I have had the same issue now since 2019.36.x. It might seem that moving to Scheduled Departure might help but it doesn't, and here is why...
Home temperature was -15°C when I got up today - Snowflake next to the battery on the app. I began preheating the cabin at 06:00. Cabin was nice and worm at 07:00 but no battery preconditioning occurred - it used to work last year.
I have Scan-my-tesla app and can see that 'Coolant Heater' does not activate until I put the car in drive so this morning my battery was sitting at -12°C, 0-regen. Then, after 42 mins of driving still 5 - 6 bars of regen limit, consumption was 334 wh/km.
If Tesla is listening - I have been trying to understand the different aspects of the current software functionality:
Several comments and observation:
Battery pre-heat/conditioning (Coolant heater) only now starts after you engage the car in Drive!
Coolant heater should come on with any activation of cabin pre-heat if battery is below +12°C. Should be a manual function in the app actually.
Cut-off temperature for Coolant Heater should increase from +12°C (which is where scan-my-tesla shows it kicks OFF now) to 17° - 20°C especially on shore power first thing in the morning. This will give nearly full regen when driving starts. Kicking out too early on cold days means battery pre-heater pretty much will remain ON during entire trip to/from work (40 - 45 mins).
No Regen and all battery pre-contioning after driving commences means I burn way too much energy/km.
Scheduled Departure seems not to pre-condition the battery at all if you manually activate the cabin pre-heater before scheduled departure begins to its thing.
Impact on me/my family:
No impact on work days - tons of range
Burning too much energy/km in my S75D means that since the first leg of my family holiday trip to NJ requires me to reach (the only option) the closest Supercharger that is 240 kms from home and at > 270 Wh/km I cannot reach the charger especially if we encounter any kind of in-climate weather like heavy snow or freezing rain coming off the eastern end of Lake Ontario. Therefore, with this morning's energy usage as an example, I wouldn't even make it much past the border heading south.
b/c of lack of battery pre-conditioning, I have actually canceled my trip to NJ this holiday season. Note: we have done this trip before in cold weather and bad conditions and roll into that Supercharger at ~20 to 30 kms (tight but not too bad) left on the clock. Wont attempt without battery pre-heat from home/cold start of my first leg as it is now.
Solution:
Battery preconditioning needs to come back to be part of cabin pre-conditioning - please.
Manual activation of battery pre-conditioner should be built into the app, perhaps even with option to pick +12, +16, or +20°C as the coolant heater cutoff temperature. It should in no way be coupled with Scheduled Departure.
... did I mention Please bring back the battery pre-heater asap?