How many solar panels do I need on my camper van?

This depends on your consumption and travel destination. An average camper van with a fridge and basic electronics needs 200-400Wp (2-4 panels of 100Wp). If you spend a lot of time off-grid in Northern Europe, plan for 400Wp or more.

Are solar panels enough to power a camper van?

In summer in Southern Europe, often yes. In winter or bad weather, solar panels alone are usually not enough. Combine them with alternator charging (B2B charger) and/or shore power for a reliable system.

Do I need an MPPT or PWM charge controller?

An MPPT charge controller is 20-30% more efficient than a PWM, especially in cloudy weather and with higher panel voltages. For a camper van installation of 200Wp or more, MPPT is almost always the better choice.

How much Wp fits on a camper van roof?

Reckon on roughly 150 to 200 Wp per square metre of usable roof. On a medium wheelbase van such as a Ducato L2H2 you can realistically fit 300 to 600 Wp, depending on how much space your roof hatches, fan and roof rack take up. Measure your roof before ordering panels, and allow for the mounting frames: they need a few extra centimetres all round.

Why do I never reach the wattage printed on my panel?

The Wp figure applies under test conditions: 1000 W/m² irradiance, perpendicular incidence and a panel temperature of 25 °C. On a van roof you rarely meet all three at once. Heat costs about half a percent per degree above 25 °C, a flat roof does not catch the sun head-on, and the charge controller plus cables cost another 10 to 20 percent. So calculate with 70 to 80 percent of the panel rating.

Can I combine panels of different wattage?

Preferably not within the same string. In series the weakest panel sets the current for the whole string; in parallel the lowest voltage governs the behaviour. Either way you lose part of the stronger panel's output. If you do want to mix, give unequal panels their own string, or if necessary their own charge controller.

Are solar panels still worth it in winter?

In north-west Europe they deliver roughly a fifth of the summer yield in December and January, and the low sun angle makes it worse still. That is not enough to keep a fridge running. They remain useful for offsetting standby draw and keeping the battery topped up. For genuine winter camping, combine solar with alternator charging or shore power.

Solar panels on your camper van: how many do you need?

Solar panels are one of the most popular ways to power your camper van when off-grid. But how many panels do you actually need? That depends on your power consumption, where you travel and in which season. In this guide we help you make the right choice.

Calculate your solar setup

Electrical Planner→MPPT sizing calculator→Energy Timeline→

How much power do you use per day?

The first step is calculating your daily power consumption. Add up all the devices you use and estimate how many hours per day they are on. Typical consumption for a camper van: • Fridge: 30-50 Ah/day (compressor, depending on outside temperature) • LED lighting: 2-5 Ah/day • Phone charging: 2-3 Ah/day • Laptop charging: 5-8 Ah/day • Water pump: 1-2 Ah/day • Diesel heater: 1-3 Ah/day An average camper van with fridge, lighting and basic electronics uses about 40-70 Ah per day on a 12V system.

How much do solar panels actually produce?

The output of a solar panel depends on three factors: the panel's power rating (in Wp), the number of sun hours and the efficiency of your system. As a rule of thumb, a 100Wp panel in summer in Southern Europe produces about 5-6 peak sun hours worth of energy, or 500-600 Wh per day (40-50 Ah at 12V). In Northern Europe this is 3-4 peak sun hours in summer and only 1-2 in winter. Account for losses: the MPPT charge controller loses 5-10%, and heat and cables another 5-10%. So calculate with 70-80% of the theoretical yield.

Fixed, flexible or portable panels?

There are three ways to mount solar panels on your camper van: Fixed panels (with frame) are the most popular. They are affordable, durable and easy to mount on the roof. Downside: you lose roof space and they don't always face the sun optimally. Flexible panels are lighter and thinner, ideal when weight is a concern or the roof is curved. They are more expensive and have a shorter lifespan due to higher temperatures (no air circulation underneath). Portable panels you set up next to the van on the ground. Advantage: you can angle them toward the sun. Downside: you need to set them up and store them each time, and they are vulnerable to theft.

Series or parallel wiring?

With multiple panels you can wire them in series or parallel. Series: voltage adds up, current stays the same. Advantage: you can use thinner cables and efficiency is higher in partial cloud cover. Downside: if one panel is shaded, the output of all panels drops. Parallel: current adds up, voltage stays the same. Advantage: shade on one panel doesn't affect the others. Downside: you need thicker cables. For most camper vans with 2-4 panels on a 12V system, series is the best choice, provided you use an MPPT charge controller.

Yield per season and per region

Sun hours vary enormously with latitude and month. These are the peak sun hours per day our solar calculator works with, for three regions campers frequent: Netherlands, northern Germany (52° N): • January 1.0 · April 4.0 · July 5.4 · October 2.0 Central France, northern Italy (45° N): • January 1.8 · April 4.8 · July 6.6 · October 2.8 Southern Spain, Sicily (37° N): • January 3.0 · April 5.5 · July 7.3 · October 4.0 What that means for 300 Wp of panels at 80% system efficiency: in the Netherlands in July you get roughly 1300 Wh per day, in January roughly 240 Wh. That same array still produces around 720 Wh in southern Spain in January, three times as much. The mistake almost everyone makes is sizing for summer. You build in spring, test in July, and discover in October that your battery starts every day a little emptier. Size for the worst season you actually travel in. If you only tour France between May and September, calculate with April. If you head to Scandinavia in winter, solar alone simply will not do it.

