High-Power Fast Charging Is The Leading Cause Of EV Battery Degradation: Report

Fancy, high-power EV charging stations are becoming commonplace in North America. This is how they affect batteries.

• Batteries in electric vehicles that regularly use fast chargers of more than 100 kilowatts deteriorate faster than those that rely primarily on slow charging, according to a new study.

• It is claimed that more frequent use of fast chargers could cause some packs to lose almost a quarter of their capacity within eight years.

• We’ve seen other studies suggesting that fast charging has little impact on long-term battery health, so this isn’t a settled debate yet.

America deploys public fast charging stations record speedAs companies build ahead of demand and pave the way for an increasingly electric future. There’s no denying that stopping at these high-powered charging stations is undeniably convenient and helps drivers get back on the road quickly. But using them in certain ways may have unintended consequences in terms of battery health and degradation in the long run, according to a new study.

Canadian based research firm Geographic tab It analyzed more than 22,700 EVs across 21 models and found that high-power public fast charging stations were the biggest contributor to faster battery aging. No, this does not automatically mean that fast charging is directly harmful to batteries. Instead, the study outlined specific charging patterns in which cells experience significantly more stress compared to slower charging.

The study outlines that frequent use of Level 3 charging stations that provide more than 100 kilowatts of power can double degradation rates compared to regular charging at slower Level 2 charging stations or fast chargers that provide less than 100 kW of power. EVs that used fast chargers for less than 12% of total charging sessions experienced an average annual degradation of 1.5%. Those who fast-charged more than 12% of their total sessions experienced 2.5% annual degradation.

The results got worse when owners used 100+ kW stations for more than 40% of total charging sessions. They experienced a 3% annual deterioration. (But keep in mind that batteries deteriorate most rapidly in the first few years, with the rate of degradation decreasing gradually over time.) Those who charged less than 40% of their total charging sessions at speeds below 100 kW saw battery capacity decline by a modest 2.2% annually. In other words, it’s the combination of high power and high frequency that seems most detrimental to battery health.

While this data is crucial to our understanding of long-term battery health, I’d still like to approach this issue with caution. For starters, charging behavior is just one variable in a very complex equation. Battery health is affected by everything from cell chemistry to manufacturer design choices to driving habits to climate. Extreme heat and cold can stress batteries; but nearly all modern EVs are now equipped with heat pumps, preconditioning, and advanced thermal management systems designed to keep the packs operating in a safe temperature zone.

The study also contradicts another report from the battery health and data company Recurrent. After analyzing 13,000 Teslas in the US, he found that there was no statistically significant difference between EVs that frequently charge fast and EVs that rely more on slow charging. But this study had a big caveat. The sample size of frequently fast-charging EVs was only 344, while the rarely fast-charging models had a sample size of over 13,000, making it difficult to draw a definitive conclusion.

Geotab said in its study that average battery degradation in 2025 is 2.3%, meaning the average pack will have about 81.6% of its original capacity after eight years. This is higher than 1.8% in 2023, but is the same as 2020, when the average impairment was also 2.3% per year.

The company attributed the increase in disruption from 2023 to 2025 to the growing network of high-power charging stations now popping up across North America. Growth is particularly strong in the US, where networks such as Tesla Superchargers, Electrify America, ChargePoint and Ionna have doubled their charging deployments. Projected cooling period for EV sales After the $7,500 federal tax credit expires. Geotab said there’s also a potential impact on long-term battery health, as high-power stations are more accessible to EV drivers.

The good news is that automakers and battery companies have been aware of this for a long time. Modern EVs are equipped with in-package protection measures designed to slow degradation no matter how you charge them.

To limit stress on the cells, battery management systems (BMS) automatically reduce charging rates when the battery is nearly full and throttle rates when the temperature gets too high. Most automakers also recommend keeping the state of charge between 10-80% for normal driving; because constantly keeping a battery in a nearly full or nearly empty state also accelerates aging.

Manufacturers often create buffers at both ends of the usable range for drivers who need to regularly charge and discharge the battery to 100% for operational reasons (think ride-sharing or delivery drivers). When your screen reads 100%, there is usually unused capacity above that ceiling. The same applies to 0%; where a lower buffer is one of the packet deep discharge statemay damage the battery. You and I will never see these margins in the real world, but they play a critical role in protecting the battery.

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In my opinion, the takeaway is pretty simple. If you care about maintaining maximum range for eight to ten years, don’t over-rely on high-power fast chargers when you don’t need them. At the same time, you can rest assured that frequent fast charging isn’t a death sentence for your high-voltage pack. A Tesla Model Y Premium, which had an EPA range of 357 miles when new, could still get about 285 miles at 80% capacity after eight years. So it will still be an extremely useful and journey-worthy vehicle for many years to come.

Unless you constantly fast-charge every day using high-power stations, the likelihood of serious degradation remains low. As many other studies have concluded. It is also important to follow your manufacturer’s recommendations. Most do not warn users about fast charging, and using fast chargers will not void your battery warranty. Battery warranties in the US are a minimum of eight years and 100,000 miles, so there’s not much to worry about. Use cheaper slow chargers to avoid losing sleep when fast charging stops occasionally. Today’s EVs are designed with enough guardrails to keep their batteries healthy for years.

Do you have a tip? Contact the author: suvrat.kothari@insideevs.com