × 50mm | 3–5kg | 100–200W | £80–200 | Medium (cells protected in folds) |
| Rollable (flexible) | 300mm dia × 100mm | 2–4kg | 50–150W | £50–150 | Low (cells can crack when rolled) |
| Foldable with stand | 600 × 500 × 60mm | 5–8kg | 120–200W | £120–250 | Good (integrated stand) |
| Ultra-light (backpacker) | 300 × 250 × 40mm | 1–2kg | 20–50W | £50–100 | Low (thin fabric, fragile) |
Best for van life: A 100W or 160W foldable solar blanket with built-in stand or tilt legs. This gives you enough power to make a difference and can be angled toward the sun.
Real-World Output
I tested a 100W foldable blanket (SunPower cells) against my roof-mounted 300W array:
| Condition | Roof Array (300W) | Blanket (100W) | Blanket + Roof |
|---|---|---|---|
| Sunny June, both flat | 240W (80%) | 65W (65%) | 305W |
| Sunny June, blanket angled 35° | 240W | 92W (92%) | 332W |
| Bright overcast, both flat | 120W | 40W | 160W |
| Bright overcast, blanket angled | 120W | 55W | 175W |
| December sun (low), roof flat | 105W | 25W (flat) / 65W (angled 50°) | 170W |
Key insight: In winter, a 100W blanket angled at 50° towards the low sun can out-produce a 300W flat-mounted roof array. The difference between 25W and 65W from the same 100W blanket is simply the angle.
Positioning Strategies
Summer
- Deploy the blanket on the south side of the van, away from shade
- Angle it toward the sun (adjust every 3–4 hours if possible)
- Use rocks or water bottles to hold down the edges (wind lifts them)
- Run the cable under the van door or through a window to the charge controller
Winter
- Park facing south (roof panels get maximum exposure)
- Deploy the blanket on the ground with a 50–60° tilt (low winter sun)
- Angle it directly at the sun — even a 10° misalignment costs 15% output
- Brush off snow or frost before deploying
Charging Strategy
- Connect the blanket to a separate MPPT controller or to the same controller as your roof array (if the controller supports dual inputs)
- For a Victron SmartSolar controller: you can connect the blanket to the same controller as the roof panels — the MPPT handles the combination
- For Renogy or EPEver controllers: use a separate controller for the blanket (wire the output to the battery busbar)
- Never plug the blanket directly into the battery without a charge controller
Recommended Solar Blankets
| Brand | Power | Cell Type | Weight | Folded Size | Price | Best For |
|---|---|---|---|---|---|---|
| Renogy 100W | 100W | Monocrystalline | 3.0kg | 550 × 420 × 40mm | £120 | Good all-rounder |
| Renogy 160W | 160W | Monocrystalline | 4.5kg | 620 × 480 × 50mm | £180 | Larger capacity |
| Big Blue 100W | 100W | SunPower (high efficiency) | 2.8kg | 500 × 400 × 35mm | £150 | Best efficiency |
| AllPowers 120W | 120W | Monocrystalline | 3.5kg | 550 × 450 × 45mm | £100 | Budget option |
| Eco-Worthy 100W | 100W | Polycrystalline | 4.0kg | 600 × 450 × 50mm | £80 | Lowest cost |
My recommendation: The Renogy 100W foldable blanket (£120). It has good build quality, comes with a kickstand for angling, and includes MC4 cables for connecting to your controller. The Big Blue 100W is better if you want the highest efficiency (SunPower cells) and lighter weight.
Cable Management
| Cable Type | Length | Connector | Cost |
|---|---|---|---|
| MC4 extension | 5–10m | MC4 male → female | £15–25 |
| Anderson PowerPole | 3–5m | PP45 or PP75 | £10–20 |
| Cigarette plug (avoid) | — | 12V socket | £5 (not recommended for >100W) |
Do not use the cigarette lighter plug that comes with many solar blankets. It is a 10A max connector — a 100W blanket at peak output draws 8A (acceptable), but the connection is unreliable and creates voltage drop. Replace it with an MC4 or Anderson connector to your charge controller.
Storage
| Storage Method | Space Needed | Protection |
|---|---|---|
| Under the bed | 600 × 500 × 60mm | Good (stack with bedding) |
| In a rear garage | 600 × 500mm footprint | Good (stand on edge) |
| Roof box | Full roof box width | Excellent (dry, secure) |
| Behind the driver seat | 600mm high | OK (but in the way) |
Storage tip: Keep the blanket in its padded carry case when not in use. The solar cells are fragile when folded — do not stack heavy items on top of the case.
FAQ
Q: Can I leave my solar blanket deployed in the rain? A: Solar blankets are weather-resistant but not waterproof. Rain does not damage the cells or the electrical circuits. Prolonged rain can seep into the folds and cause corrosion. Dry the blanket before folding and storing.
Q: Can I charge my battery directly from a solar blanket? A: No. You need a charge controller between the blanket and the battery. Most solar blankets do not include a built-in controller. You need an MPPT controller (Victron, Renogy, or the controller built into some blanket kits).
Q: Do solar blankets work on cloudy days? A: Yes, at 20–40% of the rated output. On a bright overcast day, a 100W blanket produces 20–40W. On heavy overcast, 10–20W. Every watt helps in winter.
Q: Can I walk on a solar blanket? A: No. The cells are embedded in fabric and can crack under pressure. Treat a solar blanket like a laptop screen — handle carefully, do not step on it.
Q: How long do solar blankets last? A: Foldable blankets with high-quality cells (SunPower, monocrystalline) last 3–5 years of regular use. The fabric degrades from UV exposure and the fold points develop micro-cracks. This is why roof-mounted panels (lasting 25+ years) are a better long-term investment.
Q: Can I use a solar blanket to charge a power station (Jackery, Bluetti)? A: Yes. Most power stations have a solar input (MC4 or Anderson connector). The blanket connects directly. The power station's built-in charge controller handles the regulation.
