Feature Request - Eco-Mode Air Conditioning

[derotam]

I agree the test scenarios were not clearly presented like the manual vs auto HVAC mode tests and dropping the temp to verify the current sensor also would read 0.
When changing the temp on the car there is a ramp rate where the cabin heater will try to stay off but as a steady state temp forms so does the cabin heater staying on 98% of the time.
At 24:40 the cabin heater starts getting close to steady state on above 300 watts.

I will try to make another video with clearer test conditions with clearer results but there has only been a few cases I've seen where the cabin heater is not used when only cooling is desired and thats during a couple short drives when it's 90F plus outside. When the outside temp is just a few degrees above your temp setpoint seems to be the worst case where the cabin heater is used even more.

Others like Josh Wardell who made the model 3 can dbc file verified this behavior as well. Will dig up his post.

GitHub - joshwardell/model3dbc: DBC file for Tesla Model 3 CAN messages

DBC file for Tesla Model 3 CAN messages. Contribute to joshwardell/model3dbc development by creating an account on GitHub.

github.com

Turns out it was a private message. This is what he wrote, also attached the graph of his can output showing the cabin heater use.
"So here's a new shot of the same run, and I added cabin humidity as well, though that doesn't seem to really be affected (I guess you could say that shows things working).
The heaters quickly spike to 2kW each but quickly stabilized at about 800W each. But I would prefer to repeat the test for a longer time to see what the heater use averages. Of course it won't be warm enough for another 6-7 months"

So I know it's not just me. Please run a can test with your test setup if you could.

You are not fully understanding the situation. Yes you can show the cabin heater being on at the same time as the AC given specific hvac temperature set points, yes you can run a test and ONLY show what you want to show. But you can NOT prove that the cabin heater is ALWAYS on when the AC is running.

I am working on getting CAN data, but you still have not specifically confirmed to me what your stance is so it is hard to get you the data you need. I could easily show you that the PTC heater is not constantly on. You even showed that in your youtube video so I don't know what you are trying to say because what I think you are trying to say was disproven in your own youtube video. Yesterday on my way home I did some quick checks to figure out how to best get complete data and this is what I saw.

Outside temp 67F, Cabin temp started at about 90 degrees. Sunny day. Started my drive with set point at 67 to match outside temp, started my drive and waited till the PTC heater started to twitch on. Dropped set point to 62. Never saw the PTC heater twitch on again for the rest of the drive(about 15 minutes). And I will note that the HVAC wattage dropped down to idle usage as opposed to active cooling usage by the time I finished my drive.

So again, what is your claim?

If you want to claim that the PTC heater is constantly on, fine I can disprove that easily enough with CAN data

If you want to claim that the PTC heater always comes on after a defined(by you) set period of time, fine we can run that test too.

And just so everyone else understands how important this is...we are arguing over 5-16Wh/mile(at 60mph) excess usage(@beachmiles own 300-1000W numbers). Unnecessary usage, sure, life changing, no.

An additional correction to past statement, LO setting kicks on below 60F setpoint.

@beachmiles Make your claim and we will test for it and I will provide data. Data, data data, I love data.

Edit: Again, I agree that the PTC heater does come on unnecessarily in some common use scenarios, but it is not constantly on all the time.

 

[beachmiles]

Let's be clear here about what your opinion is first because I don't want to get caught in a moving goal post scenario which you just kind of did I think unknowingly. You have made very opinionated statements which is fine but from a testing standpoint we need to get a set theory down to be able to test against. I am working of your below statement:



There is technical issue with the statement but I am interpreting pretty strictly, based on other comments you have made, that you are saying PTC cabin heater is "constantly" used when in ANY AC cooling scenario. Let me stop there and see where you are standing. I ONLY got into this discussion with you because of your insistence that the PTC heater is CONSTANTLY on which I do not agree with.

I don't have a problem in testing against and politely DISCUSSING a clearly defined theory. I also don't have a problem arguing against emotionally charged statements, but those are two completely different paths of conversation. I have done both on this forum and others.

When you turn your dimmable LED lights on and dim it down a bit humans see the light as being constantly on but if you slow the time down you will see periods where the LED is completely turned off. These periods where the LED is off and ON is averaged out by the human brain which is what we perceive as brightness levels.

At 50% brightness most humans would say the light is is still being constantly on.

The PTC cabin heater appears to also be driven by a similar PWM style signal where it rapidly changes the power every couple milliseconds as commanded by the HVAC code.
Time 0ms=0 watts
Time 100ms=300 watts
Time 200ms=150 watts
Time 300ms=0 watts
Time 400ms=300 watts

This small snippet of time above averages around 150 watts. So when I say "constantly" being used I mean the average wattage sent to the cabin heater over say 30 seconds.

Also i should clarify constantly used is only after the cabin temp reaches steady state temp that equals our 1 temperature setpoint that is slightly below the outside temperature the PTC cabin heater will eventually start to be rapidly cycled on and off. A test setup is outside temps above 72F, a 72F temp setpoint, and cabin cooled to 72F. This can sometimes take some time so there are def some periods where the cabin heater is not used so "constantly" needs to have an asterisk saying shortly after cabin temperature reaches steady state.

