The battery health report, line by line

What you are looking at

Since August 2024 EU law requires the battery management system of an electric car to hold up-to-date data for determining the state of health of its battery; for electric vehicle batteries the parameter the law names is the state of certified energy, the share of the certified energy that is left.¹ The longer list of the same annex, remaining capacity, power fade, internal resistance, energy throughput and the record of harmful events, is what the law requires of stationary storage and light means of transport; a workshop report of a car lays out what its battery management system logged, with the warranty and the legal minimum added for the owner. Euro 7 adds, for new car types from November 2026, an on-board monitor of the traction battery's state of health.² The rates the report compares against come from telematics studies such as the one in stop 08.³

Select the lines to see what each one measures.

Which lines explain the 94%

• Charging history. 83% AC and 41 fast sessions in four years: the pattern the telematics study tied to about 1.5% loss a year, against 3% for frequent fast charging.⁸
• Temperature history. Two percent of the time above 35 °C: little calendar ageing from heat.
• State of charge history. An average of 58% and little time full or empty: the 80% charging limit of stop 09 at work.
• Throughput. 156 full cycles is light use for the cells; cycle ageing is the smaller part here.

The report cannot say which habit mattered most. It can say that none of the three accelerators, heat, high state of charge and fast charging, was present for long.

What the report says about the next four years

Three lines look forward. The warranty gives a floor of 70% until eight years or 160,000 km; the forecast at the car's own rate puts it at about 88% then, and the Euro 7 minimum of 72% at eight years, which does not apply to a 2022 car, would be met with room to spare.⁹ For a buyer, the report is worth more than the odometer: it says not only how far the car has gone, but how it was treated. How the same data serve a car that powers a house is shown in Bidirectional charging, stop 05.