The car in question just used solar, when the sun was shining, as a mini top-up. In no way was it meant to be as a means of recharging the vehicle,
Copenhagen's International School generates 300-megawatt hours of energy per year from their solar panels. Though energy production decreases with increasingly dense cloud cover, panels continue working to a greater capacity than one may expect. The good news is that even when covered with snow, solar panels can generate electricity.