VAN-COMPARATOR Guide
Off-grid power in a camper van: battery, solar panel, inverter
Leisure battery, solar panel, inverter: how long the power really lasts off-grid, how to recharge while driving, and what to check before booking a van for wild camping or long stopovers.
Running out of fuel worries everyone; running out of battery worries no one — until the fridge starts warming up on day two of wild camping. Off-grid power is the second pillar of camper van independence, right after water, and it takes ten minutes to understand.
The three building blocks
- The leisure battery: separate from the engine battery, it powers the lights, the fridge, the water pump and the USB sockets. Two technologies coexist across rental fleets: AGM (the most common, but only safely usable down to about half its rated capacity) and lithium (LiFePO4), pricier, lighter and usable almost in full — increasingly common on Roadsurfer's fleet and on newer Indie Campers vans.
- The solar panel: 100–200 W on the roof of most recent vans and campervans, missing from a chunk of entry-level semi-integrated and A-class motorhomes. It charges while driving and while parked, as long as it can see the sky.
- The inverter: converts the battery's 12 V into 230 V to run a laptop charger or a standard plug. Not every vehicle has one — without it, only the USB and 12 V sockets work off-grid.
How long it actually lasts
A 100 Ah AGM battery gives you roughly 600 Wh of usable capacity (about half its rated capacity, to avoid damaging it); a same-size lithium battery delivers about double that, around 1,200 Wh. On the consumption side, a compressor fridge alone draws 500–800 Wh per day — by far the biggest single load — while LED lighting and the water pump are negligible, and a full laptop charge costs 50–90 Wh. The practical upshot: with no sun and no driving, a standard AGM setup lasts a day and a half to two days with the fridge running, a lithium setup three to four days. A well-angled 150 W solar panel adds 300–600 Wh on a sunny day — enough to run indefinitely in summer, far less in midwinter or under tree cover.
Recharging on the road or at a campsite
The engine recharges the leisure battery whenever it's running, through a split-charge relay that isolates it from the starter battery — two to three hours of driving a day is usually enough to cover a normal evening. When parked, service areas and campsites with mains hook-up (often €3–6 for a top-up, sometimes included in the pitch fee) recharge everything within a few hours and run the electric heater or fan without touching the leisure battery. Plugging in every two or three days is the sensible habit even when you're mostly wild camping the rest of the time.
The mistakes that drain a battery fast
- Running the fridge on its coldest setting in summer: one notch down is plenty to keep food safe and roughly halves its draw.
- Charging a power-hungry laptop through a small inverter: beyond its rated output (often 150–300 W on compact models), it trips or overheats — check the stated wattage before packing demanding gear.
- Parking in the shade for several days with solar as the only input: with no sun and no driving, the battery never recovers, even in summer.
- Leaving a light or the water pump on overnight: individually minor, they add up and finish off an already low AGM battery.
What to check before booking
If your trip mixes wild camping with off-grid stopovers, or if you plan to work from the van for several days in a row, ask the owner three questions before paying: the battery's capacity (in Ah, and its technology), whether there's a solar panel and how powerful it is, and the same for the inverter. This information rarely appears on the standard listing — a message to the owner on Yescapa or Goboony, or to customer support on the professional fleets, usually gets an answer within minutes. Our pickup checklist includes a point on testing this electrical circuit when collecting the keys, just like the water level — a dead fridge in the middle of a national park is far harder to fix than an empty fuel tank.
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