Free calculator
Campervan solar and battery calculator
Set the vehicle, destination, battery and solar. The calculator shows what your van uses in a day, what sun and driving put back, and how many days the power lasts.
The calculator needs JavaScript. In the studio you can run the same numbers with your own floor plan.
Opens without signing up, the van stays in your browser.
How the calculator works
Yield: solar power × peak sun hours at the destination × 0.72 for heat, angle and charge controller. On the Mediterranean that is about 6 peak sun hours a day, in the Alps at around 4 °C 2.2 and at the North Cape in winter 0.2.
Driving: charging booster in amps × 13.6 volts × hours of driving × 0.9. A 50 A booster adds about 610 Wh per hour of driving.
Battery: LiFePO4 at 12.8 volts, 90 % usable. So 200 Ah is about 2.3 kWh you can actually use.
Use: fridge (more in the heat), work with two laptops, lights, pump and electronics, cooking, heater fan in the cold, roof air conditioning in the heat and the inverter on standby.
Furniture, insulation, heater, fridge and roof space come from the studio’s suggested layout for the chosen vehicle. Solar goes on the roof in panels of about 210 Wp, as many as fit.
Frequently asked questions
How much solar does a campervan need?
Mostly it depends on where you go. On the Mediterranean 300 to 450 Wp cover a frugal day. In the Alps at around 4 °C, 400 Wp only give about 630 Wh a day, and a day with fridge, laptop and heater fan needs more. The calculator shows the wattage at which the balance works out at your destination.
How big should the battery be?
Big enough to bridge days without sun. The calculator gives the size for three overcast days: daily use × 3, divided by 11.5 Wh per Ah (12.8 volts, 90 % usable).
Is a DC-DC charging booster worth it?
If you drive most days, yes. A 50 A booster adds about 610 Wh per hour of driving, as much as 400 Wp on an autumn day in the Alps.
Does the calculator work with lead-acid batteries?
No, it assumes LiFePO4. Lead-acid batteries should only be discharged to about half, so the same capacity gives roughly half the usable energy.
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