Why you get less in practice than on paper

The wattage on the sticker (Wp) is measured under test conditions you will never meet on a van roof: 1000 W/m² irradiance, perpendicular incidence and a panel temperature of 25 °C. In practice you lose out in four places. Temperature. A panel on a black roof easily reaches 60 to 70 °C in summer. Above 25 °C output drops by roughly half a percent per degree, so on a hot day you readily give up 15 to 20 percent. This is also the argument against gluing flexible panels flat onto the roof: without airflow underneath they get even hotter. Angle. A flat roof rarely catches the sun head-on. In summer that costs little, but in winter the sun sits so low that a flat panel misses much of the irradiance. That is why the gap between summer and winter on a camper is even wider than the table above suggests. Shading. A roof hatch, an aerial or a branch does not just disable that patch of panel. With panels in series the shaded panel drags the whole string down. So plan your roof layout with the sun in mind and keep panels clear of obstacles. Losses down the chain. The charge controller, the cables and the battery taking the charge together cost another 10 to 20 percent. Calculate with 70 to 80 percent of the theoretical yield; that is what our calculator assumes.

What you need besides the panels

A solar installation is more than panels on a roof. A charge controller between panel and battery. MPPT or PWM, see the FAQ below. The controller has to match both the voltage and the current of your array: with panels in series the voltage climbs quickly, and you must calculate it at the lowest expected temperature, because cold panels deliver a higher voltage. Cable from roof to controller. This is a run where you want to be stingy with loss, because every percent here costs you yield directly. Keep the voltage drop below 1% and work out the cross-section with the cable calculator. A fuse between controller and battery. It protects the cable, not the panel. With parallel strings you also want a fuse per string. A waterproof roof gland. In practice this is the single most common source of leaks in self-builds. Use a cable gland made for the job and seal it with a sealant suited to your roof material. Mounting that survives the motorway. Panels take serious forces at 100 km/h. Bonding onto a properly prepared surface works, provided you follow the adhesive instructions and use enough surface area.

More panels or a bigger battery?

When your system falls short, the question is which of the two to grow. That depends on where it goes wrong. If you consistently run out at the end of a sunny day, your generation is too small: more panels. If you gather plenty on sunny days but run dry after two overcast ones, your buffer is too small: a bigger battery. If your battery is already full by two in the afternoon on a sunny day and you still fall short in the evening, you are throwing away yield. Here too a bigger battery helps more than another panel, because you simply are not capturing the peak. The energy timeline tool shows this pattern across a full day, so you do not have to guess which of the three situations applies to you.

Calculate your solar setup

Use our free tools to calculate the right number of panels, battery capacity and MPPT charge controller.

Electrical Planner→MPPT sizing calculator→Energy Timeline→

Frequently asked questions

How many solar panels do I need on my camper van?: This depends on your consumption and travel destination. An average camper van with a fridge and basic electronics needs 200-400Wp (2-4 panels of 100Wp). If you spend a lot of time off-grid in Northern Europe, plan for 400Wp or more.
Are solar panels enough to power a camper van?: In summer in Southern Europe, often yes. In winter or bad weather, solar panels alone are usually not enough. Combine them with alternator charging (B2B charger) and/or shore power for a reliable system.
Do I need an MPPT or PWM charge controller?: An MPPT charge controller is 20-30% more efficient than a PWM, especially in cloudy weather and with higher panel voltages. For a camper van installation of 200Wp or more, MPPT is almost always the better choice.
How much Wp fits on a camper van roof?: Reckon on roughly 150 to 200 Wp per square metre of usable roof. On a medium wheelbase van such as a Ducato L2H2 you can realistically fit 300 to 600 Wp, depending on how much space your roof hatches, fan and roof rack take up. Measure your roof before ordering panels, and allow for the mounting frames: they need a few extra centimetres all round.
Why do I never reach the wattage printed on my panel?: The Wp figure applies under test conditions: 1000 W/m² irradiance, perpendicular incidence and a panel temperature of 25 °C. On a van roof you rarely meet all three at once. Heat costs about half a percent per degree above 25 °C, a flat roof does not catch the sun head-on, and the charge controller plus cables cost another 10 to 20 percent. So calculate with 70 to 80 percent of the panel rating.
Can I combine panels of different wattage?: Preferably not within the same string. In series the weakest panel sets the current for the whole string; in parallel the lowest voltage governs the behaviour. Either way you lose part of the stronger panel's output. If you do want to mix, give unequal panels their own string, or if necessary their own charge controller.
Are solar panels still worth it in winter?: In north-west Europe they deliver roughly a fifth of the summer yield in December and January, and the low sun angle makes it worse still. That is not enough to keep a fridge running. They remain useful for offsetting standby draw and keeping the battery topped up. For genuine winter camping, combine solar with alternator charging or shore power.