What happened to my battery preheat?!!

[David29]

I thought that was the rear-defrost

I do have a question though - when I either precondition and/or manually enable the heated steering wheel, there are times that it get HOT - like I mean almost too hot to touch. Is this normal behavior for the car? I've had other cars with heated steering wheels and they never got as hot as my Model S does.

I agree, sometimes it gets very hot. I worry about degradation of the leather (but i do love the warmth for my arthritic hands!). I have found that it seems to cool a bit, but remain warm, after it has been on for quite a long time.

 

[David29]

Today, I preheated the car before leaving to do errands. It was not terribly cold out (mid or high 30s, maybe) but my car was parked outside overnight and was not used at all yesterday, so the battery could have been quite thoroughly chilled. When I first started the cabin heater, the battery heater indicator lighted up in the phone app, but when i looked at it again just a few minutes later, it was gone. So, either the car decided that little to no heating was needed today, or this is another data point on the observations above that the battery heater is not running, or not running as much as before. (I had not carefully watched for the battery heating indicator on other recent cold starts, until I read through this thread.) I might need a colder day to be sure there is a change in behavior.

 

[wodnik7]

As we have it in the other threads already: from 2019.32 on there is no battery preheating on S and X any longer when preheating the cabin! Simply they seem to have canceled it, which is odd. Some say this is a bug, but I do not know, if they fix it. The only way to have battery preheated is having the car in P or D when preheating the cabin.

 

[Dan Baldwin]

My garage was 50F and outside temp was 56F today. Range mode was off. I turned climate on (74F) for 2 hours and went for a drive. The dotted yellow line was about halfway (50) and it took about 20 minutes of driving before I had full regen. I checked my app during the climate on as well as while I was driving and I never saw any red for the battery warming.

 

[wodnik7]

You could not ser the red battery symbol in the apo, as tesla no longer preheats the battery. So zou can preheat the cabin for 3 hours, and the battery still stays cold.

 

[Spacey73]

I used to see the little 'frozen' snowflake icon on app before updates on S85 2014, now I get bugger all regen which really affects how I drive now. 9deg C and only 50% regen available after 15 miles of big hills (450kwh) driving.

 

[Battpower]

Do you have a solid source for this statement, or is it speculation? I see a few people suggesting what Tesla's reasons might be -- assuming this is deliberate -- but I have not seen any evidence that Tesla has stated this is the case. I am not disagreeing, just trying to separate speculation from facts.

Also longing for this info.

My reading of posts is that there is pretty solid evidence of a change in behaviour, so presumably the missing part is a statement from Tesla confirming the reason.

Today I had available regen drop off from nearly max to about 30kw when driving at steady 60 mph on freeway with 8 Dec C ambient. Seems right on the temp point where very slight drop in battery temp turned down available regen.

 

[pjw65]

One Swiss said preheating will work again with 2019.40.50.1
Can someone aprove this?

 

[Battpower]

One Swiss said preheating will work again with 2019.40.50.1
Can someone aprove this?

Raven S 40.50.1, in UK. Ambient 6 deg C, cold battery.

Turning on climate in app does not show battery heat indication.

 

[whitex]

Do you have a solid source for this statement, or is it speculation? I see a few people suggesting what Tesla's reasons might be -- assuming this is deliberate -- but I have not seen any evidence that Tesla has stated this is the case. I am not disagreeing, just trying to separate speculation from facts.

You are correct, Tesla never shares with customer any reasons why they make software changes. The fact is, they neutered yet another set of features. Are they doing it to protect the battery to avoid warranty costs? Are they doing it because they are incompetent at code management and some old bugs got sucked into the code tree? Are they just just dropping support for older cars and make the run code fro new cars which is not compatible, but nobody at Tesla bothers to even validate? Or did the head of battery management quit and the person who replaced them has a different "philosophy of battery management", so new thresholds and algorithms were implemented? Or are they trying to screw with older cars to get people to upgrade? Or are they just outsourcing the software to the cheapest web development contractor who screwed the pooch, never having driven a Tesla and having no clue about embedded software beyond web portals? Given that Tesla communicates nothing, customer can do nothing but speculate, and any reason is possible in an Elon company.

