Battery expert examines Tesla Roadster claims

Elon Musk raised some eyebrows when he announced that the new Tesla Roadster will do 0-60 in 1.9 seconds and have a range of 620 miles. That would make it not only by far the longest-range EV in existence, but also the quickest car ever produced. “These numbers sound unreal but they’re not,” said Musk.

Jalopnik’s David Tracy was a little skeptical, until he spoke with battery expert Venkat Viswanathan, a Mechanical Engineering Assistant Professor at Carnegie Mellon, who says that the 1.9-second figure actually seems reasonable.

The Roadster’s promised 200 kWh battery pack will be a key factor not only in enabling greater range, but also in delivering that world-beating acceleration. Viswanathan explains that the power output of a motor is limited by the power draw from each battery cell. Because the Roadster’s pack is double the size, the power draw may not be that much more than that of a Ludicrous Model S.

Weight is also an important factor. Viswanathan told Jalopnik that the most modern battery cells offer specific energy of about 240 watt-hours per kilogram. Using that assumption, a 200 kWh pack should weigh about 1,800 pounds, a huge advance over the previous-generation Roadster. With clever use of lightweight materials, the Roadster could still come out under the nearly two-ton curb weight of the Nissan GT-R, an acceleration benchmark among sports cars.

Viswanathan concludes that a 0-60 time of 1.9 seconds and a range of 620 miles are quite feasible, although there are several other factors that will come into play – much depends on the vehicle’s tires and aerodynamics.

 

Source: Jalopnik