The Corsa-e supermini has been given a 6% boost in range, taking its official WLTP range to 222 miles, up from 209.
The larger Mokka-e crossover, which uses the same 50kWh battery and 135bhp motor as the Corsa, gets a smaller 4% improvement, taking its single-charge range from 201 to 209 miles.
Vauxhall has achieved the improvements through changes to the cars’ heating and ventilation systems as well as to the propulsion system.
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The heat pump, which controls the interior temperature of the vehicles is now more efficient, with Vauxhall saying drivers will particularly notice the benefit in winter.
A new transmission reducer which sends the motor power to the wheels has also been developed to aid efficiency and new tyres with lower rolling resistance are also now standard fit.
The changes apply across the range of Corsa-e and Mokka-e, which are priced from £30,305 and £33,865 respectively.
Both cars also qualify for Vauxhall’s new Plug & Go offer. This includes a free home charging unit, eight years’ roadside assistance and battery warranty, a free six-month BP Pulse subscription and three years’ free servicing.