<P> Some solar cars use gallium arsenide solar cells, with efficiencies around thirty percent . Other solar cars use silicon solar cells, with efficiencies around twenty percent . </P> <P> The battery pack in a typical solar car is sufficient to allow the car to go 250 miles (400 km) without sun, and allow the car to continuously travel at speeds of 60 mph (97 km / h). </P> <P> The motors used in solar cars typically about 2 or 3 horsepower, yet experimental light solar cars may attain the same speed as a typical family car (100 mph (160 km / h)). </P> <P> To keep the car running smoothly, the driver must monitor multiple gauges to spot possible problems . Cars without gauges almost always feature wireless telemetry, which allows the driver's team to monitor the car's energy consumption, solar energy capture and other parameters and thereby freeing the driver to concentrate on driving . </P>

When was the first solar powered car invented