The amount of time that you can use a 100 watt solar panel to charge small electronics ranges, but generally speaking, for several hours to 24 hours under optimal battery conditions is fine.
Just remember to have a proper solar charge controller, and you'll be able to charge smartphones, laptops, routers, lamps, and LEDs with a single 100-watt panel. For more solar tips to help you harness the sun's natural energy, click or tap this for our homepage.