Dear Rivian Engineers who worked on the Air Conditioning

[flyingpumpkin]

Another data point for you and clarification re: the third row cooling scheme.

My R1S is in for AC service right now. Symptom was ineffective cooling above ~90F outside temperature.

(1) The refrigerant was slightly overcharged (35 grams) and resulted in the compressor shutting down at high ambient temperature due to an overpressure error. Remote diagnostics correlated the overpressure error with times that the vent air was not being cooled. I never noticed a compressor shutdown - just ineffective cooling while still running full speed - so there may be some miscommunication.

(2) Service tech confirmed that there are two evaporator coils. The second evaporator coil is for cooling the third row air and only comes on when there is a passenger in the third row or seat belt is buckled with the current software. Time to add a dummy clip to keep the dogs cool in the back. If you enable the third row vents from the front without a passenger then it is fan only, no refrigerant flow through second coil.

There is a sticker on the hood that lists the nominal refrigerant charge at 875 grams, so about 4% overcharge was enough to cause overpressure problems.

Even when the compressor was running the cooling performance was poor when it was warm outside. Hopefully explained by the overcharge reducing the cooling efficiency - too much refrigerant = the liquid line backing up into the condenser coil = less useful volume. We'll see.

I'll get the vehicle back next week to confirm that cooling performance is improved.

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[Cactus]

@flyingpumpkin- Thanks for the report and info about the third row. Hope they can fix your AC. I notice you are in Oregon. Here in Phx, 95°F would not be considered hot. Warm, maybe.
My AC cools OK when pulling out of the 95°F garage in the mornings on the way to work. It is not effective after sitting in the sun (interior temp >120°F).
From what I've experienced after owning my R1S for 7 weeks, the entire AC system is poorly engineered and has multiple weak points. I am still deciding if this is a deal-breaker for me since I live in Phx.

 

[Si.LE.R1S]

I keep it in All Purpose mode, standard height and automatic (lowers at highway speeds), but use stiff suspension, NOT soft. Setting to stiff almost completely removes the bouncy porpoising. Still have a little head toss, but my R1S feels and handles much better in stiff suspension setting.

not that it’s a great solution, but completely disabling Stability along with Soft gives a more “Lexus-like” ride. Very cushy, particularly over things like speed bumps where the porpoising is really accentuated in other modes.

 

[Donald Stanfield]

I feel like a lot of the newer people to Rivian are unaware that the loud AC happened after an update. My AC worked fine before the update but I have a feeling cooling was insufficient for the battery pack so Rivian put in a turbo mode at startup.

I agree its totally annoying but I'm sure its for a reason and Rivian weighed the noise and complaints they would get about it against performance needed and decided to deal with customer complaints.

I hate to be that guy but at the risk of being a Rivian apologist this is the risk you take in buying an untested design. I wouldnt be surprised if in future generations of the R1 we will see a beefier HVAC system. Living in TN it is hot enough here to understand the complaints about the weed whacker noise on startup but assuming this boosted mode is enough cooling for the pack and cabin, which it seems to be to me, it is a small albeit annoying trade off.

Thus far it seems as though most of the R1's design has been over engineered and there have been very few major problems. For a first attempt from a new manufacturer its very impressive. We are going to get bumps in the road like this and it also seems like owner feedback suggests that ceramic tinting on the Windows and windshield helps a fair amount.

 

[Cactus]

I feel like a lot of the newer people to Rivian are unaware that the loud AC happened after an update. My AC worked fine before the update but I have a feeling cooling was insufficient for the battery pack so Rivian put in a turbo mode at startup.

I agree its totally annoying but I'm sure its for a reason and Rivian weighed the noise and complaints they would get about it against performance needed and decided to deal with customer complaints.

I hate to be that guy but at the risk of being a Rivian apologist this is the risk you take in buying an untested design. I wouldnt be surprised if in future generations of the R1 we will see a beefier HVAC system. Living in TN it is hot enough here to understand the complaints about the weed whacker noise on startup but assuming this boosted mode is enough cooling for the pack and cabin, which it seems to be to me, it is a small albeit annoying trade off.

Thus far it seems as though most of the R1's design has been over engineered and there have been very few major problems. For a first attempt from a new manufacturer its very impressive. We are going to get bumps in the road like this and it also seems like owner feedback suggests that ceramic tinting on the Windows and windshield helps a fair amount.

Agree we are all beta testers on a very solid product that does have some flaws. Heck, Ford and GM make cars with design flaws all the time and they are legacy auto manufacturers.

We just need to decide if we can live with the R1 flaws.

 

[SoCal Rob]

Since I've never been a fan of sunroofs, I am thinking of getting the sunroof "wrapped" in white to completely block the sun. Yes, I spent good money on getting the max IR rejecting tint on all glass in the R1S, but I still feel the heat from the sun through the sunroof when driving.
Has anyone "wrapped" their sunroofs? I'm thinking the cost would be a couple hundred bucks or less?

