June 6, 2007 11:40 AM PDT

An electric Porsche at MIT

by Michael Kanellos

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A group of MIT students have retrofitted a Porsche 914 with batteries in an effort to show that electric cars could be viable in the near future.

The students, led by senior Emmanuel Sin, removed the gas engine from the car and replaced it with an electric motor. The motor runs on 12 lithium-ion batteries from Valence Technologies, one of a group of companies trying to bring lithium-ion batteries to cars. Lithium-ion batteries can hold more energy than lead acid batteries, but they can be dangerous. Remember those exploding notebooks?

Sin (second from left) and students installing batteries.

(Credit: MIT)

The students hope to conduct a number of tests and test drives in the next few weeks. According to their estimates, the car should have a top speed of 70 to 100 mph and it will run 100 miles before needing a recharge. It will take about four to five hours to recharge the batteries in full. The car, being electric, won't emit fumes from the tailpipe.

Those figures above underscore the promise and peril of electric cars. Electric cars will generally emit far fewer greenhouse gases than regular cars, even when fumes from the power plant that provides electricity to recharge them is factored in. And they can be quite zippy.

But a range of 100 miles is problematic--not many Americans buy cars that can't get them too far out of town. If you had to leave San Francisco to do a quick meeting in San Jose, Calif., you might not make it back.

Then there is the charge time. If an owner wants to go away on a weekend, who wants to double the travel time with a four-hour charge? (However, the 100 mph maximum is probably acceptable to most drivers.)

Batteries are also expensive. Even advocates of plug-in hybrids say that you can't currently justify putting more batteries in your Prius by claiming you'll save money on gas. You'd have to drive several thousand miles before hitting breakeven. The batteries to convert a car like a Honda Accord might run $30,000, Ian Wright, designer of the X-1 electric sports car, has estimated. Still, battery advocates say prices will decline.

The Porsche, by the way, was donated by Yang Shao-Horn, a professor of mechanical engineering at MIT and a specialist on advanced batteries. She and her husband bought it on eBay.

Originally posted at News Blog