The boys drove the car, named Sol Tide after Devon Prep's mascot, the Tide, for 402.6 miles.
The challenge began in 1993 as a way to get students excited about science, technology, engineering, and mathematics by building solar-powered vehicles. This year, 19 out of 131 solar car teams in 28 states qualified.
Lehman Marks, founder of the Solar Car Challenge, said he used to tell people that the students' projects were purely educational and that he didn't expect the average driver to use solar cars any time soon.
"But that's changed," Marks said. "It's really remarkable."
He cited Ford Motor Co.'s collaboration with Georgia Tech University to develop a solar car and advancements Stanford University has made in battery life. Marks predicts solar cars on the market within seven years.
Devon Prep's Sol Tide is about 16 feet long, weighs 880 pounds, and reaches a speed of about 40 m.p.h. Metal rods on its body hold five solar panels that power four 69-pound lead-acid batteries.
The car cost about $30,000 to build when the team started competing in 2011. The boys raise money from an annual pancake breakfast and corporate sponsors, and use donated materials at times.
The team won fourth place at the 2011 competition and second place in 2012, and came in fourth place last year in an open road race from Fort Worth to Los Angeles.
Yellow sunrays stream across the blue fabric stretched across the car's frame, a design by Devon Prep senior Russell Emery of Phoenixville. The pink fuzzy steering wheel cover is a fashion statement.
Senior Evan Hennessy of Paoli refers to the car as "solar goddess."
In March, the boys started making adjustments to the car, including redoing the wiring and improving the energy use.
"It's so congested around here, it's hard to find a place to drive it," said Scott Conser of Audubon, a team adviser and parent.
So one Saturday morning in late June, the team took the car to the parking lot of the Great Valley Corporate Center in Malvern for some test runs.
Once the boys got to Fort Worth in the third week of July, their first test was passing the many safety checks. Brakes had to work. The drivers had to maneuver the car. Whenever the judges yelled, "Fire!", the driver had to be out and the car turned off within 15 seconds.
During the first two days of competition, the boys raced the car around the Texas Motor Speedway, and even had a pit crew. Unlike the speedway's usual racers, the team didn't have to worry about filling a gas tank.
The final two days of the competition found the boys driving up and down hills on the roads of Texas. The boys slowed the car during sunny weather to charge the batteries and hurried to pass cloudy skies. Two houses passed them on trucks.
"The chaperones were more scared than the boys," said Raj Bharne, father of team cocaptain Soham. He and other adults joined the team in an entourage that drove with the solar car for safety.
Cocaptain Michael Horbowy of Malvern, who graduated this year, said his team learned to overcome obstacles during the Solar Car Challenge, including repairs needed after the car was rear-ended on the track.
"To be able to come back and do so well throughout the competition is a real achievement, I think," Horbowy said.
Soon, the team may not have to travel to Texas for a competition. Within the next year or so, Solar Car Challenge officials hope to start its first regional competition, most likely in the Northeast.