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

SigNC

Active Member
Aug 23, 2017
1,515
1,340
NC
kinda sucks though for some of the slower chademo charging. Battery likely doesn't need to be very warm and could be wasting a large % of the charge on some of the slower say, 25kW ones.
 
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derotam

Member
Oct 31, 2018
825
701
Oak Hill, VA
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.

Ok, so from that description you have only absolutely proven that the car is always drawing 24A which is expected when charging in any scenario. There is no reason for the car to vary the 24A input while charging, it is a very small charge rate in the first place(in contrast to the what... 300A while supercharging...)

In order for YOU to prove battery heating is to give more information. You said "added is less than the normal 22 to 23 miles per hour" but that leaves a lot in terms of interpretation... Now I am going to guess here because I am not home to check...but theoretically, on the charging screen, I THINK the kW value on the left will be less than 5-6kW if it is heating the battery. Heating the battery will use about 3-3.5kW, so I would expect the value on the charging screen to show 2-3kW if it is heating the battery. So that would put your miles per hour of charging to show somewhere between 8-12 miles per hour vs ~22.

Can you take a picture of your charging screen when you think battery heating is occurring and post it please?

And yes I WOULD absolutely see battery heating with my OBDII adapter. I would see the motor power go to 3-3.5kW, the stator temperature going up, the battery inlet temperature going up, and finally the battery temperature going up... See the Second image HERE.

EDIT: OBDII adapter - OBDLINK MX+, Amazon, ~$79. You also need the model 3 interface cable. https://www.xtss.com/ ~$54. ScanMyTesla App $10.
 
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rrolsbe

Member
Feb 18, 2017
220
126
Albuquerque
Ok, so from that description you have only absolutely proven that the car is always drawing 24A which is expected when charging in any scenario. There is no reason for the car to vary the 24A input while charging, it is a very small charge rate in the first place(in contrast to the what... 300A while supercharging...)

In order for YOU to prove battery heating is to give more information. You said "added is less than the normal 22 to 23 miles per hour" but that leaves a lot in terms of interpretation... Now I am going to guess here because I am not home to check...but theoretically, on the charging screen, I THINK the kW value on the left will be less than 5-6kW if it is heating the battery. Heating the battery will use about 3-3.5kW, so I would expect the value on the charging screen to show 2-3kW if it is heating the battery. So that would put your miles per hour of charging to show somewhere between 8-12 miles per hour vs ~22.

Can you take a picture of your charging screen when you think battery heating is occurring and post it please?

And yes I WOULD absolutely see battery heating with my OBDII adapter. I would see the motor power go to 3-3.5kW, the stator temperature going up, the battery inlet temperature going up, and finally the battery temperature going up... See the Second image HERE.

EDIT: OBDII adapter - OBDLINK MX+, Amazon, ~$79. You also need the model 3 interface cable. https://www.xtss.com/ ~$54. ScanMyTesla App $10.


The temperature has warmed up and the garage is now 50F or above. Next time I charge when the motor heats the battery at the start of a charging session, I will report the center screen MPH and KWH rates at the start of charging. I had not driven the car for a week and it was parked in the garage unplugged the entire time prior to the charging session I describe previously. It did start out charging adding about 8MPH which would be 3.5-4KWH for heating which I believe is the maximum heat the motor can provide while parked? I was not instrumented last winter to measure the power being sent through the Mobile charger. If I had to guess, when the temp gets down to where no miles are being added for 10 to 20 minutes during the start of a charging session the current will be around 14-17A or 3.360-4.080KW. I will report back to this thread later. It might be possible that if you drive the car daily, the traction battery internal temperature never drops below 50F even though the ambient temp might be hovering around 30F?

Thanks for the info regarding the OBDII interface did you also purchase the Geotab G09? is it also required?
 
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derotam

Member
Oct 31, 2018
825
701
Oak Hill, VA
It might be possible that if you drive the car daily, the traction battery internal temperature never drops below 50F even though the ambient temp might be hovering around 30F?

