MvdV> Look at it this way: The battery in my cell phone (Siemens
 MvdV> M35i) is 3.6 Volts, 500 mAh. Or 1.8 Wh. That's enough for 3
 MvdV> to 4 days of average operation. A 500mW generator could
 MvdV> charge the battery in less than 4 hours. So 500 mW is
 MvdV> plenty for a cell phone.

 MvdV> Not for a laptop though and I suspect they are aiming for
 MvdV> that...

How about a hybrid laptop?  The battery will last much longer if the 0.5-W
microgenerator is used as a supplemental energy source.

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