[oil pan 4]

Say you have a 100 watt solar panel. It would be safe to assume it would make 100 watts right? Wrong.
Unless the manufacturer "under rated" the panels to reflect real world out put you never get name plate wattage. Only a few manufacturers do this.
So your 100w panel now produces 70 to 90 watts. That's if it's actually pointed at the sun.
Then you lay it flat on top of a vehicle. Now you just cut the output in half.
So now the 100 watt panel is producing 50 watts and you have not gotten to the charge controller.
To take panel voltage of let's say 24 volts because if you just series up panels for hybrid battery voltage wich can be over 300 volts one splat of bird poop, one smeared bug, one cell facing away fron the sun on a series of 700 cells would cut output by over half. That's just shading one cell. So realistically you go for 24 to 36 volt panels.
The charger to step the 36 volts up to 270 to 330 volts might be 80% efficient if you are luckily.
So you started with 100 watts of solar panel and you end up with 40 watts and that's being generous and not even counting battery charge and discharge losses or the fact that laying the panels flat cuts your typical 4 to 5 hours of good charge time down to 3 if you even consider a flat panel producing 50% of name plate rating good production.