Hey .
Take a look at this : http://www.overunity.com/index.php/topic,311.0.html
I'm doing that today .. .
Briefly : Remove the Cap of a 2N3055 Transistor, with a magnifying glass focus sun on the silicon part of the transistor ..
Should generate 5 Amps at 0.5 Volts !!!! ..
Impressing stuff if it works ..
Now, put 3 of these in series .. and you have 1.5 Volts 5 Amps ..
Now, put some more in parallel and get more amps . .
Now, put your electrolyser on this thing in the sun and get H2 ..