Use this free van solar calculator to size the right solar array and battery bank for your camper conversion. Tick the 12V appliances you run each day, set your typical hours, and we’ll estimate your daily power use, the solar wattage you need, and the battery capacity to keep you off-grid.
| Add | 12V Appliance | Hrs/day | Wh/day |
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Tip: solar is sized for ~3.5 peak-sun hours and battery for 1.5 days of autonomy. Add panels and lithium capacity if you boondock in cloudy regions or run a fridge year-round.
How to use this van solar calculator
Check every 12V appliance you plan to run in your van, then adjust the hours per day to match your lifestyle. The tool multiplies each device's wattage by its runtime to get watt-hours per day (Wh/day), sums your selections, then sizes a solar array (assuming 3.5 peak-sun hours) and a usable battery bank with 1.5 days of autonomy so you can survive a cloudy day without a hookup.
Solar wattage vs. battery capacity
Solar panels replace energy during daylight, while your battery stores it for nights and bad weather. A fridge that pulls 600 Wh/day needs both: roughly 200W of panels to recharge it and enough amp-hours to coast through clouds. Lithium (LiFePO4) batteries let you use nearly 100% of their rated capacity, whereas lead-acid/AGM should only be drained to 50% — so you need twice the rated Ah to get the same usable power.
Copy this code to add the Van Solar & Battery Calculator to any page (link-back appreciated):