The Scooblite can be charged from any light source even artificial light. When charging, let absorb sunlight for 5 minutes. The Scooblite will glow intensely for a few min then will dim to a consistent light for an hour or more if fully charged. It will actually glow all night long at a lower intensity. At any time you can recharge your Scooblite with your flashlight even underwater. The brighter the light you are using to charge, the brighter and longer the glow.