Discussion of A/C use in cold weather

[TimothyHW3]

Hm, 10-15% is a big range difference. City speed will be even more...

That is because the test was flawed.

If you look at the first part of the test, they had both cars on manual. Then he changed her setting and put it on Auto, basically turning on AC in the winter which is an overkill. His setting remained on manual.

I am not quite sure why Tesla does this, because AC off and just using normal heating is perfectly fine and is not clouding the windows. Anyways, turning the 2019 on Auto and the 2021 on manuel (you can see at one point it says "manual") we are not quite sure it the AC is on in the 2021.

I have made a test of an 2019 and I clocked it at about 1-1.2kW using the heater (no AC, turned off) when the car is warm.

If you turn on the AC on, it jumps to 3-4kW. (we take 3kW at 125km/h which equals 2.5kW spend in 1 hour for 100km travelled vs lets say around 500W spend for the 2021 which is exactly the 0.2-0.25kWh/100km difference we see here.) I explain this at the 5 minute mark.

With smart heating management - put it on manual, set to 3, set to 22.5C/70F and AC icon off (confirmed in the first part of the test, where they had both cars on manual and both were pulling the same consumption), then you can expect almost no difference (about 500W or about 35Wh/km which is about 1.5-2% difference. At lower speeds in the city it might jump to about 5% diffence at best at avg speeds of 40km/h

Also bear in mind that 6C is like the perfect sweet spot for a heat pump. There is another video they tested and the heat pump on the 2021s can go to as low as 400W where as the PTC can go as low as 900W-1.2kW at these temperatures, which is roughly the 1:3 ratio you would expect in ideal conditions.

It is something, but def not 10% on the highway and not that much as it is represented in the video.

I will be doing my own test in a few weeks and will show exactly that.

 

[solar3]

basically turning on AC in the winter which is an overkill. His setting remained on manual.

I am not quite sure why Tesla does this, because AC off and just using normal heating is perfectly fine and is not clouding the windows. Anyways, turning the 2019 on Auto and the 2021 on manuel (you can see at one point it says "manual") we are not quite sure it the AC is on in the 2021.

That is one of the things that bugged me since day 2 of owning the car. I actually emailed Tesla executive team about it, asking them to decouple the AC button from the auto button, and they actually replied saying they'll take my request into consideration. In every car with auto climate control, if I manually change any of the settings such as fan speeds and vent position and of course the AC compressor, all the other settings remain on auto. In the Tesla, change anything and everything is on manual. So in my Model 3, the only time I use auto is during the summer. All other times it's on manual.

 

[Saturday]

I feel like an easy way to fix this is to have a default AC on/off toggle option in a settings menu somewhere. Should only have to hit it basically twice a year, each at the change of seasons.

 

[TimothyHW3]

I feel like an easy way to fix this is to have a default AC on/off toggle option in a settings menu somewhere. Should only have to hit it basically twice a year, each at the change of seasons.

I don't really understand what the point of AC in the winter is anyways. Having the heater on 2-3 without AC is perfectly normal and is not resulting in foggy windows. I think this is just something they never tested, because Fremont and California.

I am not quite sure I really like the idea of the heat pump. In the other thread a Model Y never gets past 170-180kW on a V3 Supercharger in the winter and we have another Model 3 from Denmark on a video stopping shy of 175kW exhibiting the same slow charge. I will have to test this myself how the heat pump affects charging in the winter, because it seems Tesla ditched the stators heating for the heat pump. Less power used, but slower charging seems to be the result. And more noisy heating.

 

[Marius A]

I don't really understand what the point of AC in the winter is anyways. Having the heater on 2-3 without AC is perfectly normal and is not resulting in foggy windows. I think this is just something they never tested, because Fremont and California.

I am not quite sure I really like the idea of the heat pump. In the other thread a Model Y never gets past 170-180kW on a V3 Supercharger in the winter and we have another Model 3 from Denmark on a video stopping shy of 175kW exhibiting the same slow charge. I will have to test this myself how the heat pump affects charging in the winter, because it seems Tesla ditched the stators heating for the heat pump. Less power used, but slower charging seems to be the result. And more noisy heating.

My 2020 TM3P never supercharged above 60kW, 20 min preheat, 40% SOC, all other cars in the lot were charging at 120-150kW
Tesla checked it 3 times, said nothing was wrong. However, I spent all of my 3000km referral charging on that car and never got above 60kW.
Even tested a TMS I got as a loaner, over 100kW on the exact same charger.
Long story short: might have nothing to do with the heat pump

 

[TimothyHW3]

My 2020 TM3P never supercharged above 60kW, 20 min preheat, 40% SOC, all other cars in the lot were charging at 120-150kW

20 minutes on a cold battery is nothing. 40% SOC is high - low battery with high SOC - slow charging , happened to me many times. 60kW the best you will get.
And was there any car in the adjucent B slot? You do know about the A -B stuff do you? Did you never supercharge that car below 10% in the summer?!

