The Model S, Tesla Motor's newest offering.

Tesla Motors unveiled its newest and cheapest electric car Thursday, cutting the price tag to $57,000 US from over $100,000, in a move that could transform the boutique California firm into a mainstream automaker.

The Model S prototype debuted amid much hubbub at a rocket factory in Southern California, the main market for its electric cars. Automobile Magazine has described the vehicle as a cross between an Aston Martin and a Maserati.

The Model S is powered by a massive lithium-ion battery pack composed of 8,000 individual cells. The pack, which uses the same technology found in laptop computers and cell phones, weighs about 454 kilograms and generates enough heat that it needs to be liquid-cooled. It's floor-mounted and takes up most of the car's rear half.

Jeremy Snyder, the Southern California general manager of Tesla Motors, compared the charging procedure to that of a mobile phone. All you need is an electrical cord that can plug into a normal household socket.

450-kilometre range claimed

According to the Tesla's website, the Model S costs about $4 to fully charge, and charging can take as little as 45 minutes, depending on the battery size. The smallest battery allows the car to go about 250 kilometres, while the largest can extend that range to 480 kilometres. The car doesn't have a clutch or gears and can reach a maximum speed of 200 km/h.

Tesla leaped into the headlines two years ago when it launched its critically acclaimed two-seater Roadster, which is built in England. About 300 Roadsters have been sold so far, despite their price tag of $109,000 US, and about 1,000 more customers are on a waiting list.

The firm got star power with customers like California Governor Arnold Schwarzenegger and Hollywood actors George Clooney and Dustin Hoffman. And in Los Angeles, Roadsters have reportedly replaced Ferraris and Lamborghinis as the new green status symbol.

Besides being bigger than the Roadster, the batteries in the Model-S have been improved in weight and performance, and feature more advanced cell chemistry in each cell.

The Model-S will be built in southern California where there's a glut of abandoned aircraft factories. Tesla hopes to build 20,000 per year by mid-2012, according to a report in the Los Angeles Times.

Tesla is competing with several other companies to deliver the first mass-produced electric or plug-in electric car to consumers. GM plans to begin selling its plug-in hybrid Volt in late 2010, and Fisker Automotive Inc. of Irvine, Ca., is expected to launch its Karma sedan early next year. That car will be built in Finland.