Originally posted by TheRegular
...Yet where would all that power come from?
Charging an ipod takes a very small amount of power: At UK/EU mains voltage a single ipod step-down transformer will draw < 50mA (probably actually less than 25). If you have, say, 200 ipods charging at once then that amounts to a total mains current of 5 to 10 Amps, which is the equivalent of 10 to 20 standard (100W) mains light bulbs. In reality the figure will be lower, because the transformers will be more efficient than standard consumer items. This level of demand is insignificant in comparison with the generator capacity of a passenger aircraft.
So, you won't cause the aircraft to run out of power because you charge your ipod!

Best wishes
David