8,000 used electric cars under the microscope: Their batteries exceed expectations

New evaluations from Great Britain paint a relaxed picture of the longevity of electric car batteries. The starting point is a comprehensive analysis of which auto motor und sport reports. For the so-called “Battery Performance Index 2025”, more than 8,000 electric vehicles from 36 manufacturers were evaluated – from almost new models to vehicles up to twelve years old and mileages of more than 250,000 kilometers.

On average, used electric cars still have 95 percent battery capacity

The focus is on the State of Health (SoH)i.e. the percentage of battery capacity still available compared to when it was new. The central result: On average, the SoH was over 95 percent.

Even vehicles aged eight to nine years still had around 85 percent remaining capacity, well above the usual warranty limits of many manufacturers, which are usually 70 percent after eight years or 160,000 kilometers.

Particularly noteworthy: Even cars with very high mileage performed surprisingly well. High mileage alone is therefore not a reliable indication of a weak battery.

Why age and mileage aren’t everything

While the year of manufacture and mileage are decisive evaluation criteria for combustion engines, the calculation works differently for electric cars. The research shows that the battery condition depends more on the Usage and charging behavior depends more than on the mere number of kilometers.

If you frequently charge quickly in extreme temperatures or leave the battery permanently at 100 percent, aging will accelerate. However, if you charge moderately, move the vehicle regularly and avoid extreme charging conditions, you can significantly extend the service life.

What is also interesting is the increasing spread among older vehicles: While the average value remains high, individual examples vary more widely. This means: It is not the age that decides, but the specific condition of the individual vehicle. For buyers, this means taking a closer look instead of generally discounting older models.

The principle: A diagnostic device is connected to the OBD interface while the vehicle is driven from 100 to less than 10 percent battery level. The buyer or seller then receives a certificate with the confirmed SoH value and other technical data.

In the CHIP test of a four-year-old VW e-Up, the remaining capacity was 96 percent – a value that reflects the study results. Although the test costs 99 euros, it can be a strong argument when selling and reduce uncertainty.