HOW FAR CAN ELECTRIC CARS REALLY GO IN SUMMER?

We put 11 of the latest electric cars and one 258,000-mile Tesla - through their paces in the ultimate test of EV stamina

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Twice a year (in the height of summer and the depths of winter), we put a selection of electric vehicles (EVs) through a 'drive 'em until they die' endurance test. The aim? To find out how far they can really go on a full charge and how efficiently they use the electricity stored in their batteries.

Some of the cars lining up this August, such as the BMW i5, Cupra Born and Tesla Model 3, had taken part in previous tests - but there were plenty of newcomers, including the Audi Q6 e-tron, Mini Cooper SE and Volvo EX30.

And for those in the market for a used EV, or anyone concerned about the longevity of electric cars, we also included a nine-year-old Tesla Model S with a whopping 258,000 miles on the clock. Believe it or not, it's still on its original battery.

HOW WE DID IT

For obvious reasons, it wouldn't be safe to deliberately run EVs out of charge on the public road, which is why we conduct our electric car range tests at the Horiba-MIRA proving ground in Warkwickshire. We follow a simple test route of roughly 19 miles, which includes 2.7 miles of simulated stop-start urban driving, 5.5 miles at a steady 50mph and 11 miles at a constant 70mph. The rationale for the high percentage of high-speed cruising is that drivers who want to travel long distances in one hit are likely to be using the motorway network.

The 12 cars were charged to 100% and then left out in the open overnight, for roughly 14 hours, in 15-21deg C ambient conditions. The following morning, all of the cars were plugged in again to make sure they were fully charged, before the tyre pressure were checked, the climate control was set to 21deg C and the headlights were switched on.