When Kerry Dunstan and his partner started looking for an electric car this summer, one question topped their list: “How’s the battery?” They soon found a 2021 Nissan Leaf with 29,000 miles on the clock. The dealer said its state of health (SOH) was still at 93%. That was enough to convince them. For £12,500, they bought a roomy electric car with space for passengers and luggage.
Dunstan, a cabinetmaker who also drives a sleek electric Volvo SUV, admits the Leaf doesn’t thrill him. “I like cars with energy and flair – this one’s a bit plain,” he says. Still, he’s satisfied. “It’s done exactly what I expected,” he adds.
The new benchmark for used cars
Used car buyers once focused on age and mileage. Now, battery health decides whether a car feels worth the money. Shoppers want to know how it’s been charged and cared for. Did the previous owner fast charge it too often? That can shorten the battery’s lifespan.
This uncertainty has made some drivers hesitate about second-hand EVs. But data analysis firms say they can now reveal the true state of a battery with precision. Experts add that many electric cars are lasting far longer than expected.
Dunstan’s Nissan Leaf shows why that matters. It lacks the liquid cooling systems found in many modern EVs. Nissan fixed that in later models, but earlier Leafs lose range faster, according to US research firm NimbleFins. Dunstan remains unconcerned. “I charge both my EVs to 100% when needed,” he says. “I don’t worry about it.”
Technology that takes the guesswork out
For buyers nervous about EV batteries, Austrian firm Aviloo offers a solution. “We can independently measure the true state of health,” says chief product officer Patrick Schabus. The company provides certificates for British Car Auctions and offers two kinds of tests.
The premium test uses a small device that records battery performance over several days as it discharges from 100% to 10%. The faster “flash test” connects directly to the car’s software and analyses the data in under two minutes.
The detailed test can detect small voltage and current variations, revealing issues in individual cells. Chief executive Marcus Berger says Aviloo’s results sometimes differ significantly from what cars display. He rejects the idea that 80% SOH means the end. “A car at 75% can still perform well – it just needs the right price,” he says.
What real drivers have discovered
In New Zealand, Lucy Hawcroft bought a Nissan Leaf with her husband three years ago. The dealer claimed its battery had 95% health. A year later, a mechanic found it had dropped noticeably. “My husband was concerned,” she says.
Even so, the car still manages 160km on a full charge. The couple use it mainly for short daily trips under 10km. “Some of our friends get 400km,” she says. “That would be ideal.”
At Cleevely Electric Vehicles in Cheltenham, battery condition reports are now standard. “Most buyers ask about it,” says sales director David Smith. The firm uses ClearWatt’s independent SOH reports. “We can’t change the results,” he says. “Once customers see them, nine times out of ten, they buy.” Managing director Matt Cleevely adds that repairs are often affordable. “You can replace a few modules instead of an entire battery,” he explains.
Charging habits and the future of batteries
How should EV owners charge their cars to extend battery life? According to Stanford researcher Simona Onori, moderation matters. “There’s probably a balance between charging too fast and never fast charging,” she says. But more research is needed.
Battery technology itself has advanced fast. Max Reid from CRU says older EV batteries handled 500 to 1,000 charge cycles. “Now, some new cells can last up to 10,000,” he says.
Even when a battery no longer fits an EV, it can still serve a purpose. Paul Chaundy from Second Life EV Batteries in Dorset says many firms reuse them for power storage. Some companies charge forklifts using old EV batteries to balance limited grid capacity.
Chaundy says the industry now needs clearer rules. “We need standard ways to measure and report battery health,” he says.
