A/C Effectiveness in 5-seat configuration - Predictions?

[AnxietyRanger]

Very nice @essmd - thanks! Read it with interest. Am now more informed.

 

[Jrogville]

I see you are EU, so may not be familiar with the dramatic summer climate variances in the U.S.

Hating to sweat and having lived in NY, Mn, Fl, Ia, Ne, Az, Ca, and now Tx, I have a clear understanding of the essential need for good A/C in the home and car.

The key factors that impact the functionality for adequate A/C is heat and humidity.

Overall, California is not very humid, despite being on the coast, since the Pacific is a cooler ocean compared to the Atlantic, and the climate is impacted by the prevailing W to E winds, the ocean, and the mountains.

Southern Ca on the coast is almost always a beautiful temperature (San Diego, many don't have A/C in homes, up through the Bay area), and the further north the cooler the summers are (San Francisco is delightful in the summer, mostly unless a heat wave) . Once you get inland however, the air dries and temperatures can soar as approaching Arizona and Utah. Death Valley, Ca is the hottest and driest location at times, then the other western states.

Florida is completely different, for the southern peninsula has very hot and humid summers where the A/C is more challenged for cooling.

The rest of the U.S. also has significant summer heat variations, as the upper midwest (ie - Omaha, Neb) can be just as hot and humid as southern Florida.

The southeast U.S. is reliably hot and humid in the summer, as can be parts of the Northeast

A Model X with all the overhead glass in the summer can reach temps of over 140 deg F or 60 deg C, so forgetting to pre-cool can be a miserable environment to get into, and the ability to cool off the cabin off quickly depends on cooling capacity of the compressor and airflow.

Plus for humans to cool, the better airflow of cool air, the more comfortable as evaporating sweat helps to cool..

Science lecture over...more than you probably cared to know, but some insight to how Tesla may have missed a significant detail when removing the 2nd fan.

Read today that Tesla was test driving a Model 3 in Cincinnati. Maybe they're catching on.

 

[AnxietyRanger]

I wonder if Model X 5-seater would have more functional rear cooling if they'd just gone all Model S and removed the B pillar vents as well?

Might that have allowed for more actual moving air in the middle and less wasted in the ducting somewhere... Direct all that air to the central vents?

I get it that Model S is notoriously hot in the trunk but at least its second row is tolerable. No? (Smaller space to cool, though.)

 

[essmd]

Read today that Tesla was test driving a Model 3 in Cincinnati. Maybe they're catching on.

As in thinking "beyond California"? Interesting.
I doubt for the climate, but possible.

My first thought is what is there to warrant that expense, unless there was some unique traffic condition they were testing EAP on,
For example, although we have small roundabouts in Texas, they are nothing like those in Boston.

Wow, there is actually a database on that traffic element, and my local ones are even listed, among the 3450 of them in the U.S., complete with overhead pictures.... Who'd-A-Thunk-It???

Talk about a challenge for Autonomous vehicles despite whatever hardware...

 

[boaterva]

As in thinking "beyond California"? Interesting.
I doubt for the climate, but possible.

My first thought is what is there to warrant that expense, unless there was some unique traffic condition they were testing EAP on,
For example, although we have small roundabouts in Texas, they are nothing like those in Boston.

Wow, there is actually a database on that traffic element, and my local ones are even listed, among the 3450 of them in the U.S., complete with overhead pictures.... Who'd-A-Thunk-It???

Talk about a challenge for Autonomous vehicles despite whatever hardware...

And since people not trained on roundabouts/rotaries seem to not be able to handle them, that would a sight to see: an autonomous vehicle attempting to navigate one!

We have several new ones here in Loudoun County, and it's a sight to behold....

 

[Neil schoe]

I really hope you get somewhere with this, but not holding my breath...

I also am talking with corporate. The A/C in the rear of our vehicle is almost non existent. Has anyone talked to tesla and gotten anything that could possibly correct this defect?

 

[verygreen]

I also am talking with corporate. The A/C in the rear of our vehicle is almost non existent. Has anyone talked to tesla and gotten anything that could possibly correct this defect?

I had driver side b-pillar vent having almost nothing airflow-wise, it was found that some duct was not properly connected.
I can feel some air now, not as much as from the two center vents, but so far has not been able to see if in the current state the total airflow is enough or not.

 

[Neil schoe]

I live in florida and this rear A/C issue is a big deal with the coming summer. It was inadequate during our warm winter so it's going to be downright disgusting when the temps get into the high 90s.

Anyone have any pearls of wisdom on getting this issue corrected by Tesla?

 

[Neil schoe]

I had driver side b-pillar vent having almost nothing airflow-wise, it was found that some duct was not properly connected.
I can feel some air now, not as much as from the two center vents, but so far has not been able to see if in the current state the total airflow is enough or not.

