Plug-in American’s data shows that Tesla Model S battery packs have little capacity degradation over high mileage
One of the key issues of electric vehicle (EV) buyers is lithium battery degradation and there is limited long-term data on large battery pack, since EVs were recently revived. Despite being the only car maker having over 30kWh battery pack, Tesla Motors Inc. (NASDAQ:TSLA) has only a few owners (excluding Roadster owners) with accumulated high mileage on their cars.
Plug-in American, an EV advocate group, has been collecting data on Tesla car via its Model S Survey. With more than 90 additions so far this year, the organization now has data of 497 Tesla cars with more than 12 million total miles driven, providing an fascinating view on potential battery capacity loss. The organization created a chart of ‘reported battery capacity’ versus ‘miles driven’ for each of the Model Ss:
Tesla offers cars with battery warranty of 8 years (unlimited miles) called “Infinite Mile Warranty”, which doesn’t include battery capacity loss due to normal usage overtime. The chart shows normal capacity degradation on normal usage.
The capacity of the battery can be impacted by many reasons, including fast charging, periods of time uncharged, and frequently charging to battery’s capacity. The data also represents that major maintenance rates, battery/charger/drive unit swaps, have significantly reduced since 2012:
While the initial data is promising, the company is striving to further improve its battery cell and pack technology. It entered into an agreement with a battery-research group of Jeff Dahn at Dalhousie University. Mr. Dahn specializes in lithium-ion cell durability, which should assist owners in achieving high mileage with little capacity degradation.