A recent study shows Tesla batteries degrade much faster than expected, raising concerns about the true range of these popular EVs.
Tesla vehicle batteries are showing significant degradation in range over time, which has raised concerns among owners and potential buyers. According to a study by Recurrent, Tesla Model 3 and Model Y batteries drop to around 64% of their original EPA-rated range after just three years. This finding is based on data from 12,198 Teslas, using nearly 1.6 million observations.
Battery degradation is a common issue for all electric vehicles (EVs), much like how smartphone batteries lose capacity over time. As batteries age and go through charging cycles, their capacity diminishes. Recurrent’s study illustrates this trend by showing how Tesla batteries degrade following an S-shaped curve. Initially, there’s a noticeable drop as the battery settles, then a slower, linear decline over the next two to three years, and finally, a leveling out at a sub-optimal level before the battery eventually fails.
It’s important to note that even when new, Tesla vehicles don’t actually achieve their full EPA-rated range. The study found that brand new Tesla Model 3 and Model Y vehicles achieve only about 70% to 72.5% of their advertised EPA range. This means a 2023 Tesla Model 3 Performance, which is rated for 315 miles by the EPA, might realistically achieve around 230 miles on a single charge according to Recurrent’s data.
This isn’t a problem unique to Tesla. The basic EPA testing protocol has been criticized for not accurately reflecting real-world conditions. It doesn’t account for factors like temperature changes or driving speeds over 60 miles per hour. This leads to discrepancies between the EPA-rated range and actual performance.
Despite the degradation, Tesla offers long warranties for its vehicles. Tesla guarantees that its batteries will retain at least 70% of their original capacity for eight years or 100,000 miles, whichever comes first. Higher-priced models, like the Model X, have even longer warranties. This warranty means that owners can have their batteries replaced if the range drops below the guaranteed level. However, dealing with service centers can sometimes be a hassle, which adds another layer of concern for Tesla owners.
Interestingly, Tesla’s data, presented by Martin Viecha, the company’s VP of Investor Relations, shows a different perspective. Tesla’s study, which focuses on battery retention relative to vehicle mileage, indicates that their batteries retain more than 80% of their capacity over 150,000 miles. While this study presents a more favorable view, it does highlight the difference in methodology between Tesla’s study and Recurrent’s age-based analysis.
Another positive note from Recurrent’s data is that Tesla batteries don’t seem to be as adversely affected by DC fast charging compared to other brands. This is a plus for Tesla owners who frequently take long road trips or don’t have access to Level 1 or Level 2 home charging options.
Thus, while battery degradation is an expected aspect of EV ownership, the degree to which Tesla batteries degrade over three years is notable. With the added context of EPA testing limitations and warranty protections, Tesla owners can have some reassurance. However, it’s clear that the real-world range of Tesla vehicles may not live up to the expectations set by their EPA ratings.
