I have a great "shake" flashlight. It has two large copper coils, I believe a big capacitor and some electronics and it holds a charge for months. When shaken for two minutes you have power for quite awhile, I've never tested it for maximum time. It's called "New Deluxe Forever Flashlight." I believe the company was "itouchless.com" It cost me about $20.00. I've had it since April and have used it quite a bit. Of course, it's not equivalent to the power of a battery operated light, but it's fine for in the house or yard. Just think what one of these would be worth if no batteries could be obtained!