I don’t understand your math, I’m sorry. Why would you divide by 24 hours? There is not 24 hours of sun for your PV to capture and put into the car. Peak solar generation is 3-6hrs/day depending on region and time of year.
4m length * 2m width * 1kw/m^2 insolation * 50% loss due to the panel area being calculated by ground area and it not tracking the sun and therefore not getting peak output * 20% cell efficiency = average power 800 W
My BOTE calculation above should use 25% instead of 50% for day-night average of PV panels horizontal to the ground. Can’t edit now, though. 25% is the planet-wide average for day-night and seasonal variation because that’s the ratio of the surface area of the Earth to the area of a disk intersecting the same flux of sunlight at 1AU (4πr^2 : πr^2).
With that correction, that’s 400 watts average over 24 hours (as in: no not merely the peak at noon); which means 24 h * 400 W = 9.6 kWh per day.
If you drive 60 miles per day, and each mile consumes 241 Wh of energy, then you consume 14.41 kWh of energy per day.
