2023 M3 air conditioner using 70% of energy

[stopcrazypp]

Ok, Saturday Morning, to recap , trying to figure out why my 2023 LFP battery M3 strandard range is drawing so much power when running the AC on LO Ssetting when the summer heat hit. (Fan on HI setting). We were loosing 200%+ of range . At 80 % charge it was difficult to even get 100 miles of range. We got our Car in November and but never experienced any issues until May & June heat hit. So now we are attempting to figure this all out with help from all of you.
And darn it, yesterday was the coldest day in weeks and did not even reach 100 degrees and plus we did not get out until later in the day, so my test results do NOT show what I experience on hot days. But after thinking about this, I am glad to have this cool day to level set with all the drivers that consider this to be hot and do not have any issues. Attached are the drives from yesterday with the time and temperatures. The LO setting when the temp is only in the 90's really did pretty good - no complaints - even with the AC on the LO setting the car did pretty good. But as I said this is a good bench mark for days in the 90's.please note the temperatures shown at the top of the screen capture, the next capture is of the Trips screen and always follow that order for all photos. Also note the AirConditioner setting for that trip is shown at the bottom of each screen print. I hope to evidence what I am saying on my next serious of screen prints on a hot day. For these for serious I am not going to precondition cabin and begin to not the starting cabin temperature on my next series on a hot day. I am going to post results again when the heat comes back and daily until I reproduce the negative results. We have hot days coming this week...109 to 110, then on Jul 2nd 113 degrees.

The 230-240 Wh/mi is totally within normal range even without accessory usage. Your Wh/mi numbers peaked at 312Wh/mi, which again isn't too excessively high (especially depending on how fast you travel on the highway). I guess it remains to be seen if you have numbers for later trips that that reproduce whatever you previously claimed.

I personally keep one of the trip meters permanently not reset so that I have a lifetime counter.

 

[jmichaeltracy@]

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You still haven’t said what happens if you use “auto 68” or some other number instead of “lo”. (Or I missed it)

Thanks, This coming week we will try it. We have our daily 58 mile round trip to take the grandson home at 4PM should be hottest time of the day, we will try some at auto 68 and some and LO and see what the benefits are.,. Just waiting for the hot days to come back this coming week. I was pretty happy to see that in the cool 90's the car does very well every on LO. (Not that there isn't room for improvement - with all the great idea's everyone is giving us.) In Phoenix when we get to 114 degrees next Sunday the surface temps will reach up near 160 degrees in the direct sun, those tests will be interesting. And I plan on as many "USE CASES" as possible to figure this all out. The temp's in the 90's are clearly not going to hot enough to for what I want to see.

 

[jmichaeltracy@]

JM:

I don't want to be a bore and keep repeating myself, but looking at percentage or miles both bring in the question of driving habits. The best way to attack this is to get speak in terms of amp hour used. We take out duration, speed, etc if you just focus on two things: 1) Is the unit performing correctly, and 2) What are the heat load variables. I"ve already told you the two things to check for #1. Get those, talk only in those, and this will come to closure very quickly.

Luck to you,
-d

Does the info I posted today provide that information ? Or do I need to include any addtional informatin? You said to "Talk in power consumption of the A/C and the rest is obvious" How do I measure that other than the energy app? Others recommended apps like "ScanMyTesla", what would give me that data?.

 

[jmichaeltracy@]

The 230-240 Wh/mi is totally within normal range even without accessory usage. Your Wh/mi numbers peaked at 312Wh/mi, which again isn't too excessively high (especially depending on how fast you travel on the highway). I guess it remains to be seen if you have numbers for later trips that that reproduce whatever you previously claimed.

I personally keep one of the trip meters permanently not reset so that I have a lifetime counter.

Yes, I am happy with the 90 temperature results.. And Thanks for the idea of the lifetime counter. I will post more when it gets hot, look for those next week.

 

[rrolsbe]

Not sure how the heat pump differs from my former 2018 Model 3 but in Auto AC Mode with the temp set to 72F power was sent to the two PTC heater elements from time to time. I verified this, when the car was about a year old, using SMT and a DC current clamp around the orange power cable attached to the PTC heater elements. Did not think heat needed to be used when ambient temp was 90F+ and the humidity was 15% or less. My method might not be automatic but I saw almost no hit in range on my 2018 Model 3 running the AC with temps north of 100F and the cabin was comfortable. Things could have changed after my 2019 testing and the heat pump Tesla's probably work different. When I get SMT up and running on the new car, I will monitor power usage in both modes.