 

[Battpower]

customer can do nothing but speculate

Which for me is the biggest problem. Along with others on here and other forums, some super knowledgeable individuals shoot down honest observations as though there are some certain facts. I don't want to be part of a rumor mill, but how else can you work towards even a minimal understanding without information from the horse's mouth? With regional and national factors effecting how cars behave, as well as all the car-based variations, this can only go one way in my opinion.

All of the heating / charging / range discussion seems to stem from battery life and safety factors. The need for more openess from Tesla about reasons for changes and specifically who is effected is because of the way these cars are being developed in the public space.

 

[tyler2323]

Do you have a solid source for this statement, or is it speculation? I see a few people suggesting what Tesla's reasons might be -- assuming this is deliberate -- but I have not seen any evidence that Tesla has stated this is the case. I am not disagreeing, just trying to separate speculation from facts.

This is not directed at you David29 as I see you put informative so I don’t want you to think it is.

Consistently heating the battery like it does in max power will degrade the battery as well as potentially cause voltage issues if you are doing it with the car charging or even with the charger still plugged in. If you have ever kept your car charger plugged in than put it on max battery or preheat you will see the car pulling kw/amps like it is charging even though the charge is complete. This is how it can cause a fire/voltage issues if it’s still plugged in. You have too much that the car is pulling energy for, when using any type of charger at your home. Now if at a super charger it will not be effected. This was even more the case with the old charges that they have replaced awhile ago and the recent update also fixed bugs associated with the voltage issues. I had 2 outlets get fried from the old chargers, that could have led to potential fires. And yes Tesla isn’t going to tell you this cause it’s not good news that they want the public to know. Since I have friends who work for Tesla they won’t necessarily tell people but if you were to ask them if for example the old charges were replaced due to concerns of fires starting they are not going to lie to you. The old charges also allowed you to use the max amps from any outlet which is not how you should ever use any outlet at your home. 90% is usually the recommended amount because it can cause fires or at least trigger the breaker to shut down the power to it. So Tesla went one step further with the new charging equipment which only allows 80%. So 30 amps will only allow 24. And 50 amps 40.
As far as adding miles to my car I will show you over the course of few thousand miles how my car managed to add miles so than you can see it with your own eyes rather than disagree with something you don’t really understand. As stated I do not follow Tesla’s guidelines to charging, in fact Tesla changed the daily amount to 90% based on who

The highest it got up too was 277

 

[kpeters000]

Where are you getting this information that heating the battery is bad for it? The active heating of the battery via preconditioning is no different than the "passive" heating of it via the drive unit + regen.

The car will pull grid power when plugged in if on board systems are active, be it climate preconditioning, fans, or battery heating. It will not pull more than the charger is rated for. Saying that this is how fires are started is absolutely preposterous. Are you concerned about your refrigerator drawing power when it's running? When charging, it will take the maximum current, prioritize heating with some percentage of that input power, then route the remaining to charging. Otherwise, it will just tether the minimum remaining power needed for those maintenance functions.

The old chargers (UMC Gen 1) were capped at 40A continuous from a 14-50 outlet just like everything else on the market that adheres to NEMA electical code - 80% of max rating

 

[tyler2323]

Where are you getting this information that heating the battery is bad for it? The active heating of the battery via preconditioning is no different than the "passive" heating of it via the drive unit + regen.

The car will pull grid power when plugged in if on board systems are active, be it climate preconditioning, fans, or battery heating. It will not pull more than the charger is rated for. Saying that this is how fires are started is absolutely preposterous. Are you concerned about your refrigerator drawing power when it's running? When charging, it will take the maximum current, prioritize heating with some percentage of that input power, then route the remaining to charging. Otherwise, it will just tether the minimum remaining power needed for those maintenance functions.

The old chargers (UMC Gen 1) were capped at 40A continuous from a 14-50 outlet just like everything else on the market that adheres to NEMA electical code - 80% of max rating

So have you actually owned the first gen chargers? If not it explains everything cause you just looked up what the charger is capable of lol.
Have you ever adjusted the amps on your MCU Screen when it’s charging?
Do you know what the max charging amps is of certain Tesla’s that have Dual chargers or High Amperage Charging?
Do you realize you could be plugged into a 30 amp outlet and set your settings to 40 amps with the first gen chargers?
Do you think pulling 40 amps from a 30 amp outlet is safe and won’t cause a fire?