Sorry. I didn't see your response. Yeah. They took it all apart too and gave me the raised shoulders and quizzical look in response.

 

[essmd]

I also am talking with corporate. The A/C in the rear of our vehicle is almost non existent. Has anyone talked to tesla and gotten anything that could possibly correct this defect?

Any improvement with closing 2 of the 4 front vents? Kind of pathetic to have to do so in a $100K vehicle, and sucks for the front passengers, but in my tests it restored the B-pillar vents to 6/7 seater flow rates.

 

[essmd]

I live in florida and this rear A/C issue is a big deal with the coming summer. It was inadequate during our warm winter so it's going to be downright disgusting when the temps get into the high 90s.

I also am talking with corporate.

Anyone have any pearls of wisdom on getting this issue corrected by Tesla?

Let me tell you something about "taking it to Tesla corporate"... it don't get you anywhere. I tried several times with an issue that they finally decided to buy back my X, but there is no corporate department to deal with, no Customer Satisfaction team, no complaint dept, no return of emails or phone calls. Tesla simply does not operate like every other auto manufacturer n that way.

All of these issues are handled by the Service Managers, starting with your local one, then eventually escalated to the Regional Service Manager. It is at that level that critical decisions are made.

I hope I am currently wrong and you get somewhere with someone, but as of 6 months ago, that is how it was.

And they will try to manage your expectations, with language such as "it's a normal variant", and "it matches factory specs", all of which is mostly true, since it was a design flaw to remove the rear fan, and to not boost the single fan for all ducts.

The only viable argument you have is that you never had the opportunity to demo the 5-seater HVAC system in the summer heat if you ordered and committed prior to any being available for demo.

However, that will apply to many others, and it is not likely they will start to buy back multiple 5-seaters based on this issue.

So either they continue with the quizzical looks and managing unsatisfied owner's expectations, or they come up with a fix...

What do you think is more likely???

 

[boaterva]

One answer (unlikely as it may be) would be to install the 'normal' AC in the 5-seater. Wonder what that would take? What fraction of the $3000 differential between the 5 and 6-seater? I'd definitely pay that on a new order (not $3K, the cost for the AC...). This is really nuts, that you may have to order a 6-seater to get 'adequate' AC.

On the fix (adding back the usual 6-seater AC system), all the parts have to fit, of course, it's not like any special work has to be done. Am I missing something major here?

 

[Jrogville]

One answer (unlikely as it may be) would be to install the 'normal' AC in the 5-seater. Wonder what that would take? What fraction of the $3000 differential between the 5 and 6-seater? I'd definitely pay that on a new order (not $3K, the cost for the AC...). This is really nuts, that you may have to order a 6-seater to get 'adequate' AC.

On the fix (adding back the usual 6-seater AC system), all the parts have to fit, of course, it's not like any special work has to be done. Am I missing something major here?

Seeing the way Tesla has worked in the past, the high voltage wiring to the rear HVAC unit is likely to be there and so would the space for the unit itself. The problem would be that I don't think the ducts would be. The ones going from the rear unit to the 3rd and 2nd row seats. The existing 2nd row ducts go forward, not back. It seems that they would have to take a major part of the interior out to install the rear AC. I think it would take a lawsuit or major lemon law action for them to add the rear AC. Maybe what they could do is replace the existing fan with a stronger one, but they'll resists even that.

 

[essmd]

Seeing the way Tesla has worked in the past, the high voltage wiring to the rear HVAC unit is likely to be there and so would the space for the unit itself. The problem would be that I don't think the ducts would be. The ones going from the rear unit to the 3rd and 2nd row seats. The existing 2nd row ducts go forward, not back. It seems that they would have to take a major part of the interior out to install the rear AC. I think it would take a lawsuit or major lemon law action for them to add the rear AC. Maybe what they could do is replace the existing fan with a stronger one, but they'll resists even that.

Fully agree, however one other possible fix is to increase the single fan RPM when set at 11 if the fan specs support it. This theory is extrapolated from the ability to make the FWDs open/close quicker in a prior update.
At least this can facilitate physically reducing airflow to the front vents to divert to the rear, but still have adequate front airflow.
At this point, noise is not a concern.

However, I just connected with a reliable 5-seater owner who now has 90 degree weather, and he commented his family felt the A/C 2nd row was more effective than his previous MS, but never compared to another MX.

Clearly this can be a subjective issue, and opinions can vary from individuals even in the same vehicle.
Perhaps those of you with severe complaints may actually have a fixable issue, like a loose vent.

Please keep us posted with updates from dialogue with Corporate or Service managers.

Does this diagram help anybody figure out the wiring specs?

