Tesla is promising impressive gains in range with a new upgrade package for its all-electric Roadster. Thanks to the advances made in battery technology since 2008, and some lessons learned when developing the Model S, the American brand says the Roadster 3.0 upgrade will deliver a range of 400 miles (644 km) on a single charge.

The main area of improvement will be in the car's battery pack. Whereas the original battery pack produced around 53 kWh, the new unit manages to squeeze 70 kWh out of the same size package. Telsa says this is because "cell technology has improved significantly" since the launch of Roadster in 2008, when it was the world's first car to be fitted with a lithium-ion battery pack.

The upgrade will also include a retrofitable aerodynamic body kit, which bring the Roadster's drag coefficient down from 0.36 Cd to 0.31 – a 15 percent improvement.

Rounding out the package are a set of tires that have about 20 percent less rolling-resistance than those on the original. More efficient wheel bearings and a reduction in residual brake drag also help to improve range.

To demonstrate the reworked Roadster's range, Tesla is planning on driving one non-stop from San Fransisco to Los Angeles in early 2015. Owners keen to get their hands on the upgrade, however, will have to wait for the battery to pass safety certification tests. Tesla expects to begin taking appointments around Q2 but has not yet announced pricing.

Source: Tesla Motors

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