How the Tesla Roadster Works

The heart of the Tesla Roadster is its 3-phase, 4-pole electric induction motor, which weighs just 70 pounds. Tesla's claims and independent testing show that the Roadster can reach 60 mph in about four seconds and its speed will top out somewhere around 130 mph. But the Roadster's performance isn't just about speed and acceleration. The unique properties of an electric motor give it a huge advantage over a combustion engine in terms of torque, force that tends to rotate or turn things, and power band, the range of operating speeds under which the engine operates efficiently. The Roadster can generate large amounts of torque even at very low RPM, and the motor can always turn out major horsepower. It can reach over 13,000 RPM, something very few large combustion engines can do. The Tesla Web site includes the following: "A favorite trick here at Tesla Motors is to invite a passenger along and ask him to turn on the radio. At the precise moment we ask, we accelerate. Our passenger simply can't sit forward enough to reach the dials" [ref].

That kind of motor response eliminates the need for a complicated transmission, so the Roadster has just three gears -- two forward gears and one reverse gear. Shifting is manual, but there's no clutch. That also means there's no stalling or "jerk" when you shift between gears.

The Tesla Roadster can go a lot faster than previous electric cars, but perhaps more importantly, it can go a lot farther. The Roadster's estimated range is 250 miles on a single charge, at least 100 miles more than General Motors' EV1, which could go almost 150 miles under optimal conditions.

Most of the hype surrounding the Roadster is about its status as an electric vehicle. But while earlier electric cars tended to be cramped and lacking in features, the Tesla Roadster looks and feels like a sports car. In addition to basics like heated seats, a stereo with CD player, ABS brakes and dual airbags, the Roadster has a few unique features:

Since it's a convertible, the Roadster comes standard with a soft top. Options include a hard top as well as features like a full leather interior and a satellite navigation system.

The Tesla Roadster and the Tesla company have an unusual history. The company has almost no connection to the traditional American auto industry, and its founder had no experience in the auto industry when he decided to create the world's first high-performance electric car. Martin Eberhard and his business partner Marc Tarpenning founded a company based on a portable eBook reader. Frustrated at the mainstream auto industry's inability to create an effective electric car that had mass appeal (he often refers to early electric cars as "punishment cars"), Eberhard decided to create one himself.

Instead of creating an entire car and all its systems from scratch, Eberhard took advantage of outsourcing, which made the various elements easy to acquire. After netting $60 million in investment funds, (including over $30 million from Elon Musk, co-founder of PayPal), the new company chose a design from England-based Lotus.

The Tesla-Lotus partnership works well for several reasons. Lotus' Hethel, England facility is well suited to producing cars in small runs. This allows Tesla to basically manufacture cars to order, rather than building thousands and spending money to warehouse the overstock. Also, the Tesla Roadster is based on the Lotus Elise -- they look superficially similar and have the same basic chassis (though the Roadster's chassis is heavily modified) and other parts. This added to the savings. While most of the Roadster's parts and systems, such as the stereo, the brakes and the battery chargers are off-the-shelf, final assembly happens at Lotus facilities.

Are Electric Cars Finally the Next Big Thing?

Tesla's business plan recognizes that innovative technology is often very expensive and that the very rich are usually the first people to adopt it. Once prices come down, the technology can move down into the market. That's why Tesla's first car is a high-end sports car only made in limited numbers. However, Tesla has set its sights on a 2008 release of a four-door electric sedan (codenamed White Star). The Roadster seems to be a success within its limited production numbers -- the first 100 limited edition "Signature Series" Roadsters sold out, and the next run of 100 is ready for pre-orders. A fully-loaded Roadster will cost $100,000, with a $75,000 down payment required to reserve one.

Electric cars will probably always be more expensive than cars that use combustion engines. The savings comes when you look at its the fuel costs and environmental impact. An electric car has zero emissions and doesn't add to pollution. Driving an electric car a mile costs a fraction of what it costs to drive a gas-powered car a mile. Critics rightly point out that the energy to power an electric car still comes from somewhere -- in this case, a power plant that provides energy to the electrical grid. Shifting the source of the energy from oil to coal doesn't necessarily make it any cleaner.

Tesla and other electric car proponents respond that electric cars are more efficient for several reasons. First, generating power at a power plant, even a coal power plant, is more efficient and creates less pollution than millions of small combustion engines creating the power. Plus, some of our electricity comes from cleaner power plants like hydroelectric plants, wind farms and solar cells.

In an interview with Wired.com, Eberhard claimed that the energy in a gallon of gasoline could drive an electric car 110 miles. Comparing average gas prices and electricity prices, the Roadster could go 150 miles for the price of one gallon of gas. Tesla reports twice the efficiency of even the greenest hybrid cars.

For lots more information on the Tesla Roadster, Tesla Motors, electric cars and related topics, check out the links on the next page.