Armando Nargi, bottom center, and William Masiello spray water on the Drifter 2.0 solar car to cool it off. The UA solar racing team will try out the Drifter 2.0 this month during the American Solar Challenge, which starts in Texas and ends 2,400 miles away in Canada.

A.E. Araiza / Arizona Daily Star

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Hannah Kosinski wasn't thinking about becoming the next Danica Patrick when she joined the University of Arizona's solar car team.

"I just thought it was cool," said the 19-year-old mechanical engineering student.

Turns out it's not cool — at least not in the car's cockpit, where Kosinski has signed on to share driving duties with three other students in a 2,400-mile road race — the North American Solar Challenge. "I forgot about the whole no-AC thing," Kosinski said.

It's hot driving the solar car in Arizona, and it'll be hot in Texas, where the race begins July 13. The team is hoping for some cool — but still sunny — weather up north.

This car won't go far on a cloudy day, and it must make it to Calgary, Alberta — 2,400 miles from the starting line — by July 22. And that can be done driving only in daylight, of course.

First, though, the team must put the car through its paces at a qualifying event in Cresson, Texas, next week.

Kosinski has been practicing her figure eights and her entry into the car's cockpit. She must complete her entry in 10 seconds and do it without touching the car's body, which is covered with gallium arsenide solar panels that would be damaged if she stepped on them.

"I stand on a bucket and just kind of jump in," she said.

Older, wiser members of the team have opted to do more technical work. Wei-Ren Ng, who calls himself "the only surviving member" of the team that entered the Drifter in its first American Solar Challenge in 2005, didn't use his seniority to demand a cockpit seat.

"I'd much rather sit in the air-conditioned van, watching the data," he said.

Ng said this revamped model of the 2005 car, dubbed Drifter 2.0, will out-perform the original, which didn't make enough qualifying laps.

The car had "lots of mechanical and some electrical bugs," that year, he said.

"This year, we're all set to go," said Ng, a recent UA graduate in electrical engineering.

The most important thing in driving a solar-powered car, said team member Oliver Stickroth, is balancing the demand on the battery with the need for speed.

The car can cruise at up to 70 mph but only by drawing heavily on a bank of lithium-ion batteries, said Stickroth, a senior studying materials science and engineering.

The Drifter 2.0 can putt along at 50 mph almost indefinitely while the sun is shining.

Its gallium arsenide panels are much more efficient than the silicon panels generally used in photovoltaic systems.

The trick is to use the battery to boost performance without draining it completely.

The panels have an efficiency of about 16 to 18 percent, greater than silicon, said Joseph Simmons, director of the University of Arizona's Arizona Research Institute for Solar Energy.

That still leaves more than 80 percent of the sunlight that hits the panels as a heat source, hence the need to trade drivers often.

"It's gonna be really hot," said driver Justin Gatz, a mechanical engineering student who described himself as a "walk-on" member of the team.

He saw the car on campus and signed up. "I like to drive, and I'm a supporter of any kind of alternative energy," he said.