After holding 72F for a while eventually the heater will be cycled on at lower wattages averaging under 100 watts and then heater power slowly creeps up over a couple minutes averaging above 300w. If the car was baking in the sun the time to get to steady state cabin temp may take 15+ minutes but eventually the PTC heater will be "constantly" used. Any fan speed will cause the effect but the higher the fan speed the higher the cabin heater use.

I am doing the verification with the can bus through the scanmytesla app which I verified matched 2 difference DC current clamp meters.

I've brought it to the Tesla service center 4+ times while my car was under warranty to fix this issue and they could not fix as it was a software issue that needs to be fixed by a software update which many are still waiting for.

The more people with CAN adapters that can verify this behavior the better, especially those who strongly believe this could not be happening.

 

[derotam]

When you turn your dimmable LED lights on and dim it down a bit humans see the light as being constantly on but if you slow the time down you will see periods where the LED is completely turned off. These periods where the LED is off and ON is averaged out by the human brain which is what we perceive as brightness levels.

At 50% brightness most humans would say the light is is still being constantly on.

The PTC cabin heater appears to also be driven by a similar PWM style signal where it rapidly changes the power every couple milliseconds as commanded by the HVAC code.
Time 0ms=0 watts
Time 100ms=300 watts
Time 200ms=150 watts
Time 300ms=0 watts
Time 400ms=300 watts

This small snippet of time averages around 150 watgs. So when I say constantly being used I mean the average wattage over say 30 seconds.

Once the cabin temp reaches steady state temp that equals our 1 temperature setpoint that is slightly below the outside temperature the PTC cabin heater will eventually start to be rapidly cycled on and off. Like temps above 72F outside, 72F temp setpoint, and cabin cooled to 72F.

After holding 72F for a while eventually the heater will be cycled on at lower wattages averaging under 100 watts and then heater power slowly creeps up over a couple minutes averaging above 300w. If the car was baking in the sun the time to get to steady state cabin temp may take 15+ minutes but eventually the PTC heater will be "constantly" used. Any fan speed will cause the effect but the higher the fan speed the higher the cabin heater use.

I am doing the verification with the can bus through the scanmytesla app which I verified matched 2 difference DC current clamp meters.

I've brought it to the Tesla service center 4+ times while my car was under warranty to fix this issue and they could not fix as it was a software issue that needs to be fixed by a software update which many are still waiting for.

The more people with CAN adapters that can verify this behavior the better, especially those who strongly believe this could not be happening.

Ok great, I agree that in the scenario of Outside temp and setpoint being the same temperature that the PTC heater will cycle on.

Since you sem to be stuck in one scenario to make a wide claim... Here is my statement. With and outside temperature of 80 degrees on a sunny day and the HVAC set to 60 degrees, I do not think the PTC heater will ever come on and stay on constantly.

 

[beachmiles]

Ok great, I agree that in the scenario of Outside temp and setpoint being the same temperature that the PTC heater will cycle on.

Since you sem to be stuck in one scenario to make a wide claim... Here is my statement. With and outside temperature of 80 degrees on a sunny day and the HVAC set to 60 degrees, I do not think the PTC heater will ever come on and stay on constantly.

I stated the outside temp is above the temp setpoint in the test setup. If it's at all warmer outside than inside the car then heating the car with the PTC cabin heater does not make sense.

Make the outside temp 80F and your temp setpoint 72F and you will see the same behavior. I've gone down to a temp setpoint of 62F with it 80F outside and have still seen the cabin heater being used but it takes longer to get there. It does seem like at 62F and below the cabin temp stops getting used so much when it is 80F outside.

Not many folks run the temp at 60F with it 80F outside but with this test I agree the cabin heater will prob likey not come on. But this is not a likely real world use case.

 

[derotam]

I stated the outside temp is above the temp setpoint in the test setup. If it's at all warmer outside than inside the car then heating the car with the PTC cabin heater does not make sense.

Make the outside temp 80F and your temp setpoint 72F and you will see the same behavior. I've gone down to a temp setpoint of 62F with it 80F outside and have still seen the cabin heater being used but it takes longer to get there. It does seem like at 62F and below the cabin temp stops getting used so much when it is 80F outside.

Not many folks run the temp at 60F with it 80F outside but with this test I agree the cabin heater will prob likey not come on. But this is not a likely real world use case.

Ok, looks like we have gotten to a bit of an agreement. My main issue with the way you were making your statements is the implication that this is such a HUGE issue and seeming to make this sound like a bigger issue than what it is. So I think we can agree that the PTC heater is not constantly on. I agree that the heater does come on in common use scenarios when reaching equilibrium between the setpoint and cabin temp which is unnecessary, and I have said all that before. Do I think there is this HUGE amount of wasted power though, no. I also say that the higher the differential between outside temp and setpoint, the less of an issue this is.

