2. Determine RV Solar Panel Wattage – We’ve calculated our daily power consumption, and know what size of battery bank we need. Now it’s time to decide just what it’s going to take to keep those batteries charged up and ready for action. Since the sun doesn’t always shine (even in Arizona!) you’ll need to take into account your latitude and how often clouds appear.
- The Southwest sees plenty of sunshine. Therefore 1 watt of solar panel output for every 1 amp-hour of battery capacity is recommended. With 200 amp-hours of battery capacity, 200 watts of solar power should do the job.
- The Pacific Northwest sees many cloudy days and since Alaska is so far north, the sun is not very intense, even in summer. At least 1.5 watts of solar panel output for every 1 amp-hour of battery capacity is recommended. A 200 amp-hour battery bank should receive 300 watts of solar panel power.
- Parking in the shade will decrease solar output and several cloudy days in a row can hamper battery charging. Having a few more watts in your RV solar array can help out in times like these. You can never have too many solar panels.
Can’t afford to purchase all the RV solar panels needed for your power requirements? Not a problem. It’s very easy to add additional panels later. Just remember to leave enough room on your roof to grow your solar farm. It’s also important to choose a solar charge controller with a peak power amp rating that will handle your future solar panel additions.
How many watts do I need for a solar panel?
How many hours of sunlight can you expect in your area? – The peak sunlight hours for your particular location will have a direct impact on the energy you can expect your home solar system to produce. For example, if you live in Phoenix you can expect to have a greater number of peak sunlight hours than if you lived in Seattle.
- That doesn’t mean a Seattle homeowner can’t go solar; it just means the homeowner would need more panels.
- The Renewable Resource Data Center provides sunlight information by state and for major cities.
- Now multiply your hourly usage (see question No.1) by 1,000 to convert your hourly power generation need to watts.
Divide your average hourly wattage requirement by the number of daily peak sunlight hours for your area. This gives you the amount of energy your panels need to produce every hour. So the average U.S. home (900 kWh/month) in an area that gets five peak sunlight hours per day would need 6,000 watts.