Opel has begun testing two development cars of the Ampera extended-range electric vehicle (E-REV) on its Dudenhofen proving ground, keeping the revolutionary four-seater on schedule for a late 2011 production date.

Engineers have installed the Ampera’s revolutionary Voltec electric propulsion system – including the battery, motor, engine and electric-generator – inside the body of an existing production car. They call this kind of a development car a mule because, like their namesake animals, the mules are a mixture of two species. Mule cars help engineers test technology at an early stage of vehicle development.

The five-door, four-seat Opel Ampera uses the groundbreaking electric propulsion technology called Voltec, which operates differently from other advanced propulsion systems, like a hybrid. The Voltec electric propulsion system uses electricity as its primary power source. A petrol engine-generator as a secondary power source generates electricity when the battery is depleted to ensure a seamless and continuous drive.

Unlike a conventional battery-electric vehicle, the Ampera eliminates “range anxiety”, giving the confidence and peace of mind that a depleted battery will not strand the driver.

When the battery’s energy is low, electricity from an on-board engine-generator extends the Ampera’s range to more than 500 km. A petrol/E85-fueled engine-generator seamlessly provides electricity to power the electric drive unit while simultaneously sustaining the charge of the battery. This mode of operation extends the range to 500 kilometres until the battery can be re-charged by plugging the vehicle’s on-board charge system into a standard household 230v outlet.

Opel estimates that an electrically driven kilometre in the Ampera will cost about one-fifth compared to a conventional petrol vehicle at current fuel prices.

The Ampera can be plugged into any household 230v outlet and re-charged in about three hours. Opel is analysing the requirements for standardization and a recharging infrastructure for plug-in electric cars with energy companies, including Iberdrola of Spain.