Battery & Solar Calculators
Size your leisure battery, solar panels, inverter, fuses and cables.
Free battery & solar calculators for van leisure battery & solar
Quick, accurate tools to help you plan, size and budget the battery & solar side of your van conversion. Pick a calculator below to get started.
Battery capacity
Work out how many Ah of leisure battery you need from your daily appliance load.
Battery runtime
Estimate how long your battery will last running a given load.
Solar panel size
Find the panel wattage needed to break even on a typical day.
Solar charge time
How many sun-hours to recharge your battery from empty.
Appliance usage
Add appliances and see Wh, Ah and £/day at your tariff.
Inverter size
Pick the right inverter wattage for your peak load.
Fuse size
DC fuse rating from device wattage and cable run.
Cable size
Minimum DC cable size for current and run length.
Daily energy
Plan your daily Wh budget across all appliances.
Why van leisure battery & solar planning matters
Avoid costly mistakes
Sizing your battery & solar correctly up front saves money, weight and time. Use these calculators before you buy components or commit to a layout.
Built for van life
Every formula is tuned for real campervan and motorhome use cases, with sensible defaults so you can get a useful answer in seconds.