Temperature rise after Supercharging

[Erie Electric]

just finished a nice trip in my 2016 Model X P90D. I have owned it since April.

One issue seems to happen consistently since warm summer weather has started and I don’t know if it is normal or abnormal. Please give me your opinion.

When i stop to supercharge, my car always seems to be the loudest at the supercharger with the jet engine roar starting almost immediately on starting to charge. I do not ever hear other Tesla’s making this noise. Everything seems to work ok so I have not engaged Tesla Service on this.

But I have noticed that when I am done charging and I disconnect and start to drive away, I notice my outside temperature reading on the dash starts climbing rapidly and then it seems the AC starts blowing hot air. The actual air temperature today was about 75 to 80 degrees and really not that hot. But after stopping charging, the temperature display would climb to over 100 degrees and often to 110 degrees or a bit higher. I could also hear the jet engine roar inside the cabin.

My mind told me to get on the highway and drive to allow the flowing air to help cool. And that seemed to help. The temp would gradually drop down to accurately read the outside temp.

Normal or abnormal?...

 

[animorph]

I'm surprised it's that bad at 80 degrees. I don't think the outside temperature reading says much other than the A/C exhaust has heated up the sensor. It's normal for the A/C to run when Supercharging. It keeps the battery from getting too hot. I've only had the A/C blow warm air once after a charge, and that lasted the whole trip segment, but it can happen if the car needs to cool the battery and leaves you with little to nothing. Some X's had A/C assembly mistakes, o-ring or reversed compressor connections, that caused the A/C to work harder than normal. That is certainly a possibility. The problem is describing the symptoms well enough to convince Service there is something wrong.

 

[mongo]

just finished a nice trip in my 2016 Model X P90D. I have owned it since April.

One issue seems to happen consistently since warm summer weather has started and I don’t know if it is normal or abnormal. Please give me your opinion.

When i stop to supercharge, my car always seems to be the loudest at the supercharger with the jet engine roar starting almost immediately on starting to charge. I do not ever hear other Tesla’s making this noise. Everything seems to work ok so I have not engaged Tesla Service on this.

But I have noticed that when I am done charging and I disconnect and start to drive away, I notice my outside temperature reading on the dash starts climbing rapidly and then it seems the AC starts blowing hot air. The actual air temperature today was about 75 to 80 degrees and really not that hot. But after stopping charging, the temperature display would climb to over 100 degrees and often to 110 degrees or a bit higher. I could also hear the jet engine roar inside the cabin.

My mind told me to get on the highway and drive to allow the flowing air to help cool. And that seemed to help. The temp would gradually drop down to accurately read the outside temp.

Normal or abnormal?...

When supercharging, check that the front lower louver doors for the side air intakes open.

 

[JasJ]

Sounds like freon level is off (likely low, but could be way high)... good enough for most of the time, but struggles with a real demand. Does your A/c work hard at low speeds, but seems to cool great at freeway speeds? If so, you need an A/C check for proper freon charge. My $0.02

 

[Rocky_H]

When supercharging, check that the front lower louver doors for the side air intakes open.

I will go with this one. These symptoms would have sounded completely normal if the outside temperature were about 105 degrees. It would have to work pretty hard to cool things off and sometimes will sacrifice cooling the inside cabin for a minute or two to divert the A/C chilling to the battery pack coolant.

But with it doing this at 80 degrees outside temperature, it does seem like it's having to ramp the cooling up and up because it's not working effectively. I've heard of this symptom a few times here on the forum, where it's trying to use the fans and radiators at the front to cool, but because the louver doors are blocked closed for some reason, it keeps trying to blow harder and harder but still can't get air flow through there.

 

[Erie Electric]

I will go with this one. These symptoms would have sounded completely normal if the outside temperature were about 105 degrees. It would have to work pretty hard to cool things off and sometimes will sacrifice cooling the inside cabin for a minute or two to divert the A/C chilling to the battery pack coolant.

But with it doing this at 80 degrees outside temperature, it does seem like it's having to ramp the cooling up and up because it's not working effectively. I've heard of this symptom a few times here on the forum, where it's trying to use the fans and radiators at the front to cool, but because the louver doors are blocked closed for some reason, it keeps trying to blow harder and harder but still can't get air flow through there.

