EV batteries have huge capacity and last a long time, but they will slowly lose some of their capacity over their life. Most manufacturers provide warranties for 100,000 miles or 8 years of use, whichever comes first.
Battery warranties that manufacturers provide are a good way to see how long a manufacturer would comfortably expect their batteries to last. A newly purchased EV these days will most likely have a battery warranty which covers it for the first 8 years or 100,000 miles, so there is very little to worry about with a car battery if you're buying new.
Buying second hand
Although the cost of EV batteries has reduced over 87% in under ten years, they are still currently the single most expensive component in an electric vehicle. Whilst replacing one is possible, for an owner it hasn't yet made the best sense, financially. So if you're buying second hand, it's important to check what warranty the battery has for any vehicle you're looking to buy. Consider the mileage and age of any potential vehicle purchase against the remaining battery warranty.
Reduction of capacity
As a battery is used over time, it's total capacity will reduce slightly, affecting the range of the vehicle. The amount it reduces by will depend on many factors including driving style, charging habits and the environment.
There are some real-world examples out there, such as vehicle rental firm Tesloop, whose vehicles do many long-distance trips and high-voltage DC charging; they saw the range of their Tesla Model X drop from 260 miles to 200, a big 23% reduction although perhaps not that bad considering the vehicle had clocked up over 330,000 miles of driving. Another example is from C&C taxis in Newquay, who after 100,000 miles of driving their Nissan Leaf, had not seen any noticeable reduction in capacity.
Battery manufacturing and technology are moving at a breakneck pace and it's expected that within the next 5 years, new battery technology will be available that's not only cheaper than existing batteries but more hardwearing. Tesla is expected to announce a million-mile battery in 2020.
Article last updated on June 1st 2020.