A study of electric vehicles (EVs) has shown that older batteries perform better than expected, even when a significant amount of mileage has been achieved.
In the largest study of its kind to date 2025 Generation Battery Performance Index Industry Benchmark Reportexamined more than 8,000 electric passenger cars and light commercial vehicles in the UK.
It included 36 different vehicle brands and both plug-in hybrid (PHEV) and battery electric vehicles (EVs) with an age range of zero (factory new) to twelve years and a mileage of up to 160,000 miles (257,495 km).
While no information was provided about the battery types of the vehicles examined, it was found that the average condition of the battery when new remained at 95.15 percent of original capacity – known as State of Health (SoH).
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Older electric vehicles between eight and nine years old still retained 85 percent of their original capacity, according to the data, suggesting that age does not significantly impact battery health.
It also showed that high-mileage vehicles – those that had driven more than 100,000 miles (160,000 km) – had battery health between 88 and 95 percent.
The study found that minimizing mileage did not result in significantly longer battery life, as the battery health of younger, high-mileage vehicles tends to be better than that of older, low-mileage vehicles.
It concluded that a well-maintained three-year-old fleet electric vehicle with 120,000km on the clock could be a better purchase than a six-year-old vehicle with just 50,000km on the clock.
It also showed that most manufacturers’ battery warranties are more than long enough and that batteries typically exceed warranty parameters – often beyond the life of the vehicle – resulting in few complaints from customers.
In Australia, battery warranties are typically around eight years, with some brands even offering up to ten years.
The report says battery degradation no longer poses the “systemic risk” it was previously viewed as, as battery condition is still the primary factor in the long-term resale value of used electric vehicles – as opposed to their mileage.
| Age (years) | 25th percentile | 50th percentile | 75th percentile |
|---|---|---|---|
| 0-1 | 97.91 | 100.00 | 100.00 |
| 1-2 | 97.23 | 100.00 | 100.00 |
| 2-3 | 95.00 | 96.94 | 99.89 |
| 3-4 | 92.98 | 95.17 | 98.19 |
| 4-5 | 91.64 | 96.49 | 96.49 |
| 5-6 | 89.01 | 92.26 | 96.00 |
| 6-7 | 88.13 | 90.75 | 93.50 |
| 7-8 | 87.96 | 90.00 | 93.85 |
| 8-12 | 82.00 | 85.04 | 90.00 |
MORE: World’s first solid-state battery for electric vehicles, offering a range of 600 km on a 10-minute charge