 

[beachmiles]

Ok, looks like we have gotten to a bit of an agreement. My main issue with the way you were making your statements is the implication that this is such a HUGE issue and seeming to make this sound like a bigger issue than what it is. So I think we can agree that the PTC heater is not constantly on. I agree that the heater does come on in common use scenarios when reaching equilibrium between the setpoint and cabin temp which is unnecessary, and I have said all that before. Do I think there is this HUGE amount of wasted power though, no. I also say that the higher the differential between outside temp and setpoint, the less of an issue this is.

Glad to be in agreement that in common use cases the cabin heater is eventually unnecessarily used, dare I say "constantly" used.

Would you agree to this statement?
For the normal use case of wanting the cool the car when it's hot outside and you only want to cool the car to a comfortable human temperature like 70F the PTC cabin heater will eventually "constantly" be used averaging between 300-1000 watts depending on things like the fan speed.

Next up is discussing how significant this unnecessary use of cabin heater is. You like many other folks don't seem to really mind wasting 300-1000 watts in your battery powered car. For me there are a couple reasons why I consider this waste of power to be significant.
1) I don't like feeling luke cold air blowing through the vents after the cabin heater reheats the air that we just cooled down. I want cold air not luke cold air.
2) An average of 300-1000 watts is being wasted in my battery powered car decreasing my range on road trips.
3) This waste of power will require more charge cycles and wear and tear on the battery reducing its capacity.
4) I don't have solar power so this extra power usage has to come from the grid and is not free.
5) Most power grids like mine are not 100% renewable yet.
6) I don't like wasting resources in general. I never want to leave on 30-100 10 watt led bulbs in my house when I'm not home, and I def don't want to effectively do the same inside my battery powered car while on the road.

 

[derotam]

Would you agree to this statement?
For the normal use case of wanting the cool the car when it's hot outside and you only want to cool the car to a comfortable human temperature like 70F the PTC cabin heater will eventually "constantly" be used averaging between 300-1000 watts depending on things like the fan speed.

Not necessarily because it really comes down to the heat load on the car vs the setpoint. Lets say it's 105F outside, do you still believe that a setpoint of 70F will cause the unnecessary heating? I don't think so, but I have no way to test that...well I guess I could close my garage and turn on a propane heater to simulate it. The other way would be to put a small electric heater in the cabin.

Next up is discussing how significant this unnecessary use of cabin heater is. You like many other folks don't seem to really mind wasting 300-1000 watts in your battery powered car. For me there are a couple reasons why I consider this waste of power to be significant.
1) I don't like feeling luke cold air blowing through the vents after the cabin heater reheats the air that we just cooled down. I want cold air not luke cold air.
2) An average of 300-1000 watts is being wasted in my battery powered car decreasing my range on road trips.
3) This waste of power will require more charge cycles and wear and tear on the battery reducing its capacity.
4) I don't have solar power so this extra power usage has to come from the grid and is not free.
5) Most power grids like mine are not 100% renewable yet.
6) I don't like wasting resources in general. I never want to leave on 30-100 10 watt led bulbs in my house when I'm not home, and I def don't want to effectively do the same inside my battery powered car while on the road.

I didn't say I don't mind, I'm just saying the sky isn't actually falling.

1 - Here is an interesting thought, might have to look at this...in an ICE car after reaching equilibrium in the cabin, does the air coming out of the vents stay at max cool temperature from the AC? Also, the temperature of the air isn't all due to the PTC heater, at equilibrium the AC cuts down and adjusts its target temp which would also increase air temperature.

2 - You are right, that is ~1-6% (~5-20 miles) lost at 60mph.

3 - I'll just say negligible to this one.

4 - You are right. At my power prices($0.12/kWh) that would be $10-$33 per year in extra cost from grid

5 - Sure, general environment argument. You don't buy anything from China right? I say that not to be argumentative, just that people could probably save more carbon footprint by cutting down on made in China items considering almost 60% of their power is from coal.

6 - Sure, general environment concern.

Look, I don't have a problem with your environmental concerns but that weighs into the emotional aspect of the types of statements you have made. Again, my biggest issue with this whole conversation is that you are trying to say that the PTC heater is "constantly" on all the time putting out 300-100W of power. From a literal standpoint, that is just false. I have data to show that, you have your own video that shows that.

Do I agree that this is something that needs to be addressed by Tesla, absolutely...but I don't think it is as big of a real(subjective obviously) problem as you made it out to be.

"how significant this unnecessary use of cabin heater is."
Depends on how you want to look at this...so far you SEEM to be using your personal feelings. I have provided some numbers to define the range hit based on your numbers. I don't necessarily want to agree with your numbers as an average though. They might be good, might not. I do plan on looking at this more as it starts getting warmer out.

