Solar Sizing Calculator

Divide the watt-hours you need to generate per day by the peak sun hours in your area, then add 20% for real-world efficiency losses. For example, to replenish 500Wh per day with 5 peak sun hours: 500 / 5 = 100W, plus 20% buffer = 125W of solar panels recommended.

Peak sun hours represent hours of sunlight at full 1,000 W/m2 intensity — not total daylight hours. A location with 14 hours of daylight might only have 4-5 peak sun hours. Morning, evening, and cloudy periods produce significantly less solar energy. The US averages 4-5 peak sun hours per day, varying from 3 in the Pacific Northwest to 6+ in the Southwest deserts.

No. Every power station has a maximum solar input wattage (e.g., 400W or 2,400W). Connecting more solar wattage than this limit will not charge faster — the charge controller will cap the input. Always check your unit's solar input spec before buying panels. Exceeding the voltage limit (not just wattage) can also damage the charge controller.

Multiple smaller panels (100W-200W) offer more flexibility — you can angle them independently, carry them more easily, and replace one if damaged. Larger panels (400W) are more efficient per square foot and require fewer cables, but are heavier and harder to position. For portable use and camping, 200W panels offer the best balance of output and portability.

Solar panels lose about 0.3-0.5% efficiency per degree Celsius above 25 degrees C (77 degrees F). On a hot 40 degrees C day, a panel rated at 200W might only produce 185W. Conversely, panels can exceed their rated output in cold, sunny conditions. This is why our calculator includes a 20% efficiency buffer to account for temperature and other real-world losses.