Tesla Roadster

The Tesla Roadster is the first automobile to be produced by electric car firm Tesla Motors. Tesla claims prototypes have been able to accelerate from 0-60 mph (100 km/h) in about 4 seconds, and reach a top speed of 130 mph (210 km/h). Additionally, the car will be able to travel 250 miles (400 km) on a single charge of its lithium ion batteries.

While the Roadster does not actually use gasoline, an equivalent fuel efficiency of 135 mpg (57 km/l, or 1.75 l/100 km) can be calculated using energy equivalency.

The car was officially unveiled on July 19, 2006 in Santa Monica, California. By late August the company claimed that its first run of 100 cars, for delivery in 2007, had been completely sold.

The Roadster was developed in collaboration with Lotus and AC Propulsion. Roadster propulsion technology is principally matured from that seen in the tzero, Venturi Fetish, and Wrightspeed X1. Lotus supplied the basic chassis technology from its Lotus Elise. Tesla engineers designed a new chassis with this technology, lengthening it, lowering the door sills, and adjusting its strength to match the weight of the Tesla Roadster. Besides the chassis, the Roadster appears to share a number of key components with the Elise, such as the windshield, surround, and suspension components. The styling was penned by Barney Hatt at Lotus' design studio with significant input from Tesla. The car will be assembled at the Lotus factory in Hethel, England, with all drivetrain components and body components supplied to the factory by Tesla. 

Moniker

The Tesla Roadster is named after Nikola Tesla, an inventor, electrical engineer and scientist. Among other inventions, he developed three-phase electric motors like the one used in the Tesla Roadster.

Specifications

Motor

• Type: 3-phase, 4-pole electric motor
• Max net power: 185 kW (248 hp)
• Max rpm: 13,500
• Efficiency: 90% average, 80% at peak power

Transmission

• Type: Two-speed sequential manual

Performance

• 0-60 mph (0-100 km/h): approximately 4.0 s
• Top speed: 130 mph (210 km/h)
• Range: 250 miles (400 km) on the EPA highway cycle
• Fuel efficiency: 200 watt-hours per mile - the electrical equivalent of about 135 miles per gallon 

Battery

• 6,831 Lithium ion battery cells
• About 450 kg
• Full-charge time of three and a half hours
• ~50 kWh capacity

Fuel Efficiency

While the Roadster does not actually use gasoline, equivalent fuel efficiency can be calculated based on Tesla Motor's reported  motive efficiency of 110^Wh/_km and charging efficiency of 86%. Using the DOE's published energy content for a U.S. gallon of gasoline of 33705 ^Wh/_gal yields an equivalent fuel efficiency of:

For CAFE regulatory purposes, the DOE's full petroleum-equivalency equation uses a factor of 82,049 ^Wh/_gal and yields a regulatory fuel efficiency of:

For comparison, an internal combustion engine produces 7000 to 9000 Wh of output energy for each gallon of gasoline input. The state of tune and seasonal variations in gasoline formulation account for the output range. 

Pricing

Pricing for the base model Tesla Roadster has not been announced, although Tesla Motors CEO Martin Eberhard has speculated that it would "cost between US$85,000 and 120,000." Eberhard recently revealed that the price would be in the range of a Porsche 911 Carrera S, which has an suggested retail price of approximately US$80,000. In an August 2, 2006 blog post, Tesla Motors Chairman Elon Musk alluded to the "$89k price point of the Tesla Roadster". The web page describing a second run of 100 cars  states that these cars "will come fully loaded (as opposed to our base model) with all Tesla Roadster optional equipment" and that the price is "$100,000 (excluding taxes, title, etc)