How is it that exhausted batteries gain some charge when exposed to the sunlight?

3 ⤊

How is it that exhausted batteries gain some charge when exposed to the sunlight?

I knew this from my childhood, when we used to put exhausted carbon batteries to the sunlight for a couple of hours, to discover that they have gained some charge, and could be used again.

Today I read in the newspaper that 2 lost young men lost in the mountains could re-charge the Ni-Cd battery of a cell phone by exposing it to the sunlight for 15 minutes. The battery gained enough charge as to let them send some SMS with their position, and finally they were rescued.

Can anyone explain me the physical / chemical basis for this phenomena?

2007-04-09 05:08:27 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Physics

2 answers

The batteries warm up and the chemical reactions in the battery can proceed better than when they're cold or at room temperature.

2007-04-09 05:13:52 · answer #1 · answered by Gene 7 · 2⤊ 0⤋

because heat "excites" molecules

2007-04-09 05:17:03 · answer #2 · answered by dad 4 · 1⤊ 0⤋