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Take part nowElectric car battery degradation: fact or fiction?
There are plenty of reasons to switch to an electric car, but is the lifespan of their batteries something to worry about?
With a masters degree in automotive journalism, Dino has a forensic knowledge of the car industry and works closely with our lab to find the best (and worst) models.
Fear over how long the battery will last is a key reason why many drivers are reluctant to make the switch to an electric car.
In a recent report, research company Cox Automotive found that 60% of those who haven’t driven an electric car said that battery life was a concern.
But is battery degradation in electric vehicles (EVs) fact or fiction? To find out, we asked thousands of EV owners about the condition of their car’s battery.
Read on to discover what our latest research shows and whether you should be worried about electric car battery degradation.
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Do electric car batteries degrade?
Like all batteries, the cells that power an EV will degrade over time, but not as much as you might expect.
In fact, our latest survey suggests that battery degradation isn’t a significant issue in electric cars, even in models aged up to eight years old.
In the latest Which? car survey, we asked more than 4,000 EV owners who have had their car from new how much the range had dropped since they bought it. This year, we’re able to report on degradation figures for EVs first registered between 2018 and 2025.
| Year of registration | Average remaining range |
| 2024-25 | 97% |
| 2022-23 | 95% |
| 2020-21 | 95% |
2018-19 | 94% |
Source: Which? Car survey 2025, conducted April-June 2025. Based on 4,444 EV owners who bought their car brand new and self-reporting how much range the car has now versus when they first purchased it.
For EVs up to two years old, the average range was 97% of the original figure, with 66% of owners in this age group telling us that their car had suffered no drop in range.
Cars aged three-to-six years old had 95% on average of their original range. This dropped to 94% for cars between seven and eight years old; for an EV with a 250-mile range when new in 2018, this would leave you with a 235-mile range today.
Will the warranty protect you?
By law, EV manufacturers must provide a warranty for the main batteries that lasts a minimum of eight years or 100,000 miles, whichever comes sooner.
This offers some comfort, but other terms may apply, such as a specific threshold of range degradation to be met before the warranty kicks in, such as the battery dropping to 70% of its total original capacity.
Our data shows this doesn’t happen often, but a 30% drop in range is significant – that 250-mile range we quoted earlier would have to drop to 175 miles before the manufacturer deemed it faulty.
If you're buying a used electric car, it's worth checking the warranty that came with it when it was new and that the car has been maintained according to its service schedule.
Additionally, find out whether the current or previous owner has done anything to the car that could invalidate that warranty, such as making modifications.
If you're unsure whether the warranty is still valid, check with the manufacturer directly.
For more tips, see our guide to buying a used car.
How to look after your EV battery
EVs use a variety of battery materials and technology, all of which have different requirements in terms of how to best maintain them. It’s therefore worth following any instructions in your car’s manual to find the most relevant advice on how to look after your EV’s battery.
However, in general it's best to avoid regularly charging your EV above 80% or letting it fall below 20%, as this can stress the battery cells and cause them to degrade quicker. Regular use of ultra-rapid chargers can also put strain on the battery.
If your car has pre-heating technology, use it before driving on very cold days. The car's manual should contain information on how to do this.
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Expert opinion: good news overall, but still buyer beware
Dino Buratti, Which? researcher & writer
While the overall picture for EV battery degradation looks good, our figures are averages and there were some cases where drops in range were much more significant.
It's definitely worth asking about when buying used. Many dealers run tests on the battery when preparing cars for sale, but you can usually check battery condition yourself via the car's infotainment system. You might also want to consider a professional battery check from companies such as Clearwatt.
And while small percentage drops in range might not sound much, the actual range lost can be significant depending on the size of the battery. A 5% drop on a BMW iX xDrive50 (which has an official driving range of 380 miles) represents a 19 mile loss – roughly the same distance as driving from Leeds to Huddersfield. Meanwhile the same percentage drop on a Smart Fortwo EQ with a range of 80 miles would result in a loss of just 4 miles.
Looking to the future, there are promising signs for EV batteries. The vast majority of EVs currently on the road use lithium-ion or lithium-phosphate batteries, but batteries made of cheaper materials such as sodium are now being developed.
Solid-state batteries (which have a higher energy density than existing types of battery) have also been in development for several years and could be both cheaper and more efficient than existing EV batteries.
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