 

[beachmiles]

Not necessarily because it really comes down to the heat load on the car vs the setpoint. Lets say it's 105F outside, do you still believe that a setpoint of 70F will cause the unnecessary heating? I don't think so, but I have no way to test that...well I guess I could close my garage and turn on a propane heater to simulate it. The other way would be to put a small electric heater in the cabin.



I didn't say I don't mind, I'm just saying the sky isn't actually falling.

1 - Here is an interesting thought, might have to look at this...in an ICE car after reaching equilibrium in the cabin, does the air coming out of the vents stay at max cool temperature from the AC? Also, the temperature of the air isn't all due to the PTC heater, at equilibrium the AC cuts down and adjusts its target temp which would also increase air temperature.

2 - You are right, that is ~1-6% (~5-20 miles) lost at 60mph.

3 - I'll just say negligible to this one.

4 - You are right. At my power prices($0.12/kWh) that would be $10-$33 per year in extra cost from grid

5 - Sure, general environment argument. You don't buy anything from China right? I say that not to be argumentative, just that people could probably save more carbon footprint by cutting down on made in China items considering almost 60% of their power is from coal.

6 - Sure, general environment concern.

Look, I don't have a problem with your environmental concerns but that weighs into the emotional aspect of the types of statements you have made. Again, my biggest issue with this whole conversation is that you are trying to say that the PTC heater is "constantly" on all the time putting out 300-100W of power. From a literal standpoint, that is just false. I have data to show that, you have your own video that shows that.

Do I agree that this is something that needs to be addressed by Tesla, absolutely...but I don't think it is as big of a real(subjective obviously) problem as you made it out to be.

"how significant this unnecessary use of cabin heater is."
Depends on how you want to look at this...so far you SEEM to be using your personal feelings. I have provided some numbers to define the range hit based on your numbers. I don't necessarily want to agree with your numbers as an average though. They might be good, might not. I do plan on looking at this more as it starts getting warmer out.

Ok, gotta make sure we dont go off the rails with much rarer use cases like when it's 105F+ outside. How about this?
"For the normal use case of wanting the cool the car when it's hot outside (71-85F) and you only want to cool the car to a comfortable human temperature at say 70F the PTC cabin heater will eventually "constantly" be used after the cabin cools and reaches the temp setpoint averaging between 300-1000 watts depending on things like the fan speed."

I live in a desert and hate the heat forcing me to run the AC almost always. It sucks that the only way to turn off the cabin heater is to set the temp LO and throttle the cabin temp with the fan speed. I really don't think I'm crazy here and am justified to have strong negative feelings about this multi year unfixed HVAC bug.
Having strong feelings about something doesn't generally mean people are making *sugar* up.

Unfortunately the scanmytesla app doesn't allow exporting data anymore which would allow for much better data plots but video screenshots is enough to get an average power usage along with the DC current clamp meter verification that I've done.

I've also previously pulled the cabin heater CAN bus connection to the PTC heater to physically disable it and experienced some very wacked out behavior like with a temp setpoint of 70F the cabin temp will quickly drop to 60F. It's like the AC evaporator doesn't know how to throttle down and/or it is expecting the cabin heater to raise the temp but since it's not plugged in the cabin temp just keeps dropping. Will try to make some movies with better test setup and data presentation.

1) Maybe it's the lack of vents in the Tesla M3 but in every other car I've driven the air coming out of the AC feels colder than what comes out of the Tesla when the cabin heater is being throttled when it's not in LO mode. Next time I'm in another car I'll breakout my IR thermal camera and do some tests.

2) not sure where you are getting these numbers. My commute is about 2 hours each day. In my case more than half that time is with the ac on. If I didn't have it set to LO that would be close to 1 kWh wasted per day or 240kwh per year just from my commute.

3) 240kwh wasted every year is over 3 full wasted battery cycles which is not negligible.

4) here in socal it's 40c per kwh off peak which is 96 bucks wasted per year. Def not the end of the world but a waste all the same.

5) yes I don't source everything from carbon neutral sources, but I try my best. Yes there are staving people in Africa and war and many other much shittier things in the world. Seems like you really want to be argumentative here and don't want to address the issue at hand.

6) yes I have environmental concerns, and every little bit helps, right? If you sum up this small waste from every car across the entire Tesla fleet with PTC cabin heaters then it becomes a much larger thing.

Ill look forward to it getting hotter outside so you can run some tests to validate what me, Josh Wardell, and others have seen. Found a better public post from josh validating my results.

Any way to disable heat in Model 3?

www.teslaownersonline.com

https://www.reddit.com/r/teslamotors/s/SwkejHuKWB

cabin heater coming on when only cooling desired

teslamotorsclub.com

 

[derotam]

Ok, gotta make sure we dont go off the rails with much rarer use cases like when it's 105F+ outside. How about this?
"For the normal use case of wanting the cool the car when it's hot outside (71-85F) and you only want to cool the car to a comfortable human temperature at say 70F the PTC cabin heater will eventually "constantly" be used after the cabin cools and reaches the temp setpoint averaging between 300-1000 watts depending on things like the fan speed."