Nope... 30F ambient will drop the pack temperature below 50F after a few hours.

Thanks for the info regarding the OBDII interface did you also purchase the Geotab G09? is it also required?

Nope. The thing you have to watch out for is that the adapter is different depending on your build date. I think the website talks about that.
 

joelliot

Supporting Member
Aug 25, 2018
83
101
Rhode Island, USA
IMG_0075.jpeg
IMG_0076.jpeg
IMG_0076.jpeg IMG_0075.jpeg
Ok, so from that description you have only absolutely proven that the car is always drawing 24A which is expected when charging in any scenario. There is no reason for the car to vary the 24A input while charging, it is a very small charge rate in the first place(in contrast to the what... 300A while supercharging...)

In order for YOU to prove battery heating is to give more information. You said "added is less than the normal 22 to 23 miles per hour" but that leaves a lot in terms of interpretation... Now I am going to guess here because I am not home to check...but theoretically, on the charging screen, I THINK the kW value on the left will be less than 5-6kW if it is heating the battery. Heating the battery will use about 3-3.5kW, so I would expect the value on the charging screen to show 2-3kW if it is heating the battery. So that would put your miles per hour of charging to show somewhere between 8-12 miles per hour vs ~22.

Can you take a picture of your charging screen when you think battery heating is occurring and post it please?

And yes I WOULD absolutely see battery heating with my OBDII adapter. I would see the motor power go to 3-3.5kW, the stator temperature going up, the battery inlet temperature going up, and finally the battery temperature going up... See the Second image HERE.

EDIT: OBDII adapter - OBDLINK MX+, Amazon, ~$79. You also need the model 3 interface cable. https://www.xtss.com/ ~$54. ScanMyTesla App $10.

...not the original poster, but here are some examples.

It was slightly below freezing 0C/32F the morning I got these. This was when cabin heat and battery heating was going full at the start.
IMG_0075.jpeg
After the cabin heated up I started to get 9 mph, normally get 44/45 when the battery is warm when drawing 48 Amps
View attachment 485413
 
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SageBrush

REJECT Fascism
May 7, 2015
12,333
15,241
New Mexico
For the ODBII, to see heating you should see the battery inlet temp go up, likely along with the inverter/stator temp(s).
While the battery is being actively heated. At some point the battery will continue to heat from the charging without additional rotor heat.
 

SageBrush

REJECT Fascism
May 7, 2015
12,333
15,241
New Mexico
Nope... 30F ambient will drop the pack temperature below 50F after a few hours.
Without active cooling ? I'm skeptical

Bjorn Nyland just posted a 'car camping' video today since he was interested in how much energy it takes to keep the car warm while staying in it overnight at -9C ambient. The 'scan my tesla' app shown in the video displays battery temperature.
 

SageBrush

REJECT Fascism
May 7, 2015
12,333
15,241
New Mexico
kinda sucks though for some of the slower chademo charging. Battery likely doesn't need to be very warm and could be wasting a large % of the charge on some of the slower say, 25kW ones.
IF the battery arrives cold, and
IF the charging session is short.

Otherwise figure ~ 1 kWh heating for e.g 30 kWh charge.

**Yawn**
 

vickh

Active Member
Dec 16, 2018
3,106
485
az
Re: "conditioning battery for Supercharging while navigating to a Supercharger - it starts the heater "early" and continuously heats from the moment you start navigation until you're done charging"

So Would it be advisable not to get directions to an SC (if you don't care about time at SC (shopping,eating etc) and don't want to waste Kwh? What is the time to Kwh savings by conditioning
 

diamond.g

Active Member
Nov 5, 2015
2,421
1,362
Moyock, NC
Re: "conditioning battery for Supercharging while navigating to a Supercharger - it starts the heater "early" and continuously heats from the moment you start navigation until you're done charging"

So Would it be advisable not to get directions to an SC (if you don't care about time at SC (shopping,eating etc) and don't want to waste Kwh? What is the time to Kwh savings by conditioning
It all depends on the speed of the unit. If it is a low power site then not preheating is not going to make much of a difference in speed. High power sites will be slower till the battery gets to temp.
 

kbecks13

Active Member
Dec 27, 2017
1,916
2,278
SoCal
Just found this thread and noticed weird heating behavior yesterday too. Was charging up to 80% and the car kept heating the battery (generating heat with stator and i saw increasing stator and battery inlet temps) ALL THE WAY to 80%, even when the car "knew" it would be finished charging in a few minutes.

