200W vs 400W Solar for an RV
Solar-panel wattage is only useful when matched to daily energy consumption and battery storage. Doubling panel rating can help, but weather, shading and charge-controller limits still shape real output.
Panel watts are a peak rating
A 200W array does not produce 200 watts every daylight hour. Sun angle, clouds, heat, shading, wiring and controller efficiency reduce daily harvest. Planning in watt-hours per day is more useful.
Battery size and solar size work together
A large battery bank with too little solar may take days to recover. A large solar array paired with a small battery may waste potential energy once the battery is full. Size generation and storage as a system.
Shade can erase the paper advantage
RVs are often parked near trees, air conditioners and roof accessories. Partial shade can materially reduce output depending on panel and wiring configuration, making portable or tilting options useful for some campers.
Start with measured daily consumption
Monitor or estimate refrigerator, fan, lighting, pump, electronics and inverter loads for a normal day. Then size the array to replace a realistic share of that energy under the conditions you expect.