A large-scale study by Aviloo, an Austrian company focused on diagnosing electric vehicle (EV) batteries, analyzed 500,000 batteries from 20 popular EV models over five years of real-world use. The study evaluated how well each battery retained its original capacity at three key mileage points: 50,000 km, 100,000 km, and 150,000 km. These results are expressed as percentages of the original usable battery capacity. At 50,000 km, the Hyundai Ioniq 5 had the highest battery retention with a median capacity of 97.13%, followed closely by the Mercedes EQA at 96.56% and the Hyundai Kona EV at 96.27%. At the 100,000 km mark, the Ioniq 5 remained in the lead with 95.27% capacity, while the EQA and BMW i4 followed with 95.01% and 94.34%, respectively. In contrast, the Nissan Leaf ZE1 and Renault Zoe had significantly lower retention rates, at 88.27% and 88.87%, respectively. The Leaf's use of a passive air cooling system and a smaller battery size were cited as factors contributing to its faster battery degradation. By the time vehicles reached 150,000 km, the Mercedes EQA took the lead with a median capacity of 93.97%, edging out the Ioniq 5 at 93.79%, with the BMW i4 finishing third at 93.62%. Tesla models, however, performed less well, with the Model Y retaining 90.32% of its capacity and the Model 3 at 88.94%. The Ford Mustang Mach-E and Volvo XC40 Recharge both outperformed the Tesla models, with retention rates of 92.53% and 92.79%, respectively. The Nissan Leaf ZE1 had the lowest performance at this stage, retaining only 86.67% of its original battery capacity. The study involved a large number of tests, with over 92,000 tests conducted on the Tesla Model 3, more than 53,000 on the Model Y, and over 24,000 on the Volkswagen ID.3. The battery retention percentages were translated into real-world driving range. For example, at 150,000 km, the Tesla Model Y retained enough battery capacity to drive 361 km, while the Hyundai Ioniq 5 could still travel 321 km and the Volkswagen ID.4 355 km. The Nissan Leaf ZE1, however, had a much lower range of 185 km. All the tested vehicles use lithium-ion batteries, a common technology in EVs that researchers are actively working to improve or replace with newer alternatives.