Battery always preconditioning in cold

[ResHacker]

Hi guys, just curious about the behavior of preconditioning (heating) of the battery on my MS 100D (was 85D), SW 2022.8.10.8. The "problem" I'm experiencing is the preconditioning to be working every time I sit in the car and turn the clima on while cold in outside. On long trips this might be beneficial as I can get the energy back by regenerative braking, but on short trips it just raises the consumption into very high levels (up to 350Wh/km or so) and the battery still isn't warm enough to enable regen breaking.
I'm also asking as I think this became recently as a new feature and was not present in the past when battery was preconditioning only while navi set to Supercharger. Or am I wrong? Is there a way to limit the heating? Thanks for the responses!

 

[philip295]

Isn't the battery temperature maintenance more concerned with preserving the life of the battery cells ; with regen a secondary benefit. If that is the case, then preconditioning is worth it even on short journeys. I try to precondition for 20 mins before I set off, plugged into the charger.

 

[ResHacker]

Isn't the battery temperature maintenance more concerned with preserving the life of the battery cells ; with regen a secondary benefit. If that is the case, then preconditioning is worth it even on short journeys. I try to precondition for 20 mins before I set off, plugged into the charger.

Well, so far what I have understood, cold temp doesn't harm the cells at all. Higher temp does (even it is true, it is not significant if it is under approx 40°C). The only problem of cold temp is the regen unavailability, higher internal resistance and slightly lower capacity of the cells I believe. But it should not be harmful to use them or is it?

 

[philip295]

I'm not sure, you could be right about cold cells, but old Nissan leaf batteries lose more of their capacity with no temperature management.

 

[appleguru]

turning on “range mode” (which should be available on your car?) should prevent battery heating.

 

[ResHacker]

turning on “range mode” (which should be available on your car?) should prevent battery heating.

Yes, that might be it! As I recently turned it off due to lower heating power... Thanks for the tip...

I'm not sure, you could be right about cold cells, but old Nissan leaf batteries lose more of their capacity with no temperature management.

Problem of Nissan Leaf battery is in absent thermo management as you correctly mentioned (there's only some not sufficient air cooling I think) so the battery at high outside temperature especially during longer trip with DC charging gets easily hot (60deg Celsius or so) which is very harmful for the battery.

 

[Big Earl]

Hi guys, just curious about the behavior of preconditioning (heating) of the battery on my MS 100D (was 85D), SW 2022.8.10.8. The "problem" I'm experiencing is the preconditioning to be working every time I sit in the car and turn the clima on while cold in outside. On long trips this might be beneficial as I can get the energy back by regenerative braking, but on short trips it just raises the consumption into very high levels (up to 350Wh/km or so) and the battery still isn't warm enough to enable regen breaking.
I'm also asking as I think this became recently as a new feature and was not present in the past when battery was preconditioning only while navi set to Supercharger. Or am I wrong? Is there a way to limit the heating? Thanks for the responses!

How do you know it’s heating the battery? It should only heat the battery if you enable climate control from the app or if you navigate to a Supercharger.

 

[vcor]

The battery needs to be heated to charge at a fast rate. When the battery pack is below 32F, you can't charge at all. It must be heated first, getting the temperature up. At low temps, regen (which is charging the pack) is minimal to protect the battery. Seems lately, a pack between 32-50F or so will not allow full regen. My understanding is the optimal pack charging temperature is 90F. (P.S. these numbers are from others and could be slightly off, but you get the idea).

For discharging (i.e. driving), cold is not an issue, and it supports down to -20F or so.

 

[Lasttoy]

I've gotten two SW updates in a week. I noticed that now when I select super charger that message pops up saying Pre condition battery. I never had that before. I read where it helps the pack take more charge faster if pack is at 68 degrees.

 

[ResHacker]

How do you know it’s heating the battery? It should only heat the battery if you enable climate control from the app or if you navigate to a Supercharger.

When I depart with outside temp under +-5°C, I see the yellow intermittent line around power meter - regen limited.. And during even slow ride the limitation gets quite fast away. I can also check it via SMT tool - coolant heater running at 100% and consumption crazy high. All of that are clear symptoms of running battery heater I believe, it really is connected with range mode turned off, will test it wit range mode on soon.

