HVAC question. What does "AUTO" do?

[DopeGhoti]

Indeed. You are exactly correct in saying that you use more energy using auto.

I proved that as I was sitting at a Tesla Destination Charger and had auto temp set to off. At that point I had 1 hour left to charge.

I turned on auto and my charge time to completion went up 15 min.

This morning I did the same thing and my charge time went up 25 min.

That does not mean that Auto uses more energy overall. That means that Auto uses more energy right in that moment where you turn it on. The charging ETA is based on nothing more than power input and power output and state of charge at that moment. If you watch it over time, with Auto engaged, you will see the estimated time to charge drop back down when the AC compressor is disengaged by Auto.

 

[Garlan Garner]

That does not mean that Auto uses more energy overall. That means that Auto uses more energy right in that moment where you turn it on. The charging ETA is based on nothing more than power input and power output and state of charge at that moment. If you watch it over time, with Auto engaged, you will see the estimated time to charge drop back down when the AC compressor is disengaged by Auto.

Question: Do you think that its possible for "auto" to use less power than it not being engaged?


The answer to the question is why I say that it uses more power than it not being engaged. The fan ALWAYS kicks up when "auto" is engaged...regardless of the compressor.

 

[thefortunes]

Question: Do you think that its possible for "auto" to use less power than it not being engaged?


The answer to the question is why I say that it uses more power than it not being engaged. The fan ALWAYS kicks up when "auto" is engaged...regardless of the compressor.

This is absolutely not true. If your car is already at the requested temp and you have fan set higher than auto would use then you are consuming more energy.

Another example of why your "data" is faulty - if you have the temp set at 70F and fan at 1 (manually) but those settings are only resulting in the interior temp being 62F, then OF COURSE placing it into auto is going to consume more energy. You are now requesting 70F vs the 62F you were heating to previously.

What you have been seeing (and others are trying to explain) is that you are taking one specific moment in time (when you switch to auto) and extrapolating that to expect to continue. It will not.

 

[Garlan Garner]

This is absolutely not true. If your car is already at the requested temp and you have fan set higher than auto would use then you are consuming more energy.

Another example of why your "data" is faulty - if you have the temp set at 70F and fan at 1 (manually) but those settings are only resulting in the interior temp being 62F, then OF COURSE placing it into auto is going to consume more energy. You are now requesting 70F vs the 62F you were heating to previously.

What you have been seeing (and others are trying to explain) is that you are taking one specific moment in time (when you switch to auto) and extrapolating that to expect to continue. It will not.

If If If. It absolutely is true.

Please don't assume I don't understand what other people are saying.

Rarely is my car the exact same temp inside as it is outside where "auto" is perfectly happy and shuts both the fan and the compressor off <------ no matter what I set the temp to.

If I set my car for 70 and its 60 outside.....my fan never goes down to 1 or 2 with auto on. <----- even after I have been sitting in the car for an hour and the inside reaches 70.

I can maintain 70 degrees without auto just fine with the fan on 1 when its 32 degrees outside.

As I stated in my original post......I was just playing with the temp controls after about an hour of sitting the car and noticed that my cozy 70 degrees was fine …… and then I changed to auto and it was still 70 with the fans up to 4 or 5 and the compressor turning on.

 

[derotam]

Indeed. You are exactly correct in saying that you use more energy using auto.

I proved that as I was sitting at a Tesla Destination Charger and had auto temp set to off. At that point I had 1 hour left to charge.

I turned on auto and my charge time to completion went up 15 min.

This morning I did the same thing and my charge time went up 25 min.

The only difference between yesterday and today that might be causing my charge time to increase is that I moved my temp up 1 degree.

Hmmmmm……..

I did not say that. I said that NOT on auto may use more energy because of lack of airflow over the heating element.

What you did doesn't really prove it. Your experiment needs to be refined a bit.

 

[derotam]

If I set my car for 70 and its 60 outside.....my fan never goes down to 1 or 2 with auto on. <----- even after I have been sitting in the car for an hour and the inside reaches 70.

