Despite being one of the main concerns with potential new electric vehicle buyers, battery degradation is starting to look less like an actual issue. Earlier this year, we reported on new data showing very little capacity loss over high mileage and now we have significantly more data backing this claim through a new survey.
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The data clearly shows that for the first 50,000 miles (100,000 km), most Tesla battery packs will lose about 5% of their capacity, but after the 50,000-mile mark, the capacity levels off and it looks like it could be difficult to make a pack degrade by another 5%.
The trend line actually suggests that the average battery pack could go another 150,000 miles (200,000 miles total) before coming close to 90% capacity.
Despite a few outliers, the data looks consistent:
The study tried to explained the outliers with data on frequency of 100% state of charge, use of Superchargers, and near full discharge.
It’s hard to get much out of the data at this point, but it seems that 90% charge level appears to be the ideal daily charge level and surprisingly, frequent Supercharging (twice a week to daily) appears to actually be beneficial in preventing battery degradation.
Coming back to overall battery degradation. Looking at the data from a mileage standpoint is probably the most simple way to interpret it, but it can also be interesting to look at age and battery cycles.
They made similar charts using those metrics instead:
CEO Elon Musk once referred to a battery pack Tesla was testing in the lab. He said that the company had simulated over 500,000 miles on it and that it was still operating at over 80% of its original capacity. It sounds crazy. The car itself is more likely to give up than the battery pack at this kind of mileage, but based on this new data, it looks a lot more plausible.
The next step is a 1 million-mile battery pack. Considering Tesla is aiming for its drive unit to last 1 million miles, it would make sense to have the same goal for the battery pack.
Of course, it would take 80 years for an average driver to travel 1 million miles, but that’s expected to change. With the advent of self-driving cars and car sharing networks, like ‘Tesla Network‘, it is expected that cars will travel a lot more miles in much shorter periods of time.
The capacity for a drivetrain to handle 1 million miles might sound like an overkill now, but that may not be the case in the near future.