Just curious do you own a P85D, P85DL, P90D, P90DL, P100D, or P100DL?
I bet you don’t.
The first gen chargers will allow you to set your car to 40 amps regardless if it’s plugged into a 30 amp outlet.
The second gen on the other hand will only let you charge to 24amps into 30 amp outlet and 32 amps into 50 amp outlet.
Why do you think that is?
Do you think an overheating charging cable can cause fires or fry an outlet?

Well let me explain since clearly you never understood or took the time to understand the reasoning behind Tesla switching from gen 1 to gen 2. Gen 1 chargers would overheat especially if let’s say you HAD THE PREHEAT BATTERY ON! Or if you had it set to Max Power while it’s charging which would do the same thing but at a much higher level in regards to the temperature of the battery. Nevertheless you could just have the AC running , heater running , etc and the cable would get extremely hot. If you ever owned a Gen 1 charger you would already know this as it would be impossible not too.
When the Gen 2 charger starts to get too hot it will simply drop the amps accordingly all the way down to 8 amps. It is built in to protect the charger from overheating thus causing an outlet to fry or worse catch on FIRE.
Now back to Dual and High Amperage Chargers. Dual Chargers were capable of 80 amps and High Amperage 72 amps. Guess which one came before the other? Dual!
So do you see a pattern here yet?
Now guess what the maximum charge rate is as of 2018? 48 amps
Why do you think this is? To piss off owners especially ones who idk say owned 80 amp or 72 amp options?
No it’s because it’s not good for the battery and will cause battery degradation.
Do you know what causes more battery degradation than anything else?
Excessive use of Superchargers.

So comparing a refrigerator to a Tesla is quite laughable and telling of your understanding of Tesla in general and what their primary reasoning is almost always based around. Which is....
To protect the battery that they don’t want to have to replace for free.
But please if you have a performance Tesla start charging on max battery every time you charge and than come back with the first hand knowledge and enlighten everyone if it has had a negative effect on your range.

 

[Battpower]

So have you actually owned the first gen chargers? If not it explains everything cause you just looked up what the charger is capable of lol.
Have you ever adjusted the amps on your MCU Screen when it’s charging?
Do you know what the max charging amps is of certain Tesla’s that have Dual chargers or High Amperage Charging?
Do you realize you could be plugged into a 30 amp outlet and set your settings to 40 amps with the first gen chargers?
Do you think pulling 40 amps from a 30 amp outlet is safe and won’t cause a fire?

Just curious do you own a P85D, P85DL, P90D, P90DL, P100D, or P100DL?
I bet you don’t.
The first gen chargers will allow you to set your car to 40 amps regardless if it’s plugged into a 30 amp outlet.
The second gen on the other hand will only let you charge to 24amps into 30 amp outlet and 32 amps into 50 amp outlet.
Why do you think that is?
Do you think an overheating charging cable can cause fires or fry an outlet?

Well let me explain since clearly you never understood or took the time to understand the reasoning behind Tesla switching from gen 1 to gen 2. Gen 1 chargers would overheat especially if let’s say you HAD THE PREHEAT BATTERY ON! Or if you had it set to Max Power while it’s charging which would do the same thing but at a much higher level in regards to the temperature of the battery. Nevertheless you could just have the AC running , heater running , etc and the cable would get extremely hot. If you ever owned a Gen 1 charger you would already know this as it would be impossible not too.
When the Gen 2 charger starts to get too hot it will simply drop the amps accordingly all the way down to 8 amps. It is built in to protect the charger from overheating thus causing an outlet to fry or worse catch on FIRE.
Now back to Dual and High Amperage Chargers. Dual Chargers were capable of 80 amps and High Amperage 72 amps. Guess which one came before the other? Dual!
So do you see a pattern here yet?
Now guess what the maximum charge rate is as of 2018? 48 amps
Why do you think this is? To piss off owners especially ones who idk say owned 80 amp or 72 amp options?
No it’s because it’s not good for the battery and will cause battery degradation.
Do you know what causes more battery degradation than anything else?
Excessive use of Superchargers.

