New data indicates that Tesla batteries lose less than 10% of their energy capacity after over 250,000 kilometers. Tesla owners from a Dutch-Belgium Tesla Forum are gathering data on batteries from over 350 Tesla vehicles across the world and compiling the results. The group is updating a public Google file to keep track of their research.
From the results so far the data shows that for the first 100,000 km, most Tesla battery packs will lose about 5% of their capacity. But after this initial drop-off, the capacity seems to level out and rarely do batteries degrade more than another 5%.
Trends suggest batteries will maintain capacity until 300,000 km
The trend clearly shows indicates that the average battery pack could cycle through over 300,000 km before coming close to 90% capacity. Interestingly, there are some outliers to this strong data trend.
There could be many possible reasons for this including frequency of DC fast-charging and daily state of charge. Renowned battery researcher and leader of Tesla's research partnership with the battery research group at Dalhousie University, Jeff Dahn, recommends Tesla owners only charge to 70% daily to extend battery life.
Tesla offers new warranty to Model 3 owners
Tesla make it clear to Model S and Model X owners that they do not cover battery degradation from “battery usage”.
The car’s warranty states: “The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use. Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered under this Battery Limited Warranty. See your owner documentation for important information on how to maximize the life and capacity of the Battery.”
But for Model 3 owners, Tesla has a different warranty that includes a new 70% battery capacity retention guarantee. This can be offered to lucky Model 3 owners as the car is equipped with different battery cells and a new battery pack architecture.
However, the existing data coming from the Model S seems to show that there isn’t any risk of major degradation. Battery degradation can be a serious concern for electric vehicle owners or people considering the switch.
Nissan Leaf lags behind
The Nissan Leaf, the world’s most sold electric vehicle has a fairly poor degradation rate. Data shows that the original 24 kWh pack loses about 20% of their capacity over 5 years and the new and 30 kWh battery pack loses capacity even more quickly.
Tesla has spent a serious amount of time and money researching their batteries and the results seem to be worthwhile. CEO of Tesla, Elon Musk once boasted that the company had tested a battery by simulating over 800,000 km on it and that it was still operating at 80% of its original capacity.
While there aren’t any Tesla’s out there with that kind of km’s on the road to prove it. The data we have so far seems to indicate it could be a possibility.