Kia e-Niro battery health remains among the strongest after high mileage.
Buying a used electric vehicle often comes with one major concern: the condition of the battery. A new Swedish study suggests that fear may be overstated, especially for several of today’s most popular electric cars.
An analysis of nearly 10,000 battery health tests has found that many electric vehicles still retain well over 90% of their original battery capacity even after travelling more than 100,000 kilometres. The Kia e-Niro battery health performance stood out as the strongest in the study, highlighting how far battery technology has progressed in recent years.
The research was conducted by Swedish used electric vehicle retailer Carla using 9,954 battery tests carried out between 2022 and 2026. The battery inspections were performed with diagnostic technology from Austrian battery testing company AVILOO and covered a wide range of used electric vehicles sold across Sweden.
The Kia e-Niro equipped with a 64 kWh battery delivered the highest average battery health score in the study. Even after exceeding 100,000 kilometres, the vehicle retained an average of 97.25% of its original battery capacity.
Close behind was the Hyundai Kona with the same battery size, recording 97.18% battery health. Third place went to the Kia EV6 with its larger 77.4 kWh battery, which maintained 95.95% of its original capacity.
These figures suggest that some electric vehicles experience very little battery degradation even after years of regular driving. For buyers considering a used EV, this offers reassurance that battery life may last much longer than many people expect.
Several other electric vehicles also posted impressive results after crossing the 100,000-kilometre mark.
The Volvo XC40 Recharge fitted with a 69 kWh CATL battery achieved an average battery health of 94.70%. It was followed by the Polestar 2 with a 78 kWh CATL battery at 94.35%.
The BMW i3 with the 120 Ah battery completed the top six, retaining 93.77% of its original battery capacity.
Audi, Volkswagen and Skoda also featured among the best-performing brands. Models including the Audi e-tron 50, Audi e-tron 55, Volkswagen ID.4, Volkswagen ID.3 and Skoda Enyaq iV all ranked highly for long-term battery condition.
One of the study’s most interesting findings was that battery performance depends not only on the vehicle itself but also on the battery chemistry and manufacturer.
Tesla’s Model 3 provided a clear example.
The version fitted with a CATL lithium iron phosphate battery retained an average of 93.34% battery health after 100,000 kilometres. Models using LG Chem batteries averaged 91.5%, while versions equipped with Panasonic batteries recorded 89.8% and 88.2%, depending on battery size.
Although all of these figures remain relatively strong, the differences show that battery technology can significantly influence long-term durability, even within the same vehicle model.
For many people shopping for a used electric vehicle, battery condition remains the biggest question. Replacing a battery can be expensive, making long-term reliability an important part of the buying decision.
The findings suggest that most modern electric vehicles lose battery capacity much more slowly than many buyers assume. In several cases, vehicles still retained between 95% and 97% of their original battery capacity after travelling well beyond 100,000 kilometres.
That does not mean every used EV performs the same. Battery age, charging habits, climate and driving conditions all affect long-term performance. Even so, the study reinforces the value of having a professional battery health test completed before purchasing a used electric vehicle.
The study paints an encouraging picture for the growing used electric vehicle market. As more EVs enter the second-hand market, buyers are gaining access to vehicles that continue to offer strong battery performance after years of everyday use.
Rather than focusing only on mileage or the vehicle’s age, buyers now have another useful measure to compare cars. Battery health reports can provide a clearer understanding of how much usable capacity remains and help reduce uncertainty before making a purchase.
For manufacturers, the results also reflect steady improvements in battery design and durability. As technology continues to evolve, concerns about rapid battery degradation may become less significant for future generations of electric vehicles.
