While Segun Oyeyiola was a student at Obagemi Awolowo University, he converted his gas-guzzling Volkswagen into a fossil-fuel free machine by installing a giant solar panel on top and a wind turbine under the hood. The idea is that it becomes "Nigeria's future car."
At inception, the battery took 4-5 hours to charge, which was not ideal. The biggest challenges, according to Oyeyiola, was finding the best materials to use, and the people telling him he was wasting his time.
Here is an animation of a solar/wind powered car, showing how batteries are charged via the multiple turbines.