Okay, maybe the original goal isn't possible, but how about some help with this alternative?
What if I want to be able to run the robot at any given time, provided it's charged enough to run? For instance, the robot might be in my basement 24/7 with the light on, and it has an onboard battery and solar panel charging the battery. Then I just have to wait until it's charged before operating it again after wearing the battery/solar panel combination down.
Sorry, I probably should explain that for what I want to do, it's not reasonable to presume that the robot will be "docked" at a pre-determined position for the purpose of recharging after each use. For that reason, I came to the conclusion that some kind of solar power or tethering (the latter I really don't want to do!) was the way to go.
Any hints for the solar panel/battery idea? I'm not too sure what I should be taking into consideration, especially for determining the recharge time, and making sure the battery is charged properly (e.g. not undercharged or damaged). Any circuits, ideas, etc are greatly appreciated, as always!