You are assuming that the fan uses a lot of energy, or you are assuming that a fan speed of 3 uses a great deal more energy than a fan speed of 1. If you don't know how much energy the fan uses vs speed setting please don't assume.

 

[Garlan Garner]

I did not say that. I said that NOT on auto may use more energy because of lack of airflow over the heating element.

What you did doesn't really prove it. Your experiment needs to be refined a bit.

Turn auto on.....takes longer to charge - every time.

LOL....This is not an experiment.

Good luck.

 

[Garlan Garner]

You are assuming that the fan uses a lot of energy, or you are assuming that a fan speed of 3 uses a great deal more energy than a fan speed of 1. If you don't know how much energy the fan uses vs speed setting please don't assume.

I'm not assuming anything. "Great deal of energy"? What? Who said anything about that? I'm not interested in the amount of power the fan uses or the amount of power the compressor uses or anything of the kind.

Turn on auto.....and my charge time increases every time.

LOL.....

Turn auto off and the charge time goes down.....every time.

Its simple.

 

[thefortunes]

I'm not assuming anything. "Great deal of energy"? What? Who said anything about that? I'm not interested in the amount of power the fan uses or the amount of power the compressor uses or anything of the kind.

Turn on auto.....and my charge time increases every time.

LOL.....

Turn auto off and the charge time goes down.....every time.

Its simple.

I know you won't listen, but just because your setting is 70 doesn't mean that is your interior temp.

If you really want to test this:
1) Park outside at night (so there isn't solar gain difference) and set the fan to one (which is apparently your default) and your temp to 70. After 30 minutes see (on the app) what your interior temp is.
2) Now using some tool (TeslaFi, Stats, etc...) see what your kWh usage is for the next 30 minutes.
3) Change the requested temp to what the inside temp actually is and turn to Auto.
4) Now using some tool (TeslaFi, Stats, etc...) see what your kWh usage is for the next 30 minutes.
5) Compare 2 and 4

I'll bet you dinner they are within a sampling error (and this isn't a sample - so to really do this you would need to rinse/repeat multiple times).

 

[Garlan Garner]

I know you won't listen, but just because your setting is 70 doesn't mean that is your interior temp.

If you really want to test this:
1) Park outside at night (so there isn't solar gain difference) and set the fan to one (which is apparently your default) and your temp to 70. After 30 minutes see (on the app) what your interior temp is.
2) Now using some tool (TeslaFi, Stats, etc...) see what your kWh usage is for the next 30 minutes.
3) Change the requested temp to what the inside temp actually is and turn to Auto.
4) Now using some tool (TeslaFi, Stats, etc...) see what your kWh usage is for the next 30 minutes.
5) Compare 2 and 4

I'll bet you dinner they are within a sampling error (and this isn't a sample - so to really do this you would need to rinse/repeat multiple times).

I measured my inside temp. My phone has an app for that. Its easy.

Sampling error? I'm not sampling anything.

I'm using the charging time of the car to determine that auto appears to use more power. I don't need a 3rd party app. I would NEVER use a 3rd party app.

Let me ask you a question.

What is the problem with auto using more power than non-auto? What's the hangup? You can do it yourself in your own car if you don't believe me.

Everyone that reads this can do it themselves.

 

[DopeGhoti]

Question: Do you think that its possible for "auto" to use less power than it not being engaged?

Yes, in at least one case:

Auto set to (say) 22.5C, interior temperature of 22.5C

compared to

Manual fan set to 3, temperature setting of 22.5 C, interior temperature of 22.5C

Again, your observing of "Time to charge" going up and down as you turn Auto on and off is an instantaneous estimate. Pretend that does not exist. Turn on Camp Mode to keep the A/C on, turn Auto on, and measure actual time to charge in minutes. Not estimated time, but actual time. Then, get the car down to the same SoC in the same weather and temperature conditions and do it again with Auto disengaged. Measure actual time to charge.

