- Key Findings of the Study
- Annual Degradation by Charging Pattern
- Factors Affecting Battery Degradation
- Conflicting Opinions
- Recommendations for Drivers
- Long-Term Effects of High-Power Charging
With the increasing availability of high-power fast charging stations, a new report raises questions about their effect on the health of electric vehicle batteries. A study by the Canadian company Geotab revealed that regularly using fast charging at 100 kW or more significantly accelerates battery degradation. While these stations offer convenience to drivers, they may lead to a 25% loss of battery capacity within just 8 years. This article reviews the study’s findings, influencing factors, and recommendations to protect your battery.
Key Findings of the Study
In a study conducted by Geotab on electric vehicles, 22,700 EVs across 21 models were analyzed. The study showed that high-power fast charging stations (>100 kW) are the primary factor in battery health degradation. The study also found:
Vehicles using fast charging less than 12% of total charging time experience 1.5% annual battery degradation.
Increasing fast charging usage above 12% raises degradation to 2.5% per year.
Frequent use of fast chargers over 40% of the time (>100 kW) results in 3% annual degradation.
Meanwhile, slower charging (<100 kW) for less than 40% of the time maintains only 2.2% annual degradation.
Annual Degradation by Charging Pattern
Factors Affecting Battery Degradation
Several factors influence the lifespan of electric vehicle batteries, including:
Cell chemistry, manufacturer design, driving habits, and climate — all affect battery health.
Extreme heat and cold stress the batteries, though modern thermal management systems provide protection.
Higher degradation occurs in the first years, then gradually slows.
The average battery degradation in 2025 is estimated at 2.3% per year, meaning 81.6% capacity remains after 8 years.
Conflicting Opinions
The study contrasts with another report from Recurrent, a company specializing in battery health and data. After analyzing 13,000 Tesla vehicles in the U.S., they found no statistically significant difference in range between EVs frequently fast-charged and those relying mostly on slow charging.
However, this report has limitations: only 344 vehicles were frequently fast-charged, while nearly 13,000 vehicles were rarely fast-charged, making it difficult to draw definitive conclusions.
Recommendations for Drivers
Despite the convenience of fast-charging stations, the report shows that frequent use of >100 kW chargers accelerates degradation. Recommendations include:
Avoid relying exclusively on high-power fast chargers.
Use slow charging whenever possible.
Modern EVs are protected, but keeping the charge between 10–80% ensures a longer battery lifespan.
After 8 years, batteries should retain about 80% capacity, sufficient for daily use and long trips.
Long-Term Effects of High-Power Charging
As high-power stations become more accessible to EV drivers, this may also impact battery health over the long term, according to Geotab.
The good news: automakers and battery manufacturers have long been aware of this. Modern EVs include built-in battery protection systems designed to slow degradation regardless of charging method.
To reduce stress on cells, Battery Management Systems (BMS) automatically:
Slow charging when the battery is nearly full
Reduce charging speed if the temperature rises excessively
Most manufacturers also recommend keeping battery levels between 10% and 80% for normal driving. Constantly charging to nearly full or empty accelerates battery wear.
For drivers who regularly charge to 100% and deplete for operational reasons — such as rideshare or delivery drivers — manufacturers typically include a safety margin at both ends of the charge range.
When the battery indicator shows 100%, it usually includes unused capacity above that limit.
Similarly, a 0% reading prevents deep discharge that could damage the battery.
These levels are not visible to users but play a critical role in battery protection.
