What do people think will be the driver for the life of the battery, its age or its mileage (or rather number of charges)?
I put pretty low miles on my car, about 6,000/yr., so that the battery lasts a long time is more important to me than that it lasts long miles/charges.
Put another way, 10 years into my 5-series BMW, I have driven 60,000 miles. In combined driving it averages a bit above 20 mpg, but lets use 20 and estimate I've bought 3,000 gallons of gas in that time. Let's say the average price over that time is $3/gallon (I think it's actually a bit less). So I've spent $9,000 on fuel. I haven't, nor do I expect to, replace the gas tank (storage compartment for energy) or engine (user of energy) anytime soon.
Now lets say I'll pay 10 cents per KWhr over the next 10 years, so it will cost me about $7/to fill up the 85 KW battery pack (the useable middle 80% of charge) and lets say I get 250 miles out of that. So electricity will cost $1,680 to drive 60,000 miles the next 10 years.
That looks like I'll save over $7,000 on fuel costs, and perhaps it will be more if gas keeps going up, but this is where my question comes in. Will my 85 KW battery back be at about half its expected lifetime (60,000 miles of 125,000+ estimated) or will it be over the hill (10 years old vs. 8 years promised)? Because even if replacement 300 mile packs are only $10,000, 10 years from now, the cost of fuel (electricity) + storage device (battery) will likely do no better than wash the ICE cost of fuel (gas) and storage device (gas tank). In this exercise, I have chosen to ignore the cost of other repair issues in the costs of ICE vs. EV.
So where this is leaving me is: Since I don't drive a lot of miles, I can't buy this car because it will save me money - I have to buy it because I love it.
Well, I'm OK with that.