mw3230 wrote:Inappropriate expression.
The guy sat behind me doesn't think so and he's of Chinese origin. Still perhaps he's as politically incorrect as I (probably) am.
Back to the OP. The trick with this device is to design it properly, the clever thing about Bayliss's wind up radios is that they don't have a battery. Instead they run a clockwork mechanism to a generator that is used to charge a small capacitor. Once charged the circuit 'shorts' the generator to bring it to a near stop, power is used and when the voltage across the capacitor drops below some level the short is removed and the generator allowed to run to charge the capacitor again.
If the lights used this principle they'd be fine, but all the wind up lights I've ever seen don't. They're not clockwork, they're simply handles to generators and shoddy batteries. Once they've been in the cupboard for a few months then they're only fit for the bin.