New Study Shows Wide Gaps in EV Battery Health

A comprehensive study conducted by the Austrian firm AVILOO has challenged common assumptions about which electric vehicles hold their value and range best. By analyzing over 500,000 data points collected across five continents from 2022 to 2026, the research found that battery health is less about the manufacturer's marketing and more about the specific circumstances of each vehicle. The results indicate that Mercedes, Hyundai, and BMW models often outperform Tesla vehicles in terms of remaining capacity, though the differences are rarely uniform.

The study highlights a critical trade-off for buyers: while brand reputation matters, individual variation is far more significant. For any single model, the gap between the best-performing car and the worst-performing car can reach up to 13.5 percent. This means two identical cars, driven in different climates or used in different ways, can end up with vastly different usable ranges, making used-car pricing a complex calculation rather than a simple deduction based on mileage.

Climate And Usage Drive Variance

One of the most surprising findings is the impact of local weather on long-term battery health. The AVILOO team noted that hot and cold climates limit operating capacity and accelerate component damage. This explains why smaller vehicles with shorter ranges, such as the Mini Cooper SE, showed the widest spread in health, ranging from 77.46 percent to 93.85 percent remaining capacity at high mileages. In contrast, larger models like the Ford Mustang Mach-E and Polestar 2 showed tighter consistency, hovering around an average of 92.5 percent.

The data suggests that location is as important as the car itself. A vehicle driven in a temperate zone may retain significantly more charge than an identical model driven in extreme heat or cold. For consumers, this means that a car's history is just as vital as its odometer reading when estimating future range and resale value.

Hyundai And BMW Lead Retention

At the 150,000-kilometer mark, the Hyundai Ioniq 5 topped the list with an average remaining battery health of 93.79 percent, narrowly edging out the BMW i4 at 93.62 percent. These results were consistent across the study's various mileage intervals, with the Ioniq 5 also leading at the 50,000-kilometer stage. This performance places these models ahead of the Tesla Model 3 and Model Y, which showed lower average retention rates in the same dataset.

Tesla Faces Highest Uncertainty

While the Nissan Leaf demonstrated the most predictable behavior, the Tesla Model Y showed the highest variation in both lab testing and real-world conditions. This inconsistency creates a significant uncertainty for potential buyers, as the actual range of a used Model Y can deviate widely from its original specification. According to GN auto tech/ev, this variance is the primary factor that complicates the valuation of Tesla vehicles compared to more consistent competitors like the Hyundai or Nissan.