I have an enormous amount of grass and the yard is also very hilly.  I got an extra set of batteries.  Though I can't do the whole yard on 2 sets of batteries, I wouldn't want to.  My attention span for mowing is exhausted by the time I have run down the second set.  I  finish the yard on another day.   We still have the gas mower, but we never use it, because it is so much more pleasant to mow with the cordless self-propelled electric.  We give it a beating but after 2 full seasons, it is still going strong.

BoxtopJim

Boxborough, MA