Equinox is the eighth generation vehicle of the Stanford Solar Car Project, a completely student-run group at Stanford University that has been building, testing and racing solar-powered vehicles since 1989.

Green car enthusiasts might be proud of the Toyota Prius hybrid’s impressive fuel efficiency, but at this year’s Pacific Coast Dream Machines Show, some innovative and hard-working students at Stanford University will be showcasing a speedy vehicle that pays nothing at the pump, fueled only by the sun.

Equinox is the eighth generation vehicle of the Stanford Solar Car Project, a completely student-run group at Stanford University that has been building, testing and racing solar-powered vehicles since 1989. The team builds an entirely new vehicle from scratch every two years to compete in the World Solar Challenge in Australia, where teams from across the globe race from the tropical northern city of Darwin to the finish line in the parched desert of Adelaide on the southern coast.

In July 2005, Stanford’s earlier generation car, the Solstice, won the stock car class with only commercially available, off-the-shelf parts. Equinox uses the same tried-and-true body design of Solstice, but sports some cutting-edge technology upgrades that translate into considerable performance boosts, including an expensive space-grade solar array and a digital electrical system. The car boasts 32 solar modules, totaling about 2800 individual gallium arsenide solar cells.

Equinox can cruise at an impressive 55 mph on pure solar energy alone, says team member Sasha Zbrozek, and can reach a top speed of 83 mph with the help of battery power. “It has better solar cells than the majority of solar cars, allowing it a higher break even speed. It was definitely a new and improved car.”

Unfortunately, the impressive new design did not translate into a big payoff in the 2007 World Solar Challenge. The team had a strong start to the race and had reached as high as third place in the “Adventure Class,” the lower division of the World Solar Challenge. However, the car began to fall behind the head of the pack in the middle of the race and became unstable. With the car moving at about 50 miles per hour, a tire exploded, causing the vehicle to spin out of control and flip over. It landed about 30 feet from the side of the road. Fortunately, the roll-cage functioned perfectly during the crash and the driver was uninjured, but the car, including the $150,000 solar array, was badly damaged and had to be withdrawn from the race.

Zbrozek says that Equinox has now been repaired and is drivable once more, but its racing days are over. “Equinox is no longer rules compliant, so it’s pretty much a retired vehicle at this point,” he said.

The team is using lessons learned with Equinox and previous solar cars to design its next generation vehicle and plans to compete in the upper division races in both the 2009 World Solar Challege and the 2010 North American Challege.

For information on the Stanford Solar Car Project, visit http://www.stanford.edu/group/solarcar/

Equinox will be showcased at the Pacific Coast Dream Machines Show on Sunday, April 27 from 10 a.m. to 4 p.m. at Half Moon Bay Airport.