So comparing a refrigerator to a Tesla is quite laughable and telling of your understanding of Tesla in general and what their primary reasoning is almost always based around. Which is....
To protect the battery that they don’t want to have to replace for free.
But please if you have a performance Tesla start charging on max battery every time you charge and than come back with the first hand knowledge and enlighten everyone if it has had a negative effect on your range.

View attachment 493663

So from your post I take it that you have had these experiences directly yourself.

Could you please relate these figures to kw as I am never clear what supply voltage is being referred to. You obviously know, but I don't.

I can say first hand that I see my Raven S doing a lot of battery charge limitation both Supercharging and with Regen under certain conditions. I see enough correlating evidence from loads of owners that battery capacities have been capped and that regen has been limited further at low temp. I have no problem accepting that Tesla has made and will make mistakes and will also hopefully learn from experience. Some of those mistakes will have been made before I bought my car and others after, which could have a big effect on my view of Tesla's responsibilities to me.

In the UK, a type 2 domestic single phase charge socket runs into a 32a or 40a breaker at 240v single phase and delivers upto 7.5kw.

If the battery heater is going to heat such a big mass as the battery in a worthwhile time to benefit charging at 7kw while overcoming thermal loss due to cold weather, I would expect at the very least 1kw needed for heating and probably more like 3kw. That would be a huge hit on efficiency and at 7kw probably not needed.

Pre-heating the battery under any circumstances could have very different cost-benefits because how much energy it's worth using to pre-heat can only be decided based on how much energy you intend putting into the battery and at what rate. 1kwh to kick-start and protect a 60kwh charge is probably justified, while 5kwh to speed up a 15 min charge of 25kwh makes far less sense.

The simple message (that Tesla has also been pushing much harder recently imo) is to slow charge overnight whenever possible. Much kinder to your battery as well as less load on Super Chargers.

Yesterday I took very careful notice of battery / regen / supercharge behaviour.

At 6 - 7 deg C ambient, 40% soc, steady driving for 60 mins on lanes and freeway, regen started at zero and crept up to about 45kw and never went higher. My guess from driving other Ev's over a similar route is that instantaneous battery power likely hovers mainly between - 10kw and + 20kw with a level cruise at 65 mph being around 10-12kw. Unavoidable self heating of the battery at these power levels needs to be minimal to maintain efficiency and my guess is that 2kw of over-all losses battery and motor would make sense. With ambient at 7 deg C at any car speed I'm sure losing / dissipating that 2kw heat is easy, leaving nothing to raise the battery temp.

On my return journey with very similar conditions, I set a supercharger stop 20 miles into the journey. Regen stayed limited to 35 to 45kw until maybe 5 miles before the charger where it could clearly be seen climbing to around 55kw where it stayed right up to arrival at the charger. Interestingly, I checked on the app during that period and there was no sign of a battery heater indicator being 'on'. I'm not sure of the gradient profile in the 5 miles immediately before the supercharger, but while the regen limit decreased (suggesting battery heating ready for charging), my energy consumption was the lowest for the whole trip at 306 Wh/mile.

The charging station was very busy, so can't conclude much from the charge power which stayed at around 55kw for the entire 1h10 charge session. As I pulled out of the charging stall regen was no longer limited at all. For the remaining steady drive home (25 miles 20% freeway 80% lanes) regen remained unlimited.

So I read that as suggesting that with a stationary car (no cooling airflow) and unavoidable self heating of the battery due to charging, the whole battery temp raises, possibly with an equivalent of 1kw - 2kw internal dissipation. The only time preheating would make sense would be right at the start of the cycle so that you can safely charge at a high enough rate to kick-start the self heating effect.

For those here who prefer tables of numbers and calculations, that's not this post, but my observations are none the less careful and comments based on genuine experience! I'll be happy to see this addressed from a more data / calculation perspective.

