Peak Sun Hours

Peak sun hours are the number of hours of full-strength sunlight that would deliver the same solar energy a location gets in a whole day. They turn a day of changing light into one number you can multiply by panel output.

A 200 watt panel at 75% system efficiency gives 150 Wh per peak sun hour. Charging a 100 Ah, 12 volt battery from 50% to full takes 600 Wh, or 4 peak sun hours. At 5 peak sun hours a day, that is 0.8 days.

Your number depends on location, season, weather and panel angle. Enter it in the solar charging time calculator, and see the guide to solar battery charging for the full method.