California start-up carmaker Tesla Motors says its upcoming electric premium sedan will have a range of up to 300 miles (483 km).

This set of spy shots shows the upcoming 2012 Tesla Model S doing some hot-weather testing in Death Valley, USA.

The premium 4-door electric sedan looks like it is still deep in development, given all that gear we spot inside the cabin of this prototype. But Tesla has previously said the Model S is due in mid-2012 and that is still a year from now.

The California start-up says the Model S's top variant, the 300M, will have a range of 300 miles (483 km) on a single charge. Power is supplied by a 42 kWh lithium-ion battery driving an electric motor that enables the Model S to accelerate from 0-60 mph (96 km/h) in 5.6 seconds and hit a top speed of 125 mph (201 km/h).

Be part of something big