The battery needs to be heated to charge at a fast rate. When the battery pack is below 32F, you can't charge at all. It must be heated first, getting the temperature up. At low temps, regen (which is charging the pack) is minimal to protect the battery. Seems lately, a pack between 32-50F or so will not allow full regen. My understanding is the optimal pack charging temperature is 90F. (P.S. these numbers are from others and could be slightly off, but you get the idea).

For discharging (i.e. driving), cold is not an issue, and it supports down to -20F or so.

Yes, that is all clear to me. Regarding the "optimal temp", my 100kWh pack gets almost full power (120kW on V2) when temp gets above 68-77°F, the cooling system then works to keep the temp at around 104°F.

I've gotten two SW updates in a week. I noticed that now when I select super charger that message pops up saying Pre condition battery. I never had that before. I read where it helps the pack take more charge faster if pack is at 68 degrees.

In my case I definitely used to have this message even before when the pack was cold and I navigated to Sch. My concern now was regarding battery heating ALWAYS on when clima is on (turned via app or when I sit in the car and drive) until the pack reaches approx 70°F and enables the full regen then. And this might be caused by the mentioned range mode off....will try it out and let here know..

 

[ResHacker]

So I tested the behavior also with Range mode turned on and it seems to be without any difference, the car always heats also battery while clima turned on. The only difference will be probably power reduced to 50% (3kW), same limitation as for cabin heating/cooling. So I think, the "always preheating" behavior is some recently added feature officially called as "Cold weather performance increase" or similar which was included in latest SW versions.

 

[KalJoMoS]

I have always used (four winters now) Range mode on long distance drives and one odd thing that I have now noticed is that if the ambient temperature is below freezing, setting the heating on my car uses mainly that battery heater and if the temperature is above freezing the preconditioning is also using (don’t know if both) AC for the heating. I can notice that if getting in and opening the climate window. My car still have MCU1 and I have not yet downloaded v.11 software.
This is interesting, since the beginning of this winter I had to tow my car to SeC for battery heater change, it was at the end of November. And before that change I did not noticed this change, it has always used AC to heat the cabin. At least I never noticed that on opening the climate window on the main screen. Maybe my battery heater was already on the way to quit and the car had to support preconditioning, maybe it’s the new cold weather upgrade that they gradually are adding to the new SW versions.
One thing that I do notice is that as soon the limited regeneration is gone and the battery is in ideal condition (I have no gadgets to monitor), my consuption is dropping down to optimal for that kind of weather (around 218Wh/km)

 

[Electroman]

Hi guys, just curious about the behavior of preconditioning (heating) of the battery on my MS 100D (was 85D), SW 2022.8.10.8.

What do you mean by "was 85D"?
You got a battery pack upgrade? You paid for it or did Tesla upgrade it as warranty coverage from 85 to 100 kWh pack since they don't the older packs anymore ?

 

[ResHacker]

What do you mean by "was 85D"?
You got a battery pack upgrade? You paid for it or did Tesla upgrade it as warranty coverage from 85 to 100 kWh pack since they don't the older packs anymore ?

Yes, I got the battery swapped for a 100kWh one.. see Pre-facelift 85D => 100D upgrade

 

[ResHacker]

I have always used (four winters now) Range mode on long distance drives and one odd thing that I have now noticed is that if the ambient temperature is below freezing, setting the heating on my car uses mainly that battery heater and if the temperature is above freezing the preconditioning is also using (don’t know if both) AC for the heating. I can notice that if getting in and opening the climate window. My car still have MCU1 and I have not yet downloaded v.11 software.
This is interesting, since the beginning of this winter I had to tow my car to SeC for battery heater change, it was at the end of November. And before that change I did not noticed this change, it has always used AC to heat the cabin. At least I never noticed that on opening the climate window on the main screen. Maybe my battery heater was already on the way to quit and the car had to support preconditioning, maybe it’s the new cold weather upgrade that they gradually are adding to the new SW versions.
One thing that I do notice is that as soon the limited regeneration is gone and the battery is in ideal condition (I have no gadgets to monitor), my consuption is dropping down to optimal for that kind of weather (around 218Wh/km)

Sorry, but not sure if I understood it correctly...so the precond is always running on no matter if below or above freezing point?

