New data from Geotab reveals that charging behavior has become the dominant factor affecting electric vehicle battery health, with high-power DC fast charging significantly accelerating degradation compared to lower-power alternatives.
The study analyzed real-world battery health data from more than 22,700 electric vehicles across 21 makes and models. Geotab’s updated analysis shows an average annual battery degradation rate of 2.3%, up from 1.8% reported in the company’s 2024 findings.
Highlights
- Vehicles using DC fast charging above 100 kW experience degradation rates up to 3.0% per year, roughly double the 1.5% rate seen in vehicles primarily using AC or lower-power charging
- Climate plays a secondary role, with EVs in hot regions degrading approximately 0.4% faster annually than those in mild conditions
- Higher-use vehicles show only modest additional degradation of around 0.8% per year compared to lowest-use groups
- State-of-charge extremes matter only when habitual, with degradation accelerating when vehicles spend more than 80% of their time at very high or very low charge levels
Charging Power Identified as Primary Factor
The analysis positions charging power as the strongest operational influence on EV battery longevity. The gap between fast-charging and standard-charging degradation rates represents a measurable variable that fleet operators can control through charging strategy decisions.
“EV battery health remains strong, even as vehicles are charged faster and deployed more intensively,” said Charlotte Argue, Senior Manager, Sustainable Mobility at Geotab. “What has changed is that charging behavior now plays a much bigger role in how quickly batteries age, giving operators an opportunity to manage long-term risk through smart charging strategies.”
Rigid Charging Rules May Be Unnecessary
The data challenges conventional wisdom about strict day-to-day charging constraints. Vehicles regularly using wider state-of-charge ranges did not show meaningfully higher degradation unless they spent prolonged periods near full or near empty charge levels.
For fleet operators, slightly faster degradation in higher-use vehicles represents an acceptable tradeoff. Productivity gains from keeping vehicles in active service translate directly into lower cost per mile over the vehicle’s lifespan.
“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.”
Understanding Battery State of Health
Battery degradation reduces energy storage capacity over time, measured as state of health (SOH). A 60 kWh battery operating at 80% SOH effectively functions as a 48 kWh battery.
Geotab’s findings indicate the majority of modern EV batteries remain fit for purpose well beyond typical ownership and fleet replacement timelines. Accurate SOH information through telematics data enables operators to:
- Track real battery capacity across their EV fleet
- Monitor degradation rates by individual vehicle
- Optimize deployment decisions based on actual performance data
- Maximize lifecycle value through informed charging strategies
Additional insights are available in Geotab’s EV Battery Health report at www.geotab.com.
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