Tesla checked it 3 times, said nothing was wrong. However, I spent all of my 3000km referral charging on that car and never got above 60kW.

Read above, A+B or the battery was cold or high SOC or both. You should charge from 10% when the batter is warm (like in above 30C, which might take 1.5 hours of preheating in Norway)

Long story short: might have nothing to do with the heat pump

Oh, I am pretty sure it does have something to do with it and will prove it soon - we have a confirmation that the LR 2021 model doesn't use the motors/stators to heat up the battery which results in 7kW more charging speed, but if the battery is not wam enough, the heat pump can't get it to temperature like the motors did on the 2018-2020 models.

I never charged at below 170kW on V3 in my old Model 3, even in the winter. Always at least 200kW-220kW or about 180kW on IONITY. And so far I have seen 4 videos where the Y or 3 with heat pump can't get anywhere near 200kW, mostly below 170 to 150kW and also very slow charging to 80% - sometimes 50 minutes. To me it seems unles the battery is warm after a highway run, the 2021 will struggle in the cold.

Model Y Supercharger V3 kW Speeds in Cold weather

This could also be because of the battery, we don't know yet.

 

[Ofarlig]

I don't really understand what the point of AC in the winter is anyways. Having the heater on 2-3 without AC is perfectly normal and is not resulting in foggy windows. I think this is just something they never tested, because Fremont and California.

Try going in - 20 without AC after getting in loads of snow, you will have ice forming on windows even with AC running but without it there will be loads. The windscreen might fog over completely in a second as well if you are unlucky. You will have partly the same problem even at - 10 with.

 

[Mash]

I have to say that Tesla measures the humidity of the air inside and multiple points of temperature - I trust that Auto mode does the most reasonable thing in most conditions. And if not - it will improve that. I also have a feeling that they measure CO2 to decide the level of ventilation, except if you put it on recirculation it follows it and quickly goes to 2-3x above level of drowsiness.

If they removed the battery warming from stators it will be a bummer. I don't think that heat pump can pull 7kW. On the upside - it's hard to go on Autobahn after SC because the whole system is close to the critical level of temperatures.

 

[TimothyHW3]

will have partly the same problem even at - 10 with.

No, I had about -7 last year no fog. Only with 4 people in the car at manual 1, put it on 3-4 and it was ok. Plus the car should be smart enough to differentiate between -20C and 5C and not turn AC simply by default. It is just poorly written code for California weather.

have to say that Tesla measures the humidity of the air inside and multiple points of temperature - I trust that Auto mode does the most reasonable thing in most conditions

Does it, how, where are these sensors, do we have parts number? I am pretty sure it doesn't, otherwise it wouldn't turn on AC by default always.

 

[Mash]

No, I had about -7 last year no fog. Only with 4 people in the car at manual 1, put it on 3-4 and it was ok. Plus the car should be smart enough to differentiate between -20C and 5C and not turn AC simply by default. It is just poorly written code for California weather.


Does it, how, where are these sensors, do we have parts number? I am pretty sure it doesn't, otherwise it wouldn't turn on AC by default always.

Just because button is on doesn't mean it works. Also, it's variable frequency compressor, so even if it works - doesn't mean it works on full power. Check available CAN data - you will see tons of interior hvac data. Assumption that Tesla engineers are stupid at saving electricity requires very serious proof.

You have a choice of saving electricity even more by setting your temperature during winter much lower and using seat heaters to warm yourself. Whether you going to be ok with that Tesla doesn't know, so it's not an automatic mode. But suggesting those hacks on a basis that you know better how to save electricity than the company that makes most efficient electric vehicle is a joke.

 

[TimothyHW3]

Just because button is on doesn't mean it works. Also, it's variable frequency compressor, so even if it works - doesn't mean it works on full power. Check available CAN data - you will see tons of interior hvac data. Assumption that Tesla engineers are stupid at saving electricity requires very serious proof.

Yes, I have checked it. I will make a video if you like. The difference is anywhere between 900W without AC and the minute you turn AC on it goes to about 3kW. Straight away. And yes, it is variable and can go to abou 7kW at some points.

Who said anything about stupid? Lazy is a more accurate term. They just say - f ck it, we put it on Auto just in case to be on the safe side. They are located in California after all, they don't have time to do long tests with 4 people in the car at -5 0 +5C ambient temperatures to test how it affects the windows at different conditions.

