Battery degradation is one of the most common concerns we hear from drivers thinking about making the switch to electric. How long will the battery last? Does fast charging damage it? And will range drop off faster than expected?

New real-world data from Geotab, one of the world’s leading vehicle data and telematics companies, offers some reassuring answers. The headline takeaway is simple: modern EV batteries are holding up extremely well, even as fast charging becomes more common.

Modern EV Batteries Are Ageing Well

Geotab’s latest battery health study analysed data from over 22,700 electric vehicles across 21 different makes and models, using several years of real-world driving and charging information. According to the updated findings, the average EV battery degrades by around 2.3% per year.

To put that into context, after five years of ownership, most EVs would still retain close to 90% of their original battery capacity. That’s well within the expectations of manufacturers and far beyond what most drivers would notice in day-to-day use.

While this figure is slightly higher than Geotab’s previous 2024 estimate of 1.8%, the increase reflects how EVs are being used today rather than a drop in battery quality.

Fast Charging Has the Biggest Impact on Battery Health

One of the clearest insights from the Geotab data is the role charging behaviour plays in battery degradation. Vehicles that rely heavily on high-power DC fast charging above 100 kW showed higher degradation rates of up to 3.0% per year. In contrast, EVs that mainly use AC charging or lower-power DC charging averaged closer to 1.5% per year.

That doesn’t mean fast charging is bad or should be avoided. It simply highlights that using rapid chargers every day, rather than occasionally, can accelerate battery wear over time. For most private owners who fast charge on longer trips and use workplace or home charging the rest of the time, the impact is minimal.

Climate Matters, But Less Than You Might Think

Temperature does play a role in battery health, but Geotab’s data shows it’s less influential than charging power. EVs operating in hotter climates degraded by around 0.4% more per year than those in milder conditions. For Irish drivers, this is good news. Our relatively cool and moderate climate is naturally well suited to EV battery longevity.

You Don’t Need to Be Overly Strict With Charging Habits

Another reassuring takeaway is that drivers don’t need to obsess over day-to-day charging limits. Geotab found that batteries only showed accelerated degradation when vehicles spent more than 80% of their time at very high or very low states of charge. In normal use, regularly charging above 80% or dipping below 20% does not cause meaningful harm, as long as it isn’t the vehicle’s default state.

This means the occasional full charge before a long trip, or running the battery low now and again, isn’t something to worry about.

Higher Mileage, Slightly More Wear – But It’s Worth It

Vehicles that were used more intensively did show slightly higher degradation, increasing by around 0.8% per year compared to low-use vehicles. However, Geotab notes that this is more than offset by the productivity and cost benefits of higher utilisation.

In simple terms, using your EV more doesn’t cancel out its value. The battery is designed to be used, and even higher-mileage EVs remain well within acceptable performance levels over their lifespan.

What Is Battery Degradation, Exactly?

Battery degradation refers to the gradual reduction in how much energy a battery can store over time. It’s measured using State of Health (SOH), which starts at 100% when the vehicle is new.

For example, a 60 kWh battery at 80% SOH effectively behaves like a 48 kWh battery. While that sounds significant, most drivers never notice the change because the decline is gradual and spread over many years.

Geotab’s data shows that the vast majority of modern EV batteries remain fully fit for purpose well beyond typical ownership and fleet replacement cycles.

The Bottom Line for Irish EV Drivers

The latest Geotab data reinforces what we’re already seeing across the EV market: battery degradation is far less of a concern than many people still believe.

Modern EV batteries are robust, predictable and built to last. Even with increased fast charging and higher daily use, most batteries will comfortably outlive typical ownership cycles. For Irish drivers, sensible charging habits and our mild climate only strengthen that position.

As EV adoption continues to accelerate, understanding battery health is key, but the evidence is clear: going electric no longer comes with the battery risks it once did.