Dropbox - 2016_ModelX_LHD_SOP3.pdf

 

[Jrogville]

Fully agree, however one other possible fix is to increase the single fan RPM when set at 11 if the fan specs support it. This theory is extrapolated from the ability to make the FWDs open/close quicker in a prior update.
At least this can facilitate physically reducing airflow to the front vents to divert to the rear, but still have adequate front airflow.
At this point, noise is not a concern.

However, I just connected with a reliable 5-seater owner who now has 90 degree weather, and he commented his family felt the A/C 2nd row was more effective than his previous MS, but never compared to another MX.

Clearly this can be a subjective issue, and opinions can vary from individuals even in the same vehicle.
Perhaps those of you with severe complaints may actually have a fixable issue, like a loose vent.

Please keep us posted with updates from dialogue with Corporate or Service managers.

Your source with a comparison to the Model S might be faulty in that the Model S rear seat AC may be even worse than the present X 5-seater. I don't often have 2nd row passengers in my Model S, but when I do, they invariably ask if I can turn on the AC, and we're talking Florida spring weather here. I then have to turn the temp down to 60 and the blower way up. So I end up freezing so they can have some comfort. Others may be happy with their Model S performance, I'm just speaking of my own experience. I come from a cavernous GMC Yukon XL and I never had complaints even from the distance 3rd row. Of course that model has a rear AC unit.

Your idea of increasing the fan speed would help, but didn't they already increase fan speed by software update? I have a feeling that when they did that, they would have maxed out the capacity of the fans. Why do a partial improvement when the users can themselves turn the fan down if it's too much. Beyond that, I know that you don't agree with my speculation, but I think the reason the 6- and 7- seaters work is because they have an extra evaporator in the rear AC, therefore more cooling capacity as well as more airflow. I agree there is an airflow problem with the current design that needs to be fixed, but my suspicion is that if that's take care of, it will improve the situation, but it still will not work as well as the 6/7-seaters. And I think people want a fairly even temperature throughout the cabin, even it's just a cargo space with the 5-seater.

I originally wanted a 5-seater for the cargo flexibility, but I'm kind of glad I ended up reserving a 6-seater (from lack of choice). I think I'm going to appreciate the AC in muggy hot Florida more than that cargo flexibility. Don't mean to rub it in, I hope this problem can be resolved because the 5-seater appears to be very popular right now. That may not hold after they start selling them in the summer if the AC doesn't improve.

 

[essmd]

Your source with a comparison to the Model S might be faulty in that the Model S rear seat AC may be even worse than the present X 5-seater. I don't often have 2nd row passengers in my Model S, but when I do, they invariably ask if I can turn on the AC, and we're talking Florida spring weather here. I then have to turn the temp down to 60 and the blower way up. So I end up freezing so they can have some comfort. Others may be happy with their Model S performance, I'm just speaking of my own experience. I come from a cavernous GMC Yukon XL and I never had complaints even from the distance 3rd row. Of course that model has a rear AC unit.

Your idea of increasing the fan speed would help, but didn't they already increase fan speed by software update? I have a feeling that when they did that, they would have maxed out the capacity of the fans. Why do a partial improvement when the users can themselves turn the fan down if it's too much. Beyond that, I know that you don't agree with my speculation, but I think the reason the 6- and 7- seaters work is because they have an extra evaporator in the rear AC, therefore more cooling capacity as well as more airflow. I agree there is an airflow problem with the current design that needs to be fixed, but my suspicion is that if that's take care of, it will improve the situation, but it still will not work as well as the 6/7-seaters. And I think people want a fairly even temperature throughout the cabin, even it's just a cargo space with the 5-seater.

I originally wanted a 5-seater for the cargo flexibility, but I'm kind of glad I ended up reserving a 6-seater (from lack of choice). I think I'm going to appreciate the AC in muggy hot Florida more than that cargo flexibility. Don't mean to rub it in, I hope this problem can be resolved because the 5-seater appears to be very popular right now. That may not hold after they start selling them in the summer if the AC doesn't improve.

You misread my comments - "he commented his family felt the A/C 2nd row was more effective than his previous MS", just as you said.

In your Model S, why did you not turn off the front vents so you would not freeze? That is essentially how to improve the 5-seater 2nd row airflow, crank the fan and close front vents.

I never heard of a software update before to increase the HVAC fan speed, is that a fact? If so, what did they do it for? How would any of us know if they maxed out the RPM, or did they simply added some RPMs, but have much more to go, especially if for correcting this critical problem is worth the extra battery drain.

I think perhaps you are referring to an update last year when the fan's max number was increased from 8 to 11, to commemorate the movie "this is Spinal Tap", one of Elon's favorite movie. Had nothing to do with actually increasing the RPM's, just the numbers.
The reason why the radio goes to 11...... | Tesla

I think you are really missing the point, nobody is questioning the cooling capacity of the A/C compressor or system, with or without an extra evaporator, given an adequate time, the entire cabin will eventually cool off, even faster and better if a thermal blocking tint is added.

