Use this worksheet to figure the total number of solar modules required for your system.

To find average sun hours per day in your area (line 3), check local weather data, or go to the Solar Insolation page. If you want year-round autonomy, use the lowest of the figures. If you only want 100% autonomy in summer, use the higher figure.

The peak amperage of the module you will be using can be found in the module specifications. You can also get close enough if you divide the modules wattage by the peak power point voltage, usually (17 to 18.5).