How is electric car range measured – and is it realistic?

YOU may have noticed that the battery range of electric cars quoted by makers has changed in some cases in recent years, and not always for the better. This is especially true of some plug-in models that were often rated as capable of 150mpg-plus, which was unrealistic and unattainable.

This is because the fuel economy of cars was previously tested via a typeapproval system called the New European Driving Cycle (NEDC), which was designed in the eighties. This was replaced in 2018 by the Worldwide harmonised Light vehicle Test Procedure (WLTP) and Real Driving Emissions (RDE). These testing regimes have brought in tougher and more realistic laboratory criteria for fuel economy, CO2 and NOx assessments.

WLTP has a more realistic drive cycle than NEDC, which lasted for just 20 minutes and a total of 11km (6.8 miles) with strict speed, gear and even temperature controls. Testers cover over twice the distance on the WLTP test to get an official economy figure, while the average speed of the test has risen to 29mph (from 21mph), with a maximum of 81mph attained (up from 75mph).

All new cars on sale now have their fuel economy and CO2 emissions or their battery range tested via WLTP, meaning drivers are more likely to be able to achieve their car’s stated figures. Bear in mind, though, that WLTP range figures for EVs are still often greater than what you’ll achieve in real life, where congestion, driving style and ambient temperatures also play a big part.

“Cold affects EV batteries because it slows the chemical reactions they rely on. This can cause a dramatic loss in range – but what’s left may still be enough for most drivers’ daily needs”

Richard Ingram Deputy editor