Solar power has gotten a lot more efficient over the past decade, and the way things are heading, it’ll only improve. Ten years ago, the efficiency of solar energy was around 13 percent. But in 2019, typical solar energy efficiency is 20 percent. When you’re looking for the right rig, remember to consider how many Watts (W) each solar panel is capable of producing. Under the most direct, powerful sunlight, a 100W solar panel will produce 100W of power per hour. Because optimal conditions are hard to come by and don’t last all day, keep in mind that solar panels can take a while to juice-up a device.