 

[Ostrichsak]

Where are you getting this information

So have you actually owned the first gen chargers? If not it explains everything cause you just looked up what the charger is capable of lol.
Have you ever adjusted the amps on your MCU Screen when it’s charging?
Do you know what the max charging amps is of certain Tesla’s that have Dual chargers or High Amperage Charging?
Do you realize you could be plugged into a 30 amp outlet and set your settings to 40 amps with the first gen chargers?
Do you think pulling 40 amps from a 30 amp outlet is safe and won’t cause a fire?

Just curious do you own a P85D, P85DL, P90D, P90DL, P100D, or P100DL?
I bet you don’t.
The first gen chargers will allow you to set your car to 40 amps regardless if it’s plugged into a 30 amp outlet.
The second gen on the other hand will only let you charge to 24amps into 30 amp outlet and 32 amps into 50 amp outlet.
Why do you think that is?
Do you think an overheating charging cable can cause fires or fry an outlet?

Well let me explain since clearly you never understood or took the time to understand the reasoning behind Tesla switching from gen 1 to gen 2. Gen 1 chargers would overheat especially if let’s say you HAD THE PREHEAT BATTERY ON! Or if you had it set to Max Power while it’s charging which would do the same thing but at a much higher level in regards to the temperature of the battery. Nevertheless you could just have the AC running , heater running , etc and the cable would get extremely hot. If you ever owned a Gen 1 charger you would already know this as it would be impossible not too.
When the Gen 2 charger starts to get too hot it will simply drop the amps accordingly all the way down to 8 amps. It is built in to protect the charger from overheating thus causing an outlet to fry or worse catch on FIRE.
Now back to Dual and High Amperage Chargers. Dual Chargers were capable of 80 amps and High Amperage 72 amps. Guess which one came before the other? Dual!
So do you see a pattern here yet?
Now guess what the maximum charge rate is as of 2018? 48 amps
Why do you think this is? To piss off owners especially ones who idk say owned 80 amp or 72 amp options?
No it’s because it’s not good for the battery and will cause battery degradation.
Do you know what causes more battery degradation than anything else?
Excessive use of Superchargers.

So comparing a refrigerator to a Tesla is quite laughable and telling of your understanding of Tesla in general and what their primary reasoning is almost always based around. Which is....
To protect the battery that they don’t want to have to replace for free.
But please if you have a performance Tesla start charging on max battery every time you charge and than come back with the first hand knowledge and enlighten everyone if it has had a negative effect on your range.

View attachment 493663

Most all of this is wrong. So much so that it's difficult to know where to start and it's especially annoying that you're attacking others who you claim don't know what they're talking about.

The gen 1 UMC will NOT allow you to manually set it to 40A draw on a 30A outlet. Never has. If you have a Tesla 30A adapter plugged into a 30A outlet the MCU will automatically lower the draw to 24A which is 80% of that circuits rating. You can't override this. Your entire soliloquy is void. The ONLY way you can run into trouble is if you make your own adapters for different outlets and override the UMC/adapters built in ability to cap draw based on the type of outlet. If you're smart enough to be building your own adapters I would hope that you're also smart enough to follow proper safety guidelines and properly set your draw limit each time though. Really no relevance to what you're talking about though.

The process where a UMC senses heat from an overloaded circuit and lowers draw to a safe range is present in BOTH gen 1 and gen 2 UMCs. Tesla never made a charger that didn't in fact and it would stupid of them to produce such a thing. The difference lies primarily in the components being analog v digital and the Gen 2 is far less expensive to make. There's a cost delta with several of the related components that made sense to have it only charge to 32A especially since it had been determined that most owners used their UMCs to charge their cars overnight so the real world difference between 32A and 40A was negligible. If an owner truly needed faster charging they likely would have a HPWC installed anyway.

There was a lot more in there that was completely false (your various battery pack heating scenario dangers are idiotic) but I think we've covered the important parts. The amount of rampant misinformation that is spewed on this forum as fact by people who clearly don't know the first thing of what they speak is staggering.

Before you ask, yes I own a P85D, yes it has dual chargers, yes I own Gen 1 UMCs and yes I've charged at just about every imaginable outlet type using them.

 

[Battpower]

Most all of this is wrong. So much so that it's difficult to know where to start and it's especially annoying that you're attacking others who you claim don't know what they're talking about.

