Exactly how quickly EV batteries degrade revealed in shocking new study

A survey has revealed how quickly an electric vehicle's battery can decline over a seven-year period.

At the beginning of 2025, Elon Musk's Tesla reported a decline in sales for the first time in over a decade - with some speculating that his endorsement of the far right and President Donald Trump.

But it's not just Musk's electric vehicles, as other electric cars are also facing scrutiny with potential buyers questioning just how well their batteries last - after all, we've all seen how quickly our phone battery can dip over time.

The survey

Which? conducted a survey after noticing it's a 'common worry among people that are looking to buy their first electric car' about how quickly the battery life will degrade over time.

The company surveyed 3,595 owners of electric vehicles who purchased their vehicle over the past seven years asking how much their battery has decreased since they first bought it, Mail Online exclusively reports.

Owners of electric cars who bought them seven years ago - around 2017 or 2018, yup, feel old yet? - saw the battery percentage dropped to around 93 percent from a starting point of 100.

"So, if your car's range when new was 180 miles (around the average for all EVS we've tested), you could expect this to drop to 167 miles," Which? explained.

If the electric car owner bought their car in around 2019 or 2020 - four to five years ago - their car's battery had dropped to 96 percent. And those with electric cars purchased in 2021 until last year reported their battery reading around 97 percent.

Which? noted: "The average annual mileage for all EV respondents in our survey was 6,001 miles, so if you drive fewer miles than that in a year, you may see better figures."

But what impacts your battery's lifespan?

The study looked into how quickly the battery lifespan drops (Getty Stock Images)

What impacts your battery health?

Which? revealed how many times you charge your car affects your battery's health, alongside factors such as weather and the strength of the charger too.

In cold weather, the company noted some cars can lose 'as much as 40 of their range' and cars also 'charge more slowly' in colder temperatures.

So when do you need to start worrying about how much your battery's lifespan has dropped?

Weather impacts your battery's health (Getty Stock Images)

How much of a drop may impact your journey

Well, Which? noted if your battery drops by around 30 percent then this could potentially make your journey a bit hellish.

"A 30 percent drop in range is a significant chunk which could affect your ability to make some journeys free of interruptions for charging stops," it said.

The survey resolved: "Like all batteries, the cells that power an EV will degrade over time. However, our data shows that while battery degradation in EVs is an issue, it's not as bad as you might think in the first few years of ownership."