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

camalaio

Active Member
May 28, 2019
1,483
2,095
Vernon, BC, Canada
I agreed with the fact it could be unnecessary in some scenarios. I just don't see what the point of this discussion is because we've all known about the battery conditioning since it came out. It was in the release notes and the car tells you about it on-screen. No CAN sniffing needed. The thread title wasn't a small technicality. It made it very clear using plenty of words that the car was doing something incredibly stupid, which it doesn't do.

Oh well, you can carry on without me. I'd say Happy Thanksgiving, but I see you're in Canada, so I'll just say enjoy the rest of your week :)

To clarify, this topic is not the battery pre-conditioning that the car tells you about. This active-heating-while-charging feature was not in any release notes to my knowledge (I could be wrong, I'm a newer owner). The car does not tell you that it is doing this. This thread does point out an action that the car does do which is otherwise not explained anywhere. The "stupidity" of it mostly applies to situations with slower DC charging conditions (likely 50kW or less, but perhaps applicable to Urban Superchargers as well).

Happy belated Canadian Thanksgiving, and happy current American Thanksgiving! We now get to enjoy American Black Friday sales since we don't have a matching "Canadian Black Friday" for our Canadian Thanksgiving. Random trivia for ya.
 

FalconFour

Supporting Member
Mar 25, 2016
140
237
San Jose, CA
If I recall correctly, the DC charger does not include its specs in the handshake.
CHAdeMO does indeed constantly communicate its amperage (max voltage/max current are part of the exchanged messages, and the car's measurement must constantly match the station's report at the 1/10 second scale, or it shuts down), and at a minimum, it can be inferred - the car asks for a specific voltage and amperage target, and if the station isn't delivering kW enough to worry about, don't bother heating. So there's two mechanisms that can be used here - if there were any logic to say "hmm, this DC charger is more similar in profile to AC charging than 250kW Supercharging, so we don't really need to heat", then it could easily pick out this data from the exchanged messages, either as a "hey this station says it can't deliver much power", or a "hey this station isn't delivering much power" thing.

Really, it should have been obvious in the beginning, but absolutely none of this has to do with 250kW charging. Not only because 250kW is a unicorn that's basically never achievable at the Fremont v3 stations, but also because it's not the point of my complaint. My complaint is that those power levels are never available *at the station*, yet the car is preparing as if the bottleneck were in the battery.

Just as @camalaio says, this is more about the absurd waste of spending a non-trivial fixed amount of energy heating the battery even when the station is slow. The "If DC, then heat battery" logic, without any conditionals around it. It doesn't help the battery except at actually high charging rates. And if the "Li plating" theory is true, then regen wouldn't be a thing either - it charges the battery just as fast as some of these DC stations we're referring to.

It shouldn't be happening for "slow" DC charging. That's my point.

I had no idea there would be this many people saying basically "shut up and trust the infallable logic of Tesla" but I've really thought about deleting and re-doing this thread because now I see how people react and how widespread Scan My Tesla is (for a thing I've never seen anyone share in this forum, in the FB groups, or on YouTube, it's funny that all these threads and videos NOW show up, despite searching on it before-hand).
 
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camalaio

Active Member
May 28, 2019
1,483
2,095
Vernon, BC, Canada
[QUOTE="FalconFour, post: 4244944, member: 44721"
...

I had no idea there would be this many people saying basically "shut up and trust the infallable logic of Tesla" but I've really thought about deleting and re-doing this thread because now I see how people react and how widespread Scan My Tesla is (for a thing I've never seen anyone share in this forum, in the FB groups, or on YouTube, it's funny that all these threads and videos NOW show up, despite searching on it before-hand).[/QUOTE]

Ah. New to sharing information online I see? :p

There are very vocal people here, it's what forums attract. Heck, I'm one of those too. These vocal people will fall on either side of whatever fence is put up. My favorite was the trainwreck of a thread I had on cost comparisons to gas vehicles (showing that a Tesla really isn't a universal money saver). That really got people going. It's very hard to mention anything here that doesn't put Tesla in a positive light or implies they've half-baked something: every decision must somehow have been absolutely intentional and beneficial. Classic brand worshipping, basically.

