Used electric-car buyers should have firmer expectations about battery life after an Austria-based analytics firm measured more than half a million battery health tests and found a consistent median near 90 percent after 150,000 kilometres. Aviloo analysed data from 2022 to 2026 across 20 popular models, including Tesla’s Model Y and Volkswagen’s ID.4, and reports median state of health figures grouped roughly between 87 percent and 94 percent at that mileage.
The company also looked at earlier points in vehicle life, finding higher medians after 50,000 km, and slightly lower medians at 100,000 km. Aviloo excluded Chinese models because it did not have sufficient data. Despite reassuring median results, the study highlights substantial differences between individual cars of the same model, driven by regional climate, battery capacity and how drivers park and charge.
The Nissan Leaf ZE1 showed the largest scatter: Aviloo says median state of health at 150,000 km varied by as much as 13.5 percentage points, a gap the firm equates to about 29 km of real-world range per charge. Other models also showed wide spreads, with individual cars diverging by up to 11 percentage points for Tesla’s Model Y, 11 and 12 points for the ID.4, and more than 12 points for the Hyundai Ioniq 5.
Marcus Berger, Aviloo’s chief executive, warned that battery condition does not map neatly to a car’s age and mileage in the way a combustion engine’s wear usually does. “In contrast to a combustion engine car, where age and mileage would more or less carry the value of the car and technical condition, that’s not the case for an EV,” he said. Berger offered a practical tip to preserve batteries: “What very few consumers know is: don’t park your cars with 100, 90 or 80 percent state of charge. It’s just harming the battery,” and he recommended maintaining charge between 30 and 70 percent.
The findings arrive as long-term durability remains a concern for some buyers. Manufacturers commonly warranty batteries for eight years or 100,000 miles (160,000 km), with replacement required if capacity falls below 70 percent. In the UK three major EV organisations have urged government action, pushing for mandatory battery health certification to improve transparency. “We see the customer demand for confidence in battery health,” said James Strong, used-car sales and delivery manager at Tesla UK, adding that “a nationally recognized battery state of health standards” would strengthen confidence in the used EV market and improve transparency for consumers.
For buyers and regulators the takeaway is mixed: median battery performance supports used-EV reliability at scale, but the wide internal variation underlines the value of certified state-of-health checks or a formal standard before purchase.