Thanks for taking the time to respond. I looked at my front end tonight when I got home and the horizontal louvers located under the nose of the car were open and air was easily moving thru them. More importantly, the noise was very low. Not the jet engine noise. I am really not sure those louvers never really close but I will watch them.

I am wondering if the louvers were closed I would guess the noise level would really increase. I will monitor and report.

 

[ajdelange]

If the louvers were closed the high head pressure (high side) would go up and the fan would speed up to try to get the head pressure back into range. Were it unable to do that the system would shut down. If this happened during charging would be terminated to protect the batteries. All speculation, of course. Perhaps something got in there and jammed or blocked the louvers but eventually worked free. Perhaps its something else altogether.

 

[mongo]

If the louvers were closed the high head pressure (high side) would go up and the fan would speed up to try to get the head pressure back into range. Were it unable to do that the system would shut down. If this happened during charging would be terminated to protect the batteries. All speculation, of course. Perhaps something got in there and jammed or blocked the louvers but eventually worked free. Perhaps its something else altogether.

Isn't the compressor variable speed (thus displacement)? If so, in the case of high head pressure, wouldn't it slow down (rather than shut off entirely) to maintain design operating pressure while the fan runs at max to try to dump heat?

 

[ajdelange]

Yes, it is variable speed and the control algorithm, whatever it may be, might indeed take that approach rather than adjust the louvres and fan speed or it might do both or all three. In any case, were the louvers blocked the control system would sense high head pressure and low supercooling and make adjustments. As i said earlier: all speculation. The one thing I am pretty sure of is that there are protective features that would prevent damage to the battery were the cooling system unable to remove sufficient heat.

 

[Erie Electric]

I supercharged again today and the “loud shop vac” noise was there from the start for about 20 minutes. Then for whatever reason it went away but supercharging continued. By that time I was charging at a bit over 120 miles per hour. The ambient temperature was 75 to 78 degrees.

I did take the opportunity to carefully get down on my knees in my work clothes and look at the front air intake and I saw the louvers and they appeared to be open. I say “appeared” to be open.

I washed the car in the driveway tonite and took another more careful look. I realized that there are horizontal and vertical plastic “slats” that appear to be sort of a “grill”. They seem to be fixed in place and do not open and close. But behind that grill appears to be a solid door or panel that opens and closes. It was closed as the car was parked being washed and detailed.

Next time I am supercharging and the noise exists, I will examine much more closely.

By the way, I went ahead and made an appointment with the Cleveland Service Center for August 22. My first service appointment since I picked up the car in early April. We will see what they say.

 

[ajdelange]

It (the noise) happens with AC charging too. I happened to be working in the garage yesterday charging from a plugged HPWC at 40 Amps when the fan came on quite loud, ran for a while and quit. It did not come back on for quite a while. Thinking about it a bit the charger runs at about 90% efficiency at 240*40 = 9,6 kW meaning there are 960 W waste heat. This all has to go into the rectfier/boost circuit and battery cold plates so the glycol is going to warm up and that heat is going to have to be dumped overboard. I wasn't particularly paying attention to the time but I did note that the charging current history showed the car's draw dropping from 9.3 kW to 2.1 kW for a brief period about 45 minutes into the charge. This may have been when the A/C was heard to cycle. At that point the car had drawn 7.28 kWh which means about 0.9*7.28 = 6.6 kWh to the battery and indeed the display in the car showed 6 kW added. But it also showed the SoC had increased by about 12%. This is an X 100D so 1 kW is about 1%. And as the car continued to charge past this point the SoC indication continued to advance but the kW added indication did not. Also Teslafly concluded that at the time of the current drop the car added 6.5 kWh without taking anything from the line and without changing the SoC. This charge started at 13% SoC, lower than I've ever been before so perhaps that had something to do with this squirrelly behavior. Ultimately the charge completed and everything looks normal so perhaps the conclusion is that this sort of abnormal behaviour is normal.

Later last night a new version of the software downloaded.

 

[npardo]

Not to revive an old thread, but has anyone heard back from a service center on this quirk?

I just finished super charging at 11pm, ambient temperature at 40 degrees. The ambient temp readout is accurate in my car until I put it in drive, then it jumps up immediately to around 85 degrees, then gradually drops again to the accurate temp. Seems odd that it only occurs when you put the car in drive.