I for one appreciate your analysis, anecdote, and posting. Please continue to post any interesting findings like this. I myself was going to on the Scan My Tesla train and even start developing my own app, I just haven't got that far yet. One thing I really want the answer to is when the front motor is actually used in my AWD vehicle during regular driving. It appears to be almost never.

FWIW, there is precedent that when information is available, Tesla may disable it or physically take it away in the future. The fact we have OBD II access at all seems to have been a happy finding rather than something intentionally physically exposed by Tesla. You just are definitely not the first to find, use, and display information from this interface.
 

SageBrush

REJECT Fascism
May 7, 2015
12,333
15,242
New Mexico
it's funny that all these threads and videos NOW show up, despite searching on it before-hand
They did not show up "now," you finally caught a clue.
I presume that eventually you will realize that you should read up on Li plating and take some steps to avoid showing up at a DC charger with a very cold battery. This is not unexplored territory.

As for your initial impulse to hide your use of 'scan my Tesla' -- that was just retarded. I cannot even begin to fathom why you would think that the vendor would only sell to you. You are not a special snowflake, but you are poorly informed. I recommend you take a refresher in modesty.
 
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FalconFour

Supporting Member
Mar 25, 2016
140
237
San Jose, CA
FWIW, there is precedent that when information is available, Tesla may disable it or physically take it away in the future. The fact we have OBD II access at all seems to have been a happy finding rather than something intentionally physically exposed by Tesla. You just are definitely not the first to find, use, and display information from this interface.
It really isn't OBDII though. It's just some enterprising folks that hacked around and discovered a CAN line buried in the back seat, and the only way to make it mainstream viable is to convert it to an OBDII port so they can hack a commercially available OBDII adapter to work with the CAN they're seeing. That's why I worry Tesla would impede this method if they wanted to hide this info instead of fixing it. They have zero reason to make it accessible, not even OBDII, as that's not something Tesla did. It's 100% hackery start to end. Hackers (in a positive way) discovered the CAN, hackers decoded the messages, hackers made an OBDII port available.

I super appreciate the positive encouragement though. I've just got to ignore the haters/self proclaimed "Li Plating" experts I guess :)
 
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camalaio

Active Member
May 28, 2019
1,483
2,095
Vernon, BC, Canada
They did not show up "now," you finally caught a clue.
I presume that eventually you will realize that you should read up on Li plating and take some steps to avoid showing up at a DC charger with a very cold battery. This is not unexplored territory.

As for your initial impulse to hide your use of 'scan my Tesla' -- that was just retarded. I cannot even begin to fathom why you would think that the vendor would only sell to you. You are not a special snowflake, but you are poorly informed. I recommend you take a refresher in modesty.

Dude, you're coming in way too hot on this. Darn near one of the first things they say is that the method is publicly available. They rightly don't want to expose it because it may be used wrongly and/or taken away in the future. Tesla has done this in the past when people had "too much" access to their own vehicles. They didn't even expose an OBD II port on the Model 3, people had to find an alternative that Tesla likely didn't intend for the average person to use.

And for everyone, battery chemistry is insanely complex with a large number of intricate actions and happenings that even legitimate battery chemists are still quantifying. The stated purpose of heating the battery is to increase charge rate, not to prevent health impacts to the battery.

Suggesting that we read up on it isn't sufficient or even helpful, honestly. We just don't know. We don't know the exact chemistry of the cells used in Model 3. We don't know the complex internal environment of those cells mapped against all possible variables. Reading may give us info, but the balance of that info and various internal battery events is incredibly unknown to the average person reading an article on the internet for a potentially different battery chemistry.

It really isn't OBDII though. It's just some enterprising folks that hacked around and discovered a CAN line buried in the back seat, and the only way to make it mainstream viable is to convert it to an OBDII port so they can hack a commercially available OBDII adapter to work with the CAN they're seeing. That's why I worry Tesla would impede this method if they wanted to hide this info instead of fixing it. They have zero reason to make it accessible, not even OBDII, as that's not something Tesla did. It's 100% hackery start to end. Hackers (in a positive way) discovered the CAN, hackers decoded the messages, hackers made an OBDII port available.

I super appreciate the positive encouragement though. I've just got to ignore the haters/self proclaimed "Li Plating" experts I guess :)

Fair, my wording was incomplete! We just have to hope that Tesla continues to provide such info over regular CAN bus... things. Not entirely impossible, maybe just hard to find and access in the future.

