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Battery Conditioning in HOT Climate

At what temperature does the battery conditioning cool the battery? Does it vary between plugged-in and not plugged-in? Does this vary for battery type (wife has LFP, I have NCA).

It's supposed to hit 114 F next week and I want to know if keeping it plugged in will help keep the battery from getting too hot, which I believe is not healthy for the battery. I will be keeping it under 80% SOC whenever not needed for a long trip but I intended to let the wife charge the LFP to 100%. Is that still advised in the heat?

Thanks for any help.

P.S. Forgive me if all this has been answered previously. I did a lot of searching but nearly all the information on battery conditioning is about heating it up in the winter or heating it up for charging.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
13,366
17,015
San Diego
At what temperature does the battery conditioning cool the battery? Does it vary between plugged-in and not plugged-in? Does this vary for battery type (wife has LFP, I have NCA).
All good questions, I don’t know the answer to any of them as I have never seen any battery conditioning (cooling) take place. I don’t even know whether it happens at any realistic temperature. It might, no idea.

I would be surprised if it kicks in at 114F.

Best bet is to keep the car in an air-conditioned garage and failing that (or in addition) keep it at as low an SOC as possible, 40-50% or lower would be good but don’t inconvenience yourself.
 
You'll be fine leaving the vehicle exactly how it is, whether that be plugged in or not.
Well, I know it won't spontaneously combust or anything. But I also know it's not good to leave Li-Ion cells at elevated temperatures for long term, especially at high SOC. I think there's a lot of Leaf owners that can attest to this. The Chevy Bolt does this and it is well known at what temperatures it activates and it's lower if it is plugged in. It's surprising that it's a mystery for Tesla's.

Best bet is to keep the car in an air-conditioned garage
Unfortunately I've got a single, non air conditioned garage and two Tesla's.
 
114F really is not that hot.... At all.
Like previously mentioned, you don't have anything to worry about. The vehicle will take care of what it needs to. Your battery gets MUCH hotter when using a supercharger.

Charging to 100% is fine just don't leave it at that state for too long too often, even in cold weather.
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,334
10,712
Boise, ID
It's a decent question to ask.
The Chevy Bolt does this and it is well known at what temperatures it activates and it's lower if it is plugged in. It's surprising that it's a mystery for Tesla's.
Teslas are set to do exactly that same thing. At least they were on the older cars, and I would think that is still in place on all of the newer ones, since it's just sensible.

I don't want to go find the threads now, because they are years old and may be tough to search, but I can describe it. They have internal temperature targets of what is too hot, and the car will just manage itself and cool the battery as needed. BUT it does have two different high temperature limits--one when unplugged and one when plugged in. People have reported the exact numbers from internal data of the car of what those two labeled temperature targets are, but I don't remember the numbers now.

So what that means is that yes, it will let the battery stay hotter if it doesn't have access to external energy. But if it's plugged in, so it knows it's not going to deplete your range, it uses a lower target temperature and will fire up the chilling to cool the battery down more.

I have a 2014 Model S and I and some other owners have observed this in action. During the summer when the car has sat out in a parking lot when it's 103 degrees or something, the car is pretty hot but not actively cooling. I drive it home and get into the garage, and park the car and get out, and it's still not actively cooling. But then when I plug it in, it fires up the air conditioner for a while and starts cooling the battery down because it knows there is energy available to get to a more ideal level.

I haven't seen this talked about in several years, so I'm not certain it's applicable to the Model 3 or Y, but on the older S and X it was set up that way.
 

smatthew

Active Member
Jun 9, 2018
1,532
2,564
CA Bay Area
Whether the car is LFP or not, it is still most healthy for the battery to kept at as low of a state of charge as possible (but not BELOW 0% stated!)
LFP cars just have a less steep penalty near 100%, and Tesla uses non nuanced communication to keep things simple, which is what one must do when communicating to the masses.

Supporting Data:
Your "Supporting data" doesn't support your hypothesis at all.
 
Can you explain what you think the graphs are saying?
Or provide a link to the research paper this came from?
Sure, they took some cells with a known initial capacity, and stored them at various states of charge, for various lengths of time, and at two difference temperatures, then measured the % of initial capacity after the storage time.

With all 3 chemistries you can see that more initial capacity remained when the storage time was shorter (of course), an when the temperature was lower (also expected) and when the state of charge was lower. LFP is interesting in that a state of charge of 100% is no worse (maybe even better!) than 80% at moderate temperatures, but you can still do even better if you only charge to 70% or lower

@AAKEE should have the full article handy, I'll try to dig it up though
 
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Can you explain what you think the graphs are saying?
Or provide a link to the research paper this came from?
Here is a link where AAKEE posts various links to similar research and dives a bit deeper in the nuance on this:

 

smatthew

Active Member
Jun 9, 2018
1,532
2,564
CA Bay Area
Here is a link where AAKEE posts various links to similar research and dives a bit deeper in the nuance on this:

So you're unable to post a link to the research paper that graph came from. Great.

BTW - who is storing their vehicle for 2+ months? I drive my vehicle every day so that chart is useless.
 
So you're unable to post a link to the research paper that graph came from. Great.

BTW - who is storing their vehicle for 2+ months? I drive my vehicle every day so that chart is useless.

The chemistry of aged based degradation is occurring even as you drive. So if you own the car for 2 months, you get 2 months worth of age degradation. Cycling the battery causes additional degradation as well, but the battery is always aging, and it ages slower when kept at a lower state of charge, and/or colder temps.
 

AAKEE

Member
Jan 8, 2021
971
1,393
Sweden
So you're unable to post a link to the research paper that graph came from. Great.

Here you go:
Calendar aging

BTW - who is storing their vehicle for 2+ months? I drive my vehicle every day so that chart is useless.

So you drive your car 24 hours a day, and only stop for charging?

Most other of us drive 15K mi / 25K km with an average speed of 30mph / 50kph.

This means our batteries is driven about 5% of the hours each year, and maybe charged 10% of the hours.

The rest of the year, about 85% of the time or some ten months each year the battery sits, waiting. That is exactly what calendar aging is about.
Calendar aging for a car used as we most other use our cars work out more or less just like these graphs.

You now have got the link. You’re welcome to read it. :)
If you need more inputs I’m happy to supply you with that.

Anyone has the right to hims/hers own opinion . If you would like to disregard all the research data out there, you can do that (…I sense a slight resistance in your post…), but if your battery show more degradation in the future than you hoped, you then can read this thread again and find the misstakes that lead to that. ;)
 

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