Range test: How far can electric cars really go?

Twice a year (in the height of summer and the depths of winter), we put a selection of electric cars (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 we lined 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.

Read more: Complete list of real-world EV ranges

How we test real-world EV ranges

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.

Eco (or the closest equivalent) driving mode was selected, and the cars were left in their default regenerative braking setting – or if an ‘automatic’ or ‘adaptive’ mode was available, this was selected.

The cars were then driven repeatedly around our test route in convoy, with driver changes and a switch in running order at the end of each loop. It was a dry and mostly sunny day, although not especially warm; the temperature during testing ranged from 17deg C to 23deg.

The EVs with the shortest ranges

If you’re assuming that the quarter-of-a-million-mile Model S would grind to a halt within about 10 minutes on the road, prepare for a surprise: it wasn’t even the first to die. Nope, that dubious honour went to the new Mini Cooper SE, after 211 miles. On a more positive note, that’s almost twice as far as the previous-generation Mini Electric managed in our 2023 winter range test, and the Cooper SE proved the second most efficient car on test, averaging 4.3 miles per kilowatt hour (kWh).

Just a mile later, the Mini was joined at the side of the road by the Peugeot e-308 SW. This family-friendly estate may not have a brilliant range, but it did at least prove   efficient, averaging 4.2 miles/kWh. A minute or so later, after a total of 213 miles, the ageing Model S finally gave up the ghost. Our tests showed that its battery had lost around 13% of its original capacity – not bad at all, given that it has effectively been to the Moon and is on its way back. Mind you, the Model S was the least efficient car on test; it averaged 2.9 miles/kWh.

After that initial flurry of dropouts, almost 30 miles went by without any further drama, until the Volvo EX30 fell out of the running, after 242 miles. That’s a relatively disappointing 18% shy of its official range, and its 3.8 miles/kWh efficiency isn’t spectacular for such a small EV.

Two cars ground to a halt at 255 miles: the Hyundai Kona Electric and the Model 3. The latter edged it by a few hundred yards, and it’s important to note that this is the cheapest version of the Model 3 (£39,990), versus the most expensive Kona (£43,095). The former was also the most efficient car in the entire test, returning 4.4 miles/kWh, whereas the Kona posted a fair-to-middling 3.9 miles/kWh.

The most expensive of the dozen was next to die. Yes, the new Q6 e-tron is available in both cheaper and longer-range forms, but our £86k Launch Edition car fell a disappointing 16% short of its official range, at 289 miles. You could argue that’s still enough range for many buyers, but there’s no excuse for the Q6’s hugely disappointing efficiency of 3.0 miles/kWh.

The EVs with the longest ranges

Although the Born has featured in some of our previous range tests, this is the first time we’ve included the hot VZ version. It has more than 320bhp, for seriously nippy acceleration, and a bigger (79kWh) battery than other versions. Our car had the optional 20in Tornado wheels, which knock 31 miles off the official range – but it still kept going for an impressive 294 miles at an average of 3.7 miles/kWh.

The final five passed the 300-mile mark, proving that – in the summer at least – plenty of modern EVs can get you from London to Land’s End without you needing to stop for a top-up. One such car is the i5, which managed 310 miles and came closest of all to matching its official range (it was 8% adrift). This exact car took part in our winter range test back in February, where it managed a respectable 253 miles in much cooler weather and heavy rain.

Third place went to the seven-seat Kia EV9, the car with the biggest battery of the bunch. It finally died after an impressive 314 miles, although its brick-like silhouette meant efficiency was less remarkable (3.3 miles/kWh).

So, which of our remaining two contenders travelled the farthest? Well, there were only 11 miles in it, and both cars managed more than 320 miles. Aerodynamics won out, though, with the Renault Scenic E-Tech stopping after 322 miles and the sleeker Polestar 2 racking up 333 miles.

Both cars showed up some far more expensive machines, and the Polestar even proved surprisingly efficient by averaging 4.2 miles/kWh – a figure bettered only by the Model 3 and Mini. That’s testament to the overhaul Polestar gave the 2 last year, because when the Model 3 rival first went on sale, efficiency was actually a weakness of the car.

*Approximate secondhand value

Why EV efficiency matters

Only a few years ago, when electricity was dirt cheap and any EV cost far less to run than an equivalent petrol or diesel car, efficiency didn’t seem to matter that much. However, with energy prices high and due to rise further, it’s now a much bigger consideration, and you might be surprised to see how different the running costs can be between one electric car and another.

Take the Tesla Model 3 RWD, the most efficient of our 12 contenders. If you charge it up exclusively at home and pay 22.4p per kWh (the current electricity price cap), you’ll spend roughly £508 on electricity every 10,000 miles. Do all your charging at a typical public charger at, let’s say, 79p per kWh (Tesla Supercharger prices vary but are generally a bit cheaper), and that cost rockets to £1795.

Meanwhile, 10,000 miles in the new Audi Q6 e-tron costs £745 or £2633 respectively, based on the same charging costs. So, you could potentially be spending up to an extra £838 on electricity every 10,000 miles by choosing one EV over another.

True, many EV owners will opt to sign up to a tariff that offers cheaper overnight charging in return for slightly higher day rates. This reduces the overall cost of charging and, as a result, the difference between models. Nevertheless, efficiency is still an important factor that not all electric car buyers think about.

*Based on current energy price cap of 22.4p per kWh  **Based on Gridserve DC public charging cost of 79p per kWh

Are EV efficiency readouts reliable?

All modern EVs have a readout designed to tell you how efficiently the car is using electricity. Usually, this information is displayed on the instrument panel behind the steering wheel, or on the infotainment touchscreen – either in miles per kWh (miles/kWh), kWh per 100 miles or sometimes even Wh per mile. But how accurate are these figures, and should they be relied upon? Well, the short answer is: it depends.

We found that the efficiency readouts in six of our contenders – the Audi Q6, BMW i5, Cupra Born, Mini Cooper SE, Peugeot e-308 SW and Renault Scenic – were fairly accurate, reading within 3% of our calculations (dividing the range achieved on test by the usable battery capacity).

However, other models showed bigger discrepancies. The readout in the Model S – perhaps understandably, given the car’s age – was wildly optimistic about its energy usage, with the car claiming 3.4 miles/kWh when it actually averaged around 2.9 miles/kWh. That’s an error of more than 15%. The energy gauge in the Model 3 – a brand new car – was also on the optimistic side, by around 4%.

Mind you, the readouts in the Hyundai Kona Electric, Kia EV9, Polestar 2 and Volvo EX30 claimed they were delivering worse efficiency than they actually were, by between 5% and 8%.

*Estimated, based on testing 85.5kWh model when new  **Achieved test range divided by usable capacity of battery

For all the latest reviews, advice and new car deals, sign up to the What Car? newsletter here

Read more: What happens when an electric car runs out of charge? >>