battery longevity question…

[refusedmd]

i’m sure this has been asked before (if so delete this).

in terms of battery health (for a model 3 LR) — is the ACT of charging to 90-100% detrimental to longevity or is it charging to that amount and letting the car sit at that SOC?

i.e. if i charged to 100% but theoretically drove off uphill right when it hit 100% OK vs. having it sit at that SOC for several hours.

 

[pilotSteve]

You have it right. Think of it as air or water pressure stored in a in a bottle... stress cracks happen more at max pressure when held for longer time than when partially full. Same with the battery electrolyte.

 

[AAKEE]

i’m sure this has been asked before (if so delete this).

in terms of battery health (for a model 3 LR) — is the ACT of charging to 90-100% detrimental to longevity or is it charging to that amount and letting the car sit at that SOC?

i.e. if i charged to 100% but theoretically drove off uphill right when it hit 100% OK vs. having it sit at that SOC for several hours.

The time at 100% is not at all as bad as the forum myth says.
It seems not possible to uploads pictures today, but I would have placed a research graph of degradation cause by the time at different SOC here.
NCA calendar aging — Postimages

The lower SOC the better, but there is only small variations for the degradation between about 65-100%. At normal temperature the difference is almost negligable. The inrease of degradation is not dooming the battery but perhaps 10% higher than at 70-80%. This means, 9hours at 100% is not worse than 10 hours at 80%.

The main reason for the 90-100% should not be used daily is that the cyclic aging increases quite much.

 

[teddytoons]

Just FYI: I regularly charge from 50-80% except when going on long trips, I'll go to 90-100%. My Model S is nearly 6 years old and my range is down about 11%. That's with a mix of L1, L2, L3 charging.

 

[AAKEE]

Just FYI: I regularly charge from 50-80% except when going on long trips, I'll go to 90-100%. My Model S is nearly 6 years old and my range is down about 11%. That's with a mix of L1, L2, L3 charging.

If you live in a not hot climate, and have an average of lets say 70% SOC you perhaps would have 5% loss after one year (part of this is probably hidden dure to the degradation threshold)
.
5 Years with 5 x (square root of 6)= 12.2%. That is an easy estimate of what you probably would have in calendar aging. Cycles have taken a much smaller part, perhaps 1-2%.

If you took a look at the BMS estimated capacity you would probably see a larger loss than 11%, as the Model S probably hides about the same loss as model 3 does (about 2% for most Model 3).