By the way,

If you're really just interested in mowing a 10 acre lawn, as opposed to developing an electric work tractor to brush hog a field, then it is very feasible to use an electric mower. It has been done.

The simplest approach I've read about was one wherein the mowers (approximately 24" diameter cutting path) run continuously. Instead of following a well defined pattern they simply mowed in a random direction, until they came to a perimeter at which time they switched to another random direction. Since they were always mowing, the grass never got very tall and didn't require as much power to cut. The units used solar panels to help keep the batteries charged. If I remember correctly, one unit running 24 hours a day, seven days a week, could pretty much keep 4 or 5 acres under control. And since it was electric, there was no noise issue with it running all the time.

For larger areas, for better efficiency, and perhaps for security (theft prevention), one might add a communication link to a master control that could keep multiple units evenly distributed over an area. If one unit started noticing a heavier current load (as would be the case with taller grass) then the controller could send another unit to help out (on the assumption that the grass was growing faster in that area). One might even add GPS capabilities to the units. With relative position beacons GPS accuracy can get down to centimeters. This would allow for more efficient cutting patterns than just random motion. Moreover, all of these added features could actually make this an 8052 project (and thus on-topic).