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Battery degradation: what data from tens of thousands of cars say

Part of the Guide Electro-mobile batteriesAre you choosing a car? The battery chemistry of specific models can be found in catalogue of electric cars.

The January 2026 Geotab update shows the average annual degradation 2,3 % for more than 22 700 wagons, compared to 1,8 % in analysis 2024. The difference reflects a different sample and method of use; it is not a life guarantee or proof of the result of a particular chemistry. Primary resourceThey want real SoH measurements when they buy used materials.

How the curve works

Degradation is not a straight line: at the beginning it is faster (formation of layers on the anode "swallows" the first 2-4 % often in the first year), then the process is flattened and the years run linearly slow. The end of life is defined as 70-80 % SoH - and even then the battery works only with a shorter range.

What really accelerates degradation

There is no universal order of causes for each car. Depending on the temperature, long standing close to full or empty charge and the use of high DC power. Geotab 2026 finds the connection of frequent high power DC with faster ageing; however, no specific damage can be derived from the individual stop.

SoH: number they want when buying used

State of Health gives the current usable capacity to the new. Since the EU's "battery pass" era, it can be read by service and independent tools (Aviloo, OBD readers). Orientally: 3-year-old car below 88% SoH = ask why (taxi? permanent 100 %?); above 93 % = above average. More in the article about guarantees and purchase of used materials.