...long wire(s)/cable(s) stuck in ground to recharge batteries...
This is actually a radio transmitter, but I'm lucky to have found it...
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US750429.pdf
Here's a whole thread on the subject. I intend to try and improve upon this information, if possible...
http://www.energeticforum.com/renewable-energy/2209-earth-battery-sg.html
Joule Thief application...
http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/msg352238/#msg352238
More specific earth batteries later.
--Lee