Solar Panel Wattage for RV Setups
Panel wattage gets recommended as a flat range ("400–800W for most RVs") almost everywhere, which is a reasonable starting point but skips the thing that actually determines the right number for your setup: how much usable sun you actually get where you park.
The panels' job: recharge what you use, in the sun hours you have
Your battery capacity (see our battery guide) determines how much energy you need to replace each day. Your panel wattage determines how fast you can replace it — which depends on peak sun hours, not just daylight hours. Peak sun hours are the equivalent hours of maximum-intensity sunlight a location gets per day on average; a cloudy or far-northern location might realistically get 3–4 peak sun hours in winter, while a sunny desert location might get 6+ in summer.
Rough sizing approach
- Take your daily Wh use estimate (from the battery guide).
- Divide by your region's realistic peak sun hours for the season you'll actually be using the rig.
- Divide again by a system-efficiency factor (commonly estimated around 0.75–0.8, accounting for panel angle, partial shading, wiring losses, and charge-controller efficiency) to get a more realistic target wattage.
Worked example: 3,000 Wh/day ÷ 4 peak sun hours ÷ 0.75 efficiency ≈ 1,000W of panel capacity needed to fully recharge that usage in a lower-sun location — notably more than the generic "400-800W" range many sources quote, because that range usually assumes closer to 5-6 peak sun hours.
Why the generic range still shows up everywhere
Most of what ranks for "how much solar for RV" is vendor content built around their own product lineup's typical configuration, not a calculation from your actual location and usage — which is part of why it's hard to find a neutral answer to this specific question. A flat range isn't wrong exactly, it's just answering "what's typical," not "what do you need."
Practical takeaways
- If you mostly camp in sunnier regions/seasons: the lower end of typical ranges (300-500W) may genuinely cover moderate use.
- If you camp in cloudier regions, during winter, or under tree cover often: budget meaningfully higher than generic ranges suggest, or plan on supplementing with shore power / driving-alternator charging rather than solar alone.
- Panels are usually cheaper to slightly oversize than batteries are — a bit of extra panel wattage on a sunny day just means faster charging, while undersized panels on a cloudy stretch mean a dead battery.