When Kerry Dunstan and his partner started searching for an electric car this summer, one question topped their list: “How’s the battery?” They found a 2021 Nissan Leaf with 29,000 miles on the clock. The dealer said its state of health (SOH) was 93%. That was enough to convince them. For £12,500, they bought a spacious, reliable electric car with plenty of room for passengers and luggage.
Dunstan, a cabinetmaker who also owns a sleeker electric Volvo SUV, admits the Leaf doesn’t thrill him. “I like cars with flair – this one’s a bit plain,” he says. Still, he’s happy. “It performs exactly as I expected,” he adds.
Battery health now drives the market
Used car buyers once focused on mileage and age. Today, battery condition is the main factor. Shoppers want to know how it was treated. Was it fast charged to 100% regularly? That can shorten battery life.
This uncertainty makes some buyers hesitant about second-hand EVs. But new battery analytics companies say they can measure health accurately. Experts add that many electric cars last far longer than early predictions suggested.
Dunstan’s Leaf shows why this matters. It lacks the liquid cooling system of newer models. Nissan has since added this, but older Leafs lose range faster, according to US research firm NimbleFins. Dunstan isn’t concerned. “I charge both my EVs when I need to,” he says. “I don’t overthink it.”
How testing reveals the truth
Austrian firm Aviloo offers reassurance for nervous buyers. “We can independently measure a battery’s state of health,” says chief product officer Patrick Schabus. Aviloo provides certificates for British Car Auctions and offers two tests.
The premium test uses a small device that monitors the car over several days as the battery discharges from full to almost empty. The faster “flash test” reads data directly from the car’s software and produces a report in minutes.
The detailed test tracks voltage and current changes, identifying weak cells. Chief executive Marcus Berger says Aviloo’s results often differ from the car’s own readings. He also challenges the notion that batteries below 80% SOH are unusable. “A car with 75% health can still perform well – it just needs the right price,” he says.
Real experiences from EV owners
In New Zealand, Lucy Hawcroft bought a Nissan Leaf three years ago with her husband. The dealer said its battery was 95% healthy. A year later, an independent check found it had dropped noticeably. “My husband was a bit concerned,” she recalls.
Even so, the Leaf runs about 160km on a full charge. They mostly use it for short trips under 10km. “Friends of ours get 400km,” she says. “That would be ideal.”
At Cleevely Electric Vehicles in Cheltenham, battery checks are now routine. “Most buyers ask for them,” says sales director David Smith. The company uses ClearWatt’s independent SOH reports. “We can’t alter the results,” he says. “Once buyers see them, nine out of ten sales go through.” Managing director Matt Cleevely adds that many issues can be fixed. “Replacing a few modules is often far cheaper than a full battery,” he explains.
Smarter charging and longer battery life
How should EV owners charge to preserve their battery? Stanford researcher Simona Onori says moderation is key. “There’s a sweet spot between frequent fast charging and avoiding it entirely,” she explains. But more research is needed.
Battery technology has improved dramatically. Max Reid from CRU says older EV batteries lasted 500 to 1,000 cycles. “Some new models reach 10,000,” he notes.
Even retired batteries still have value. Paul Chaundy from Second Life EV Batteries in Dorset says many companies reuse them for energy storage. Some use old EV batteries to power electric forklifts when their grid connection can’t handle all chargers.
Chaundy says the industry now needs standards. “We need clear, shared methods for testing and reporting battery health,” he says.
