Ford Tested 36,000 Mustang Mach-E Batteries. Here’s How They Held Up After 100,000 Miles

Battery degradation is one of the top concerns among potential EV buyers. New data from Ford shows you probably shouldn't worry much.

Photo by: Ford

By: Tim Levin

Nov 9, at 9:00am ET

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Ford collected battery health data from around 36,000 Mustang Mach-E electric SUVs and shared the results.
Battery degradation is one of the top concerns from car buyers, but Ford's data shows that there isn't much to worry about.
Even Mach-Es with 100,000 or 200,000 miles on the odometer retained most of their original range.

It's one of the top questions I get about EVs: "How long will the battery last?" Understandably, people want to know that their car will go the distance before dropping tens of thousands of dollars on a new car with new-to-them technology.

A growing body of research shows that modern electric cars hold up just fine over years of normal use. And a huge study of Ford Mustang Mach-E SUVs further proves the point.

The Detroit automaker collected battery-health data from 36,000 Mach-E SUVs from the 2021 model year that were sold in the U.S. and Canada. The results, released Monday, should help quiet fears that EVs degrade like smartphones, which struggle to hold a charge after a few years of daily use.

On average, the cars had traveled 55,000 miles over 5.2 years and retained 92% of their usable battery capacity. That means a top-trim 2021 Mustang Mach-E with 305 miles of EPA range would in theory be rated for around 280 miles today. All the cars in the study have nickel-cobalt-manganese (NCM) battery packs, since Ford didn't introduce a lithium-iron-phosphate (LFP) battery for the Mach-E starting until the 2023 model year.

A blue 2021 Ford Mustang Mach-E GT is shown driving on the highway.

The 2021 Mustang Mach-Es Ford studied retained 92% of their battery health on average after five years on the road.

Photo by: Ford

Ford physically tests cells in the lab and tries to predict battery degradation using computer models before a model launches, Kevin Vander Lann, the automaker's technical leader of high-voltage battery cells and systems, told me in an interview. But the real test comes after a car spends years on the road.

"Our report card slowly trickles in over time," he said. "So here we are with a five-year report card, and it looks great."

Interestingly enough, putting on twice as many miles as average in the same time period barely impacted overall battery health. Ford says the over 2,000 SUVs with more than 100,000 miles on the odometer retained more than 91% of their battery capacity.

Those few drivers who put some 40,000 miles on their Mach-Es each year still had strong battery health after five years. Ford says the 30-plus cars in its dataset that had covered more than 200,000 miles showed 88% battery health.

Of course, these are just averages. So your results may vary depending on lots of factors. EVs that spend their lives in the hot American Southwest tend to age more rapidly than those driven in more temperate climates. Likewise, EV batteries that are frequently fast-charged to 100% and drained to near-empty typically wear out faster than those that are kept in the happy zone of 20% to 80%.

Still, Ford says the distribution of results is encouraging for its battery engineers: It says 95% of the 36,000 cars fell between 87% and 97%.

The results are in line with what other research has uncovered about how EVs age. Some early EVs (notably the first-gen Nissan Leaf) had less sophisticated battery thermal management and saw steep degradation as a result. But modern EVs tend to age far more gracefully.

According to Recurrent, a firm that tracks range retention in used EVs that opt in, the average EV retains 97% of its original observed range after three years and 95% after five years.

In September, battery-health startup Aviloo released the results of 500,000 EV battery tests. After 150,000 kilometers (around 93,000 miles), most models studied showed between 90% and 94% health. The Hyundai Ioniq 5, BMW i4, and Mercedes EQA stood out with readings near the top end of that range. The Mustang Mach-E did just about as well as Ford's own data show: 92.5% battery health. The Tesla Model 3 and Model Y came in at 88.9% and 90.3%, respectively.

The 2027 Ford Mustang Mach-E Trail

Photo by: Ford

Ford makes some familiar recommendations to drivers looking to make sure their EVs last as long as possible. The company says to manage temperature extremes by parking in the shade on scorching days and preconditioning the cabin while the vehicle is plugged in. It also recommends relying on Level 2 charging for daily driving, and using Level 3 DC fast chargers sparingly.

Vander Lann says the learnings from this crop of EVs and how they perform contribute to the development process for Ford's next-generation electric cars, like the sub-$30,000 Fathom pickup coming next year.

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"It's really continuous learning," he said. "We have a design that we deeply understand, the data is flowing in, we're learning learning from that, and feeding that to the engineering teams in the company here."

Contact the author: Tim.Levin@InsideEVs.com