The issue is just the airflow, which is a major part of the "cooling a person off", especially when the cabin is hot (not pre-cooled), and the passengers enter the cabin and need to cool off. That is when airflow is essential...the front is fine, the back sucks, actually blows but not enough.
Also, even at a stable and comfortable cabin temperature, the sun radiates heat and more airflow is requested to better cool.
That's why a ceiling fan reduces your A/C consumption, a breeze cools the body by evaporating sweat.

The airflow problem is essentially too small of a fan to deliver adequate airflow through 8 vents in a SUV...

Happy you're happy with your 6-seater, swapping mine for a 5-seater, crappy A/C and all. It definitely restores the SUV category and has a more comfortable 2nd row seat, even if a bench, with the ability to actually extend the back, and not just tilt the seat. Plus you can add a center console and actually have an armrest, comes in handy for the passengers during those long drives...compensates for the sweating from the heat. Plus all that cargo space, can even sleep in the back after activating Camping Mode.

 

[Jrogville]

You misread my comments - "he commented his family felt the A/C 2nd row was more effective than his previous MS", just as you said.

In your Model S, why did you not turn off the front vents so you would not freeze? That is essentially how to improve the 5-seater 2nd row airflow, crank the fan and close front vents.

I never heard of a software update before to increase the HVAC fan speed, is that a fact? If so, what did they do it for? How would any of us know if they maxed out the RPM, or did they simply added some RPMs, but have much more to go, especially if for correcting this critical problem is worth the extra battery drain.

I think perhaps you are referring to an update last year when the fan's max number was increased from 8 to 11, to commemorate the movie "this is Spinal Tap", one of Elon's favorite movie. Had nothing to do with actually increasing the RPM's, just the numbers.
The reason why the radio goes to 11...... | Tesla

I think you are really missing the point, nobody is questioning the cooling capacity of the A/C compressor or system, with or without an extra evaporator, given an adequate time, the entire cabin will eventually cool off, even faster and better if a thermal blocking tint is added.

The issue is just the airflow, which is a major part of the "cooling a person off", especially when the cabin is hot (not pre-cooled), and the passengers enter the cabin and need to cool off. That is when airflow is essential...the front is fine, the back sucks, actually blows but not enough.
Also, even at a stable and comfortable cabin temperature, the sun radiates heat and more airflow is requested to better cool.
That's why a ceiling fan reduces your A/C consumption, a breeze cools the body by evaporating sweat.

The airflow problem is essentially too small of a fan to deliver adequate airflow through 8 vents in a SUV...

Happy you're happy with your 6-seater, swapping mine for a 5-seater, crappy A/C and all. It definitely restores the SUV category and has a more comfortable 2nd row seat, even if a bench, with the ability to actually extend the back, and not just tilt the seat. Plus you can add a center console and actually have an armrest, comes in handy for the passengers during those long drives...compensates for the sweating from the heat. Plus all that cargo space, can even sleep in the back after activating Camping Mode.

That's probably what I was thinking about with the fan speed. It's kind of disappointing that Tesla would increase the fan numbering without actually increasing the speed. The reference to Spinal Tap is fine, but is should have been accompanied by an actual improvement.

 

[AnxietyRanger]

Anyone experimented with closing some Model X rear vents to improve airflow (frankly, haven't tested can you do that) from the other vents that might help, say, a single passenger point air at them?

 

[essmd]

Anyone experimented with closing some Model X rear vents to improve airflow (frankly, haven't tested can you do that) from the other vents that might help, say, a single passenger point air at them?

I don't get your inquiry.

Closing one of the B-pillar vents to get more airflow from the other one?

As mentioned, closing 2 of the 4 front vents almost doubled the B-pillar vents, making it close to the airflow of the 6/7 seaters

 

[AnxietyRanger]

I don't get your inquiry.

Closing one of the B-pillar vents to get more airflow from the other one?

As mentioned, closing 2 of the 4 front vents almost doubled the B-pillar vents, making it close to the airflow of the 6/7 seaters

I guess I could go and test in my own car, but since I haven't tested, I don't even know if you can close (all) the rear vents.

But yeah, so my idea was that if rear airflow is anemic, could it be made at least more pointed by, say, closing two vents from the side where there is no passenger (assuming one rear passenger) or alternatively by, say, closing the B pillar vents so that you end up with Model S like situation with central vents - but with more airflow that could then be pointed at rear passenger(s)?

I understand closing front vents helps. I was just looking for more options and/or an alternative that can be controlled from the back.