Research from Plug In America and others shows Tesla owners don’t need to be overly concerned about battery loss. In 2013, PIA did a study of Tesla Roadster battery longevity using data from 126 Roadsters driven a total 3.2 million miles. The study concluded that the typical Roadster would still have 80-85 percent battery capacity after 100,000 miles (though some Roadster owners have lost much more). The Model S has a superior battery management system to the one found on the Roadster, so it stands to reason that battery degradation should be even less.
And according to a Dutch engineering professor, it is. Based on 84 data points from the 85-kWh version of the Model S and six from 60-kWh cars, the study concludes that the Model S will retain about 94 percent of its capacity after 50,000 miles, with losses thereafter shrinking to about 1 percent per 30,000 miles. That means that after 100,000 miles, the typical Model S is projected to retain about 92 percent of its battery capacity and range.
Tom Saxton, chief science officer for Plug In America, says a Model S85 is projected to retain about 90 percent battery capacity until 86,000 miles according to Green Car Reports. According to Saxton’s data, the S60 version, whose smaller battery must undergo more charge/discharge cycles to travel the same distance, retains 90 percent capacity to about 67,000 miles. The high-mileage car in the ongoing study had 92,000 miles as of last summer and still retained 92 percent of battery capacity.
While there is no data or scientific evidence, many electric car owners believe that not charging their battery to 100% capacity regularly prolongs battery life. The same goes for not overdoing it with high powered DC fast chargers. As the saying goes, it’s true if you believe it’s true.