The truth about electric car battery degradation

Anyone with a laptop or smartphone will have experienced the inevitable reduction in the charge held by the battery, and how long the device can subsequently run before it needs a top up. Unsurprisingly, this is also a common worry among people that are looking to buy their first electric car.

But is battery degradation in electric cars (EVs) fact or fiction? To find out, each year we use our car reliability survey to ask thousands of EV owners about the condition of their car and its battery.

Read on to discover what our latest research shows and whether you should be worried about battery degradation in electric cars.

Looking to go electric? Discover the best electric cars for 2023

Do electric car batteries degrade?

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 our survey, we asked over 3,000* owners of EVs to tell us by how much the range of their car had decreased since they bought it.

*Source: Latest Which? Car Survey (April 2022 to June 2022, covering the ownership experience of 58,532 cars - of which 3,262 were electric models)

As you might expect, newer EVs manage to maintain their range better than earlier models, with cars registered from 2019 onwards managing to deliver 98% of their original range on average.

Drivers of cars that are slightly older (registered as far back as 2015) reported a slightly greater decline in the range their cars can travel (95% of the original range). There’s a more noticeable drop in the oldest electric cars we surveyed (registered in 2014), but it’s still relatively small at 9%.

To put these figures into context, the average tested range for all electric cars we’ve reviewed is 188 miles. A drop of 2% would reduce this to 184 miles, while a 9% drop would result in a range of 171 miles.

So, although battery degradation occurs in EVs, our data shows it’s not something you should be overly concerned about.

Looking to buy a second-hand EV? Discover what to look for in our guide to buying the best used electric car.

Electric car battery warranties

Of course, there will always be EV batteries that perform worse than others.

The good news is that if you’re unlucky enough to find yourself with a battery that’s degrading quicker than expected, it’s likely any repairs (or even a full battery replacement, which can be very costly) will be covered under the manufacturer warranty.

The table below gives an overview of electric battery warranties provided by popular EV manufacturers.

Updated (19/6/23): Fixed error that prevented Tesla appearing in the table

As you can see, manufacturers typically offer a 7 or 8-year warranty for their EV batteries (or around 100,000 miles, whichever comes sooner). Be sure to check with the manufacturer of the EV you’re thinking of buying, though, as warranty terms can vary depending on the precise model you’re purchasing (will kick in only when the battery drops below 70% of the original capacity).

If you're buying a used electric car, check that its service history is up to date - if not, the warranty (both for the car and its battery) may be invalidated.

The 2023 Which? Car Survey is now open. Take part today and be in with a chance of winning £2,500