Range test: How far can electric cars go in winter?

Twice a year, in the height of summer and the depths of winter, we put a selection of electric cars 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 winter, such as the Mercedes EQE and MG 4, have taken part in previous tests – but there are plenty of newcomers, too, including the BYD Seal, Jeep Avenger and heavily updated Tesla Model 3. We’re also including two examples of the Volkswagen ID 7 – one with an optional heat pump and one without – to find out if it’s really worth paying extra for this energy-saving feature.

How we did it

For obvious reasons, it wouldn’t be safe (or potentially even legal) to deliberately run our electric vehicles (EVs) out of charge on the public road. That’s why we use a test centre in Bedfordshire.

We follow a relatively simple test route of roughly 15 miles, which includes 2.6 miles of simulated stop-start urban driving, four miles at a steady 50mph and eight 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 6-10deg C ambient conditions. The following morning they were plugged in again to check they were fully charged, plus we made sure their tyre pressures were correct, set the climate control systems to 21deg and switched the headlights to dipped beam.

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 lap. It was a relatively windy day with plenty of rain and standing water on the road, and the temperature during testing ranged from 10-11deg C.

The winners and losers

Shockingly, it was one of the most expensive cars in the line-up that ground to a halt first. The trip computer in the £74,000 Lexus RZ was showing a remaining range of zero after just 136 miles, and although the car kept going for 21 miles after that, the last three or so were at jogging pace. A total range of 157 miles can only go down as a huge disappointment, as did the RZ’s worst-in-test efficiency figure of 2.5 miles per kWh.

The Jeep Avenger ran out of charge next, after 163 miles. It has the excuse that it costs roughly half as much as the RZ to buy and has the shortest official range of the dozen, but it’s hardly cheap at £38,700, and a real-world efficiency figure of 3.2 miles/kWh is nothing to write home about.

Another Lexus, the UX 300e, was third to drop out, after 170 miles, and actually fell farthest (37.9%) short of its official (WLTP) range. Efficiency of 2.7 miles/kWh was also the second worst of the dozen, after the RZ.

The UX’s limited range is even more of a concern when you consider that, despite costing £57,095 in the form tested here, it’s the only one of our contenders that uses an old-fashioned CHAdeMO connector to rapid charge. Not that many people would describe waiting almost 1hr 30min for a 10-80% top-up as particularly ‘rapid’ (the UX can accept a maximum charging rate of just 50kW).

Next to fall out of the running, after 188 miles, was the BYD Dolphin. Okay, that isn’t a particularly long range by modern electric car standards, but given the Dophin’s small footprint (it’s about the size of a BMW 1 Series) and urban intentions, it’s likely to be more than enough for most potential buyers. Plus, it’s the cheapest car here, at £31,695. Our only real gripe was efficiency of 3.1 miles/kWh.

Our remaining eight contenders all managed at least another 39 miles, before the MG 4 finally gave up the ghost after 227 miles. We’ve featured MG 4s in our range tests before, but this is the first time we’ve included the Extended Range, which has a bigger battery than other versions. That’s an impressive range for a sub-£37k EV, even if most buyers will be better served by cheaper, more efficient versions (our favourite is the £26,995 SE).

Next to drop out, five miles later, was the Volvo XC40 Recharge. This is the recently updated version of Volvo’s electric SUV, which has a bigger battery than before (with a 79kWh usable capacity) and two motors to give it rapid acceleration. While the range is respectable, a test efficiency of 2.9 miles/kWh definitely isn’t.

Not that efficiency was all that brilliant in the new BMW i5 either, because it managed 3.1 miles/kWh. You might also expect a better winter range than 253 miles, given the near-£80k asking price, although the i5 did get relatively close to its official range, falling 25.1% short.

The ID 7 without the heat pump dropped out just one mile later and, considering that it’s almost five metres long, returned respectable efficiency of 3.3 miles/kWh.

Another mile later, the new BYD Seal finally fell out of the running. Beating far more expensive electric executive cars, such as the i5 and ID 7, is no mean feat, although the Seal is smaller than those models, so efficiency of 3.1 miles/kWh is a little disappointing.

So, which of our remaining two contenders travelled the farthest? Well, there was only a distance of seven miles in it, but sheer battery size eventually won the day, with the Model 3 Long Range grinding to a halt after 293 miles and the EQE racking up 300 miles exactly.

