I've got a small solar panel that came with a science kit (about 3" x 1") that says .5v - 300 mA on it.

Could this do anything useful (charge a 900 mAh AAA protected rechargable battery / perhaps a cell phone battery) or is it too small?

Also, I have a grundig radio with the hand crank on it. Would I be able to charge a cell phone battery using that? What about a small laptop battery (7.4v - 5200 mAh) (although I'm sure it would take forever....) would I need a voltage regulator?