General Motors Europe says initial testing of its range-extender Ampera electric car has thrown up the need to address petrol sitting for long periods in the tank.

In the Ampera, a 1.4-litre petrol engine takes over the running of the electric motor when the battery runs out of charge, an ability that Opel says eliminates so-called ‘range anxiety’ and allowing for several hundred miles of driving.

However, operational testing of the Ampera – or VOLT in the US – has shown the need to address gasoline that is unused.

“There are people who have had these cars for testing purposes and they never [or] hardly ever put new petrol in,” president GM Europe Nick Reilly told just-auto. “That has interestingly posed a problem which we never anticipated.

“Which is how long can you have petrol in the tank and in the engine sitting there, if you don’t do anything for six months? Is the petrol the right quality? So we have put in a [measure] that says if this engine is not turned over for two months, it starts up.”

Reilly added Opel was “pretty satisfied” with commitments from various European governments to subsidise initial purchases of electric vehicles. Opel has previously noted the Ampera will retail at EUR42,900 (US$60,300).

“It [subsidy] is peanuts to them for the number of electric cars on the road so it is helping a bit of momentum,” said Reilly.

“It is quite [an] expensive car but we have sold out 80% of next year’s production already. For some fleet buyers it is perfect.”

The Opel chairman conceded the manufacturer would not make any return on first generation Amperas, but was looking to become financially viable with the second generation models as battery costs potentially drop by up to 50%.

Reilly remained tight-lipped as to any future location of European production for the Ampera – although he noted Ellesmere Port in the UK,widely touted as a possible site – would “certainly be a candidate”.