I should add that I went back and ran across Musk’s tweet about the battery life on the 3. He said that the cells should last 1,500 cycles on the current Model 3 hardware. [remember, a cycle is considered full to empty. If you only used 20% of the battery five times that would roughly equal one cycle)
That means “life” should be well over 300k on the SR+ model. (Again there will be capacity loss, but probably not below 70% of original capacity.)
What can 6,000 electric vehicles tell us about EV battery health? | Geotab
That’s some decent reading too. If you look back at the 2015 or 2016 Model S you’ll see that somewhere in 3 to 5 years they saw an average of probably 8 to 10% capacity loss. It’s hard to tell, but you can see the curve actually smoothing out around that point (which trends with the smaller data sets that say once it hits this level the capacity loss seems to slow down/stop until well over 100k or even 150k miles).
Model 3 appears to be on about the same curve. So I would say plan for about 10% capacity reduction over the life of the vehicle (life being 10 years and maybe 120k miles, so maybe a bit more loss over your “drive it into the ground” mentality, but I highly doubt it’ll be like going over a cliff). Also expect a gradual 5 to 8% loss over those first three or four years.
You obviously alway want to buy the most battery you can afford. Increased usage in the winter is a REAL thing and you need to plan for that. (Example, on heavily wet roads, standing water basically, in 35 degree temps [so heat on in the car] and at highway speeds in my SR+ with snow tires I saw probably 60% of rated range. I could do about 145 miles on a full charge. Without heavy rain and standing water on the road things were much better, probably 170 miles. At highway speeds, 70mph, on a nice 70 degree day with no wind I see probably 180 to 185 miles, maybe 190) But I wouldn’t be afraid that the battery is fragile or not designed for real world use. Charge at home when you can (spend the money in a 50 amp circuit instead of just hitting a supercharger every week) and try to charge to 80% or less when only driving daily in town and you’ll be golden.
Also factor in the residual value of the vehicle. Even at 100k miles with a “crap” battery at 80% capacity I probably could sell my SR+ for at LEAST $5k and maybe more like 8 to 10k. Now if gas is up near $3/gal (some day it’ll get there again) and I replaced a 30 mpg car and average 10k miles a year... I’m saving about $822/year. Say it takes 10 years to reach 100k miles and I trade/sell my car for $5k and add up my fuel savings. The value was $13k ($5k grade value & $8.2k in fuel savings), well that’s ~30% of the cost of a new SR+ right now. Maybe you’ll actually decide to treat yourself to a new car sooner with a Tesla... (make a separate bank account and look at what you spend on average for gas, then look at the difference in your electric bill, any difference transfer into new account and watch it grow as your new car savings.)
[I should note that electricity is very cheap where I live, eastern WA, at ~$0.08/kWh. I averaged over 6,000 miles about 240 Wh/mi (that’s winter driving, highway, city, etc). 10k miles at 240 Wh/mi is 2,400,000 Wh, or 2,400kWh to drive 10k miles in a year. That’s $0.08*2400 = $192/yr or $16 extra a month on the electric bill.]
