The official figures don’t tell the whole story, as with petrol and diesel cars – here’s what you can expect on the road from an EV battery.
It’s one of the biggest criticisms levelled at modern electric cars: yes, the official range figures look fine – but you’ll rarely get close to them in the real world.
In the years up to and beyond 2030, when the sale of brand new petrol and diesel cars will end, many more of us are going to have to get used to life with an electric car – and one of the incontrovertible facts of that life is that an EV will rarely travel as far on a charge as the figures say it will.
Why is that? What can we do about it? And what sort of range can one really expect to get before one runs out of charge? To answer these questions, we’ve combined our own experience of road testing cars with insight from an expert to give you the best idea of what to expect if you’re considering making the switch to battery power.
Why don’t electric cars go as far as it is claimed they will?
The answer lies in the official test. Currently, the range figures the manufacturers are allowed to publish are dictated by the WLTP, or World-harmonised Light vehicle Test Procedure. This is the same test used to calculate fuel economy for petrol and diesel cars and as is widely understood, it doesn’t fully replicate the sort of conditions you’ll encounter in the real world.
To put it another way, the discrepancy between the real-world range of your electric car and its official range figure occurs for the same reason there’s a difference between the fuel consumption you’ll achieve in your petrol or diesel car and its official fuel economy figure: while the latest WLTP test is more realistic than the old NEDC (New European Driving Cycle) economy test, it still doesn’t quite reflect real-world conditions accurately (more of which we’ll come onto).
With an electric car, that discrepancy is often more noticeable because a drop in range can make the difference between having to stop for a lengthy charge during your journey, or not.
But this isn’t the only reason. The other issue is that electric cars’ batteries perform better in warmer temperatures, and worse when it’s colder. So modern EVs have sophisticated battery heating and cooling systems to keep the battery operating at its optimum temperature. These systems drain energy themselves, though, so their usage still results in a drop in range.
Given that the WLTP tests are carried out at 23 degrees and 14 degrees, with the latter test factored into the former using a complex formula, it’s inevitable that the colder temperatures we usually see here in the UK in autumn, winter and spring will result in lower ranges than predicted in those official tests; there’s no escape even in summer, though, because batteries operate best in a fixed temperature range, so on the warmest of days extra energy must be expended cooling them.
What’s more, this effect is exacerbated in extremes of temperature because there’s an additional drain on the battery from the car’s electrical accessories. Heating elements and fans, heated seats, lights, and wipers will all reduce the car’s range further if they’re activated in cooler temperatures; likewise, air-conditioners working hard against the midday sun will reduce range in particularly hot weather.
Some of this effect, it should be noted, can be mitigated by preconditioning – which is to say, using an app or on-screen menus to tell the car in advance when you plan to leave, either manually or by setting a timer. That way, the car can heat or cool the battery and the car’s interior while it’s still plugged in, using power from the mains, which causes less of a drain on the battery than if it has to do so once it’s unplugged.
However, this requires one to plan ahead and precondition the car to get the best of it – something some drivers simply can’t or won’t remember to do.
How far will my electric car actually go?
This is where it becomes tricky. You see, because there are so many variables, it’s hard to predict. But Andrew English, the Telegraphs motoring correspondence, says his personal rule of thumb is to prepare for the worst – that way, his expectations will always be bettered.
“In cold weather, with the heaters going, at speed and going up and down hills, I always expect to halve the official range,” he says. “You probably won’t use quite that much, but it’s better to be pleasantly surprised if you don’t, then caught out if you run out early.”
And as English points out, it’s not just about whether you’ll get there – it’s about how many miles you’ll want to have available when you arrive. “If you want to get home again, you might need to get to a charger first, so you’ll want to have at least a few miles in reserve – not arrive on zero.”
