The amount of electricity a solar panel generates depends on several factors: the surface area, the efficiency of the cells, and the quality of the sunlight.

Photograph by Ruslan Dashinsky/Shutterstock

Usage Tips

  • Quality AND quantity matter. The quality of the sunlight has a large effect on the efficiency of solar cells. Bright, direct sunlight will provide a better charge than sun obscured by clouds or windows.
  • Check the current. PV cells generate direct current (DC), the same kind of current a battery provides. To power alternating current (AC) devices that are plugged directly into a wall outlet and don't usually contain batteries (like a lamp, for example), you need to buy an inverter that switches DC to AC. Some solar chargers can’t handle inverters, so be sure to check with the manufacturer before you use one.

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