How much solar do you actually need for a campervan?

Get the solar array size right by starting from your daily energy use and your charging behaviour, not a guess.

Start from your daily watt-hours

Your daily energy use is the number that drives everything. In a typical van with a compressor fridge, lights, phone charging and a laptop, that is roughly 1,200 to 2,000 Wh per day.

A practical rule of thumb for solar: 200 to 400 W of panel per 100 Ah of battery. On a 200 Ah (LiFePO4) bank, that points to roughly 400 to 800 W of solar, depending on how heavily you rely on the sun.

How much of your day is sun

Solar only produces while the sun is usefully up. A panel's real output equals its rated wattage multiplied by its "sun hours" and a derating factor (clouds, angle, heat). In summer, expect around 5 to 6 effective sun hours; in winter in northern Europe, that can drop to 1 to 2.

The practical guidance

• Weekend van with mains or alternator charging: 200 to 400 W is usually enough to keep batteries topped up.
• Full-time vanlife: start with 400 W of roof-mounted solar, and consider 600 W or more if you rely on solar alone or live in a cloudy place.
• Heavy users (AC, constant Starlink): plan for 600 W to 1,000 W.

Use MPPT

An MPPT charge controller squeezes noticeably more power from the same panels than an older PWM unit, and it is the standard worth installing from the start.

Solar works best with other charging

Pair solar with alternator (DC-DC) charging so travel days top the battery up even in cloud. That combination lets you run a smaller, cheaper array with confidence.