Thanks to all in this thread for posting valuable info.
Regards!

​

For what its worth check out this old Youtube video.

Tesla Model 3 Disable Cabin Heater and save 1-2kW when trying to cool car w AC (~5% Range increase)​

 

[jmichaeltracy@]

The energy screen is telling you directly how much range you're losing by using LO instead of 72F. On a really hot day and a short trip it will be much worse. I see also that you exceeded 70mph on some of the short trips. At speeds above ~60mph range will fall faster than the range estimate, and above 70mph it will fall much faster. There's no indication of a faulty HVAC system, IMHO.

From what I can see, preconditioning whilst charging and setting the AC to ~70F will give you a fairly typical range result even on very hot days.

Thanks for your comments, good to hear, (Some of this was highway miles, I suppose I should mention that). Maybe the excessive heat impact is going to end up being the Norm in phoenix. When I post hot days next week we will see the impact. One would assume that if 90 temps are somewhat normal, then the 110+ days are just the added load on the compressor? And yes after I finish testing with the LO settings, you and others are recommending a higher setting, we will probably try 68 degrees next (also) on the hot days to see if that is the happy compromise between comfort and power used.

 

[jmichaeltracy@]

That article you linked gave actual numbers drawn from a scan tool. You can see it is about 6.2 kW for AC with Fan 10. If it is on LO and fan HI then I can totally believe 7kW to be a reasonable approximation for peak power.

Case for Tesla Pilot Mode: Tesla Model 3 Energy Efficiency & Use of HVAC

And given the huge variation in power draw depending on configuration, it does appear to be a variable speed compressor. However, I don't necessarily agree that only variable speed compressors are affected by the temperature setting. Even a single stage compressor design will still be affected by the temperature setting. This is because the compressor can be shut down when your set temp is reached, plus "auto" mode will automatically apply recirculate as necessary for the maximum efficiency.

Heat pumps in the newer models only improved the heat efficiency (as it's basically a AC running in reverse, replacing the previous PTC heater), it does nothing to improve the AC efficiency. So I don't expect differences due to heat pump.

As for a car having a more powerful AC than a home, actually that is totally expected. Cars are extremely poorly insulated compared to a house, when it is travelling on the highway there is a lot of heat exchange on the body due to high speed airflow (a home doesn't generally have 75 mph winds travelling around it), and the ratio of glass to volume is huge (meaning the greenhouse effect works extremely strong). A Tesla is even worse due to the glass roof (I use roof shades with a reflective layer on top and it helps a lot).

Yes thanks, this is a great article. pasting the AC section :
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[jmichaeltracy@]

Yes thanks, this is a great article. pasting the AC section :
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Air Conditioning​

Keep in mind that the air conditioner in the Tesla Model 3 is a fully variable speed compressor. I’ll repeat that so you can really hear it: the cooling system in the car is fully variable speed. This means anything you can do to make it run more slowly will save power — although, not in a linear fashion (like other variable speed compressors).

The compressor’s power use can be only ~1 kW at low speed (4 range miles lost per hour) against up to 6 kW (24 lost miles of range per hour) with the compressor running very hard at full fan and at high compressor speed.

So, the key is to keep the compressor speed down and not to let the cabin temperature get really hot inside the car before you get in. We measured it with the ScanMyTesla app, going through several repetitions to get the numbers right. The compressor speed is proportional to:

The distance the cabin temperature is from the temperature setting.

The fan speed, which is the indicator for the compressor fan speed as well.

Sonically, you can hear the higher compressor speeds, particularly when you choose AUTO on entering the car after it has been sitting in a hot place. If you have ScanMyTesla, you can see in a stationary car how power increases when the fan speed is increased with the air conditioner on. Of course, we shouldn’t need the ScanMyTesla app and hardware — the car should provide this critical information, which it already has. Tesla only has to make it available.

The excess energy needed to pull down the interior temperature to the set point can be controlled to a certain extent by:

Parking in the shade.

Expert window tinting for all windows.

Shade screen insert for top window, and also adding top insulation.

Using windshield solar shade.

Also, the fact that the AC compressor is fully variable speed means that occupants are rewarded for controlling heat gain while driving (window tint, window screens) as well as choosing thermostat set points that are not too low. Generally, drivers and passengers will find the interior feels cooler at a given setting if the car has been parked in the shade. This is because human comfort is strongly related not only to the air temperature, but also to the global mean radiant temperature (MRT) from automobile interior surfaces.

