I haven't looked at your video, but you can charge an ipod w/o using the onion. You can put that to much better use
simple version: all you need is some zinc and copper strips, or iron and copper, or zinc and silver etc etc etc. as long as one metal is electonegative and the other is more electropositive; put them is a salt water or other salty type solution ( like an onion ) and complete the circuit. you should get 1V to 1-1/2V depending on the difference in electronegativity between the two metals. Of course you will have to put many of these in series to reach the appropriate voltage. And even then prolly only have a current of a few milliamps unless you have a huge surface area worth of plates. Then you electropositive plate will be consumed and corrode into the solution after time anyways. But thats how they did it in the old days on a big scale. any good chemistry book should have it.
Of course you proly can't hook it up straight to your ipod anyways cause it maybe uses a SMP ( switch mode power ) supply?
I dunno, if it doesn't then maybe you can hook up the ipod after some power regulation on these cells...
