Battery temperatures during winter drives

[AAKEE]

There seems be as many guesses around battery temps as there is Tesla owners.

Today I started from the garage, left before the charge was complete(SOC 99.8)

Battery temp was 25.8C
Outside was -20C

The heat pump used the excess heat until the battery was 11.8C after about 45 minutes driving.


Then the car let the battery heat itself from heat loss (No battery heat on, no preconditioning) until it was 18C, time from
11.8 to 18C was 1 1/2h.



After this the heat pump again took the excess heat to heat the cabin, and I arrived after 240km driving with 13.3C.

The energy app showed battery conditioning 0.0% for the whole trip.

Arrival ambient was -20C, same as at departure. Somewhere along the road it was partially warmer like -7C or so.

 

[KenC]

After our convo the last few days, I thought I'd pay more attention to what SMT said about battery cell temps, which I had totally ignored before. During our storm power outage, I thought I'd top up the car, just in case the outage was longer than 24hrs. It was 19F out, and a 15mile drive to the supercharger. You can see the car was preconditioning at an average of 432kW to try to bring the cold-soaked blue snowflake battery up to temp.

15miles wasn't much time to get the battery up to temp. When I plugged in it was 45F, and within a minute it was 50F:

SMT has a couple other screen showing battery temps. This is after 12 mins when I charged from 45% to 60%:

and:

I was thinking about that report about fast charging at below 50F causing anode plating, and was wondering if that effect was mitigated if the cell temps eventually reached above 50F. I'm assuming that the test conditions in the research kept the cells at a steady temperature state.

 

[AAKEE]

You can see the car was preconditioning at an average of 432kW to try to bring the cold-soaked blue snowflake battery up to temp.

I am sure you ment 432 Wh/mi….

 

[Regaj]

Coldest temps of the year here in the mid-Atlantic. Single digits (F) overnight.

Yesterday afternoon I walked out to the Model 3 - 150-odd feet from the house, parked in the weather outside the shed - where it had sat getting cold-soaked for two days. Ambient had warmed up considerably (32F) by that point, and the car had sat in the sun for a few hours. Cabin was 40F and the pack was 21.2F. Turned Climate on.

Thirty minutes later the pack was at 53.2F and the stators were no longer drawing power.

50ish (F) is fine for L2 charging. But not remotely warm enough for DC Fast Charging.

Here's an interesting video by Kyle Connor where he deliberately froze his pack, then plugged directly into a Supercharger. His test would have been a lot more useful if he had collected pack temps. But, regardless, it shows that a really cold pack takes a while to get to a temp where the BMS will allow it to start DC Fast Charging.

 

[AAKEE]

Here's an interesting video by Kyle Connor where he deliberately froze his pack, then plugged directly into a Supercharger. His test would have been a lot more useful if he had collected pack temps. But, regardless, it shows that a really cold pack takes a while to get to a temp where the BMS will allow it to start DC Fast Charging.

I have the data for max charging limit vs cell temperature but it is at home, and Im not. I’ll put it here when I’m back at home.
The min temp for charging is above freezing but it allows for quite fast charging at low temps.

I had to do a non preheated charging session one year ago, almost to the day.
After last christmas cristmast-update they changed the menu and I could not find the supercharger selection.
Navigating home at -20C for 250km the car did not plan for a supercharging session as it probably thought 0% was good enough to arrive with. After passing the supercharger the car started saying ”you need to limit the speed to reach home”
Now, closer to -25C I did not want to get stranded with a empty pack so I turned around and started charging, bstt temp around 15-17C if I remember.
It was a Supercharger V2 and it soon maxed out at 140-something kW. Not a good feeling.
I only charged as little needed as to be sure to come home.

 

[AAKEE]

I was thinking about that report about fast charging at below 50F causing anode plating, and was wondering if that effect was mitigated if the cell temps eventually reached above 50F. I'm assuming that the test conditions in the research kept the cells at a steady temperature state.

Lithium plating is most probably not mitigated at 50F.
The higher the charging current( charging power) the warmer the battery need to be to avoid lithium plating.

Below LCO Chemistry but lithium batteries in general seem to be about as sensitive to lithium plating. Do not use these exact numbers for other chemistrys but you can get the principer.
A bit Strange to rate in minutes when there is other standards for that.
60 min should be read as 1C, or about 75-80kW for a model 3/Y LR.
30 min is 2C or 150-160kW
20 min is 3C or 230-240kW

I’m sure Tesla has this ”under control” but I still think this is a compromise.