Copy from source:

Case for Tesla Pilot Mode: Tesla Model 3 Energy Efficiency & Use of HVAC

How do we find out how we are doing in any endeavor in a complex machine? The need is for specific performance data that allows an informed decision — at least, if we wish.

cleantechnica.com

 

[Gauss Guzzler]

There are 2 other factors that may be contributing to your unusually large jump in power consumption:

1. A/C efficiency declines very rapidly when the inside/outside temperature difference is greater than ~20F. This isn't a simple case of hotter is worse, it's due to the way the compressor and expansion ratios are optimized around the boiling point of the refrigerant for the typical use case of 70F inside vs 80-100F outside. Thus, you might see huge differences in the amount of power needed at 115F vs. 105F.
2. Warm batteries perform better so not only does the car let the batteries warm up naturally, but it sometimes even dumps A/C or other waste heat into them since that can be done very efficiently with a small water pump instead of dumping heat to the air with a big radiator fan. But the maximum allowable battery temperature of ~130F is a serious limit and the car will do everything necessary to stay below that, including using the air conditioning to directly cool the battery. So again, a short trip at 95F might involve no battery management at all, while a short trip at 110F might have the system in full panic mode right from the start.

I wouldn't be surprised if you are seeing one or both of these compounding factors occur suddenly and simultaneously as the temperatures cross a certain threshold.

 

[stopcrazypp]

There are 2 other factors that may be contributing to your unusually large jump in power consumption:

1. A/C efficiency declines very rapidly when the inside/outside temperature difference is greater than ~20F. This isn't a simple case of hotter is worse, it's due to the way the compressor and expansion ratios are optimized around the boiling point of the refrigerant for the typical use case of 70F inside vs 80-100F outside. Thus, you might see huge differences in the amount of power needed at 115F vs. 105F.
2. Warm batteries perform better so not only does the car let the batteries warm up naturally, but it sometimes even dumps A/C or other waste heat into them since that can be done very efficiently with a small water pump instead of dumping heat to the air with a big radiator fan. But the maximum allowable battery temperature of ~130F is a serious limit and the car will do everything necessary to stay below that, including using the air conditioning to directly cool the battery. So again, a short trip at 95F might involve no battery management at all, while a short trip at 110F might have the system in full panic mode right from the start.

I wouldn't be surprised if you are seeing one or both of these compounding factors occur suddenly and simultaneously as the temperatures cross a certain threshold.

Great point. I actually did think of variations in compressor efficiency due to temperature, but didn't bring it up. You see similar things happening with heat pumps as temperatures reach lower.

 

[brkaus]

Are your windows, roof, and even front windshield tinted?

 

[dafish]

JM:

I would use scanmytesla to get the actual power consumption data.

 

[brkaus]

This thread reminds me…

One day I thought I would “save energy” and have the climate control hold 80 instead on 72 while charging. I had a bunch of stuff on the car I didn’t want to overheat. The car was out in the sun on a hot sunny day.

Anyway, I accidentally set it on “Hi” instead of 80… so out in the sun and the heat was cranking full blast for an hour or so…

 

[bacevedo]

Just saw this thread and thought I'd chime in as I'm experiencing something similar. I'm also in the Phoenix area (south Chandler) and have a '22 LR-AWD 3 and '20 LR-AWD Y.

I've noticed over the past few weeks that the Y has been consuming way more energy than I remember in the past two summers that I've had it. I haven't changed my driving habits. I just submitted a service request earlier today to make sure there isn't something wrong with the AC or drive system. I haven't heard back so we'll see what they say.

My 3 has also used more energy over the last few weeks (as expected), but not substantially more like the Y.

The Y is losing like 1% every mile while driving 50 mph on a surface street. The range on the energy screen would say 90 miles at 50%, then drop to 60 miles at 48%, etc. These aren't long trips (maybe 5 - 10 miles) but I don't remember it being this bad last summer. And saying estimated range of 60 miles at 48% is way low. I did also see that range shot back up to 100 miles toward the end of the trip, so I'm sure there is something to those saying the overhead of short trips is affecting the range calculator. The estimated range doesn't bother me as much as literally watching my % drop every 45 - 60 seconds.

