I have been playing around alot and found out if you use thin wire and most importantly a full wave bridge rectifier or better yet a voltage doubling rectifier you can voltages as high 35-40 in as litttle as 2 minutes.
Forget the metal plate as i have seen no real increase in voltage or current.
With a fwb i get a constant voltage of 7.3 with 100 feet of wire .
I'm watching, as they all are.