These EVs retain their battery best, largest-ever study finds

A new study offers useful data if you're weighing a used electric vehicle. Austrian firm AVILOO tested over 500,000 EV batteries — the largest independent study of its kind — measuring "state of health" (SoH), or how much of a battery's original range it still holds, at up to 150,000 km (about 93,000 miles).

At that mileage, the Mercedes EQA held onto the most capacity, at 94% SoH, followed closely by the Hyundai IONIQ 5 (93.8%) and BMW i4 (93.6%). The Hyundai Kona EV and Volvo XC40 Recharge rounded out the top five, both above 92.7%. At the other end, the Nissan Leaf, MINI Cooper SE, and Renault Zoe finished last, all with smaller battery packs that have to cycle more often to cover the same distance. Both Tesla models landed in the bottom third: the Model Y at 90.3% and the Model 3 at 88.9%.

The bigger point for anyone shopping used is that these are averages. AVILOO found the gap between the best and worst individual copies of the same model can run as high as 13.5% in battery health — enough to noticeably change real-world range. A car's own dashboard readout won't reveal this, since every automaker calculates it differently. Overall, even the lowest-scoring models in the study still held onto the vast majority of their original capacity, suggesting battery wear is less of a worry than many buyers assume, though individual cars can vary a lot.