A study by the Swedish used-EV retailer Carla confirms other studies and says that modern electric cars retain most of their battery capacity even after high mileage. Based on almost 10,000 battery tests, the analysis also highlights differences between models, battery chemistries, and suppliers.
The ranking forms part of Carla’s Electric Vehicle Battery Study 2026. It compares average battery health across individual electric car models after more than 100,000 kilometers of driving.
A total of 9,954 battery tests were carried out for the analysis in Sweden between 2022 and 2026 using diagnostics from Austrian battery specialist AVILOO.
Carla says the dataset is one of the largest collections of battery health data from the Swedish used EV market. Only models with a “sufficiently large number of battery tests” were included to ensure meaningful comparisons, the EV retailer states.
Kia e-Niro comes out as winner
The Kia e-Niro with the 64 kWh battery achieved the highest average battery health at 97.25%, followed by the Hyundai Kona Electric (64 kWh) at 97.18%, and the Kia EV6 (77.4 kWh) at 95.95%.
Other leading models include the Volvo XC40 Recharge with the 69 kWh CATL battery at 94.70%, the Polestar 2 with the 78 kWh CATL battery at 94.35%, and the (former) BMW i3 with the 120 Ah battery at 93.77%.
Tesla’s highest-ranked model was the Model 3 with the 60.5 kWh CATL LFP battery, recording 93.34%. The top 20 also includes the Audi e-tron 50 and 55, Škoda Enyaq iV, Volkswagen ID.3 and ID.4, Tesla Model S, Model X and Model Y, and the Audi Q4 e-tron.
According to Carla, several of the highest-ranked models still retain between 95% and 97% of their original battery capacity after more than 100,000 kilometers. The company says this indicates lower degradation than many buyers expect and supports the view that modern EV batteries generally offer long service lives.
Battery chemistry and cell supplier are of significant importance
The study also found that battery chemistry and cell supplier can significantly influence long-term battery health. Comparing different battery versions of the Tesla Model 3, Carla found that the variant with CATL’s LFP batteries retained an average of 93.3% battery health, ahead of versions using LG Chem cells at 91.5% and Panasonic batteries at 89.8% and 88.2%, depending on the battery pack.
Carla says the findings highlight the value of battery testing when assessing used electric vehicles. While battery condition should be considered alongside mileage, age, and equipment, the company concludes that many of the most common EVs on the Swedish used car market continue to show high battery health after years of operation.
Further analyses covering battery health by brand, degradation over mileage, and the prevalence of severely degraded battery packs are due to be published later this summer.
