Geotab’s latest research reveals high-power charging as the primary driver of EV battery degradation, marking a shift in how electric vehicle batteries age over time.
The connected vehicle specialist analyzed real-world data from more than 22,700 electric vehicles across 21 makes and models over several years. Their findings show an average annual battery degradation rate of 2.3% – up from 1.8% in their previous 2024 study.
Ultra-Fast Charging Takes Its Toll
The increased degradation stems from changing usage patterns, particularly the growing reliance on ultra-fast DC charging stations.
Vehicles that depended heavily on DC fast charging above 100kW experienced degradation at twice the rate of those using slower chargers. Cars relying on ultra-rapid chargers saw average degradation of 3% per year, compared with around 1.5% for vehicles mostly using AC or lower-powered DC chargers.
Climate and usage patterns showed smaller but measurable effects.
Vehicles operating in hotter regions degraded around 0.4% faster annually than those in mild climates. Higher-use vehicles also showed slightly faster degradation – increasing by roughly 0.8% per year compared to the lowest-use group.
State of Charge Habits Matter Less Than Expected
The updated EV battery health study challenged conventional wisdom about charging habits. Researchers found that degradation accelerates only when vehicles spend more than 80% of their time at very high or very low states of charge.
This suggests that typical charging patterns – keeping batteries between 20% and 80% most of the time – don’t significantly impact long-term battery health.
“EV battery health remains strong, even as vehicles are charged faster and deployed more intensively,” said Charlotte Argue, senior manager for sustainable mobility at Geotab.
She emphasized that batteries continue lasting well beyond 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.”
Next-Generation Batteries Show Promise
Separate studies suggest battery degradation rates are slowing with each new generation of vehicles.
In some cases, degradation rates have dropped as low as 1% per year for newer models.
Germany’s motoring organisation ADAC revealed compelling real-world data last July. A Volkswagen ID.3 had lost just 9% of its usable capacity over four years and almost 100,000 miles of driving.
More impressively, it had lost just eight miles of usable range during that period – thanks to improved battery management software delivered through over-the-air updates.
The findings highlight how software improvements can actually improve battery performance over time, offsetting natural degradation through better energy management.
For EV owners, the research suggests balancing charging speed with battery longevity remains key to maximizing their vehicle’s lifespan.