 

[Garlan Garner]

Yes, in at least one case:

Auto set to (say) 22.5C, interior temperature of 22.5C

compared to

Manual fan set to 3, temperature setting of 22.5 C, interior temperature of 22.5C

Again, your observing of "Time to charge" going up and down as you turn Auto on and off is an instantaneous estimate. Pretend that does not exist. Turn on Camp Mode to keep the A/C on, turn Auto on, and measure actual time to charge in minutes. Not estimated time, but actual time. Then, get the car down to the same SoC in the same weather and temperature conditions and do it again with Auto disengaged. Measure actual time to charge.

Wait....you want me to pretend that turning auto on does not increase the charge time?

I'll tell you what I'll do. I'm going out to the car right now and plug in. I'll set the fan to 5 without auto and then turn it to auto to see if my charge time goes up or down.

Dog mode is the same as auto to me. That's a useless test.

Listen: I'm comparing auto to non-auto. I'm not comparing auto to other forms of auto.

 

[Knightshade]

It's adorable how you guys keep expecting Garlan to ever accept anything resembling facts or logic

 

[Garlan Garner]

Yes, in at least one case:

Auto set to (say) 22.5C, interior temperature of 22.5C

compared to

Manual fan set to 3, temperature setting of 22.5 C, interior temperature of 22.5C

Again, your observing of "Time to charge" going up and down as you turn Auto on and off is an instantaneous estimate. Pretend that does not exist. Turn on Camp Mode to keep the A/C on, turn Auto on, and measure actual time to charge in minutes. Not estimated time, but actual time. Then, get the car down to the same SoC in the same weather and temperature conditions and do it again with Auto disengaged. Measure actual time to charge.

I just did it. AGAIN.

The SOC is the same as I toggle auto on and of with the manual fan speed at 5.

Fan speed at 5 with auto off. Charge time is 30 min.

Turn auto on. Charge time is 40 min.

SOC is definitely the same as I go back and forth. Interior temp - 49 for both tests. Outside temp is 32 for both tests. Sampling within 20 seconds of each other back and forth.

Question: Why is the charge time toggling back and forth selecting auto on and off? Why do you think this is happening?

 

[thefortunes]

I just did it. AGAIN.

The SOC is the same as I toggle auto on and of with the manual fan speed at 5.

Fan speed at 5 with auto off. Charge time is 30 min.

Turn auto on. Charge time is 40 min.

SOC is definitely the same as I go back and forth. Interior temp - 49 for both tests. Outside temp is 32 for both tests. Sampling within 20 seconds of each other back and forth.

Question: Why is the charge time toggling back and forth selecting auto on and off? Why do you think this is happening?

@Knightshade You may be right. I'll try one last time...

BECAUSE YOU ARE LOOKING AT AN INSTANTANEOUS DIFFERENCE. RUN IT BOTH WAYS OVER TIME AND MEASURE YOUR KWH USAGE. Oh, and remove yourself from the equation (i.e. don't sit in the car) because you are introducing humidity that the car may be attempting to remove by cycling the A/C on and off.

ETA What temp do you have requested? 49F?

 

[derotam]

It's adorable how you guys keep expecting Garlan to ever accept anything resembling facts or logic

Yeah, reminds me of someone else. I dont have the energy to deal with a second person like this right now. Have fun guys.

Ohh and I liked one of Garlan's posts because I am happy he acknowledges that he isn't doing an actual experiment to prove his theory.

 

[DopeGhoti]

I just did it. AGAIN.

You did not just completely charge your car once, to say nothing of twice.

 

[DopeGhoti]

Yeah, reminds me of someone else. I dont have the energy to deal with a second person like this right now. Have fun guys.

Some sad folk such as myself live in the eternal hope that basic cognition will eventually overpower selective literacy if through no other mechanism than osmosis.

 

[derotam]

Some sad folk such as myself live in the eternal hope that basic cognition will eventually overpower selective literacy if through no other mechanism than osmosis.

Yep, that is my wish with another individual I am dealing with.

 

[Garlan Garner]

Why doesn't anyone here answer any of my questions?