Fresh battery data gives the used electric-car industry a more useful starting point than assumptions based on vehicle age alone. In January 2026, Geotab reported an average annual battery degradation rate of 2.3%, based on more than 22,700 electric vehicles across 21 makes and models. Its earlier 2024 analysis had reported 1.8%. These are results from different study datasets, not proof that every vehicle's battery deterioration has accelerated. [1] Geotab also reported higher degradation among vehicles relying heavily on high-power DC charging above 100 kW, with rates reaching about 3.0% annually. The results describe patterns across the study population. They do not establish a degradation rate for the XPENG G9 2026 725 Max, ZEEKR X 2026 Max 5-Seat or BYD Seal 08 DM-i. [1] What this means for used vehicle buyers For sellers of used G9 and X vehicles, the practical implication is to pair charging capability with evidence about the particular battery. An attractive specification tells a buyer what the vehicle was designed to do. A recent assessment helps explain what the individual car can deliver today. A useful condition file should identify the test date, mileage, vehicle identification number and assessment method. It can also record charging behaviour, relevant diagnostic findings and any battery-related repairs. A dashboard range estimate is helpful context, but it should not be presented as a complete battery condition report. If a state-of-health figure is supplied, the method and its limitations should be clear. For an overseas buyer, this information has practical value because a second inspection may be difficult before shipment. Dealers can reduce uncertainty with a consistent set of documents, an independent inspection where appropriate and clear aftersales terms. The opportunity is to make battery condition understandable enough for the customer to compare offers with confidence, rather than relying on a model-wide promise about future battery life.