There are an estimated 456,000 pure electric cars on UK roads, and the number is growing rapidly. A survey found that 49 per cent of UK drivers looking to buy a car would choose electric.
Manufacturers are legally required to test all electric cars to the same official standard – the Worldwide Harmonized Light Vehicle Test Procedure (WLTP) and publish only these results.
But Which? said it believes the WLTP test “has a strong tendency to overstate the efficiency and subsequent range of electric vehicles (EVs), when compared to our own tests – and that figure can vary significantly”.
It said its own tests in labs and on tracks and roads are more rigorous than those of other organisations, with around 500 miles driven in each car.
In the tests carried out by Which?, medium-sized cars managed 151 miles compared with an average official WLTP range of 205 miles, while smaller cars managed 104 miles, compared with an average official range of 128 miles.
When it comes to individual models, the recently updated version of the Polestar 2 dual-motor managed 247 miles, 55 less than its official range.
Volkswagen’s ID 4 GTX (2021) managed 193 miles, compared with an official range of 300, while its e-Golf (2014 to 2020) managed 125 miles compared with an official range of 186.
But the BMW iX (2021) bucked the trend, managing two miles further than its official range of 380 miles. The Mercedes-Benz EQV (2020) also did relatively well, managing 202 miles against an official range of 213 miles, while the Audi E-Tron (2019) managed 227 miles against an official range of 241 miles.
Volkswagen said it was unable to comment on the figures as it had not yet seen the report. However, it said that WLTP figures may vary depending on the equipment fitted to each vehicle, while actual ranges would depend on driving style, speed and other factors. Polestar refused to comment.
BMW said: “The published range figures for BMW iX, and all cars sold in the UK, are based on the laboratory-based WLTP test and the real-world range will depend on many factors.”
Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders industry group, said: “The WLTP test is regulated by government authorities and it is these results – and only these results – that manufacturers are required by law to publish.
“There will, however, always be a difference between lab tests and real-world use as well as between official and non-official tests where the parameters and methodology may differ.”