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Air conditioning diverted to battery

Zeromus-X

Member
Apr 10, 2016
206
185
Los Angeles, CA
I moved back to Phoenix recently, and noticed on a few recent road trips that my AC would blow warmer than usual for a short period of time. There was never a notification of what was happening, and I assumed it was just a fluke. On today's trip from Tucson to Phoenix, though, I noticed that when it happened, there was a red 'alert' symbol at the top of the touchscreen. No pop-up, no warning on the dash. When touching the symbol, a note would tell me that the AC was being diverted to cool the battery. Typically this would last about 2-4 minutes, and it'd be back to cold again.

My worry here is that it's only May. For those of you who live in warmer climates, is this something you see often? I've seen a few rare threads about here and on the official forums but half the people don't believe them and the other half say it should happen rarely in extreme situations. I'd say it probably happened three times on the trip back today, and once or twice the other day on the trip there. We're talking 100-105 degrees with 75-85 mph driving, so there is definitely stress on the system. But when we start hitting 115 or so, is there concern of just losing AC altogether at highway speeds?

This also brings up a related curiosity... I'm out of normal warranty (July 2016, but 52,000 miles) but if the AC system is so tightly integrated into the battery cooling function, I'd wonder if a major cooling problem would be considered a drivetrain issue?...
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,660
7,951
Boise, ID
That has always been a thing on Tesla cars, but as far as I remember, it would always put a notice on the screen when it was having to do that. Yes, I have heard of some people not believing that this happens.

I live in a desert in Idaho, where our summers do consistently get over 100 degrees every day for a month or two, but it's the normal kind, like about 104-106 maximum--nothing like Phoenix. I don't think I've ever seen 110 degrees in 18 years here. So the data point is that in over four years with my Model S, I have never had the A/C divert to the battery. However, almost all of our driving is around town at lower speeds. I rarely take highway trips, so that would be higher current and power consumption and would be that extra heat which would push it over the edge.

So that's what I got--barely over 100 degrees in city driving doesn't generally get it to that diverting point.
 

Zeromus-X

Member
Apr 10, 2016
206
185
Los Angeles, CA
So that's what I got--barely over 100 degrees in city driving doesn't generally get it to that diverting point.

Excellent data point, thank you. I don't do a ton of 115-degree 80-mph driving since traffic mostly prevents that. My bigger worry was that it was going to be an everyday thing while commuting/etc.

For everyone else who replied, I'm going to check the intakes tomorrow and make sure they're opening (and clean). Yes, the car was pretty loud. I've noticed it'll rev the fans up to "liftoff" speed on occasion while sitting still, especially after a quick trip with the AC blasting. (I'm actually worried one of my apartment neighbors will eventually complain that my car makes so much noise, ironically enough!) Sometimes when supercharging in high heat too. But I can't remember it diverting AC until recently.

Mostly, all these things are making me paranoid since I'm a thousand miles outside warranty, and I'm becoming a Tesla hypochondriac.
 

ohmman

Plaid-ish Moderator
Feb 13, 2014
10,150
18,461
North Bay, CA
I had this issue on a long road trip with my Model X when Supercharging. Charging speeds were also significantly reduced. In my case it was related to a factory issue with reversed coolant lines. But checking the louvers, as suggested above, is an excellent suggestion, and one that is documented as an issue here on the forums.

Good luck.
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,201
36,538
Oregon
This also brings up a related curiosity... I'm out of normal warranty (July 2016, but 52,000 miles) but if the AC system is so tightly integrated into the battery cooling function, I'd wonder if a major cooling problem would be considered a drivetrain issue?...

There is no drivetrain warranty. The 8-year/unlimited mile warranty is for the battery and the drive unit. They won't even cover the charger or HV junction box under it.
 
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Buster1

Member
Oct 13, 2016
582
266
Ft Worth
Checking all the front radiators is a good idea, even the two louvers. However, recall the side louvers are used for HVAC only, and the main front radiator is used to cool the battery packs based on the position of the valve that is in the upper right corner of the schematic.

This is an old schematic, but 52C (125F) was used for an active cooling target. So if the battery reaches 125F, the car should start to actively do things to cool the pack.

factory_thermal_censored.jpg
 

Zeromus-X

Member
Apr 10, 2016
206
185
Los Angeles, CA
Was the range mode off?

