Revealed: the truth about the autonomy of electric cars

It’s a problem that drivers of gasoline and diesel cars will be well aware of: a car’s advertised fuel economy is much better than what it actually ends up getting. This same problem exists for electric cars.

If you’re looking for an electric car, its range (how far the car can go between charges) is likely to be one of the first things you look at. This is especially true if you don’t have the ability to charge at home.

The claimed range from official WLTP (Worldwide Harmonized Light Vehicle Test Procedure) tests may look appealing on the showroom floor, with some models now claiming over 400 miles between charges.

But in our tests, we found that the actual range of an electric car is, on average, 18% less than the official figure. That means an electric car with a claimed range of 240 miles (the average WLTP claimed range of cars we’ve tested since 2017) is more likely to offer a maximum range of around 196 miles.

Some cars are significantly worse. When we originally tested the ‘long range’ twin motor version of the pole star 2, it had a claimed WLTP range of 298 miles, but delivered just 183 miles in our tests. That’s a colossal loss of 115 miles (39%) of range compared to the official claim.

Since then Polestar has released updates over the air and greatly improved the range of the car. After re-testing the same car, we found that its tested range is now a much better 247 miles, but still far from the official (also increased) range of 302 miles (18% less than claimed, making the car be in line with the average electric car).

The current BMW iX (2021-) however, it bucks the trend. Our tests on the xDrive50 version of the iX show that it can travel a 382 mile record before running out of juice, that’s two miles more than the official WLTP figure.

Ready to go electric? Discover the The best electric cars for 2022

revealed: the truth about the autonomy of electric cars

The best and worst cars in the delivery of its WLTP range

The autonomy of an electric car is mainly based on the capacity of its battery and the efficiency of that car. It is also influenced by factors such as weather (batteries don’t like it cold), driving style and speed. You’ll get less range miles on the highway compared to driving around town.

Since 2017, the official range tests carried out by the manufacturers use the WLTP cycle. This replaced an old test cycle called NEDC and is a much better evaluation. But while regular gasoline and diesel cars now have more realistic fuel economy figures, we’ve found that the WLTP cycle has a strong tendency to overstate the efficiency and subsequent range of electric vehicles (EVs), compared to our own. own tests, and that figure can vary significantly.

Taking the pre-updated pole star 2 as an example, the twin-motor version could currently make the biggest difference between the official range (298 miles) and the range in our tests (183 miles). But the single-engine version of the same car is significantly better.

With a single engine, the Polestar 2 has an official WLTP range of 335 miles and delivered an impressive 298 miles in our tests (that’s just 11% less than claimed) – it’s a fantastically usable car in this regard. On paper, the claimed ranges are less than 40 miles apart, but the range we got in our tests differs by more than 100 miles.

With used car prices rising, your car may be worth more than you think. We reveal the best ways to sell a car.

Differences like this highlight why our independent lab tests are so important. Our tests are tough, realistic and comparable. All electric cars we receive go through the same tests under the same conditions and include a mix of simulated city to highway driving. You’ll find the proven range of each electric car we’ve tested in our reviews.

The last time we updated our test program was in 2017. All figures in this story are from the 60 electric cars we tested in the current program.

The three cars that came closest to their official ranks in Which? tests:

And the three worst:

Range is just one aspect to consider when buying an electric car. Find out what else you need to know by listening to our Which? Short podcasts.

What you can expect from the different classes of electric cars

The size of the battery not only affects the range, it also has a great influence on the cost of the car.

While there are exceptions, you’ll usually find larger batteries in larger, more expensive cars combined with enticingly long claimed ranges.

This table shows the different classes of electric cars we’ve tested, their claimed and tested average range, and the differences.

*Typically hatchbacks

Which? Auto expert Adrian Porter says: ‘This is not an unknown problem. Leasing companies and even some car manufacturers will publish more realistic range figures in addition to the claimed WLTP range to give their customers a better idea of ​​how far they will actually travel between charges.

‘The WLTP has improved the accuracy of gasoline and diesel fuel economy. But when it comes to electric and plug-in hybrid cars, a more precise official methodology for measuring car efficiency and subsequent maximum range would be welcome, ideally with estimates of how that figure varies across different roads and temperatures.’

You can find out how we want to shape electric car charging by reading our article on build electric vehicle charging infrastructure that is fit for the future.

Drive smarter and cut costs with advice from our experts. Receive our Cars newsletter – it’s free monthly

Leave a comment

Stay up to date

Register now to get updates on promotions and coupons

Shopping cart