A recent study conducted in the United Kingdom has revealed that the average battery health of electric vehicles (EVs) is an impressive 95.15%, surpassing initial expectations. The research, which analyzed over 8,000 EVs, indicates that while factors such as age and mileage do affect battery capacity, most batteries exceed the common warranty thresholds, suggesting they often outlast the vehicles themselves.
The study was carried out by Generational, a UK-based firm specializing in evaluating EV battery health. Their findings, based on data collected from vehicles tested in 2025, suggest that concerns about battery degradation might be overstated. “Battery degradation is not the systemic risk it was once assumed to be. Real-world data shows that most EV batteries comfortably exceed warranty thresholds, even at higher ages and mileages,” the report stated.
Among the vehicles included in the study were models from a diverse range of 36 brands. The dataset comprised cars that were less than a year old to those that had been on the road for up to 12 years and had accumulated as much as 160,000 miles. While the overall average battery health was high, the study noted that the age of the vehicle plays a significant role in battery performance.
Age and Mileage Impact on Battery Health
The analysis revealed that the median battery health for EVs aged 2-3 years was 96.94%. This figure dropped to 95.17% for EVs aged 3-4 years and further declined to 85.04% for those in the 8-12 year category. Although age generally correlates with degradation, there remain many older EVs that maintain healthy batteries, keeping the overall average relatively high.
However, Generational highlighted that the variability in performance increases with age. For instance, the lowest-performing 1% of vehicles in the 4-5 year bracket showed only just over 80% of their original battery capacity. This range of outcomes aligns with previous studies, reinforcing the notion that while older batteries can exhibit signs of wear, they are not necessarily nearing failure.
Understanding Battery Health and Market Implications
The study also emphasized that mileage should not be viewed as a definitive indicator of battery health. Vehicles with over 100,000 miles frequently demonstrated between 88% and 95% of their initial battery capacity, irrespective of age. Anecdotal evidence supports this, as seen in a 2019 Tesla Model 3 that, with 113,000 miles, retained approximately 79% of its battery capacity. This degradation was attributed to extensive fast-charging and exposure to a cold climate throughout its life.
Generational advocates for improved battery health testing to enhance transparency in the used EV market, which could ultimately boost residual values. The firm argues that the existing uncertainty surrounding battery health is a barrier for potential buyers of secondhand electric vehicles. Two vehicles may appear identical, yet their usage history could lead to significant differences in remaining capacity and range.
With a growing body of evidence indicating that many used EVs, especially those just a few years old, are performing better than anticipated, prospective buyers can feel more confident about the longevity of these vehicles. The study highlights that while caution is always prudent when purchasing a used EV, the overall outlook for battery health is more positive than many had feared.
