The World Solar Challenge is a 3000 kilometre race from Darwin to Adelaide, across the Australian continent, for solar powered racing cars. Annesley College accompanied the 2001 event in an electric car powered by batteries. While one battery was used to power the car another was charged from a solar panel carried by a mobile solar power station. When the first battery became empty the batteries were interchanged and the first battery put on charge. The process was repeated throughout the event. In this paper we find a policy for interchanging the batteries that maximises the distance travelled each day.
