For more on this subject, see:
http://www.lacarguy.com/green/article/eight-tips-to-extend-battery-life-of-your-electric-car
Anyway, this thread and the above article got me to thinking about ways to increase battery life. The batteries are so expensive, that even adding a few years would save a lot money. For example, if I have to replace my battery in 8 years, I should set aside $2.5K per year in a Karma battery fund. But if I can increase that interval to 12 years, then the annual battery cost drops to $1.6K. (Batteries will be cheaper in the future, but the logic of keeping the original battery longer before it becomes a boat anchor remains the same.)
For those of you interested in the science, Google on
Electric Vehicle Battery Technologies - Springer, which discusses the factors affecting EV batteries life. I was particularly interested in the DOD (Depth of Discharge) discussion and it's affect on battery life, because that's one of the few things we can control using Sport Mode. So rather than allowing the Stealth miles go to zero, why not switch to Sport at 10 miles or 20% SOC? It might cost a couple of bucks in gas, but wouldn't that be negligible in the overall scheme of things?
I'm aware of the 15% reserve for stop and go traffic, but let's face it, when our EV range is 0, we might have deeply-discharged the battery and therefore reduced it's life-cycle.