I was only referring to preconditioning the batteries, not necessarily warming up the cabin area. It doesn't take long to warm up the cabin area after entering inside the car.
Peter
The battery is not heated when preconditioning if the cell temp is high enough. I have my car parked in a 10C ( 50F) garage and there is no battery heating for a planned departure.
The two winters before, when I used planned departure with battery preconditioning the battery was only heated to about 6.5C (44F).
This winter I havent checked if the software has changed the preconditioning target, as I changed job I do not have these daily trips.
If you charge shortly before the departure the battery will be hetated from the charge, in general to a higher level than with preconditioning.
I get temps around 22-28C (70-80F) from charging with the Wall Connector at 11kW. This is really good for the consumption/range when driving in cold if the car has the heat pump/octovalve as the battery heat is used to heat the cabin (instead of battery electric energy).
For the battery life, cell temp during cycling is not very important. The car will actively heat the battery quite quickly if needed during the drive to reach safe levels.
This chart is from a research report testing Panasonic NCA cells (18650).
We can see that when cycling at low SOC (45-20% cycles) there is not a very big difference in the cyclic aging.
The same for medium SOC ( 68-43%).
For high SOC range there is a difference but it is not big.
In context, if you charge as most people do you probably will have a cyclic aging of somewhere around 1% annually but the calendar aging might be (at least) 5-6% the first year, 2.5% the second year, 2% the third year and 1.5% the forth year. It probably takes some 8-12 years to have such low calendar aging that the cyclic aging is equal to the calendar aging.
So. Cyclic aging will be small anyway. Calandar aging will be much higher.
Source:
https://www.researchgate.net/profil...erative-Braking.pdf?origin=publication_detail
so what's the best way to precondition to maximize battery life?
—> Charge shortly before the drive, that will heat the battery. But The cyclic aging, that already is very low will only reduce by little.
If you really like to do something that reduce the degradation you should start charging to a lower SOC and using cycles that is lower in SOC.
As seen in the graph above, cyclic aging is much lower at low SOC.
Also, calendar aging is much lower so the end result might be cutting the total degradation in half.
You can search the TMC forum for my nick + calendar aging, I have written some posts about this.
I use that approach.
Since my car was new as I know Supercharging is not as bad as most people think I do this when needed without worrying (some 45 supercharges or about 17% of the total charged energy). I also have done more full charges than many other as I know it does not kill the battery (Abouts 25-30 full charges so far).
After slightly more than two years I have about 493-497km range of 507 km new range, and a battery capacity of about 78.5-79kWh when most other with the same model ( M3P 2021) have 470km or so, despite the miles driven.
