No battery capacity loss so farExtreme commuter Steve Marsh bought a Nissan LEAF electric car to ease the financial pain of his daily 130 miles (roundtrip) commute. I don't know how he drives so much and stay sane, but that's another story... What's interesting is that his extreme driving habits provide us with a good data point on how the LEAF and its battery pack perform in the real-world.
So after 78,000 miles in about 2 years (he's probably passed 80,000 miles by the time you read this, at the rate he's going), charging the LEAF at home, at work, and sometimes at fast-charge stations along the way, how is Mr. Marsh's battery doing?
Based on the LEAF's dash, perfectly fine. No capacity bars have been lost. This is further confirmed by a test done with an aftermarket GID Meter, showing only normal battery wear. No bad!
This doesn't mean that a high-mileage EV won't wear out faster than a low-mileage one (after all, this is also true for gasoline cars). But it's nice to confirm that electric cars are a lot less fragile than some people claim, and with every passing year battery technology will improve (getting cheaper, storing more energy, becoming better at handling fast-charging, etc).
Why this mattersBack in the early days of hybrid cars, the average Joe and Jane were full of misconceptions about the new technology under the hood. A frequent concern was that the battery pack would surely degrade rapidly, losing charging capacity until it was useless and needed to be replaced at a high cost. Statements by manufacturers about how batteries were designed to last the "life of the vehicle" and extended warranties helped reassure potential buyers, but I think what really did it is simply the shared real-world stories from hybrid owners (like, for example, how some taxi drivers put hundreds of thousands of miles on their Prius hybrids without problem).
Now the same thing is starting to happen with plug-in vehicles, like how this Chevy Volt owner only used 26 gallons of gasoline to drive 12,000 miles. It doesn't mean that you'll have the same experience (your mileage may vary, literally), but it's an interesting real-world data point, and that convinces people more than theoretical benefits. Surveys by independent organizations like Consumer Reports are important too (the Chevrolet Volt did very well there too)