Considering a solar panel on the hood.
Well you might be able to squeeze 500Watts of solar panel onto the hood
500 Watt is 1/2 a kilowatt and most of those mowers are 10 Kw or more
So you are charging at a rate that is somewhere between 0.5% and 4% at the rate you are consuming.
Google "World Solar Challenge"
Those cars are powered by tiny 100 to 500 watt engines and look at the size of the solar panels needed to power them.
And this in on the Stuart Highway so no trees no clouds and some of the strongest sunlight you can get on the planet
Dream on
There is a job waiting for you in the California Environmental Protection Commission.