But suggesting those hacks on a basis that you know better how to save electricity than the company that makes most efficient electric vehicle

What does having efficient motors (engineering) has to do with anything, especially software?! If you actually see all the winter tests, you will see that Model 3 fails miserably, because of this Auto setting. Most tests run it on Auto and have about 50% more consumption in the winter. Which is a very bad PR for Tesla. Besides, the koreans also make pretty efficient EVs, we have to give them credit. Tesla is just slightly better than them (but much more efficient than any german brand)

It is not a hack to simply turn off AC when not needed...

By the way, it seems like the lowest you can get the PTC to run at is about 900W, on a 2020-2019 model. And the lowest you can get the heat pump is about 300W. Which is impressive. So much for VWs amazing heat pump that uses almost no electricity, because of some amazing coolant that saves you 20% range...Sure...

 

[Mash]

Yes, I have checked it. I will make a video if you like. The difference is anywhere between 900W without AC and the minute you turn AC on it goes to about 3kW. Straight away. And yes, it is variable and can go to abou 7kW at some points.

Who said anything about stupid? Lazy is a more accurate term. They just say - f ck it, we put it on Auto just in case to be on the safe side. They are located in California after all, they don't have time to do long tests with 4 people in the car at -5 0 +5C ambient temperatures to test how it affects the windows at different conditions.


What does having efficient motors (engineering) has to do with anything, especially software?! If you actually see all the winter tests, you will see that Model 3 fails miserably, because of this Auto setting. Most tests run it on Auto and have about 50% more consumption in the winter. Which is a very bad PR for Tesla. Besides, the koreans also make pretty efficient EVs, we have to give them credit. Tesla is just slightly better than them (but much more efficient than any german brand)

It is not a hack to simply turn off AC when not needed...

By the way, it seems like the lowest you can get the PTC to run at is about 900W, on a 2020-2019 model. And the lowest you can get the heat pump is about 300W. Which is impressive. So much for VWs amazing heat pump that uses almost no electricity, because of some amazing coolant that saves you 20% range...Sure...

Usage of heater depends on the difference of target vs ambient, I doubt that any number is lowest - if 900 was lowest, it won't be able to keep the target. Consumption at a specific moment doesn't matter - for range only average matters.

Same applies to a/c. It doesn't matter that lowest is 3kw - you need to compare average across the run.

Car can't detect if your windows actually foggy or not. Because it depends on how you breath as well. So it have to be on a safer side and find a balance of air dryness from a/c and hotness from the heater to make sure that water won't condense on a cold glass.

Again, you put assumptions that Tesla doesn't care about 80% of the market and target Cali only where they are close to sales saturation point.

I don't really understand your sarcasm about heat pump, sorry.

We already know that Tesla improved range twice with hvac software updates. It's possible that there is still space for improvement. And I'm quite certain that they have more data, knowledge and motivation to improve range for average user. But it's possible that in your particular case - breath pattern or seat vs air temperature you can find more efficient settings. But it will take actual tests and data collection and won't be something you can universally claim as improvement for everyone. And if you will reverse engineer their hvac system algorithm and will have instrumental proof of improvement for math model - send them a letter.

 

[TimothyHW3]

Car can't detect if your windows actually foggy or not.

Actually it can, my old BMW did that and increased the output when it senced foggyness. As for the rest, maybe you should watch the videos I posted and the things I write before commenting.

The car CAN keep the car warm on manual 1 with AC off and pulling 900-1.2kW while driving. Tested many times in temperatures like the video - 5C.

And what my issue with the "heat pump" is explained - but you don't read: The heat pump will have very low impact in highway driving, something the video suggested because of wrong settings and also different settings between the two cars. In the first part of the video, before changing the 2019 car to auto, they were pulling identical or almost identical consumptions - a difference of about 40Wh/km which is the difference I explain above. A few people have mentioned that below the video too...

I just shoot a bunch of videos regarding the different consumptions and settings in similiar weather 3C. Will post it when I find the time.

 

[Ofarlig]

No, I had about -7 last year no fog. Only with 4 people in the car at manual 1, put it on 3-4 and it was ok. Plus the car should be smart enough to differentiate between -20C and 5C and not turn AC simply by default. It is just poorly written code for California weather.

That is not my experience with a lot of moisture in the car (say from dragged in snow that is melting), hitting a cold spot in a valley might make the windows fog or ice up a lot at that point.

Living where there is actual winter you quickly learn to run AC year round...

 

[TimothyHW3]

That is not my experience with a lot of moisture in the car (say from dragged in snow that is melting), hitting a cold spot in a valley might make the windows fog or ice up a lot at that point.

