How many solar panel watts does an RV need?
Turn a measured RV Wh/day load into a solar panel estimate with peak-sun-hour and loss assumptions.
planning · transparent planning
Panel nameplate power is an instantaneous laboratory rating. Your RV needs energy across a day, so plan in watt-hours and account for location and weather.
Start with the daily deficit
Subtract any dependable non-solar charging from your daily energy use. As an example only, assume 700Wh/day to replenish, four equivalent peak sun hours and a 75% net system factor. The simple arithmetic is 700 ÷ (4 × 0.75) = about 233W of panels. This number is not an installation specification.
Use a conservative range
A change from four to two peak sun hours doubles the calculated panel wattage needed for the same energy. Roof orientation, shade, heat, controller limits and cable losses can matter more than the first-pass arithmetic. Enter different sun-hours and derating values rather than treating a monthly regional average as an everyday guarantee.
A solar panel is not storage
The battery must cover nighttime and bad-weather demand. A controller must also be suitable for the battery chemistry, charge voltages, PV array and maximum currents. Do not infer wiring size or fuse selection from this calculator; consult the equipment manual and a qualified installer.
Turn planning into a buying brief
Record the measured energy deficit, panel mounting space, real shade, controller compatibility and days of autonomy. Compare the manufacturer's current specifications against that list before using any merchant link.
Turn your result into an equipment checklist
No fabricated product tests or affiliate claims. Compare verified specifications before buying.