When Kerry Dunstan and his partner started searching for an electric car this summer, they asked one key question: “How’s the battery?” They soon found a 2021 Nissan Leaf with 29,000 miles. The dealer told them its state of health (SOH) was 93%. That sealed the deal. For £12,500, they bought a roomy, reliable electric car that fit their needs.
Dunstan, a cabinetmaker who also drives a sleek electric Volvo SUV, admits the Leaf doesn’t excite him. “I like cars with a bit more punch – this one’s a bit dull,” he says. Still, he’s happy. “It’s done exactly what I expected,” he adds.
Battery health becomes the new mileage
Not long ago, used car buyers focused on age and miles. Now, battery condition decides the value of an electric car. Buyers want to know how the battery has been treated. Was it often charged to 100%? Was fast charging overused? Those habits can cut battery life.
This uncertainty has made some people hesitant about second-hand EVs. But new analytics companies say they can now reveal a battery’s true condition with impressive accuracy. Experts add that many EVs are lasting longer than early expectations suggested.
Dunstan’s Nissan Leaf is a good example. It lacks the advanced liquid cooling systems found in newer models. Nissan later fixed that issue, but older Leafs often lose range faster, according to US data firm NimbleFins. Dunstan doesn’t worry. “I just charge both my EVs when I need to,” he says. “I don’t overthink it.”
The rise of battery truth-checking technology
For buyers anxious about battery health, Austrian company Aviloo offers a clear solution. “We can measure a battery’s health completely independently,” says chief product officer Patrick Schabus. Aviloo works with British Car Auctions and provides two types of test.
The premium test uses a small device that drivers plug into the car. It monitors data over several days while the battery runs from full to almost empty. The quicker “flash test” connects to the car’s software and delivers a report in just minutes.
The premium version detects tiny voltage and current changes and even identifies weaker cells. Chief executive Marcus Berger says Aviloo’s readings often differ from the car’s own numbers. He also rejects the belief that 80% SOH means a dead battery. “A car with 75% health can still perform perfectly – it just needs the right price,” he says.
What EV owners around the world report
In New Zealand, Lucy Hawcroft and her husband bought a Nissan Leaf three years ago. The dealer said its battery had 95% health. A year later, an independent check showed a clear drop. “My husband was a bit worried,” she recalls.
Even so, the Leaf still drives 160km per charge. The couple mostly use it for short daily trips. “Our friends’ cars go about 400km,” she says. “That would be ideal.”
At Cleevely Electric Vehicles in Cheltenham, nearly every buyer asks about battery condition. “It’s become essential,” says sales director David Smith. His company uses ClearWatt’s independent SOH reports. “We can’t edit them,” he says. “Once customers see the results, it helps most sales.” Managing director Matt Cleevely adds that many battery issues are fixable. “You can replace a few modules instead of the whole pack,” he explains.
Charging smarter, lasting longer
How should drivers care for their EV batteries? According to Stanford researcher Simona Onori, balance is key. “There’s probably a sweet spot between frequent fast charging and avoiding it entirely,” she says. But researchers are still studying the details.
Battery technology is improving rapidly. Max Reid from CRU says older EV batteries managed 500 to 1,000 charge cycles. “Now, the best ones can reach 10,000,” he says.
Even when batteries no longer suit their original cars, they stay useful. Paul Chaundy from Second Life EV Batteries in Dorset says many companies repurpose them for energy storage. Some use old EV batteries to power forklifts when their grid can’t handle all chargers.
Chaundy believes the next big step is consistency. “We need one clear standard for testing and reporting battery health,” he says.