I’ve been considering getting the roof glass wrapped in translucent white but the HVAC performance on our R1S has been good, even in the desert to 105°. I haven’t used it in anything really hot yet. I’d be interested to see how it looks and hear how much it improves things.

One issue that people are seeing which is not unique to Rivians is the temperature increase with everything closed up while sitting in the sun. Even an all white car with a light colored interior will get to extremely high temperatures when sitting in the sun for hours.

One aspect of the Rivians does make this worse if you try to deal with it proactively, though: the lack of a venting sunroof. In other cars I tend to vent the sunroof and open the windows a bit (like Rivian’s vent setting in the app) to encourage as much air circulation as possible. On, say, a 95° day if you can keep the interior closer to 95° with venting versus creating a closed 125° greenhouse, the HVAC has an easier time bringing the temps down faster and you can switch to recirculate sooner. Without a high point vent provided by a sunroof, I find that venting the windows isn’t as effective.

 

[Meccanica]

lesson learned. I should have read the forum before my service appointment. I for sure thought something was defective with my R1S ac compressor.

It's been very hot throughout Southern California the past few weeks. the air conditioning can't keep up but the truck sounds like it's cleared for takeoff.

I'm embarrassed to have customers or friends in the vehicle. it sounds like such a piece of junk between the rattles, and air conditioning not working right.

 

[LL75]

I feel like a lot of the newer people to Rivian are unaware that the loud AC happened after an update. My AC worked fine before the update but I have a feeling cooling was insufficient for the battery pack so Rivian put in a turbo mode at startup.

I agree its totally annoying but I'm sure its for a reason and Rivian weighed the noise and complaints they would get about it against performance needed and decided to deal with customer complaints.

I hate to be that guy but at the risk of being a Rivian apologist this is the risk you take in buying an untested design. I wouldnt be surprised if in future generations of the R1 we will see a beefier HVAC system. Living in TN it is hot enough here to understand the complaints about the weed whacker noise on startup but assuming this boosted mode is enough cooling for the pack and cabin, which it seems to be to me, it is a small albeit annoying trade off.

Thus far it seems as though most of the R1's design has been over engineered and there have been very few major problems. For a first attempt from a new manufacturer its very impressive. We are going to get bumps in the road like this and it also seems like owner feedback suggests that ceramic tinting on the Windows and windshield helps a fair amount.

Yeap. Definitely turbo mode at start up after the update. It is annoying af that I have to turn off rhe ac for a few seconds and turn it back on for the turbo mode to go away

 

[jcflint]

Update: Has been 4 days since service did a rebalance in the field. That day it did not seem to be a major improvement, but over the weekend I have noticed the AC blows cool consistently. Before it was shutting off, I think because of the over charge. I have also been putting up the sun visor in the windshield and the vehicle will actually cool down now. It's not as good as my other vehicles but it seems manageable now. This week will be the real test sitting in the parking lot at work. I am just glad that there is an improvement. I will keep you guys updated over the next few hot weeks of summer.

 

[flyingpumpkin]

Got the vehicle back from service. Ditto re: blowing cold air after fixing the refrigerant charge vs shutting down when hot out.

Performance still seems marginal. While 102F outside in Portland around noon, if you run pet mode with a 72F setpoint it can only maintain 75F self-reported steady state. No tint, no roof or windshield sunshade, blue R1S, third row not buckled. Will test later with a separate temperature logger. Maybe pet mode hold ability is a useful metric to compare?

Definitely a downgrade from my old Model 3 that could hold in the mid-60s no problem and qualitativs other recent vehicles I’ve driven (Ford Maverick, Kia Niro).

I’ll add a roof shade, not trust the vehicle for pet mode, and call it done. Fine for OR but seems problematic for hotter places.

The A/C cooling performance is my only remaining concern. The service center has done what they can, but it seems like coils/airflow/compressor are potentially all undersized given the big R1S glass roof.

 

[Si.LE.R1S]

Got the vehicle back from service. Ditto re: blowing cold air after fixing the refrigerant charge vs shutting down when hot out.

Performance still seems marginal. While 102F outside in Portland around noon, if you run pet mode with a 72F setpoint it can only maintain 75F self-reported steady state. No tint, no roof or windshield sunshade, blue R1S, third row not buckled. Will test later with a separate temperature logger. Maybe pet mode hold ability is a useful metric to compare?

Definitely a downgrade from my old Model 3 that could hold in the mid-60s no problem and qualitativs other recent vehicles I’ve driven (Ford Maverick, Kia Niro).

I’ll add a roof shade, not trust the vehicle for pet mode, and call it done. Fine for OR but seems problematic for hotter places.

The A/C cooling performance is my only remaining concern. The service center has done what they can, but it seems like coils/airflow/compressor are potentially all undersized given the big R1S glass roof.

My R1S is holding after coming back from SC from under charged status. I did try the third row buckle today. I then set the 3rd row fan to level 4.

Something was definitely going because my efficiency hovered around 1.7 downhill along a stretch where it normally goes to 4.0. I did also notice the cabin cooled quicker.