 

[rrolsbe]

Coldest temps of the year here in the mid-Atlantic. Single digits (F) overnight.

Yesterday afternoon I walked out to the Model 3 - 150-odd feet from the house, parked in the weather outside the shed - where it had sat getting cold-soaked for two days. Ambient had warmed up considerably (32F) by that point, and the car had sat in the sun for a few hours. Cabin was 40F and the pack was 21.2F. Turned Climate on.

Thirty minutes later the pack was at 53.2F and the stators were no longer drawing power.

50ish (F) is fine for L2 charging. But not remotely warm enough for DC Fast Charging.

Here's an interesting video by Kyle Connor where he deliberately froze his pack, then plugged directly into a Supercharger. His test would have been a lot more useful if he had collected pack temps. But, regardless, it shows that a really cold pack takes a while to get to a temp where the BMS will allow it to start DC Fast Charging.

I assume the car was NOT plugged in when you Turned Climate on? If you precondition, the HV battery will be warmed if necessary but I did not think it would be if only HVAC climate was enabled? Specifically, I thought the traction battery was only warmed if you used scheduled departure or routed to a supercharger.

 

[Regaj]

I assume the car was NOT plugged in when you Turned Climate on? If you precondition, the HV battery will be warmed if necessary but I did not think it would be if only HVAC climate was enabled? Specifically, I thought the traction battery was only warmed if you used scheduled departure or routed to a supercharger.

No, the car was plugged in (Unless it's raining or snowing, I keep it plugged in pretty much all the time).

And, yes, the HV pack is warmed by simply turning Climate on... IF the pack is cold enough.

 

[Jeremy3292]

But, regardless, it shows that a really cold pack takes a while to get to a temp where the BMS will allow it to start DC Fast Charging.

Can confirm this is absolutely true. Tried everything I could to get my pack warm enough to supercharge in the morning last week but could not get above 50 kW.

Steps:

1. Set climate and precondition - had this going for at least 30 minutes before leaving family's house (no charger)
2. There were 2 SuC's close by - skipped the first one and navigated to the 2nd one as it was further away, probably took 15 minutes to get there.
3. Still no dice. 50 kW max and got the little icon that the battery still wasn't warm enough.

As a side note, I found out the cold REALLY, REALLY hurts your range otw back home. Preconditioned and set climate before leaving my parents house after Christmas (plugged in). Started off pulling 450ish Wh/mile and getting an estimated 165ish mile total range at the start of the trip (10-15 F outside), all while not going faster than 70 mph. Did some supercharging 90 miles in to get back up to around 70-80%. Stopped again when it was no higher than 35-40 F outside and charged to 80%, pulled 275ish Wh/mile the rest of the way home on the interstate (going 80 mph) and got an estimated 260+ miles total range. That 80% SOC got me home with 10-15% to spare, 175 miles away.

Was crazy to me the change in range over the course of the day. My only guess is it got (somewhat) warmer throughout the day and my battery was got to optimal pack temp over time.

 

[derotam]

Can confirm this is absolutely true. Tried everything I could to get my pack warm enough to supercharge in the morning last week but could not get above 50 kW.

Steps:

1. Set climate and precondition - had this going for at least 30 minutes before leaving family's house (no charger)
2. There were 2 SuC's close by - skipped the first one and navigated to the 2nd one as it was further away, probably took 15 minutes to get there.
3. Still no dice. 50 kW max and got the little icon that the battery still wasn't warm enough.

As a side note, I found out the cold REALLY, REALLY hurts your range otw back home. Preconditioned and set climate before leaving my parents house after Christmas (plugged in). Started off pulling 450ish Wh/mile and getting an estimated 165ish mile total range at the start of the trip (10-15 F outside), all while not going faster than 70 mph. Did some supercharging 90 miles in to get back up to around 70-80%. Stopped again when it was no higher than 35-40 F outside and charged to 80%, pulled 275ish Wh/mile the rest of the way home on the interstate (going 80 mph) and got an estimated 260+ miles total range. That 80% SOC got me home with 10-15% to spare, 175 miles away.

Was crazy to me the change in range over the course of the day. My only guess is it got (somewhat) warmer throughout the day and my battery was got to optimal pack temp over time.

