At what speed do hybrid cars switch from battery power to petrol power?

Asked by: Julie Blakemore, Hereford

In a hybrid car, electric motors are used most when they're travelling at slower speeds around town. Petrol is more efficient at high speed, so the conventional engine is in charge on the motorway.

For much of the time, however, the engine and electric motors run together with the car's power control unit, varying the relative amount of drive from each. So there's no set point where electric power switches off and petrol kicks in.

Read more:

• If every petrol or diesel car in the UK was replaced with an electric car, how many charging points would we need?
• Could dynamos be installed in electric cars to provide a perpetual source of power?

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