Now you might say "well it needed to be warm for the charginging" but that's actually not true. Scan My Tesla shows the max allowable charge rate for any given moment (based on temps and SoC) and i could see that the battery was able to charge at a much higher rate than i was getting (was paired with another car) so clearly at the kW rate i was using, i didn't need the batteries quite as hot as Tesla wanted.

I have no concern about wasting energy, but i then drove around for the next 20-30 minutes with my pack temp around 110F which seems a bit high. Also for track days this means that you really want to finish supercharging and start track mode ASAP to get that pack temp down before hitting the track.

Also - be nice to each other lol
 
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derotam

Member
Oct 31, 2018
825
701
Oak Hill, VA
View attachment 485412 View attachment 485416 View attachment 485416 View attachment 485412

...not the original poster, but here are some examples.

It was slightly below freezing 0C/32F the morning I got these. This was when cabin heat and battery heating was going full at the start.
View attachment 485412
After the cabin heated up I started to get 9 mph, normally get 44/45 when the battery is warm when drawing 48 Amps
View attachment 485413

Yes I believe it cold soaked at 32F..not at 50F.
 

SigNC

Active Member
Aug 23, 2017
1,515
1,340
NC
IF the battery arrives cold, and
IF the charging session is short.

Otherwise figure ~ 1 kWh heating for e.g 30 kWh charge.

**Yawn**

based on what? From what I’ve seen front and rear motors both pull 3.5 kW when heating. So we have thresholds when the heating cuts off? Just reading through thread it leads you to believe the battery is heated much warmer than needed when DC charging. When AC charging it seems fairly normal, at least from what I’ve read.
 

Dave EV

Active Member
Jun 23, 2009
1,736
1,210
San Diego
Just found this thread and noticed weird heating behavior yesterday too. Was charging up to 80% and the car kept heating the battery (generating heat with stator and i saw increasing stator and battery inlet temps) ALL THE WAY to 80%, even when the car "knew" it would be finished charging in a few minutes.
Yeah, it seems pretty clear that the pure on/off nature of the heating could use some finessing. This is probably a case of "get the heating feature out quick, fine tune it later".

Now you might say "well it needed to be warm for the charginging" but that's actually not true. Scan My Tesla shows the max allowable charge rate for any given moment (based on temps and SoC) and i could see that the battery was able to charge at a much higher rate than i was getting (was paired with another car) so clearly at the kW rate i was using, i didn't need the batteries quite as hot as Tesla wanted.
There's research that shows that charging lithium batteries while hot reduces the rate of lithium plating / dendrite growth, as long as you cool off the battery while not charging, so heating the battery should actually reduce capacity loss over time if done properly.
 

FalconFour

Supporting Member
Mar 25, 2016
140
237
San Jose, CA
I found that funny, there is never "too fast" if you're on a long trip and wanna get going...
That comment's context was specifically made in relation to non-road-trip context. Those that can't charge at home are using SCs regularly, and a 72kW SC is the happy medium where you can park in a lot, go about some dinner or shopping, come back and be charged - and not feel rushed in any case.

SCs are used by different people in very different contexts at different times, just keep that in mind.
 
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diamond.g

Active Member
Nov 5, 2015
2,421
1,362
Moyock, NC
I cold soaked her last night, unplugged. Plugged her in this morning and this is what is being reported by Statsapp.
D06304A2-E1AC-42B1-80D0-FAD3E1C269A3.png
eventually it should ramp the charge rate
 

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