ASKING THE IMPORTANT QUESTIONS: How long do electric vehicle batteries actually last?

As the fleet of EVs on the road ages, new data pooled from tens of thousands of vehicles is showing those batteries are lasting longer than expected.

Lithium-ion batteries undergo two kinds of aging. First, there’s calendar aging: They degrade as time goes on, holding less juice, even if they just sit in storage.

Then there’s cyclical aging, which is how much a battery degrades based on its use — being charged and discharged, over and over again.

That means there’s no way to dodge degradation. Whether you use a vehicle a lot or a little, eventually, the battery will hold less energy.

But the trajectory of aging isn’t a straight line. Recurrent, a research firm that pulls in data from over 30,000 EV drivers, describes it as an “S curve.” There’s a rapid decline at the beginning, a long leveling off, and then a more rapid decline at the end.

It’s nice that they last longer than initially thought. But that’s still a very expensive replacement with no repairability.