The Earth's surface, on average, receives about a thousands watts (one kilowatt) of solar light energy per square meter. So, if we were assuming perfect, 100% efficient solar panels (I believe the best ones are up to about 20% at this time), you're looking at 145 square meters of area of solar panels to achieve that rate. More realistically, you're looking at hundreds of square meters at least.
And that's to halfway charge a car in a third of an hour? An hour and a quarter for a full charge? I can completely fill the tank in my conventional car, probably in about five minutes or less. Who can spare the time to spend more of it waiting for his car to charge, compared to how long he spends actually driving it?