It's parked in an enclosed garage and I keep the AC at around 69-70 on auto. So it's not really heat soaked and I'm not running the AC at LO.

We'll see if I take any longer trips and if the range and % drop settle down. I might also try pre-cooling before I take my next short drive and see if that decreases the energy consumption while driving.

 

[jmichaeltracy@]

Are your windows, roof, and even front windshield tinted?

No, I am looking for a good source in Phoenix to get this done, and evern for the glassroof the insulated cover.. let me know if you have recommendations.

 

[jmichaeltracy@]

Just saw this thread and thought I'd chime in as I'm experiencing something similar. I'm also in the Phoenix area (south Chandler) and have a '22 LR-AWD 3 and '20 LR-AWD Y.

I've noticed over the past few weeks that the Y has been consuming way more energy than I remember in the past two summers that I've had it. I haven't changed my driving habits. I just submitted a service request earlier today to make sure there isn't something wrong with the AC or drive system. I haven't heard back so we'll see what they say.

My 3 has also used more energy over the last few weeks (as expected), but not substantially more like the Y.

The Y is losing like 1% every mile while driving 50 mph on a surface street. The range on the energy screen would say 90 miles at 50%, then drop to 60 miles at 48%, etc. These aren't long trips (maybe 5 - 10 miles) but I don't remember it being this bad last summer. And saying estimated range of 60 miles at 48% is way low. I did also see that range shot back up to 100 miles toward the end of the trip, so I'm sure there is something to those saying the overhead of short trips is affecting the range calculator. The estimated range doesn't bother me as much as literally watching my % drop every 45 - 60 seconds.

It's parked in an enclosed garage and I keep the AC at around 69-70 on auto. So it's not really heat soaked and I'm not running the AC at LO.

We'll see if I take any longer trips and if the range and % drop settle down. I might also try pre-cooling before I take my next short drive and see if that decreases the energy consumption while driving.

Stay tuned to this blog, I think we are going find out if there is a problem or how we manage this to do with Phoenix heat. Most people have know idea what heat it till they live in the desert. The direct extremes heat things up quick.

 

[jmichaeltracy@]

JM:

I would use scanmytesla to get the actual power consumption data.

checking on it.

 

[jmichaeltracy@]

There are 2 other factors that may be contributing to your unusually large jump in power consumption:

1. A/C efficiency declines very rapidly when the inside/outside temperature difference is greater than ~20F. This isn't a simple case of hotter is worse, it's due to the way the compressor and expansion ratios are optimized around the boiling point of the refrigerant for the typical use case of 70F inside vs 80-100F outside. Thus, you might see huge differences in the amount of power needed at 115F vs. 105F.
2. Warm batteries perform better so not only does the car let the batteries warm up naturally, but it sometimes even dumps A/C or other waste heat into them since that can be done very efficiently with a small water pump instead of dumping heat to the air with a big radiator fan. But the maximum allowable battery temperature of ~130F is a serious limit and the car will do everything necessary to stay below that, including using the air conditioning to directly cool the battery. So again, a short trip at 95F might involve no battery management at all, while a short trip at 110F might have the system in full panic mode right from the start.

I wouldn't be surprised if you are seeing one or both of these compounding factors occur suddenly and simultaneously as the temperatures cross a certain threshold.

This really scare me..."

1. But the maximum allowable battery temperature of ~130F is a serious limit and the car will do everything necessary to stay below that, including using the air conditioning to directly cool the battery.

Is this why I hear my car "running" when it is off in the heat? (even if I have the cabin temp protection off). it is keeping the battery cool? I usually hear this on hot days. "

1. Thus, you might see huge differences in the amount of power needed at 115F vs. 105F

And yes this is what we seem to be seeing. Just did not pay enough attention before the problem to observe what was happing.

 

[DuncanM]

No, I am looking for a good source in Phoenix to get this done, and evern for the glassroof the insulated cover.. let me know if you have recommendations.

The glass roof cover from Amazon is a self install that takes about 10min.

 

[Gasaraki]

I just drove home with the climate set to LO and consumption went from like 230 wh/mi to 400-500+.

This is your problem if you’re keeping the climate on LO or very low temps all the time.

I don't get why people run the HVAC on LO. Having a HAVC run nonstop just to try to get the interior to 60 from 110+ temps outside. It's like running your home HVAC to 60 on 110 degree days. Then people complain about power consumption... Also the HVAC system will probably die quicker also.