Ford Just Proved Its EV Battery Health Barely Degrades After 5 Years

Real-world battery life for phones, laptops and other electronic devices can diminish over years of use, but does the same happen to electric cars after thousands of miles and hundreds of recharges? According to data published by Ford this week: Yes, but not as badly as you might fear.

The automaker published a report analyzing the battery state of health of more than 36,000 Mustang Mach-E electric SUVs sold to customers across the US and Canada during the initial 2021 model year. After more than five years on the road — and an estimated 2 billion cumulative miles driven — the fleet averaged 92% battery health.

I call that impressive, but not totally surprising. That battery durability data is largely in line with what I’ve seen reported across the industry by other automakers and independent analysts. 

Why should you care about a 5-year-old car?

One of the biggest concerns of early EV adopters a decade ago (also shared by fence-sitters today) is long-term reliability. The battery is by far the most expensive component of an electric car, and owners want to know their shiny new EV will last as long as the combustion car it replaces.

Battery longevity is particularly important as more used EVs enter the market. Many experts (myself included) have touted pre-owned and off-lease EV deals as a way to bypass the electric-car price premium, but shoppers may be hesitant to roll the dice on higher-mileage vehicles. Many fear a used EV won’t meet their range needs or, worse, could blindside them with an expensive battery replacement.

Ford’s study is another data point that could help allay those worries. 

The high-mileage club

Ford examined more than 36,000 individual vehicles delivered to customers across all 50 US states and Canada during the EV’s first year of sales. A little more than five years later, the automaker says that around 95% of vehicles surveyed retained between 87% and 97% of their battery health (an average of 92%) across the entire 2021 fleet after an estimated 2 billion cumulative miles driven.

Better battery health means an EV keeps delivering more of its advertised range as the odometer climbs. The 2021 Mustang Mach-E rolled off the assembly line with an EPA-estimated range between 211 and 305 miles, depending on the spec, which means that owners lost around 16 to 24 miles of range over time, according to my back-of-the-napkin math.

That said, there’s no beating the chemistry. Around 2,000 vehicles in the group crossed the 100,000-mile mark, retaining around 91% health. A smaller subset of about 30 drivers reached 200,000 miles in their Mach-Es, with an average battery health of 88%. More miles, it seems, means more wear.

At the extreme anecdotal end of the spectrum, one owner put more than 400,000 miles on his original battery — though Ford didn’t state the specific health of that 2022 Mach-E.

In line with independent reports

An independent study published by Aviloo earlier this year adds credence to Ford’s reported numbers. An Austrian EV battery diagnostics firm analyzed over 500,000 EVs from 20 global brands to measure battery degradation — at 50,000, 100,000 and 150,000 kilometers — finding that many popular models maintained over 90% battery health at high mileage.

Tesla’s Model Y, which competes directly with the Mach-E, was found to hold around 90.3% battery health at 150,000 kilometers (93,205 miles). Aviloo reported that the Volkswagen ID4 and Hyundai Ioniq 5 showed 90.6% and 92.8% retention, respectively, over the same surveyed mileage. The first-generation Nissan Leaf — a much older EV with a smaller battery — showed more degradation at 86.3%, an unfortunate double whammy given its shorter initial range.

The future and the Fathom

According to Ford’s engineers and battery chemists, the Mach-E’s battery was designed to last at least 10 years, adding that the 2021 models in the study use an older nickel-cobalt-manganese, or NCM, chemistry. 

Ford’s new Universal Electric Vehicle platform, which will underpin the upcoming Fathom small electric pickup, will use a newer lithium iron phosphate chemistry. That will come with unique charging needs and different battery management calibration than its Class of 2021. The UEV architecture is also built around robust bidirectional charging, so we’ll have to check back in five or so years to see how using your car to power your home affects long-term battery health.

Senior Writer, Electrified Cars

Antuan has nearly 20 years of expertise and experience testing hundreds of cars, including electric, hybrid, plug-in hybrid, hydrogen, and traditional combustion vehicles. See full bio