Precondition vs HVAC

[spokey]

My question is not about going to a supercharger but the option that goes with scheduled departure

Does anyone know if there is any difference at between enabling what is called preconditioning in scheduled departure vs just toggling the HVAC button before you leave?

My reason for asking is that preconditioning happens way too early.

Let's say I plan to leave at 9:30am. If I set the departure for that I get a message the the cabin is up to the set temp by 9:15 at the latest. The app notification asks if I want to turn the HVAC off. Seems like a waste to leave it on or to turn it off at that point. So what I have been doing is to not set the departure at 9:30 but at 9:45. And that annoys me. But it does also get charging closer to the departure as well.

Except the the absolute coldest days the car will warm up by the time I get my wallet, phone, perhaps put on a coat and finally get to the garage.

So is there any reason to enable preconditioning instead on tapping the HVAC button say 5 minutes before leaving?

 

[MY1stEV]

Do you have an iPhone? In a recent update to the iOS app, they added Tesla functions to the Shortcuts app. Perhaps you could disable preconditioning under scheduled charging in your car and just create a timed iOS Shortcut that starts preconditioning at your preferred time.

 

[spokey]

no. have an android. I'm ok with tapping the HVAC button. I don't have a consistent departure time so I'd end up changing two schedules. I could also set one up with teslafi but again two schedules.

In part it is curiosity as they kind of have the two tied together but no explanation about using different terms. In part I'd rather not waste electricity with the heat going for 15 minutes more than it needs to.

 

[andaconda]

I normally don't use the precondition feature unless I taking a long trip and charge to 100% - and I make sure that I leave within 15 minutes of the battery reaching that 100% state of charge. Even in the coldest weather if I want the cabin warmed up - I will turn on the climate control to my desired temperature about 8 or 10 minutes before I leave. It doesn't take very long to warm up the cabin. If the traction battery is still cold - it is smart enough to limit its output performance until the main battery warms sufficiently.

 

[Deaf Paul]

Is there a trick to getting the car to WARM up the interior in the mornings regardless of what the HVAC system was last set at the day before? I leave pre-dawn when it’s cool and want the interior warm when I get into the car. However the day before when I get home, the AC is already on and I step out without turning it off. So when the car preconditions in the morning it seems to go with whatever the last setting was left at, and I end up with a freezing cold car with dew circles of water on front windows and end up constantly running the wipers for the first 10 minutes of my drive due to the high humidity outside. It sucks.

-Paul

 

[howardnj]

Is there a trick to getting the car to WARM up the interior in the mornings regardless of what the HVAC system was last set at the day before? I leave pre-dawn when it’s cool and want the interior warm when I get into the car. However the day before when I get home, the AC is already on and I step out without turning it off. So when the car preconditions in the morning it seems to go with whatever the last setting was left at, and I end up with a freezing cold car with dew circles of water on front windows and end up constantly running the wipers for the first 10 minutes of my drive due to the high humidity outside. It sucks.

-Paul

Yes! I have mine set at 70 degrees and my departure set at 0600. My cabin temperature is at 70 degrees at 6AM no matter how cold it is outside.

 

[Fourdoor]

Is there a trick to getting the car to WARM up the interior in the mornings regardless of what the HVAC system was last set at the day before? I leave pre-dawn when it’s cool and want the interior warm when I get into the car. However the day before when I get home, the AC is already on and I step out without turning it off. So when the car preconditions in the morning it seems to go with whatever the last setting was left at, and I end up with a freezing cold car with dew circles of water on front windows and end up constantly running the wipers for the first 10 minutes of my drive due to the high humidity outside. It sucks.

-Paul

Cool and humid here in the winter as well. Don't use de-fog, that blows cold air on the windshield and leads to MORE water condensation on the outside of the windshield, use the "defrost" option instead. About 2 min or less of defrost setting clears the windshield, and heats it up enough to stay clear for a half hour commute. Also, 2 minutes of burning hot air blowing on the windshield makes the interior of the car toasty warm As far as I can tell, this isn't an option in the precondition setting. But if it is 55F outside, my precondition gets that up to 70F before I get into the car and then the defrost gets the car the rest of the way to comfortable and clear windows in 2 min or less. You can also activate "defrost" from the phone app if you don't want the 2 min of warm up time while driving.

Keith

 

[fhteagle]

I think of getting the car ready to leave for cold weather departures as 4 stages:

- warming the air in the cabin + seat / steering wheel heating: 1-2 min / 3 degrees C below 10C, very low total kWh used
- warming the other surfaces of the cabin that might be touched: ~5 min / 3 degrees C below 10C, again low total kWh consumed
- warming the battery to normal driving operational temps (20C or so): ~10 min / 3 degrees C below 10C, this is the big consumer of heat energy and heat pump electricity (guessing ~7-10kW rate, to maybe 3-5kWh consumed?)
- recovering the charge that the Tesla will use for the stages above that is more kW than what my 16A L2 can provide: up to an hour

I've programmed HomeAssistant to consider the above, albeit in a collapsed single formula that seems to work well enough. HA Calendar controlled departure time + reported cabin temperature + reported battery temperature + charge target % drives how early the preconditioning process starts. For normal 60% departures to drive a 5 mile round trip to the store, even when it's -25C out the process only starts 15 minutes early or so. 100% departure road trips start more like a full hour early, and it really does take that to get the battery both warm and back to 100% SOC in such cold conditions.

 

[Fourdoor]

I think of getting the car ready to leave for cold weather departures as 4 stages:

- warming the air in the cabin + seat / steering wheel heating: 1-2 min / 3 degrees C below 10C, very low total kWh used
- warming the other surfaces of the cabin that might be touched: ~5 min / 3 degrees C below 10C, again low total kWh consumed
- warming the battery to normal driving operational temps (20C or so): ~10 min / 3 degrees C below 10C, this is the big consumer of heat energy and heat pump electricity (guessing ~7-10kW rate, to maybe 3-5kWh consumed?)
- recovering the charge that the Tesla will use for the stages above that is more kW than what my 16A L2 can provide: up to an hour

I've programmed HomeAssistant to consider the above, albeit in a collapsed single formula that seems to work well enough. HA Calendar controlled departure time + reported cabin temperature + reported battery temperature + charge target % drives how early the preconditioning process starts. For normal 60% departures to drive a 5 mile round trip to the store, even when it's -25C out the process only starts 15 minutes early or so. 100% departure road trips start more like a full hour early, and it really does take that to get the battery both warm and back to 100% SOC in such cold conditions.

Totally off topic:

Do you like Home Assistant? I did a whole home automation based on Alexa, but it had many limitations and I don't really like having a spy device (other than my phone) listening to my every word.

Thanks,

Keith

 

[fhteagle]

Totally off topic:

I replied in direct message to avoid thread jacking...

 

[bumcurriculum]

Calendar controlled departure time + reported cabin temperature + reported battery temperature + charge target %

How do you get the battery temperature in HA? (I cannot find this myself, although I am trying with a Model S with "Tesla Custom Integration")

 

[fhteagle]

How do you get the battery temperature in HA? (I cannot find this myself, although I am trying with a Model S with "Tesla Custom Integration")

That was a typo, should have been reported outside temperature.

I asked about getting battery temperature on the GitHub for the integration, nobody had an answer there either.