Keep on keepin' on, many will appreciate the info. Hopefully it eventually gets back to Tesla and they realise it's not currently a great solution. I would bring it to them if I knew how.
 
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drtimhill

Active Member
Apr 25, 2019
1,741
2,119
Seattle
So, after wandering through all the verbiage, your (the OP) claim comes down to: (a) the battery is being heated before and during DC charging, and (b) this is unnecessary and a waste of energy. Correct?

Assuming claim (a) to be an accurate observation, on what do you base claim (b)? You repeatedly state that the heating is unnecessary, or at least (if I read your posts correctly), excessive and uncontrolled. But I cannot find any information on why you feel the behavior you describe is erroneous.
 
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SageBrush

REJECT Fascism
May 7, 2015
12,333
15,242
New Mexico
So, after wandering through all the verbiage, your (the OP) claim comes down to: (a) the battery is being heated before and during DC charging, and (b) this is unnecessary and a waste of energy. Correct?

Assuming claim (a) to be an accurate observation, on what do you base claim (b)? You repeatedly state that the heating is unnecessary, or at least (if I read your posts correctly), excessive and uncontrolled. But I cannot find any information on why you feel the behavior you describe is erroneous.
If you try really hard, you can find a crappy CHAdeMO station that is DC charging and a low power rate. Presumably the software willl heat up the battery more than is required for that instance. For 99% of Tesla owners in the USA that never use CHAdeMO this "issue" will never come up. For the ~ 1% that use CHAdeMO, it will only affect those owners that use *really* crappy stations. And of that small group, only when they actually use the crappy station. Figure a couple kWh a year for the entire Tesla fleet

This thread has wasted more energy than the "problem" itself.
 

camalaio

Active Member
May 28, 2019
1,483
2,095
Vernon, BC, Canada
So, after wandering through all the verbiage, your (the OP) claim comes down to: (a) the battery is being heated before and during DC charging, and (b) this is unnecessary and a waste of energy. Correct?

Assuming claim (a) to be an accurate observation, on what do you base claim (b)? You repeatedly state that the heating is unnecessary, or at least (if I read your posts correctly), excessive and uncontrolled. But I cannot find any information on why you feel the behavior you describe is erroneous.

(a) is not quite accurate, but you're on track with (b).

For (a), OP mentioned CHAdeMO stations as well as Superchargers. In the distant and even near future as EV adoption grows, Tesla owners will be using "non-Tesla" charging stations more and more. For these, the battery is not heated prior to charging. Pre-conditioning is only applied for navigation to Superchargers. However, yes, for both CHAdeMO and Superchargers, heat is intentionally applied during charging.

For (b), this information is throughout the thread and in the original post.
  • A 10kW J1772 "Level 2" station does not result in intentional heating of the battery, but a 10kW CHAdeMO "Level 3" station does. Both apply the same charging power to the battery, so it doesn't make sense that heating the battery could be important for one and not the other.
  • We know via the marketing on the battery pre-conditioning feature that Tesla applies heat only to increase the possible charge rate. This works great at low states of charge when you use a very high power charging station (80kW or greater on a LR pack).
  • For slower charges (higher state of charge, CHAdeMO 50kW adapter limit, ~70kW Urban Superchargers) there is no need to heat the battery to the degree used for 150kW Superchargers. A relatively cold LR pack receives nearly 80kW from a Supercharger already, so adding heat to get higher charge rates that aren't possible at slower stations is entirely wasteful.

I also think there is no reason to always use 150kW or 6kW stations over 50kW stations. 50kW is a nice sweet spot for grabbing dinner somewhere with a low battery, and having a nearly full battery when done without needing to rush through dinner. 150kW is too fast, 6kW far too slow for that case. Wasting 10% of that 50kW for no actual benefit is indefensible. 50kW is also much nicer to the grid as it's less power and drawn out over a longer time instead of incredibly spiky loads.

As for the above poster... yes, perhaps this isn't an issue for highly populated areas in the USA where EV infrastructure is strong. More rural areas and simply non-USA countries are a different game. Tesla is a global brand.

