Shock in the EV World: The Cars with the Most Durable Batteries Aren’t from Tesla

A new study reveals that the Kia EV6 leads in battery longevity — proving that degradation isn’t the nightmare many once feared.

For years, electric vehicle skeptics filled forums and social media with claims that EV batteries would die faster than your old smartphone. But a new study shows that those fears were largely exaggerated. Thanks to major advances in battery technology, modern electric cars are aging far better than expected — and the surprise leader isn’t Tesla.

Kia Tops Tesla in Battery Health

The analysis, conducted by Swedish used-car broker Kvdbil, evaluated the State of Health (SoH) of the batteries in 1,366 electric and plug-in hybrid cars, including models from Tesla, Audi, and Mercedes. The results were striking: eight out of ten vehicles retained 90% or more of their original capacity, and the Kia EV6 showed the lowest degradation of all. Right behind it came the Kia Niro EV, confirming the Korean brand’s growing reputation for efficiency and reliability.

According to Martin Reinholdsson, Kvdbil’s head of testing, “battery degradation is more related to usage and environmental factors than to the manufacturer itself.” Key variables such as age, climate, driving style, and charging habits play a much larger role in long-term performance. In short, it’s not about the badge on the hood — it’s about how you treat the car.

Battery Degradation: Far Less Serious Than You Think

The data paints an encouraging picture. On average, the electric cars studied retained 90% of their capacity after 145,000 km, and well-maintained models kept over 80% even after 200,000 or 300,000 km. The study also found that the steepest degradation occurs in the first two years, then stabilizes. This completely debunks the myth that buying a used EV is a risk — most electric cars still deliver excellent range after years of real-world driving.

The top three models with the most durable batteries were the Kia EV6, followed by the Kia e-Niro and the Tesla Model Y. Among plug-in hybrids (PHEVs), the most robust were the Kia Sportage, Kia Optima, and Volvo XC60. A clear statement from Kia: you don’t need a luxury badge to lead in technology.

Battery Care: The Secret to Longevity

Reinholdsson also offered some familiar advice for keeping EV batteries healthy: avoid frequent fast charging, don’t exceed 80% daily charge, don’t leave the car fully charged for long periods, and avoid extreme temperatures. It’s a philosophy that even Formula 1 engineers would agree with — real performance doesn’t just come from power, but from smart energy management.

In conclusion, this research confirms that modern electric vehicles are far more durable than most people believe. As battery costs continue to drop and recycling becomes more accessible, the real challenge now lies in educating consumers. Because one thing is clear: battery life is no longer a weakness — it’s a selling point.