I live in a desert and hate the heat forcing me to run the AC almost always. It sucks that the only way to turn off the cabin heater is to set the temp LO and throttle the cabin temp with the fan speed. I really don't think I'm crazy here and am justified to have strong negative feelings about this multi year unfixed HVAC bug.
Having strong feelings about something doesn't generally mean people are making *sugar* up.

Unfortunately the scanmytesla app doesn't allow exporting data anymore which would allow for much better data plots but video screenshots is enough to get an average power usage along with the DC current clamp meter verification that I've done.

I've also previously pulled the cabin heater CAN bus connection to the PTC heater to physically disable it and experienced some very wacked out behavior like with a temp setpoint of 70F the cabin temp will quickly drop to 60F. It's like the AC evaporator doesn't know how to throttle down and/or it is expecting the cabin heater to raise the temp but since it's not plugged in the cabin temp just keeps dropping. Will try to make some movies with better test setup and data presentation.

1) Maybe it's the lack of vents in the Tesla M3 but in every other car I've driven the air coming out of the AC feels colder than what comes out of the Tesla when the cabin heater is being throttled when it's not in LO mode. Next time I'm in another car I'll breakout my IR thermal camera and do some tests.

2) not sure where you are getting these numbers. My commute is about 2 hours each day. In my case more than half that time is with the ac on. If I didn't have it set to LO that would be close to 1 kWh wasted per day or 240kwh per year just from my commute.

3) 240kwh wasted every year is over 3 full wasted battery cycles which is not negligible.

4) here in socal it's 40c per kwh off peak which is 96 bucks wasted per year. Def not the end of the world but a waste all the same.

5) yes I don't source everything from carbon neutral sources, but I try my best. Yes there are staving people in Africa and war and many other much shittier things in the world. Seems like you really want to be argumentative here and don't want to address the issue at hand.

6) yes I have environmental concerns, and every little bit helps, right? If you sum up this small waste from every car across the entire Tesla fleet with PTC cabin heaters then it becomes a much larger thing.

Ill look forward to it getting hotter outside so you can run some tests to validate what me, Josh Wardell, and others have seen. Found a better public post from josh validating my results.

Any way to disable heat in Model 3?

www.teslaownersonline.com

https://www.reddit.com/r/teslamotors/s/SwkejHuKWB

cabin heater coming on when only cooling desired

teslamotorsclub.com

I got the numbers from you(300-1000W) and I used 75kWh for bat capacity and 310miles for rated range and then did math. We can change the numbers around a bit but it won't change things much.

I see where this is going. Hows this, you show me an 85 degree day, car in the sun, set point to lets say 62 and show me the heater on. Other than that you just seem to want to live in your bubble and maintain the complain in a limited window of values because 105F outside is "much rarer". Really? You don't want to know how the system works or to what extent the heater issue is. You just want to complain for the situation that you are in. That is fine, go ahead but it makes my point of saying the sky is falling when it only looks like that to you and you don't want to acknowledge any other scenario because again it is your belief that those other scenarios are "much rarer" so they don't count. Tell that to people in Phoenix in the dead of summer.

If you want to complain then complain. If you want to characterize the issue fully and try to look at the actual bounds of the problem then great, but it doesn't look like you care about that at this point.

I have already said I agree there is an issue. You want to just stop there and claim the sky is falling. I want to characterize the problem and see how wide the problem is. I am only arguing to get more data. It's fine.

Again, 85F day, car in the sun, AC set to 62...record SMT data from the time you start to 10 minutes after the PTC heat kicks on. Make sure you add Outside temp to the SMT recording. and to make things more relevant to "normal use", make sure the car has been sitting in that sun for a couple hours(to simulate getting in and starting from the end of your work day).

I would LOVE to see THAT data, THAT would be useful, even if it is only one limited temperature scenario.

 

[beachmiles]

I got the numbers from you(300-1000W) and I used 75kWh for bat capacity and 310miles for rated range and then did math. We can change the numbers around a bit but it won't change things much.

I see where this is going. Hows this, you show me an 85 degree day, car in the sun, set point to lets say 62 and show me the heater on. Other than that you just seem to want to live in your bubble and maintain the complain in a limited window of values because 105F outside is "much rarer". Really? You don't want to know how the system works or to what extent the heater issue is. You just want to complain for the situation that you are in. That is fine, go ahead but it makes my point of saying the sky is falling when it only looks like that to you and you don't want to acknowledge any other scenario because again it is your belief that those other scenarios are "much rarer" so they don't count. Tell that to people in Phoenix in the dead of summer.

If you want to complain then complain. If you want to characterize the issue fully and try to look at the actual bounds of the problem then great, but it doesn't look like you care about that at this point.

I have already said I agree there is an issue. You want to just stop there and claim the sky is falling. I want to characterize the problem and see how wide the problem is. I am only arguing to get more data. It's fine.