Around me and in this province in general, there are actually a number of Model 3's using CHAdeMO stations. CHAdeMO infrastructure is much better than Tesla Superchargers currently, and 50kW beats the 6kW Level 2 stations. There are a few 25kW stations as well (mostly free!), and 20% of their energy is wasted with a Model 3. I realise this is not the case everywhere and is actually a more rare exception, but it's also likely to be the case going forward. The convenience of these 50kW stations is far better as there are far more of them in places I am actually going to vs. Superchargers.
 

diamond.g

Active Member
Nov 5, 2015
2,421
1,362
Moyock, NC
Interesting post OP. This is another example of folks complaining about something (you should have been here last winter when no one could charge at the rates they were seeing during the summer) and tesla “fixing” it in a way but not fully telling folks how they were doing it.
The 3 used to basically be in Range mode all the time. I would suspect they didn’t take this into account when adding support for the chademo adapter, though it could be argued that they should have due to the urban Superchargers.
 
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camalaio

Active Member
May 28, 2019
1,483
2,095
Vernon, BC, Canada
Interesting post OP. This is another example of folks complaining about something (you should have been here last winter when no one could charge at the rates they were seeing during the summer) and tesla “fixing” it in a way but not fully telling folks how they were doing it.
The 3 used to basically be in Range mode all the time. I would suspect they didn’t take this into account when adding support for the chademo adapter, though it could be argued that they should have due to the urban Superchargers.

This caught my interest, decided to look back in time prior to preconditioning when packs would have been far more likely to be cold.

Multiple info pulls from this forum between Oct 1st 2018 through March 1st 2019:
  • 60°F, 30-50%, 50kW
  • 60°F, 60%, 30kW (suspected charger pairing in the thread, though)
  • 44°F, 50%, 16kW (this one is definitely an outlier)
  • 44°F, 46%, 66kW
  • 24°F, 39%, 64kW
There's quite the spread, but yes cold does impact it. Variance may be due to different actual pack temps, pack sizes (SR+/MR/LR), and even Supercharger issues which do sometimes occur. I suppose this makes sense given that regen apparently caps off somewhere around 50-75kW, and my LR AWD starts showing regen dots around 60°F (implying, if taking the upper end, that at 60°F one would start to see max charge rates of only 70kW or so, or below 50kW on the lower end).

At around 50°F, I never had issues pulling the "full" 45kW from CHAdeMO stations immediately while the battery is still cold from sitting overnight. I'm sure below-freezing temps dig into this a fair bit, but then of course it's potentially valuable to heat the pack if a higher charge rate can be obtained that would overall speed up charging (unlike my 10kW charger case, which has the rate cut in half!). Of course, the car doesn't know how long you're going to be sitting at a charger either, so that can be an awkward judgement to make.
 

SouthSeas

Member
Nov 26, 2019
201
48
Pennsylvania
When you're talking about a cold battery, you absolutely save a lot of time. 4kW for ~15 minutes isn't that bad when your entire goal is to minimize downtime at the supercharger.

Of course you can just not navigate to it, but apparently the car will expend that energy while plugged in anyway. 4kW at ~15 minutes is 1kWh and will be under an extra minute to charge, or if you significantly increase your charge rate is almost nothing to recover.

I don't know where you got the 15 minute number. How many degrees do you think it will need to be warmed?
 

SageBrush

REJECT Fascism
May 7, 2015
12,333
15,242
New Mexico
I don't know where you got the 15 minute number. How many degrees do you think it will need to be warmed?
It varies, but 15 minutes is a ballpark average.

The other day I saw pre-heating behavior that was interesting. My battery SoC was under 10% when I set the destination to Supercharger so I was not surprised that pre-heating did not start. Then about 2-3 miles from the Supercharger pre-heating engaged despite SoC at 4%. I arrived at 3% SoC and charged at 140 kW the entire session. Pre-heating is getting smarter.
 

donkemaen

Member
Aug 10, 2017
30
39
Norway
And for everyone, battery chemistry is insanely complex with a large number of intricate actions and happenings that even legitimate battery chemists are still quantifying. The stated purpose of heating the battery is to increase charge rate, not to prevent health impacts to the battery.

This is obviously not true. The battery is heated to prevent health impacts, so that the charge rate can be increased.

