The author analyses the performances of small electric vehicles, briefly named solarcar, with batteries and photo-voltaic array (PVA) on board. The performances are evaluated by means of a computer model which implements analytical descriptions of the road-vehicle system, from the point of view of the principal energy sources or sinks: mechanical losses in motion electric engine performances battery behaviour PVA's energetic contribution mission characteristics. As example, the computer is applied to analyse the performances of a solarcar constructed for race activity, according to international regulamentations.The computer model proves to be a very usefull instrument for comparing the differences of performances caused by design characteristics of the solarcar (as weight, transmission ratio, etc.) and by the kind of utilized batteries (in particular, three types of batteries are considered: Ni-Cd, Pb and Ni-Zn). It may be concluded that the main factor affecting the performances of a solarcar (of the here considered class) are the batteries, and that the Ni-Zn type are the best ones for short time life (about 100 recharge cycles), that the transmission ratio is not a critical factor and, obviously the weight and road slope are very effective.Finally, some energetic onsiderations on PVA's contribution are explained in the perspective of its utilization for a city-car.