 

[KalJoMoS]

No, I was trying to say that it is different if below freezing and above. I can also see that my range is less used if above freezing. I was pointing out that I do notice if the preconditioning have ended. Consumption does drop to optimal usage.

 

[beatle]

How do you know it’s heating the battery? It should only heat the battery if you enable climate control from the app or if you navigate to a Supercharger.

Logging data services like TeslaFi also tell you when the battery heater is working while driving. In this drive, the battery was heated for 11-12 minutes just before arriving at the supercharger. It was cold outside, but I left my garage with a battery warmed on shore power.

The car will also heat the battery if you enable Ludicrous+ mode.

Using SMT you can see target_bat_activeheat. I believe this is the temperature the car is attempting to heat the battery to. This temp will vary depending on whether you're just departing with a stone cold battery, if you're driving to a supercharger, or if you have Ludicrous+ mode enabled. Regardless of the reason, if that target_bat_activeheat is a higher value than the current battery temperature, the battery heater is probably running.

 

[Lasttoy]

Res, I found if u turn on car heater 15 before u leave home it warms my pack and that orange Regen line is gone. Might have to do it earlier if really cold there. But by doing it while plugged in, u use home power not battery.

 

[ResHacker]

No, I was trying to say that it is different if below freezing and above. I can also see that my range is less used if above freezing. I was pointing out that I do notice if the preconditioning have ended. Consumption does drop to optimal usage.

Sorry as I read it yesterday quickly, while I was kind of busy so I misunderstood you ... Yes, that makes sense and I have the same observation as you do. As for example, last trip to the mountain cottage I did it was freezing (-3 to -4°C) with strong wind and snowing, the consumption was crazy up to 350Wh/km. Later on the highway it settled down around 250Wh/km (I had to slow down to approx 115kph as was not entirely sure with how much % will I arrive, the estimation started on 22% and went quickly down, also the highway was covered by thin layer of snow). Finally I did 180km drive for approx 60% of SOC.

In this drive, the battery was heated for 11-12 minutes just before arriving at the supercharger. It was cold outside, but I left my garage with a battery warmed on shore power.



The car will also heat the battery if you enable Ludicrous+ mode.

Using SMT you can see target_bat_activeheat. I believe this is the temperature the car is attempting to heat the battery to. This temp will vary depending on whether you're just departing with a stone cold battery, if you're driving to a supercharger, or if you have Ludicrous+ mode enabled. Regardless of the reason, if that target_bat_activeheat is a higher value than the current battery temperature, the battery heater is probably running.

I'm noticing the heating before Sch arrival to be dynamic changing according to current battery temp and time of arrival.. It could be half an hour, but also only about 5min. The target temp when I arrive or when the heater goes off is approx 25°C and under this temp the power goes up to 125kW and keeps above 100 until +- 40% SOC. It's not the full power, but still pretty high ...

Ludicrous + is nice tip for start heating which I know about, but unfortunately not all of the cars do have it My problem is opposite, nevertheless.. I'm trying to find a way, how to disable the heating when doing short trips while ambient temp is low and didn't find any so far..

Res, I found if u turn on car heater 15 before u leave home it warms my pack and that orange Regen line is gone. Might have to do it earlier if really cold there. But by doing it while plugged in, u use home power not battery.

The lowest temp setting is marked as "Lo" I believe, but this doesn't solve my problem. I want to eventually preheat the cabin without battery heating turned on.. But that seems to be not possible, maybe it has something to do with the battery longevity and its life preserving or so... not sure..

 

[KalJoMoS]

But by doing it while plugged in, u use home power not battery.

I have noticed that with my UMC if preheating, the car is still using my battery energy as well. Maybe it’s because the 240V wall plug is only supporting 3.2 kW and the settings on car require more. I wonder would there be a possibility under the settings to allow only 50% of original power. So that user can choose if this is desirable? Would Elon reagards this, like they did with the “Joe Mode”…