By FREDA LEWIS-STEMPEL, MOTORING REPORTER
Repeatedly fast charging an electric vehicle will increase how fast its battery will degrade, new research has warned.
On average, EV batteries lose just over two per cent of their capacity a year, the new study found.
However, electric car owners who frequently use high-power DC fast charging - which means plugging into a public device offering speeds above 100kW - are at risk of accelerating degradation by 100 per cent compared to those predominantly charging at slower speeds, like a typical 7kW homecharger.
Geotab, an asset management solution leader that regularly carries out analysis of EV battery performance, said fast charging results in a 3 per cent rate of degradation per year, while for slow charging it is only 1.5 per cent.
The report comes as the UK continues to expand its rapid and ultra-rapid charging network to help EV owners replenish their batteries almost as quickly as it takes to fill up with petrol and diesel at a fuel station.
Rapid and ultra-rapid devices are typically located at motorway services, major retail parks and dedicated charging hubs and can increase a battery's charge from 10 to 80 per cent in as little as little as 15 minutes.
New research shows EVs lose just over 2% of their capacity a year and therefore confidence in long term battery performance should be high with EV drivers
Battery degradation is the natural process that reduces the amount of energy a battery can store over time.
The battery health study analysed real-world battery health data from more than 22,700 electric vehicles across 21 makes and models, drawing on aggregated telematics information.
The annual average degradation of 2.3 per cent highlighted in the latest report shows a slight rise from 1.8 per cent in the 2024 findings.
This is likely a result of drivers having increased access to rapid charging solutions as countries bolster their charging infrastructures, it said.
While EV battery lifespan is a major concern for drivers and fleet operators, Geotab said battery health 'remains strong' - though motorists can learn from the data to better manage EV performance and protect battery health to extend the use of their vehicles.
Charlotte Argue, senior manager for sustainable mobility at Geotab said: '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.'
Vehicles that frequently use both high-power and high-frequency DC fast charging are projected to have a battery capacity of 76% after eight years
GeoTab measures degradation by analysing a battery's state of health (SOH) using telematics data.
Starting with 100 per cent SOH, a battery's percentage gradually drops as it ages and has been repeatedly charged.
For instance, if a 60kWh battery operates at 80 per cent SOH then it will perform like a 48kWh battery.
Battery degradation is the gradual and permanent reduction in a battery's ability to store energy
On average, EV batteries lose just over two per cent of their capacity a year, the new study found
According to the report, EVs that exceeded 12 per cent DC fast charging usage saw a full per cent increased in average annual degradation of 2.5 per cent.
As such, Geotab found that there is a clear benefit for vehicles that predominantly use lower power charging, which are projected to still have 88 per cent of their original battery capacity after eight years - 1.5 per cent annual degradation.
Contrastingly, vehicles that frequently use both high-power and high-frequency DC fast charging are projected to have a battery capacity of 76 per cent after eight years - three per cent annual degradation.
Climate was also found to have an effect on battery degradation, though at a fall smaller rate, the study said
EV used in hotter regions degraded around 0.4 per cent more than those in mild climates.
So, geographical location remains a key variable in predicting a battery's lifespan, but as the UK rarely exceeds 25 degrees Celsius, there is little worry that hot temperatures will have a limiting impact on an EV's battery performance.
