Everybody knows that it’s better to avoid fast-charging an EV to preserve its battery life and keep it in good shape for as long as possible, at least in the case of nickel cobalt manganese (NCM) and nickel cobalt aluminum (NCA) batteries.
However, new data from Recurrent, which collects information from EV owners using its platform, shows that it doesn’t really make any difference in terms of range degradation if you fast charge or slow charge.
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Modern batteries deserve more credit
Modern EV batteries are dependable and long-lasting, thanks in no small part to the advancements in thermal management. There are cars out there that have traveled hundreds of thousands of miles on their original batteries. And now, thanks to new data, we know that fast charging EV batteries doesn't do as much harm as we thought.
Recurrent gathered data from over 13,000 Tesla EVs in the U.S. and analyzed the impact on their real-world range taking into account the frequency of fast charging sessions. Full disclosure, the data for EVs that use fast chargers more than 70% of the time is quite limited, with only 344 vehicles falling into this category, while the vast majority (13,059 EVs in the data set) topped up from a fast charger less than 30% of the time.
Furthermore, the bulk of the cars were made in 2018 or later, meaning that the data is most accurate for EVs that are at most six years old. However, Recurrent said that ongoing observations from 2012 to 2023 Teslas do not show any evidence that fast charging accelerates battery degradation any more than charging from lower voltage sources.
In the chart below, provided by Recurrent, the blue curve shows the observed range one standard deviation above and one standard deviation below the mean for cars that fast charge less than 30% of the time. Meanwhile, the orange curve shows the same but for cars that fast charge at least 70% of the time.
As you can see, the differences in range degradation are negligible, with Recurrent saying that “fast charging [does not have] the negative effect we expected.”
It's worth noting that the range predictions you see in the chart above are based on what the data analytics company calls the “real range ratio.” This is calculated by dividing the observed range by the EPA range rating of a particular EV–the Tesla Model 3 and Model Y in this case.
Over time, lithium-ion batteries degrade no matter what you do, but it's refreshing to see that you can take full advantage of your EV’s battery if you need to–on long road trips, for example.
That said, there are still some best practices that should be taken into account if you want to prolong battery life. Fast charging should be avoided at extreme temperatures, either high or low, and at extreme states of charge, like 5% or 90%.