In a test of the Kia EV6, a car whose WLTP range is 300 miles, English says he struggled to get more than 237 miles’ predicted range to show on the car’s dashboard display – 79 per cent of the WLTP figure
The key, then, is to build in a margin of error, and it’s here that cars with bigger batteries start to come into their own. For example, in a test of the Kia EV6, a car whose WLTP range is 300 miles, English says he struggled to get more than 237 miles’ predicted range to show on the car’s dashboard display – 79 per cent of the WLTP figure.
That figure, by the way, was with the radio, the passenger heater and all of the other accessories inside the car switched off – so the dent in the range came purely from the need to heat the battery on a cold day.
Meanwhile, our long-term test of an Audi e-tron Sportback, with its quoted range of 247 miles, actually achieved around 190 miles, or around 76 per cent of the official figure, before it slowed to a crawl.
These examples should give you a rough idea of what can be achieved, proportionately, in an EV in the midst of the British winter. In the summer, expect better results, but in all likelihood, you’ll only ever see the official WLTP range in ideal conditions.
Do manufacturers know how far their cars will really go?
A senior EV expert at a large car manufacturer agreed to speak to us on condition of anonymity on this, but he explained that, due to the variables mentioned above, it would be impossible to come up with an exact figure. But he did say that it’s possible to get a rough idea with a bit of delving into the data.
As he put it, the WLTP test is “better than the old NEDC, but still not exactly realistic”, pointing out that the test itself takes just 30 minutes, and the average speed attained is only 28.9mph.
This is split across low, medium, high and extra-high-speed testing, with average speeds of 11.7mph, 24.5mph, 35.2mph, and 57.2mph respectively, and because the test is set up to simulate real-world driving, with lots of speeding up and slowing down, it benefits electric vehicles, which are able to use regenerative braking to charge their batteries in such conditions.
As an aside, he did point out that the real-world range he gets from his electric company car regularly is around 78 per cent of the WLTP range – which, happily, is broadly in line with our findings based on our road tests mentioned above.
How do I know an EV’s full range before I buy it?
Don’t forget to look in more detail at the quoted range figures supplied by manufacturers. The headline range figure you’ll see most of the time is the WLTP Combined figure – which is to say an average based on the entire test.
However, also available to manufacturers (but not always published) are range figures based on the different components of the test. So, for example, EVs also have a WLTP Low range figure, which gives an estimate of the range based on low-speed usage, and a WLTP Extra High figure, which does the same for high-speed use.
With that in mind, our expert suggests that, if you plan to use your EV on a motorway regularly, you can try and find out its range based on the extra-high speed section of the test. Likewise, if you’re mostly going to be driving in urban areas, you can use the Low or Medium range figures to get a better idea of what the range will look like in your specific use.
If manufacturers don’t publish these figures, ask the salesperson. The more people who ask, the more likely it is that these figures will be published and therefore make it into the mainstream, which will make it easier for buyers to work out their real-world range in the future.
Our expert also suggests looking up facts and figures at the independent website EV Database. “I suspect they get their data from one of the sites that hold the EU’s Whole Vehicle Type Approval data, which contains the emissions data for all new vehicles,” he said.
“They caused some manufacturers a few issues early on as people were looking at their dataset and questioning the official figures they (legally) have to quote. In reality, though, the figures quoted by EV Database seem to be quite realistic.”
The truth about electric cars
Firstly, it’s important to keep in mind that the range figures manufacturers are obliged to publish by law aren’t necessarily indicative of real-world ranges, as the official tests used tend to flatter electric cars (although these figures are still useful for comparison purposes).
It’s worth remembering, too, that with heavy use, up and down hills, in cold weather, and with no pre-conditioning, an EV’s range can drop by as much as half, though that is probably a worst-case scenario.
Based on our experiences and road tests, a good rule of thumb is to expect to achieve somewhere between 75 and 80 per cent of a car’s WLTP Combined range in the real world – although this is by no means guaranteed, and will vary depending on a number of factors including ambient temperature, speed, terrain, and the amount of people on board.
However, before you buy, ask your dealer to give you not just the Combined range, but also the Low and Extra High figures, so that you can better judge how far the car will go on long journeys or around town, depending on where you think you’ll use it most.