I think an easy OTA tweak would be to have a max precondition setting that recruits the third row compressor regardless of occupancy detection (seatbelt or unfolded seat). What if you actually had kids/pets that needed the back preconditioned? Just silly to have the front unit fighting against the warm air all the way in the back while preconditioning.

 

[Cactus]

For the hotter climates (I'm in Phx), Texas, Florida, etc., the R1S AC is insufficient. When it's really hot and the sun has heated up the cabin, the AC is insufficient. BUT, I was driving last night, and the temp in Phx was still 100°F, the AC seemed to cool OK. Seems like the AC can't match how much the cabin heats up in the R1S.

I wonder if Rivian would do a recall to replace the current AC compressors with properly sized AC units in the R1S? I am not an AC expert, but surely there are bigger or stronger AC compressors that could replace our current anemic units?

Problems:
1. Primary problem is an undersized AC system for R1S (maybe not R1T since smaller cabin?)

2. Compounding the primary problem is suboptimal location of the center vents (when hands are at 10 and 2 on the steering wheel, right forearm blocks air blowing toward head/face)

3. Poor design/location of the side vent which is blocked from blowing at the driver due to the wood inlay in dash. I don't think mine has ever blown air anywhere other than the side window.

4. Unnecessarily complicated "vent icon drag" on the center display makes it difficult to aim air- and some owners have noticed that they don't "stay where you put them".

5. While the AC system tries to cool a very hot cabin, it seems to go into "weed whacker mode", which requires the driver to shut off the AC for ~30 seconds, then turn it back on. Air still doesn't get cold, but embarrassing weed whacker noise subsides.

Anything else?
Summer might be ending (not in Phx), but some projections say future summers will be hotter than this one.

 

[LL75]

For the hotter climates (I'm in Phx), Texas, Florida, etc., the R1S AC is insufficient. When it's really hot and the sun has heated up the cabin, the AC is insufficient. BUT, I was driving last night, and the temp in Phx was still 100°F, the AC seemed to cool OK. Seems like the AC can't match how much the cabin heats up in the R1S.

I wonder if Rivian would do a recall to replace the current AC compressors with properly sized AC units in the R1S? I am not an AC expert, but surely there are bigger or stronger AC compressors that could replace our current anemic units?

Problems:
1. Primary problem is an undersized AC system for R1S (maybe not R1T since smaller cabin?)

2. Compounding the primary problem is suboptimal location of the center vents (when hands are at 10 and 2 on the steering wheel, right forearm blocks air blowing toward head/face)

3. Poor design/location of the side vent which is blocked from blowing at the driver due to the wood inlay in dash. I don't think mine has ever blown air anywhere other than the side window.

4. Unnecessarily complicated "vent icon drag" on the center display makes it difficult to aim air- and some owners have noticed that they don't "stay where you put them".

5. While the AC system tries to cool a very hot cabin, it seems to go into "weed whacker mode", which requires the driver to shut off the AC for ~30 seconds, then turn it back on. Air still doesn't get cold, but embarrassing weed whacker noise subsides.

Anything else?
Summer might be ending (not in Phx), but some projections say future summers will be hotter than this one.

As of right now, their fix is to recharge the AC refrigerant and it seems to work for some. Unless there are more people complaining about recharge refrigerant failure, then they will look into something further. I seriously doubt they would replace a bigger AC compressor (is there room for bigger one?)

 

[SoCal Rob]

As of right now, their fix is to recharge the AC refrigerant and it seems to work for some. Unless there are more people complaining about recharge refrigerant failure, then they will look into something further. I seriously doubt they would replace a bigger AC compressor (is there room for bigger one?)

I’m not a refrigeration person, but my understanding is that these are designed as systems. If anyone has knowledge, can you simply (?) drop-in a bigger compressor or would the heat exchangers (evaporator & condenser, I think) need to be resized as well?

 

[Zoidz]

For the hotter climates (I'm in Phx), Texas, Florida, etc., the R1S AC is insufficient. When it's really hot and the sun has heated up the cabin, the AC is insufficient. BUT, I was driving last night, and the temp in Phx was still 100°F, the AC seemed to cool OK. Seems like the AC can't match how much the cabin heats up in the R1S.

I wonder if Rivian would do a recall to replace the current AC compressors with properly sized AC units in the R1S? I am not an AC expert, but surely there are bigger or stronger AC compressors that could replace our current anemic units?

I've got some experience with sizing of refrigeration systems which is really what we are dealing with here. Systems are designed as, well, a "balanced system". If the problem is that the system is properly designed but undersized for the BTU load (such as underestimating the heat load created by the greenhouse roof in the R1S at 110 degrees ambient), just Increasing the compressor size likely won't fix this type of problem. All of the components - lines sizes (tubing), evaporator and condensor coils, thermal expansion valve or capillary tube, etc. all need to be resized. The only thing a new compressor would fix is if they somehow undersized it in the original design, but since it works fine for many people at or under 100 degrees, I think it's an overall system BTU capacity issue. The other possibility is that it was designed correctly but an OEM is not delivering components to spec.

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