EV Battery Degradation Is Nowhere Near As Bad As We Thought
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In the early EV era, manufacturers feared that battery longevity would be a major issue. The expectation was that batteries expiring before the vehicle’s lifecycle would leave owners with costly repairs. GM engineers came up with ideas like portable power generation to repurpose what they presumed would be a flood of used Chevrolet Bolt EV batteries returned after replacement. That flood has never materialized.
According to Recurrent data, 87% of electric vehicles on the road built in 2015 or before are still on their initial battery. Battery replacement on cars from 2016 onwards is less than one percent. Modern EVs with more advanced battery tech are proving far more resilient. A Geotab study showed an average degradation of just 1.8% for EV batteries (and the technology is still advancing).
Battery degradation does remain a concern for EV owners. But it’s more a matter of range falling than outright replacing the battery. And with the price of EV batteries plummeting, a battery replacement may be a cost-effective measure to keep solid used electric vehicles on the road by the time these vehicles need it.
Electric Vehicle Batteries Don’t Degrade Very Quickly
A Geotab study of 2024 found that on average, an EV battery degrades 1.8% per year. That would mean about 82% battery life after 10 years. That represents a more than 20% improvement over the company’s 2019 study, which showed 2.3% battery degradation per year, suggesting that EV battery technology is becoming more resilient. That should not be too surprising. Combustion engine vehicles also lose fuel efficiency as engines age, although that is less critical for the owner than an EV’s range. There are a few things to note.
EV Battery Degradation Is Not Linear
The 1.8% decline per year figure is an average. But as Recurrent points out, EV battery degradation isn’t linear. A common curve would show a sharper decline at the offset over the first 10,000 to 20,000 miles of ownership, followed by a gradual leveling off for much of the vehicle’s lifespan. Degradation would then pick up speed as the battery approaches the end of its life.
Battery Degradation Will Vary By Vehicle
Again, the 1.8% decline figure is an average. So it will vary by vehicle. And newer, better-performing vehicles may degrade even more slowly than that. We should take Tesla’s data (not an uninterested third party) with a grain of salt. But the brand’s 2023 impact report estimated 85% battery health remaining for a Model 3 or Model Y battery at 200,000 miles. The figure was 88% for Model S and Model X batteries. For perspective, 70% is the threshold where Tesla repairs a battery under warranty.
What Battery Range Degradation Looks Like In A Real Car
Let’s use a 2024 Hyundai Ioniq 5 SEL AWD – that we took on a road trip – as an example. The EPA estimated 260 miles of range for the AWD Ioniq 5 when new. At an average degradation rate of 1.8%, the Ioniq 5 would dip to 91% of its original range after five years. That would mean 236.6 miles of range. The Ioniq 5 would have 82% of its initial range after 10 years, which would be 213.2 miles.
It would take 13 years for the range to dip below 200 miles, as the battery capacity fell below 76%, still above the threshold where Hyundai would perform a warranty repair for abnormal degradation (70 percent). Real-life degradation may be less than that. Hyundai engineers put more than 360,000 miles on an Ioniq 5 over a 33-mile range. According to Hyundai, the battery was still at 87.7% of its initial capacity.
Average Battery Degradation Rate In A 2024 Hyundai Ioniq 5
|
Year |
Expected Battery Health |
Expected Range |
|
0 |
100% |
260 miles |
|
5 |
91% |
236.6 miles |
|
10 |
82% |
213.2 miles |
If we look at Tesla’s estimated battery degradation numbers, the top-range Model Y would still have about 303 miles of range after putting 200,000 miles on the car, from an initial range of 357 miles. A Model S AWD would have approximately 360 miles of range, down from an initial range of 410 miles. Those numbers, if even close to accurate, would keep Teslas on the road a long time before requiring battery repairs.
Factors That Affect Long-Term Battery Degradation
Temperature Extremes
EV owners cannot control the weather. But where an owner lives matters. Extreme temperature exposure on either end can hasten battery degradation. Operating in temperatures above 80°F or below 23°F for long stretches stresses the battery.
An EV battery will degrade more quickly in a place like Phoenix, Arizona – where the high temperatures can exceed 100°F for more than 100 days of the year – than in more temperate climates. But that effect may not be as pronounced as it once was. Modern EVs have more sophisticated liquid cooling setups that cool the battery far more efficiently than early air-cooled Nissan Leafs.
Charging And Battery Stress
One factor owners can control is the amount of stress placed on the battery when charging. Batteries operate most stably between a 20% and 80% state of charge. Manufacturers typically do not recommend charging beyond 80% or 90% in everyday driving when owners do not need all of the range. It can be equally detrimental to drain the battery completely. Manufacturers build batteries to last a certain number of charge cycles. So, more frequent charging is worse for the battery than less frequent charging. DC fast charging is more demanding on the battery than at-home AC Level 2 charging.
What You Should Know About Battery Degradation When Buying A Used EV
Battery Health Report
An EV battery is not a black box. A battery health report is something dealerships can and should be able to provide to prospective used EV buyers. Dealers can generate reports through a service like Recurrent or with a diagnostic tool like vsNew. A battery health report should be a particular concern for older EVs, where a battery may be nearing the end of its lifespan.
However, it’s worthwhile to conduct due diligence before making any used EV purchase. For a rough rule of thumb, an EV with 90% or more should be in good shape, an EV with 80% or more should have some life left, and below 80% would be where you would consider replacing the battery pack.
Battery Warranty
Electric vehicles come with substantial battery warranties. Owners can transfer that warranty to subsequent owners. Most newer used EVs, especially those coming off leases, should have substantial warranties remaining, offering used buyers peace of mind. Warranties vary by manufacturer. Most offer the federally mandated minimum battery warranty of eight years or 100,000 miles. Some manufacturers build on that. Hyundai provides a 100,000-mile warranty that lasts up to 10 years. Tesla offers warranties up to 150,000 miles, depending on the vehicle.