Just to nit pick a little... YOUR heater usage was more likely the culprit of the range hit....yes yes yes, it is related to the cold, but if you had the heater off you would not have seen the massive range hit.

 

[Jeremy3292]

Just to nit pick a little... YOUR heater usage was more likely the culprit of the range hit....yes yes yes, it is related to the cold, but if you had the heater off you would not have seen the massive range hit.

I had it on auto at 72 degrees the whole trip for reference. That seems like a ton of range loss related just to the heater..150+ Wh/mile loss just for cabin heating?

 

[KenC]

Can confirm this is absolutely true. Tried everything I could to get my pack warm enough to supercharge in the morning last week but could not get above 50 kW.

Steps:

1. Set climate and precondition - had this going for at least 30 minutes before leaving family's house (no charger)
2. There were 2 SuC's close by - skipped the first one and navigated to the 2nd one as it was further away, probably took 15 minutes to get there.
3. Still no dice. 50 kW max and got the little icon that the battery still wasn't warm enough.

As a side note, I found out the cold REALLY, REALLY hurts your range otw back home. Preconditioned and set climate before leaving my parents house after Christmas (plugged in). Started off pulling 450ish Wh/mile and getting an estimated 165ish mile total range at the start of the trip (10-15 F outside), all while not going faster than 70 mph. Did some supercharging 90 miles in to get back up to around 70-80%. Stopped again when it was no higher than 35-40 F outside and charged to 80%, pulled 275ish Wh/mile the rest of the way home on the interstate (going 80 mph) and got an estimated 260+ miles total range. That 80% SOC got me home with 10-15% to spare, 175 miles away.

Was crazy to me the change in range over the course of the day. My only guess is it got (somewhat) warmer throughout the day and my battery was got to optimal pack temp over time.

Navigating to a supercharger and letting the car precondition will use vast amounts of energy. If you are low on charge, but have lots of time, then I would seriously think about not letting the car precondition, because, you may make it even more difficult to make the supercharger. Yes, there's the risk of anode plating, but running out of charge before reaching a charger may be more consequential. Of course, if running out isn't a concern, then by all means precondition. Just be aware it uses a lot of energy.

Here I am on my way to a Tesla service center for my 4yr checkup. My car pre-conditioned to the Supercharger stop, the whole way, all 75miles! Never had that happen before, and look at how much energy it consumed! 10.5% of 39% consumed. It used about 27%. In miles, pre-conditioning used about 30miles of range. Just imagine if you were short on electrons.

My takeaway was to not navigate to a supercharger if I was short on electrons, navigate to the coffeeshop near the supercharger, that way you won't run out of electrons.

 

[Regaj]

Being short on charge in very cold weather, with a cold-soaked pack, is a bad place to be!

 

[derotam]

I had it on auto at 72 degrees the whole trip for reference. That seems like a ton of range loss related just to the heater..150+ Wh/mile loss just for cabin heating?

Yeah, 72 is a bit toasty when it comes to energy usage. It takes a lot to maintain that temp in cold weather.

 

[Jeremy3292]

Navigating to a supercharger and letting the car precondition will use vast amounts of energy. If you are low on charge, but have lots of time, then I would seriously think about not letting the car precondition, because, you may make it even more difficult to make the supercharger. Yes, there's the risk of anode plating, but running out of charge before reaching a charger may be more consequential. Of course, if running out isn't a concern, then by all means precondition. Just be aware it uses a lot of energy.

Here I am on my way to a Tesla service center for my 4yr checkup. My car pre-conditioned to the Supercharger stop, the whole way, all 75miles! Never had that happen before, and look at how much energy it consumed! 10.5% of 39% consumed. It used about 27%. In miles, pre-conditioning used about 30miles of range. Just imagine if you were short on electrons.
View attachment 889813
My takeaway was to not navigate to a supercharger if I was short on electrons, navigate to the coffeeshop near the supercharger, that way you won't run out of electrons.

Agreed on all accounts, but I preconditioned/navigated to the SuC's all day. So that wouldn't have been the culprit for the vast energy usage change from 8am to 12pm IMO.

 

[KenC]

Agreed on all accounts, but I preconditioned/navigated to the SuC's all day. So that wouldn't have been the culprit for the vast energy usage change from 8am to 12pm IMO.

Well, it's hard to know, but earlier in the day, when the battery was colder, the preconditioning could have been pulling more heat, while later in the day, the battery was warmer, and preconditioning might have been pulling less.