Again, 85F day, car in the sun, AC set to 62...record SMT data from the time you start to 10 minutes after the PTC heat kicks on. Make sure you add Outside temp to the SMT recording. and to make things more relevant to "normal use", make sure the car has been sitting in that sun for a couple hours(to simulate getting in and starting from the end of your work day).

I would LOVE to see THAT data, THAT would be useful, even if it is only one limited temperature scenario.

Glad that you have agreed there is a problem. I never said the sky was falling, I said the bug sucks which I suppose could be considered rude to some. Forgive me for offending you.

Sure will make a clearer video proving the edge case of my claim the next time it's 85F outside with a 70F setpoint.
Will try to make another video proving the easier to replicate case when it's 71F outside with a 70F setpoint.

In the meantime be sure to check out that post by Josh Wardell in 2019 with additional data.

Any way to disable heat in Model 3?

www.teslaownersonline.com

 

[derotam]

Glad that you have agreed there is a problem. I never said the sky was falling, I said the bug sucks which I suppose could be considered rude to some. Forgive me for offending you.

Sure will make a clearer video proving the edge case of my claim the next time it's 85F outside with a 70F setpoint.
Will try to make another video proving the easier to replicate case when it's 71F outside with a 70F setpoint.

In the meantime be sure to check out that post by Josh Wardell in 2019 with additional data.

Any way to disable heat in Model 3?

www.teslaownersonline.com

With tons of respect to Josh for all the work he has done, I am not going to entertain 4 year old data. A LOT has changed.

"Constantly" using "1000W" is sky falling talk. And from what I have seen, I would love to see 1000W "constant" PTC usage under normal cooling conditions. setpoint and outside temp being the same would not be a valid test for sky falling talk.

And here is the results of my drive home today:

Car "hot" soaked for greater than 3 hours.
Outside Temperature - 77F
HVAC Set Point - 70F Auto
1 hour drive, combo city and highway speeds.

First 45 minutes, absolutely NO power twitches on the PTC heater in SMT.
Last 15 minutes, PTC heater irregularly twitching. Max PTC heater twitch was never more that 144W. Usually alternating between 0 and 69.x

I would say those are more than reasonable conditions for a test, and there was no where near even 300W "constant" heat usage

I was even uncomfortably warm in the car given that I don't like the air blowing directly on me so for most of drive I had the vents pointed so it wasn't directly on me. I had to put the air on me at some point because I was just too warm...I would rather have dropped the setpoint(which would have nuked the little bit of PTC heater usage that was happening by the way), but I wanted to maintain testing conditions.

So what are your thoughts on that result?

 

[beachmiles]

With tons of respect to Josh for all the work he has done, I am not going to entertain 4 year old data. A LOT has changed.

"Constantly" using "1000W" is sky falling talk. And from what I have seen, I would love to see 1000W "constant" PTC usage under normal cooling conditions. setpoint and outside temp being the same would not be a valid test for sky falling talk.

And here is the results of my drive home today:

Car "hot" soaked for greater than 3 hours.
Outside Temperature - 77F
HVAC Set Point - 70F Auto
1 hour drive, combo city and highway speeds.

First 45 minutes, absolutely NO power twitches on the PTC heater in SMT.
Last 15 minutes, PTC heater irregularly twitching. Max PTC heater twitch was never more that 144W. Usually alternating between 0 and 69.x

I would say those are more than reasonable conditions for a test, and there was no where near even 300W "constant" heat usage

I was even uncomfortably warm in the car given that I don't like the air blowing directly on me so for most of drive I had the vents pointed so it wasn't directly on me. I had to put the air on me at some point because I was just too warm...I would rather have dropped the setpoint(which would have nuked the little bit of PTC heater usage that was happening by the way), but I wanted to maintain testing conditions.

So what are your thoughts on that result?

Interesting. Maybe they finally have made some fixes recently, any chance you have the ear of a Tesla HVAC engineer and they pushed a hidden update from the mothership?

If the car has been baking in the sun for a while it can take a while to reach steady state and the issue to show up. If the car is parked in the shade the issue should show much earlier. In my testing today I had similar results with a temp setpoint of 66 with it 67 outside with a fan speed of 1 as I got about 20 minutes before the cabin heater started kicking on at lower wattages. As I raised the fan speed to 4 the cabin heater started raising above 300 watts, and as I raised the fan speed higher the cabin heater usage increased as well. My cabin was already heat soaked a bit for this test unfortunately.

I was testing on this same 2023.44.30.14 build about a week ago and was seeing the same 300w + heater usage as I have for years with the temp outside at around 74 and my setpoint at 70 with the fan speed at 1 so I didn't run any more extensive tests but maybe things have improved recently so I will ramp up testing.

 

[derotam]

Interesting. Maybe they finally have made some fixes recently, any chance you have the ear of a Tesla HVAC engineer and they pushed a hidden update from the mothership?

