BTW Neuton is not the robotic mower ( but that would be cool to have also/instead)
http://www.neutonpower.com/
I have a very small yard (so I have the small mower, cause their was no choice 3 years ago) and one fluid free 12 volt battery cuts the whole thing 2x
I just happen to live in an area where our electric comes from a Nuke Plant. ( I'm OK with that)
just a note to clear that up
Schultz