However, when you consider that the EQE has a 19% larger battery, costs nearly £20,000 more to buy and takes longer to charge up, such a small margin of victory perhaps isn’t so spectacular. The Model 3 was also, by a country mile, the most efficient user of electricity here, averaging 3.9 miles/kWh to the EQE's 3.4 miles/kWh.

Why efficiency matters

A few years ago, when electricity prices were 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 electricity prices close to an all-time high, especially if you’re using the public charging network, it’s now a far bigger consideration – and you might be surprised by the difference in running costs between different EVs.

Take the Model 3 Long Range, the most efficient of our 12 cars. If you were to charge it up exclusively at home at a cost of 29p per kWh, you’d spend roughly £742 on electricity for every 10,000 miles of winter driving. Do all your charging at a typical public charger at, let’s say, 79p per kWh (Tesla Supercharger prices vary but are a bit cheaper than that) and that cost rockets to £2021.

Meanwhile, 10,000 miles in the RZ would cost £1168 or £3183 respectively, based on those same kWh prices. So, you could potentially be saving £1162 on electricity every 10,000 miles by choosing an efficient EV over a ‘thirsty’ one.

Okay, those cars aren’t direct rivals, but even if you compare the Model 3 with the Seal, the Tesla would cost you £197 less if you did all your charging at home and £536 less if you were paying 79p/kWh at a public charging station.

True, many EV owners will opt to sign up to a electricity tariff that offers cheaper overnight charging in return for slightly higher day rates. This would reduce the overall cost of charging and, as a result, the cost difference between models. Nevertheless, it’s still an important factor that not all buyers consider when choosing a new EV.

2024 winter range test results

*Based on current energy price cap of 29p per kWh

How accurate are efficiency metres in cars

All modern EVs have meters 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, 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 the efficiency meters in four of our contenders (the BMW i5, Jeep Avenger, MG 4 and Tesla Model 3) were pretty much spot on, with the readings matching the calculation of the achieved range divided by the usable battery size.

However, there were also some big discrepancies. The two BYDs were wildly optimistic about their energy usage, with the Dolphin claiming 3.9 miles/kWh when it actually averaged just 3.1 miles/kWh – an error of more than 20%. The energy gauges in the two Volkswagen ID 7s were also on the optimistic side, albeit by a much smaller degree. Mind you, the two Lexuses, the EQE and the XC40 claimed they were delivering worse efficiency than they actually were.

Is it worth spending extra for a heat pump?

Heat pumps are capable of transferring heat from the ambient air to the car’s interior, and they can also recycle unwanted heat produced by the high-voltage battery. Some electric cars come with this energy-saving feature as standard, but in many cases you have to pay extra – often quite a lot extra.

So, is a heat pump worth the money? We used our two Volkswagen ID 7s for a direct comparison. The two cars were near-enough identical, in the same trim and with the same wheels and tyres fitted. The only difference was that the model with the £1050 heat pump also had an optional panoramic glass roof fitted.

Unsurprisingly, the addition of the heat pump did improve efficiency, and by a significant 5.2% (from 3.3 to 3.5 miles/kWh). That meant we were able to cover an extra 14 miles in our range test, the ID 7 with the heat pump eventually dying after 268 miles.

The trouble is, even if you’re using the public charging network and paying, say, 79p for every kWh of electricity, you’ll need to do a massive 85,000 miles before you’ve recouped the cost of the heat pump in electricity savings. And if you’re charging at home, you’ll have to cover considerably more miles again.

How weather affects electric car range

It’s a well-known fact that cold weather is bad for batteries, and the range and efficiency of electric cars plummet in winter. But how big a difference does it actually make?

Well, last year we tested the BMW i4, Cupra Born and Tesla Model Y in both summer and winter conditions. The only notable difference was that the i4 we used in the summer had 20in wheels, while the winter test car had 19in ones.

In the cold-weather test, the three models fell an average of 18% short of the distance they achieved in summer, when temperatures ranged from 24 to 29deg C.

The Model Y range fell the least: it ran out of juice 32 miles earlier in winter. The Born’s range fell by 37 miles in the cold, while the i4 gave out 56 miles earlier than in summer.

In other words, if you’re planning a long journey by electric car, it pays to check the weather forecast.

Summer results vs winter results

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