A large-scale real-world analysis has found that modern electric vehicle batteries are designed to last longer than the vehicles they power, with average degradation happening slowly and predictably over time.
Research conducted by global telematics firm Geotab analysed data from more than 22,700 electric vehicles across 21 different models, making it one of the most comprehensive real-world assessments of EV battery health to date.
The study found that EV batteries degrade at an average rate of 2.3 per cent per year, meaning a typical battery is expected to retain around 81.6 per cent of its original capacity after eight years of use.
According to Geotab, the results confirm that current-generation EV batteries can deliver long service lives that extend beyond standard ownership and fleet replacement cycles.
Charging behaviour has the biggest impact
How a vehicle is charged has the biggest effect on battery life.The study found high-power DC fast charging above 100kW as the primary contributor to accelerated battery wear. Vehicles relying heavily on high-power fast chargers showed degradation rates up to double those of vehicles that predominantly used lower-power charging options.
Vehicles that use DC fast charging for less than 12 per cent of charging sessions recorded an average degradation of 1.5 per cent per year. By comparison, vehicles that frequently relied on fast charging saw degradation increase to around 2.5 per cent annually.
Where high-power charging above 100kW accounted for more than 40 per cent of DC charging sessions, degradation rose further to approximately 3.0 per cent per year.
Climate and usage also influence battery health
Environmental conditions were also found to play a role in battery wear. Vehicles operating in warmer climates, where temperatures exceeded 25 degrees Celsius on more than 35 per cent of days, experienced an additional 0.4 per cent degradation per year compared with vehicles in cooler regions.
Usage intensity had a measurable impact as well. High-utilisation vehicles completing a full charge cycle every one to two days degraded around 0.8 per cent faster annually than lower-use vehicles, though the study notes this is often offset by higher productivity and vehicle utilisation benefits.
The research also examined state-of-charge behaviour, finding that moderate exposure to very high or very low charge levels did not significantly accelerate degradation. Increased wear was only observed when vehicles spent more than 80 per cent of their time at extreme charge levels.
Implications for fleets and infrastructure planning
Geotab Senior Manager of Sustainable Mobility Charlotte Argue said the findings provide practical guidance for fleet operators seeking to maximise battery lifespan.
“While some battery degradation is inevitable, fleet managers can make some adjustments to get the most life out of their batteries and their investment,” Argue said.
The study recommends prioritising AC charging or lower-power DC charging where operationally possible, reserving high-power fast charging for situations where it is genuinely required.
For markets continuing to expand fast-charging infrastructure, the findings highlight the importance of balancing charging convenience with long-term battery health, particularly fleet and high-use vehicles.
Geotab said the results align with earlier research, noting that the observed 2.3 per cent degradation rate represents a return to levels recorded in 2020, following lower rates identified in 2023 studies. The shift reflects newer EV models, higher charging power availability, and evolving usage patterns.
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