I dug deep in my saved research reports to find one that is easy to read. Some are >100 pages and not that easy to read if not used to the technical terms around lithium battery chemistry. This is quite easy to read and not too long:
Lifetime analysis of EV Lithium batt
Some research reports do have wrong or partly wrong conclusions, for example can the setup of tests lead to conclusions that are not really valid. Reading a lot of Research and learning the things that is found In more than one report is good.
This report in mainly fine. They have most of the tests done with NCA-batteries In this test setup. The report is from 2015, but the results doesnt differ from mor recent tests of NCA.
The setup where they relate EFC/Equivalent Full Cycles refer to a car with quite small battery. They compare 500 EFC to 50000km. Thats 100km/62 miles range on a full charge so the example are set for a fairly small battery. For the example with 500EFC we should use the range from 100% down to the car stops times 500. For me that would be about 200.000 to 250.000km.
This also means that the power demand( ”C-rate”) is less in a Tesla than this theoretical short range car test so the degradation from the driving part should be slightly less(there are other research proving this, but to stick with one easy read report I give no reference for this statement).
I have an average SOC of about 35 to 40% when the car is not in use during a normal week. Average temp in my garage for a year is about 15C.
So I expect the calendar aging to be about 3% during the first 18 monts if I continue to use my charging schedule(Between 10 and 15C for between 30 and 40% SOC).
View attachment 719957
For the cyclic aging, 500 cycles is at least 200.000km. Im at 25000km right now and probably reach about 40.000-45.000km when the car is 18 months old. Thats roughly 100EFC or actually about 80, the degradation per cycle is small and its not that important to find the exact mileage.
Anyway, I would se about 1.5 to 2% degradation from the cyclic degradation As my charging scheduel put me close to the low SOC cycles.
Theres also a degradation add on for SuC, but I’m currently at about less then 20 sessions so that part is not big, and as this report refers to a small battery/short range, there is some headroom in the cyclic aging calc.
The total expected degradation is probably about 4.5%(to 5%) for the first 18 months for me.
View attachment 719959
If you use a higher SOC, for example 90% daily and have elevated temps, lets say 25 degrees average for the winter season and 40 for the summer season, the calendar aging would be about 8% for the first 18 months. This is also the case even if the car is not driven at all.
If you drive 80 to 100 cycles you would loose about 3% as you are in the high SOC according to the picture above.
This car would loose about 11% during the first 18 months.
We see that cyclic aging is
not the main degradation driver even if the car is driven more (twice) than the average car In Sweden(at least).
And we see that using a high SOC and letting the car be sleeping at that level eats a quite high portion of the capacity even if the car is not used, or driven only by a small amount. If the car is driven much more than average, still the calendar aging is at least twice the cyclic aging.
Calendar aging lessens with time so after a couple of years it seems to stabilize on a much smaller level.
You can calculate the aprox. degradation on your own Tesla(with NCA-batteries, which is more or less all except some 2021 SR+ at this date) with this. Remember that the degradation from temperature is not linear so its better to split the year in parts if there is a part of the year with 30-35 degrees C or more.
I calculated earlier that I would be around 2 to 2.5% degradation(another post in august or so, and maybe thread) after the holidays at 9 months and about 20000km, that should put my NFP at about 80kWh, or slightly below(79.9 today) and this is what I see since the latest F/W update So at least for me this calculation seems spot on.