I never use range mode.

Agreed about the diagram, very cool looking.

I would imagine when the car is reporting temperatures in excess of 110 and you're driving on hot asphalt with no shade, that it's pretty easy to hit 125 degrees. It hasn't happened in the days since, but I've mostly done local driving. I didn't see anything in the front radiator area, and I pressure washed the car today to make sure there wasn't a rogue leaf stuck/hidden anywhere (and to make it look pretty of course).

I need to take it in for my various recalls and I'm going to briefly mention to see if they can eyeball the system for no charge. I've never taken it in for any service in 51,000+ miles, hopefully they'll toss in a health check.
 
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animorph

Active Member
Apr 1, 2016
2,149
1,546
Scottsdale, AZ
I didn't have a problem last summer, but no super long AZ summer trips. One to Cave Creek Ranger Station in June. Never had the climate blow warm. YMMV, and others have had legit problems.

My old Porsche 911 used to blow warm every time I stomped on the gas. It would stop the A/C for max acceleration.
 

Lanber

Member
Sep 20, 2015
64
30
Norway
Under the "Driving" setting. Is the car put in "Range mode ON" ? If so you will be running the battery hotter and that leaves less margin on top before it goes into active cooling.

Also the louvers in front mentioned. Think they may be stuck closed. A very common fault.
 

cybergates

Member
Feb 14, 2017
545
232
So Cal
I had this problem coming back from phx to quartzsite and it was only 100F w range mode on as was carrying 4 passengers and a lot of luggage. And supercharging.

Took it into tesla they did find several things wrong and fixed it. So far so good. When it was malfunctioning the cooling fan was not coming on like it should and likely the louvers were not opening as they replaced something to do w that (mafunction in radiator shutter system)

Seems a number of late 2016 tesla model s have had AC issues.

I will avoid range mode esp when superhot outside
 
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Zeromus-X

Member
Apr 10, 2016
206
185
Los Angeles, CA
I've got a mobile service guy coming out tomorrow to deal with some recall items and I figure I'll ask him about it while he's here. I have no idea if the louvres are working the way they're supposed to. They look clear. But, today I had the air conditioning diverted again when I went to lunch -- about 35 minutes each way, with a high around 100, but again driving pretty fast most of the time.
 
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Cyclone

Cyclonic Member ((.oO))
Jan 12, 2015
5,058
1,143
Charlotte, NC
I’ve been in Model S on the interstate doing around 70 mph when it diverts the ac. Sadly, this was over two years ago and the car gave no indicatonnit was diverting. We just heard the ac blasting and barely anything coming out of the vents, and what was coming out was lukewarm. Ended up having to stop for 30 minutes at a Supercharger and wash up at the hotel bathroom as we were both dripping in sweat. That was thankfully long enough for the car to catch up and no issue the rest of the trip.
 

Zeromus-X

Member
Apr 10, 2016
206
185
Los Angeles, CA
Hmm... ran into this again today, but just while driving home from work, not even on a road trip. 109 degrees outside according to the dash, and I had driven 22.4 miles / 32 minutes when the alert came on. Air diverted for about 3-4 minutes.

Happening on a road trip was less concerning; if it's happening on my regular commute now, I can only imagine it will get worse as the summer gets hotter.

I don't see anything in the vents and they appear to be working as normally as I understand them to; does anyone know if Tesla offers a service to check the cooling system for problems and, if so, how much it might run?

IMG_1666.JPG IMG_1669.JPG
 

P85_DA

Supporting Member
Supporting Member
Apr 25, 2015
4,219
2,950
CA
...interesting I live part time in Indian Wells ..where summer can get to 120+ in five years of driving have yet to see that ...my car I leave range mode on all the time
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,201
36,538
Oregon
I don't see anything in the vents and they appear to be working as normally as I understand them to; does anyone know if Tesla offers a service to check the cooling system for problems and, if so, how much it might run?

Just to be clear by vents, you are saying that the louvers in the front open while the AC is running?

You can always contact them. I'm pretty sure at least once person said that Tesla diagnosed it remotely to let them know what was wrong.
 

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