We have been hearing for twenty years about how cars will some day be solar powered. While we have seen many prototypes, many of us have begun to doubt it will happen, as we still await mass-produced solar powered cars. Conspiracy theorists believe that oil companies are suppressing solar technology to keep the gasoline flowing and oil prices rising. But according to most solar technology experts, the technology is available already to produce solar-powered vehicles, but not to produce a full-size, full-power vehicle. In other words, if you want to drive a strange shaped car that has you lying down in a little cockpit, you can average 20 mph. Since there isn't much market for that, it isn't being produced.
Part of the problem with solar powered cars is how to store enough of the energy to maintain full power through nights and cloudy days. Further, it is hard for a vehicle in operation to get enough extra solar power to store some in a battery for later. The big issue really comes down to the amount of energy a photovoltaic cell can produce and how much surface space of the vehicle is required for each photovoltaic cell. The best photovoltaic cells produce only a half-watt of energy. So some way has to be found to fit more of them on the car. But if the car surface area is increased, so too is the amount of power needed to make the car move.
One of the most popular events held to encourage the development of practical solar energy cars is the 1,800 mile solar powered car race held in Australia every other year. While this race has spurred many hobbyist inventors and college students to make improvements, the cars have shown themselves to still be far from road-ready. For instance, the first race in 1987 had the top entrant averaging 42mph, while the recent race winner averaged 62mph. Of course, that was in a very sunny place during ideal conditions.
Solar powered cars are simple in structure. As mentioned, energy from the sun is converted by photovoltaic cells into electricity that is run to the batteries and to switches that connect the electricity to the motor. From the batteries the electricity can also go to the simple electric motor. Where the motor gets its electricity from is simply a matter of whether there is adequate sun available or the batteries are needed. The more sophisticated solar powered cars use regulators to prevent overcharging damage.
In order to make these cars gather enough solar power to run and charge their batteries at the same time, solar gathering efficiency must be improved. Currently, solar cells are limited to gathering about 15% of the solar energy being beamed to them by the sun. If they could find another technology that would triple this efficiency, solar scientists would be able to mass-produce solar-powered cars.