You could put in 250kW to a model 3 battery at any time but it would be ruined, and even more so when it's cold.
 

rrolsbe

Member
Feb 18, 2017
220
126
Albuquerque
This caught my interest, decided to look back in time prior to preconditioning when packs would have been far more likely to be cold.

Multiple info pulls from this forum between Oct 1st 2018 through March 1st 2019:
  • 60°F, 30-50%, 50kW
  • 60°F, 60%, 30kW (suspected charger pairing in the thread, though)
  • 44°F, 50%, 16kW (this one is definitely an outlier)
  • 44°F, 46%, 66kW
  • 24°F, 39%, 64kW
There's quite the spread, but yes cold does impact it. Variance may be due to different actual pack temps, pack sizes (SR+/MR/LR), and even Supercharger issues which do sometimes occur. I suppose this makes sense given that regen apparently caps off somewhere around 50-75kW, and my LR AWD starts showing regen dots around 60°F (implying, if taking the upper end, that at 60°F one would start to see max charge rates of only 70kW or so, or below 50kW on the lower end).

At around 50°F, I never had issues pulling the "full" 45kW from CHAdeMO stations immediately while the battery is still cold from sitting overnight. I'm sure below-freezing temps dig into this a fair bit, but then of course it's potentially valuable to heat the pack if a higher charge rate can be obtained that would overall speed up charging (unlike my 10kW charger case, which has the rate cut in half!). Of course, the car doesn't know how long you're going to be sitting at a charger either, so that can be an awkward judgement to make.

I charge at 240V @ 24A 5.76KW and when the battery is cold soaked at temps at or below around 47 degrees F I start to see heating of the battery during initial charging.. When I charged the other day, about half of the 5.76KW of power was used for the first 10 minutes to heat the battery then the car charged at the normal 22 to 23 miles per hour. As the temps drop, a higher percentage or all of the AC power supplied is used for heating and the heating duration increases as well. The ambient temp may have been 50F when you charged at 45KW but i suspect the traction battery was warmer than that due the to fact you had to drive to the CHAdeMO station to charge?
 

derotam

Member
Oct 31, 2018
825
701
Oak Hill, VA
I charge at 240V @ 24A 5.76KW and when the battery is cold soaked at temps at or below around 47 degrees F I start to see heating of the battery during initial charging.. When I charged the other day, about half of the 5.76KW of power was used for the first 10 minutes to heat the battery then the car charged at the normal 22 to 23 miles per hour. As the temps drop, a higher percentage or all of the AC power supplied is used for heating and the heating duration increases as well. The ambient temp may have been 50F when you charged at 45KW but i suspect the traction battery was warmer than that due the to fact you had to drive to the CHAdeMO station to charge?

How did you see battery heating while charging 240V 24A at 47F? I have never seen specific battery heating while charging at the same rate, even down to 30F... And I am watching the OBDII data.
 

diamond.g

Active Member
Nov 5, 2015
2,421
1,362
Moyock, NC
How did you see battery heating while charging 240V 24A at 47F? I have never seen specific battery heating while charging at the same rate, even down to 30F... And I am watching the OBDII data.
The charge rate (miles or kw) is lower than the full rate. Usually that means either you have the HVAC on, or the vehicle is routing power to some other system and not the battery (ie running inverters to heat the battery).
 

rrolsbe

Member
Feb 18, 2017
220
126
Albuquerque
How did you see battery heating while charging 240V 24A at 47F? I have never seen specific battery heating while charging at the same rate, even down to 30F... And I am watching the OBDII data.

I monitor the power where the Mobile charger plugs into NEMA 10-30R 240V AC connector. The current draw is always 24A and when it is heating the battery, via the traction motor, I can clearly hear the motor and the miles added is less than the normal 22 to 23 miles per hour. If I charged to 100%, i suspect the amperage would drop below 24A. Not sure why you would not see the battery heating using your OBDII interface? The next time I charge, I am going to lower the current level , using the car display, to see when/if the heating via the motor stops. Where did you purchase your OBDII interface? what did it cost? Thanks for your reply.
 
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mike123abc

Member
Aug 20, 2018
406
806
Norman, OK
Well this does seem to explain how without preconditioning (i.e. go to a SC without navigating to it), it will start at 146kw and slowly work its way up to 150kw, then after a while the radiator fan kicks on...
 

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