A range extender, in the context of an electric vehicle (EV) is a small auxiliary power unit within the vehicle. This is usually a small petrol engine that generates power to charge the battery, which when drives the wheels. Unlike a self-charging hybrid which uses a petrol engine to drive the wheels as well as an electric battery.
Is it another form of green washing?
There has been criticism over some car manufacturers who ‘green washing’ when advertising a new self-charging hybrid vehicle. The self-charging hybrid cars use both an electric motor and petrol or diesel engine to drive the wheels. Energy is recovered when the car is breaking and by the engine, when efficient to do so. Range extenders in EV’s don’t seem to receive the same backlash as self-charging hybrids. This may be due to the fact the small petrol engines doesn’t drive the wheels and only re-charges the electric battery.

What cars use range extenders?
There are only 2 cars in the UK that use range extenders. The BMW i3 was initially launched with a range extender option (BMW i3 REX) and Vauxhall Ampera E-REV. In the BMW the range extending motor gives you almost 50% more range (93 miles), so a worthwhile feature on longer journeys. There are currently no new vehicles in the UK that use range extenders. However, taxis, vans and some trucks will be available in the UK market soon.
Why don’t more EV’s have range extenders?
Range extenders have become mostly redundant due to development in battery technology and the UK charging infrastructure. The range anxiety sometimes associated with early EV’s has been reduced as EV ranges increase and more manufacturers releasing long-range electric cars. For vehicles with a range extender, it needs to be re-fuelled at a petrol station and recharged at home or a public charging point.
Would you buy an EV with a range extender or do you think it’s a redundant technology?