March 31st, 2007

Let's Clear the Air

Tesla Roadster Puts Spark Back into Electric Vehicle Driving

by NAFTC National Instructor Scott Martin and NAFTC student worker Andrew Schmidt

“Burn rubber, not gasoline.” That is the motto of a new all-electric, high-performance sports car that has been taking the electric vehicle (EV) world by storm. A concept version of the Tesla Roadster, a two-seat lithium-ion-powered car, was unveiled last summer, and production models will be delivered this summer. Orders for the first one hundred models, known as the “Signature One Hundred,” sold out in three weeks. More than one hundred more have since been ordered. The list of customers includes many Hollywood celebrities, and thirty prototypes were used to transport stars to the Academy Awards this year.

The new all-electric Tesla Roadster

The new all-electric Tesla Roadster has a range of 250 miles on a single charge and is capable of going 0-60mph in under four seconds. Tesla Motors

The Roadster’s aluminum chassis and body is built by Lotus in Hethel, England. The basic design is based on the Lotus Elise, with only minor modifications made to the chassis. The base price of the vehicle is $92,000, and adding options to the vehicle can put the price tag over $100,000. Tesla’s next model, the WhiteStar, will be a four-door, high-performance, all-electric sedan that costs around $50,000. The WhiteStar will be built at a new facility in Albuquerque, New Mexico. As all-electric vehicle technology grows in popularity, prices for these vehicles will likely decrease. Javlon Electric Motor Corp., a division of Miles Automotive Group, has recently announced their future all-electric XS and XM models, the XS500 and XM200, which will have the ability to travel more than 150 miles on a single charge at a top speed of 80 mph. Javlon Electric Motor estimates purchase price for these vehicles to be $29,000-$31,800 and will be on the market by the end of 2008.

The battery system in the Roadster consists of 6,831 lithium-ion batteries that are roughly the size of an AA battery. The battery pack stores 56 kWh of energy and can generate more than 200 kW of electricity, which is capable of accelerating the car from 0-60 mph in under four seconds. Although the battery pack weighs almost 900 pounds, its weight can be more evenly distributed throughout the car than could a gasoline engine.

Tesla being recharged

Three hours is the time it takes to recharge the Roadster’s battery pack, which can be recharged about 500 times over its lifetime. Tesla Motors

The Roadster’s motor is a three-phase AC induction motor that generates 250 horsepower and is 90 percent efficient. When compared to the amount of energy in a gallon of gasoline, the Roadster gets the equivalent of 135 miles per gallon. Because the motor’s maximum rpm is 13,500, Tesla decided to put in a two-speed sequential transmission. Shifting is manually controlled, but does not require a clutch. In second gear, the vehicle can reach top speeds of 130 mph.

Regenerative braking is used to maximize the range of the vehicle, which is estimated to be about 250 miles. The time to recharge the battery pack is three hours, and it can be recharged about 500 times over its lifetime. This results in a lifetime use of more than 100,000 miles.

Environmental concerns are one of the main reasons that Tesla’s founders decided to launch their business. Customers are encouraged to use alternative energy sources to recharge their vehicles. The company may also offer an optional solar panel array to be placed on your home that could generate enough electricity to drive the car fifty miles each day.

The Tesla Roadster proves that all-electric cars do not have to be slow and boring. By using lithium-ion batteries, an acceptable range of 250 miles can be achieved, which would meet the needs of most drivers. The Roadster also provides a way for Tesla to prove its technology and generate enough money to invest in models that have more affordable price tags. Although all-electric vehicles have been around for more than one hundred years, their real future may have just begun.

Tesla Motors was started in 2003 by two engineers, Martin Eberhard and Marc Tarpenning, from Silicon Valley. Their primary investor was Elon Musk, the co-founder of PayPal. Tesla Motors has its corporate headquarters in San Carlos, California, and its Research and Development center in Rochester Hills, Michigan.

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