Some folks seem to be oblivious that much of the country goes way below freezing.
This winter has been warm sofar but most years Green Bay has seen sub-zero by now as in F not C. Most years I will see -15f at home and have seen -25f a few times.
If the pack chills to 28f it only needs a few degrees to begin getting regen, if the pack falls to low single digits it needs 30degrees of rise.
You live in a place that tickles 30f daily it is a world of difference from areas where we might have a week where we barely reach 10f.
So be more forthcoming with temps you are talking about when you say "10 minutes is enough"
Here's what I've posted a few times in other threads. You can use this info and make adjustments for your situation.
"Cold weather, battery pre-conditioning, 18 minute duration. Warning, lots of nerdy tech stuff below.
I've been logging my data with the Scan My Tesla App and finally got a chance to log info with temps below freezing. The legend doesn't appear to be too legible so if you can't read it, here's what each value is along with some context.
* Outside temperature 26F, temperature inside my garage 47F, as shown in green.
* Front Stator motor started at 62F, shown in blue.
* Rear Stator Motor started at 62F, shown in pink.
* Battery inlet temp started at 51F, shown in red.
* Cell Temp Mid (battery pack) started at 52F, shown in black.
In the first image, you can see the front and rear motors quickly warming up with the front motor being warmer while the vehicle is parked. The highest I've seen the front motor get is 210F. What's happening is the refrigerant is passing by the motors and the heat is picked up via conduction. The Octovalve is then distributing the refrigerant, as needed, so initially some of the heat is sent to the heat pump to warm the cabin, and then routed to the battery pack. As long as the battery inlet temp is greater than the battery pack temp, the battery pack will warm up. The reverse is true, if the inlet temp is lower than the pack temp, the battery will go down in temp.
After 18 minutes:
* Front Stator motor started at 62F, finished at 190F
* Rear Stator Motor started at 62F, finished at 162F
* Battery inlet temp started at 51F, finished at 75F
* Cell Temp Mid (battery pack) started at 52F, finished at 69F
Some notes, observations: Each motor draws 3.5 kW max while pre-conditioning, so the dual motor Y will need 7 kW to pre-condition. With the other things running, such as the heat pump, screen, seat warmers, etc it'll typically be around 7.7 kW while parked and pre-conditioning. You'll need at least a NEMA 14-50 and 32A to keep up with this type of draw. Anything less will pull from the battery and not from the grid."