Living where there is actual winter you quickly learn to run AC year round...

Sure, but did you miss the point where I said "the car should be able to differentiate between -20C and 5C?"

Why would the car turn the AC on in 5-6C, that doesn't make any sense. Especially on a short drive (of course the car doesn't know that you will be driving just 10 minutes, but still) this will make a huge difference.

I am not saying that the heat pump doesn't have any advantage, in ideal 0+5C conditions this is the equivalent of about 1kW minimum advantage and the difference between keeping the car on auto and on manual.
Some people are lazy and like to have it on auto and forget about it - to be honest in my BMW I had the thing on Auto 22.5C and probably touched it 3 times during 7 years of ownership. Not a single fogged window and always warm (but it did take 10 minutes to warm up the car because ICE)
So yeah, I get that, the heat pump does help there - but not when you drive on the highway and you def could have a workaround. I am not quite sure I will like the noise - people are starting to complain about the noise at low speeds and when stationary with their 2021 3s.

Also, we will have to wait and see how it affects preheating the car and wether they still use the stators - to be continued.

 

[Ofarlig]

Sure, but did you miss the point where I said "the car should be able to differentiate between -20C and 5C?"

Why would the car turn the AC on in 5-6C, that doesn't make any sense. Especially on a short drive (of course the car doesn't know that you will be driving just 10 minutes, but still) this will make a huge difference.

I am not saying that the heat pump doesn't have any advantage, in ideal 0+5C conditions this is the equivalent of about 1kW minimum advantage and the difference between keeping the car on auto and on manual.
Some people are lazy and like to have it on auto and forget about it - to be honest in my BMW I had the thing on Auto 22.5C and probably touched it 3 times during 7 years of ownership. Not a single fogged window and always warm (but it did take 10 minutes to warm up the car because ICE)
So yeah, I get that, the heat pump does help there - but not when you drive on the highway and you def could have a workaround. I am not quite sure I will like the noise - people are starting to complain about the noise at low speeds and when stationary with their 2021 3s.

Also, we will have to wait and see how it affects preheating the car and wether they still use the stators - to be continued.

I want to keep humidity low even if its 5, I don't really see a point in not running the AC year round. But a toggle wouldn't hurt, it would benefit me as well that want to make sure it is on all the time and doesn't cycle.

As for heat pump I don't see a big gain from it either as at highway speed the heating is such a small factor during long distance traveling anyway.

 

[TimothyHW3]

As for heat pump I don't see a big gain from it either as at highway speed the heating is such a small factor during long distance traveling anyway.

If you like to keep the AC on(or basically keep the car on Auto) it will be somewhat of a difference on Model 3 - from the tests I have seen so far at US highway speeds you can expect 30kms(about 20 miles) more with the heat pump and I guess even more in the city due to the need to preheat every time you stop.

Not sure if that is a big or small gain to you, but if I can have 60kms on a 1 supercharging trip, that is 5 mins shorter charge time or a bit more buffer at the end. I would take it.

 

[Ofarlig]

If you like to keep the AC on(or basically keep the car on Auto) it will be somewhat of a difference on Model 3 - from the tests I have seen so far at US highway speeds you can expect 30kms(about 20 miles) more with the heat pump and I guess even more in the city due to the need to preheat every time you stop.

Not sure if that is a big or small gain to you, but if I can have 60kms on a 1 supercharging trip, that is 5 mins shorter charge time or a bit more buffer at the end. I would take it.

Yeah, over here I am either doing 130-140 km/h or it's snow on the road so my consumption for just moving the car would be slightly higher so the heat pump would probably do less in that case. For city driving I don't care about range since I won't be emptying the battery just driving in the city in one go.

As for charging it is already charging faster than I'm stopping normally so it wouldn't really help me that I have to charge 30 km less one way.

Don't get me wrong improvements are always welcome but I wouldn't want to pay extra for a heat pump as the benefits aren't that great.

 

[TimothyHW3]

to pay extra for a heat pump

Well, it was free at some point - all the refresh things. The only thing that will bother me is the noise. Hopefully it is not that loud once it gets to temperature.

 

[GoSharks]

Who said anything about stupid? Lazy is a more accurate term. They just say - f ck it, we put it on Auto just in case to be on the safe side. They are located in California after all, they don't have time to do long tests with 4 people in the car at -5 0 +5C ambient temperatures to test how it affects the windows at different conditions.

You act as if it is is always 20c+ around Palo Alto. It was 4c this morning, and during the winter, snow can be less than 30 mins away from the HQ. Also, plenty of people go skiing for the weekend.