Report finds fast charging accelerates EV battery degradation

Connected vehicle and asset management specialist Geotab has released a new report covering annual degradation rates of EV battery packs.

While the report notes that EV batteries continue to perform strongly through their lifetime, fast charging can increase overall battery capacity declines.

For the study, Geotab analysed real-world battery health data from more that 22,700 vehicles from 21 OEMs, drawing on several years of aggregated telematics information.

Compared to 2024 data, which showed an annual battery degradation rate of 1.8%, the 2025 numbers indicated a degradation rate of 2.3%.

Charging at a rate to match vehicle use is recommended (Photo: AdobeStock)

According to the report, this decline can be traced back to a greater reliance on high-output DC fast charging. While this should be ‘a concern’ for both private owners and fleet operators, it’s also put forward that battery packs still offer a working life beyond that of replacement cycles for most fleets.

“EV battery health remains strong, even as vehicles are charged faster and deployed more intensively,” said Charlotte Argue, senior manager, Sustainable Mobility at Geotab. “Our latest data shows that batteries are still lasting well beyond the replacement cycles most fleets plan for. What has changed is that charging behaviour now plays a much bigger role in how quickly batteries age, giving operators an opportunity to manage long-term risk through smart charging strategies.”

The analysis showed that recharging power is now the strongest operational influence on EV battery health. Vehicles that relied heavily on DC fast charging above 100 kW experienced faster degradation, averaging up to 3.0% per year, compared with around 1.5% for vehicles that primarily used AC or lower-power charging.

Other factors, such as climate, showed a smaller independent effect. Vehicles operating in hotter regions degraded around 0.4% faster per year than those in mild climates.

The data also challenged the need for strict day-to-day charging constraints. Vehicles that regularly use a wider state-of-charge range did not show meaningfully higher degradation unless they spent prolonged, habitual periods near full or near empty charge levels.

Higher-use vehicles showed slightly faster degradation, increasing by around 0.8% per year compared to the lowest-use group, but this is considered an acceptable tradeoff relative to the operational and cost benefits gained from keeping vehicles in service. For many fleets, these productivity gains directly translate into a lower cost-per-mile over the vehicle’s life.

“For fleets, the focus should be balance,” Argue added. “Using the lowest charging power that still meets operational needs can make a measurable difference to long-term battery health without limiting vehicle availability.”