If the car has been baking in the sun for a while it can take a while to reach steady state and the issue to show up. If the car is parked in the shade the issue should show much earlier. In my testing today I had similar results with a temp setpoint of 66 with it 67 outside with a fan speed of 1 as I got about 20 minutes before the cabin heater started kicking on at lower wattages. As I raised the fan speed to 4 the cabin heater started raising above 300 watts, and as I raised the fan speed higher the cabin heater usage increased as well. My cabin was already heat soaked a bit for this test unfortunately.

I was testing on this same 2023.44.30.14 build about a week ago and was seeing the same 300w + heater usage as I have for years with the temp outside at around 74 and my setpoint at 70 with the fan speed at 1 so I didn't run any more extensive tests but maybe things have improved recently so I will ramp up testing.

My opinion about all this is that since the problem first appeared or was found out about, that either Tesla made changes, or the problem is/was not as bad as what it seemed at first glance with limited data, or a combination of both. It's easy to go OMG look at this! and then later find out that the one specific scenario you were looking at was an anomaly or that you just ended up in that sweet spot of the failure mode.

Again, you are in a loosing scenario if your set temp is close to the outside temp, even more so if the outside temp and cabin temp are close.

Raising the fan speed is going to make things worse also because the car is trying to maintain a certain duct temperature for the conditions so if you raise the fan speed the heater is going to put out more to maintain that duct temperature. Lowering fan speeds induces different variations that the car will adjust too.

Auto, auto, auto. I think that is the main way to test this or a lot of there HVAC things unless you are trying to test something very specific or chase down a setting specific issue. Even with this testing things operation could change depending on whether the HVAC is doing fresh air or recirculate because that is going to change humidity levels going through the system which is going to possibly change how much the AC/heat is on to compensate.

In the end here, I believe that if you have a set point more than 10 degrees less than the outside temp I would think that the car could use the outside air to provide whatever heat is needed....BUT there are LOTS of variables here about what the car is doing and making decisions on. The biggest issue though is that if you are bringing in humid air and the car wants to dehumidify that, what does it have to do, it has to cool the air to condense out the moisture, and then HEAT the air to maintain the cabin set point...so it's all a matter of how it has to accomplish that goal and what is the most efficient way to do that.

I will stress again though that I don't believe a 300-1000W constant usage in a, lets just say 10 degree differential between outside temp and set point in AUTO mode. I think any situation that could cause that would be an edge case and probably not a normal situation.

Ohh and for the numbers from an earlier post... 1000W constant usage at 60mph equals 16Wh/mile. So over lets just go 15k miles a year, that is 240kWh which is a little over 3 full battery cycles. 15k miles is ~3540kWh(~236Wh/mile, parity for 2018 M3 LR). so 240kWh is about 6.5% extra usage. at 300W constant it would be 2%. And that would be if it is 300-1000W constant all year round.

The sky is not falling.

 

[derotam]

I know @beachmiles data that doesn't support your opinion is so inconvenient and annoying.

From a recent SMT data capture...was not a full up test so I don't have ALL of the pertinent info but some of the data is interesting, you'll even like some of it too.

I'll start with what you will LOVE!

Ok test conditions:
Outside temperature was 68F
Cabin temp started at 78.8F
HVAC set to auto
HVAC set to unknown setpoint but would have been between 64 and 68, likely 66 or 68

The car reports PTC heater power at irregular intervals but at quick glance it looked vary between 5 and 200ish ms.


On an 11 minute SMT data capture I recrorded the PTC heater total jumping up to a WHOPPING 646.2W! OMG!

Now for the analysis...
Tossed the data into excel and duplicated reported PTC power levels through the unreported times until the next reporting cycle. This allows for as best as we can hope for averaging calculations of power usage over time. What did it average across the entire 11 minute data capture... 68.89W which over an hour would be... 375Wh. So at 60mph for example that equals 6.25Wh per mile. With a parity of ~236Wh/mile for vehicle efficiency that means an extra 6.25Wh/mile is 2.64% additional usage. If you GENEROUSLY apply that to EVERY mile you drive for 15k miles a year, that is 93.75kWh extra per year.

It it a waste if totally unnecessary for vehicle operation, sure, but only if it is unnecessary. Is it "sky falling" amount, no.

Feel free to provide your own MATH backed by actual data captures.

I plan at some point to run my drive home test again and start capturing as soon at the car starts using the PTC heater and then re-runing the analysis on that proper data capture.

 

[beachmiles]

I know @beachmiles data that doesn't support your opinion is so inconvenient and annoying.

From a recent SMT data capture...was not a full up test so I don't have ALL of the pertinent info but some of the data is interesting, you'll even like some of it too.

I'll start with what you will LOVE!

Ok test conditions:
Outside temperature was 68F
Cabin temp started at 78.8F
HVAC set to auto
HVAC set to unknown setpoint but would have been between 64 and 68, likely 66 or 68

The car reports PTC heater power at irregular intervals but at quick glance it looked vary between 5 and 200ish ms.


On an 11 minute SMT data capture I recrorded the PTC heater total jumping up to a WHOPPING 646.2W! OMG!

