Choosing solar panels for a UK campervan or off-grid setup

Start with the roof and the job

Before choosing a brand, measure the space you can actually use. Include vents, skylights, aerials, roof rails and the clearance needed to open or maintain them. A cardboard template is a useful way to check the fit before ordering. Check whether nearby objects will cast shadows across it.

Then describe the job. Keeping a parked van's starter battery topped up is different from supporting a compressor fridge, laptops and several days away from hookup. Estimate daily energy use in watt-hours and decide how much battery reserve you need. A daily energy budget will help you work out how long the battery needs to last through grey UK weather.

Think about where and when you travel. A flat panel in winter, a roof beside trees and a clear summer campsite are different generating situations. Use a forecast as a planning aid, then compare it with actual charging data as the system develops.

More watts and higher efficiency mean different things

A panel's watt rating is its output under standard test conditions, including 1000W/m² irradiance and a 25°C cell temperature. Output changes throughout the day with the conditions. A 470W panel producing its full rating for one hour would generate 470Wh before downstream losses; actual sunlight and temperature vary.

Module efficiency describes the fraction of incoming sunlight converted to electricity across the panel's overall area. A bigger panel also has more area available to collect sunlight. For a fair comparison of roof space, use the efficiency of the complete module. Cell-efficiency headlines can describe a smaller part of the panel.

The official Victron sheet, for example, gives the 95W SPM040953003 an 18.47% module efficiency. Check this figure for each shortlisted model, as efficiency varies across both sizes. [6]

What the UK price comparison shows

On a narrow screen, scroll the table sideways to compare every column.

The seller links let you check the exact models and offers. Price and availability can change. The four exact product pages were checked on 15 October 2026. [1] [2] [3] [4]

The arithmetic is simple: £85 ÷ 470W is about 18p per rated watt, while £65 ÷ 95W is about 68p. That makes the full-size example compelling if it fits. Four compact 95W panels would give a different total rating, roof layout, wiring arrangement and number of mounts.

Delivery can materially change a small order. Bimble's mainland GB guide starts at £36 plus VAT for one panel under 25kg. On that guide, the £85 TCL becomes £128.20 delivered, before mounts, subject to the actual postcode and basket quote. Collection can change the comparison again. [5]

Compare your panel shortlist

Why full-size modules can cost less per watt

Larger modules can spread costs associated with each module across more watts. Manufacturing scale, handling, mounting hardware and the number of electrical connections can all influence costs. NREL research found potential savings from larger module area, conditional on maintaining manufacturing yield, efficiency and lifetime energy production. [7]

That helps explain the cost advantage large modules can have. Retail margins, stock clearance, technology, transport and warranty terms also matter. A specialist narrow panel may cost more per watt yet use an otherwise awkward strip of roof. Paying for a workable shape can be sensible.

Check the installation beyond the panel

A full-size module brings a substantial rectangle of glass and frame. The TCL example is nearly 1.8m long and weighs 24.8kg before brackets. Add the rack or mounting system when assessing roof load and vehicle payload. Pop-top owners must also consider the roof maker's lifting and loading limits, including what can remain fitted while travelling.

For a moving vehicle, suitability also depends on road loads and the proposed mounting method. Ask the panel, roof and mounting suppliers about the intended installation. Attachment must cope with the relevant forces without damaging the roof or creating leaks. Include a suitable fixing system in the budget from the start.

Electrical fit matters too. Check panel open-circuit voltage, its rise in cold conditions, current and the controller's limits. Two panels in series increase voltage; parallel wiring increases current. A panel sold for building use can require a different controller arrangement from a small nominal 12V leisure panel.

Choose the useful compromise

Start by shortlisting a full-size rigid option if a suitable mounting arrangement and roof space exist. Compare a compact rigid layout where obstructions make the bigger rectangle impractical. Consider flexible construction where mass, curvature or height are decisive, then read that exact model's mounting instructions and warranty.

Compare the complete shopping list: panels, delivery, mounting, controller, cable, connectors, protection and installation. Check the kit contents so you can compare the same set of parts. Leave room for maintenance and future replacement.

For a fixed off-grid building, vehicle-specific limitations disappear, but roof structure, weather loading and electrical design still matter. For either setting, the best value is a safely installed system that meets the job. Once it is running, Solar Outlook can help connect changing weather and sunlight with the performance you see from supported equipment.