Tesla Comes Up Short in New EV Battery Health Study

A large study of used EV batteries has placed Mercedes, Hyundai, and BMW at the top of the field, while the Tesla Model 3 and Model Y both landed in the bottom third — a result that cuts against the automaker's long-standing longevity reputation.

The European study, done by AVILOO, measured each model's median state of health, the share of original usable capacity remaining, at 50,000, 100,000, and 150,000 km. Rather than reading each vehicle's own battery management system, it relied on AVILOO's OBD-based FLASH Test. At the 150,000-km mark, roughly 93,000 miles, the Mercedes EQA led at 94 percent state of health (SoH), trailed by the Hyundai IONIQ 5 at 93.8 percent and the BMW i4 at 93.6 percent. Per AVILOO's rankings, the Hyundai Kona EV and Volvo XC40 Recharge completed the top five, both above 92.7 percent.

The finding matters because Tesla has leaned on battery longevity as a selling point for years, and an earlier, smaller Swedish study had reportedly placed the Model Y third overall. This larger dataset, however, reads differently. According to AVILOO, the Model Y came in at 90.3 percent SoH at 150,000 km (93,000 miles), and the Model 3 at 88.9 percent, which the firm ranks as the second-worst result among models with comparably sized packs, ahead of only the small-pack Nissan LEAF, MINI Cooper SE, and Renault Zoe. AVILOO's researchers note the absolute gap is not catastrophic, but say it undercuts the assumption that Tesla packs simply outlast rivals by default.

The bottom of the list shares a trait: smaller batteries. A 40-kWh pack cycles through more charges to cover the same distance as a 78-kWh one, and those extra cycles therefore register as faster degradation. As a result, the MINI Cooper SE dropped seven full points of SoH between 50,000 and 150,000 km, which AVILOO flagged as the study's sharpest fall. AVILOO also flags a caveat for used buyers, noting the spread between the best and worst individual examples of the same model ran as high as 13.5 percent. Two IONIQ 5 EVs on the same lot can therefore differ meaningfully in real-world range, with nothing on the dashboard reliably indicating which is which.

The broader picture, however, holds steady. According to AVILOO's data, even the worst-performing model retained over 86 percent of original capacity after 150,000 km, and examples of EVs surpassing 300,000 miles on largely original packs continue to appear across brands. What the dataset changes, therefore, is the certainty behind the "buy a Tesla for the battery" claim.