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Did you know the 3 heats the battery (actively) constantly while DC charging at any speed or temp?

SageBrush

REJECT Fascism
May 7, 2015
14,161
19,690
New Mexico
FWIW i tried this on a 2022 Model Y with the new software update 2022.40.x with a chademo adapter on 125amp station AND.........it still heated the battery the whole way at about 7kW.

In cold weather I call this a feature. The battery soaks up some heat during fast charging that is transferred afterwards to the cabin for passenger comfort, instead of using pack electricity. Nice range extender.
 

drtimhill

Active Member
Apr 25, 2019
3,512
4,538
Seattle
I expected you to read the post. the thread is about cars heating the battery during the charging cycle needlessly;)
I did read the post .. my point was (and remains): how do you know the heating was "needless"? Sure, before the recent update the car was over-doing the battery heating, but that doesnt mean that ALL battery heating is needless. So, again, why do you think in your case the heating was indeed unnecessary?
 
I did read the post .. my point was (and remains): how do you know the heating was "needless"? Sure, before the recent update the car was over-doing the battery heating, but that doesnt mean that ALL battery heating is needless. So, again, why do you think in your case the heating was indeed unnecessary?
I cannot foresee a reasonable scenario where the battery would need to be heated to accept 125 amps...much less 7 kW worth.

I couldn't get more than 36 kW out of a 50 kW station the other day before my update to 2022.40.X, so I'm hoping to try this again as well. Battery preheating icon was constantly on in the app while charging too.
 
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SigNC

Active Member
Aug 23, 2017
1,672
1,593
NC
I did read the post .. my point was (and remains): how do you know the heating was "needless"? Sure, before the recent update the car was over-doing the battery heating, but that doesnt mean that ALL battery heating is needless. So, again, why do you think in your case the heating was indeed unnecessary?
Because the battery was quite warm enough to take the 45kW up to the charge point I had set which was about 70%.
 
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SigNC

Active Member
Aug 23, 2017
1,672
1,593
NC
Obviously, it would appear that the Tesla engineers disagree with you. (BTW how warm was the coldest cell?)
Jesus you guys are anal. Maybe just maybe it still heats the cells. If itwill make people happy i'll hook up scan my tesla and get you all the details but easy math says reducing the charge by 7kW from 20% SOC to 70% SOC is slower than any gain that would have been had by heating the battery the whole time to prevent a taper at 70% when the max the station puts out is around 45kW.

FWIW it was 80f out when I did this, the car had been driven around a bit and had been kept in a warm garage all night.
 

MP3Mike

Well-Known Member
Feb 1, 2016
20,455
51,966
Oregon
Jesus you guys are anal. Maybe just maybe it still heats the cells. If itwill make people happy i'll hook up scan my tesla and get you all the details but easy math says reducing the charge by 7kW from 20% SOC to 70% SOC is slower than any gain that would have been had by heating the battery the whole time to prevent a taper at 70% when the max the station puts out is around 45kW.

FWIW it was 80f out when I did this, the car had been driven around a bit and had been kept in a warm garage all night.
What is the minimum temperature that you think the battery needs to be at to charge at 45kW from 20-70% while causing the least amount of degradation? (Since you claimed it was warm enough, you must have some number you are using to make that determination.)
 
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SigNC

Active Member
Aug 23, 2017
1,672
1,593
NC
What is the minimum temperature that you think the battery needs to be at to charge at 45kW from 20-70% while causing the least amount of degradation? (Since you claimed it was warm enough, you must have some number you are using to make that determination.)

I feel like you are missing the point in your effort to just be pedantic. I think we can all agree that the battery can EASILY charge at 45kW from 20% to 50% at 80f. At 20% it can take in 250kW when preheated and at 50% it can still do north of 100kW. It's no stretch to think 45kW is quite safe at 80f from 20-50 EASILY. Now in the course of charging those approximately 22.5kWh over a half hour at 45kW from 20% to 50% the battery would heat up all on it's own some, just from charging. Let's just say for giggles that it had to taper, because the battery wasn't warm enough to 38kW for 50% to 70%, even it it had to taper to 31kW from 50-70%. You are still coming out ahead in charge time from 20-70.

That being said, i'm happy to preheat the hell out of the battery, run scan my tesla and redo it.
 

drtimhill

Active Member
Apr 25, 2019
3,512
4,538
Seattle
Jesus you guys are anal. Maybe just maybe it still heats the cells. If itwill make people happy i'll hook up scan my tesla and get you all the details but easy math says reducing the charge by 7kW from 20% SOC to 70% SOC is slower than any gain that would have been had by heating the battery the whole time to prevent a taper at 70% when the max the station puts out is around 45kW.

FWIW it was 80f out when I did this, the car had been driven around a bit and had been kept in a warm garage all night.
But the purpose of preheating the battery is not just to optimize energy costs, it's also related to battery lifetime. And it's not a matter of being anal, it's that you declared that the car was doing the wrong thing without really explaining why. It may be doing the wrong thing, it may not be. Providing extra data will help everyone determine what changes Tesla have made and how they impact us all.

Also, are you certain the car knows what the station max power output is? Obviously it does for superchargers, but I'm not certain about 3rd party DC chargers.
 
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MP3Mike

Well-Known Member
Feb 1, 2016
20,455
51,966
Oregon
Bjorn has tested this update and how it impacts charging at a 50kW charger:


And it seems to work as I would expect. With a reasonably warm battery, ~23*C/73*F, it charges at 43kW and does not heat the battery while charging. (It did still heat the battery when the battery was colder; ~13*C/56*F.)

It switches from heating to not heating somewhere between 56* and 73*, I wonder if someone will take the time to find the exact cut-point for that.
 

SageBrush

REJECT Fascism
May 7, 2015
14,161
19,690
New Mexico
I cannot foresee a reasonable scenario where the battery would need to be heated to accept 125 amps...much less 7 kW worth.

My L2 at home is 40 Amps, or about 10 kW.
I would routinely see the Tesla send about 1 kW to the pack and the remainder to heating for the better part of the first 5 minutes of a charging session in the cold of our winter, meaning the pack started out around 20 - 25 F.

Pack damage from charging a cold pack is a very real thing, albeit to a large degree unrecognized or under-recognized by the EV community.
 
My L2 at home is 40 Amps, or about 10 kW.
I would routinely see the Tesla send about 1 kW to the pack and the remainder to heating for the better part of the first 5 minutes of a charging session in the cold of our winter, meaning the pack started out around 20 - 25 F.

Pack damage from charging a cold pack is a very real thing, albeit to a large degree unrecognized or under-recognized by the EV community.
1 kW is immaterial and wasn't what I was getting at, but I understand your point.
 

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