forget this water engine! that's a scam.. just think about the basic chemistry... if you combine hydrogen and oxygen you will get water + energy... so water is the chemical compound that has less energy than the basics its built from.. so what can you do with water to gain energy out of it? I have no idea how that could work in theory..
https://en.wikipedia.org/wiki/Stanley_Meyer%27s_water_fuel_cell

Solar will definitely be a nice add on.. at least some parts of the cars roof should be fitted..