Now for the analysis...
Tossed the data into excel and duplicated reported PTC power levels through the unreported times until the next reporting cycle. This allows for as best as we can hope for averaging calculations of power usage over time. What did it average across the entire 11 minute data capture... 68.89W which over an hour would be... 375Wh. So at 60mph for example that equals 6.25Wh per mile. With a parity of ~236Wh/mile for vehicle efficiency that means an extra 6.25Wh/mile is 2.64% additional usage. If you GENEROUSLY apply that to EVERY mile you drive for 15k miles a year, that is 93.75kWh extra per year.

It it a waste if totally unnecessary for vehicle operation, sure, but only if it is unnecessary. Is it "sky falling" amount, no.

Feel free to provide your own MATH backed by actual data captures.

I plan at some point to run my drive home test again and start capturing as soon at the car starts using the PTC heater and then re-runing the analysis on that proper data capture.

You are very intense.

Could you send me your the raw data so I could check your math? If you are seeing the cabin heater jumping up to 646.2W then I'm sure your average will be higher than 68.89W.

Today's test for me was a setpoint of 69F and outside temp at 72F.
It appears Tesla made some fixes when running at fan speed level 1 so the issue takes much longer to show up, and when it does it seems to stay under an average of 150 watts. This is def an improvement since my last testing.

But as the fan speed increases so does the cabin heater usage.
The 300+ watt usage mainly occurs when using a fan speed of 2 or above. A fan speed of 4 starts to average above 500 watts.

Setting the HVAC to auto and low fan speed instantly ramped the cabin heater average above 500 watts so it's equivalent / a tad worse than running in manual mode. Auto with medium fan speed was even worse as expected.

I'm pretty sure the HVAC usage is not coupled to the vehicle speed so we can just talk about kilowatt hours used by the heater and not watt hours/mile changes. Maybe I'm wrong in thinking this is the case though.

I wish I could export the logs from scanmytesla but the android app lost this feature in the beta release which fixed the PTC heater power calculation. I will have to take screenshot video of the app, and will try to add other data like in outside and cabin temp from the Tesla app.

 

[derotam]

You are very intense.

Could you send me your the raw data so I could check your math? If you are seeing the cabin heater jumping up to 646.2W then I'm sure your average will be higher than 68.89W.

Today's test for me was a setpoint of 69F and outside temp at 72F.
It appears Tesla made some fixes when running at fan speed level 1 so the issue takes much longer to show up, and when it does it seems to stay under an average of 150 watts. This is def an improvement since my last testing.

But as the fan speed increases so does the cabin heater usage.
The 300+ watt usage mainly occurs when using a fan speed of 2 or above. A fan speed of 4 starts to average above 500 watts.

Setting the HVAC to auto and low fan speed instantly ramped the cabin heater average above 500 watts so it's equivalent / a tad worse than running in manual mode. Auto with medium fan speed was even worse as expected.

I'm pretty sure the HVAC usage is not coupled to the vehicle speed so we can just talk about kilowatt hours used by the heater and not watt hours/mile changes. Maybe I'm wrong in thinking this is the case though.

I wish I could export the logs from scanmytesla but the android app lost this feature in the beta release which fixed the PTC heater power calculation. I will have to take screenshot video of the app, and will try to add other data like in outside and cabin temp from the Tesla app.

Sorry, I get a bit rabid when people try to blow things out of proportion and claim 1kW constant heater usage during cooling conditions of outside temp of 80F and a HVAC setting of 70F.

What exactly was the PTC heater calculation fix in the beta?

 

[Gasaraki]

This is not correct.

Incorrect.



This video is misleading and gives the impression warm air is contained within cold air - this is incorrect.

The HVAC system stands for Heating ventilation and air conditioning.
“HVAC is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space.”

The various technologies include compressed refrigerant, fans, suction, a compressor, condenser, etc.

A HVAC unit is not a “heat pump” blowing or sucking heat or cold air from one part to another. It’s more complex than that.

At the end of the day, the Polestar 2 HVAC system has an eco-mode (using about half the energy) a heater toggle and uses about 10% of the battery and around 0.3-2kw.

The Tesla Y HVAC unit is reported to use anywhere between 0.8-7kw and customers complain about the missing functions. Customers claim the unit uses up to 50% of the battery. This has been my experience also.

It would be good to have some support for these ideas instead of people just repeating random things from YouTube videos.

Wow, I did not know that -20F = absolute zero. That's new.

 

[DownshiftDre]

Really good conversations going on here. Valid points on both. Wish I can contribute but I have the heat pump system and my knowledge and opinion is around the operation of that system type which the OP was inquiring about.

For the PTC version, let’s be honest and transparent. Do you we think Tesla will ever issue a software update for anything PTC heater related? Seems like Tesla likely was aware of these corner use case conditions and the deficiencies even in the pre-2021 design, and just designed it out with the heat pump system.

The dialogue is great here and glad everybody has a level of respect with responses (and with data) compared to when this thread was first started and misinformation spreading.