The gen 1 UMC will NOT allow you to manually set it to 40A draw on a 30A outlet. Never has. If you have a Tesla 30A adapter plugged into a 30A outlet the MCU will automatically lower the draw to 24A which is 80% of that circuits rating. You can't override this. Your entire soliloquy is void. The ONLY way you can run into trouble is if you make your own adapters for different outlets and override the UMC/adapters built in ability to cap draw based on the type of outlet. If you're smart enough to be building your own adapters I would hope that you're also smart enough to follow proper safety guidelines and properly set your draw limit each time though. Really no relevance to what you're talking about though.

The process where a UMC senses heat from an overloaded circuit and lowers draw to a safe range is present in BOTH gen 1 and gen 2 UMCs. Tesla never made a charger that didn't in fact and it would stupid of them to produce such a thing. The difference lies primarily in the components being analog v digital and the Gen 2 is far less expensive to make. There's a cost delta with several of the related components that made sense to have it only charge to 32A especially since it had been determined that most owners used their UMCs to charge their cars overnight so the real world difference between 32A and 40A was negligible. If an owner truly needed faster charging they likely would have a HPWC installed anyway.

There was a lot more in there that was completely false (your various battery pack heating scenario dangers are idiotic) but I think we've covered the important parts. The amount of rampant misinformation that is spewed on this forum as fact by people who clearly don't know the first thing of what they speak is staggering.

Before you ask, yes I own a P85D, yes it has dual chargers, yes I own Gen 1 UMCs and yes I've charged at just about every imaginable outlet type using them.

Just as a matter of interest (I'm in Europe, so doesn't relate to me directly) do these chargers monitor volts drop under load or in some other way determine the supply capacity and quality? Can they auto select between 110 and 220?

 

[Ostrichsak]

Just as a matter of interest (I'm in Europe, so doesn't relate to me directly) do these chargers monitor volts drop under load or in some other way determine the supply capacity and quality? Can they auto select between 110 and 220?

Yes, they sense voltage drop under load as they slowly increase the load to determine a safe charge rate. Individual Tesla adapters use a resistor to tell the MCU what amperage draw to limit to. There's also thermal sensing that can lower this even further if dangerous levels of heat is detected even after the first two tests pass. Yes, they can auto-select between single phase (commonly referred to as "110" even though it's more like 120v) and dual phase (commonly referred to as "220" even though it's more like 240v) depending on what the circuit is. So if you have the 15A 120-volt adapter on the UMC the MCU will limit the draw to 12A for safety and monitor it for excessive heat. The same UMC with a 50A 240-volt adapter will cap at 40A and continue to monitor for excessive heat. Heat being present in and of itself isn't a sign of danger when you're dealing with such large draw. You can also go into the MCU and manually LOWER (not raise) the limit from these figures if you wanted to for some reason. It will also remember the location for these manual adjustments for the next time you plug in.

 

[tpoltron]

Except for some relatively rare sockets fed by smaller breakers and wires (eg 40A to a 14-50) the UMCs will safely limit their current draw. If the car is preheating the cabin or battery, less is flowing into the battery.

Anyway back to the topic, I experienced the lack of battery preheating with our Model 3 in Tahoe a couple days ago and it caused some range anxiety. I scheduled departure for 8am and the car was full and the cabin warm but I don’t think I the battery was. We skiied nearby for the morning, parked in the sun around freezing temp. For lunch we went back to the cabin on Donner Lake and was hoping to top the car up close to full for the drive home while we ate and closed up the cabin. For the first 20min the car only charged at 1 Amp and in the end we only added 10 miles instead on the 30 I expected. Fortunately the road were also cleaner than I expected so we still got back to Cupertino with 50 miles to spare.

 

[VT_EE]

They are trying to protect the battery from needing to be replaced and or high voltage issues. When you’re plugged in too charge and have too many things running it causes issues even will make your outlet shutoff (which the outlet/breaker does it to prevent a fire etc.) Your car is basically doing the same thing. As far as regen I don’t understand why it would effect that unless you charging close to 100%. Also when max battery is on it has to preheat the battery but its not good if you forgot you put it on and would stay on the entire time. You can leave your keys in the car and see if that works, it should. If you really wanted too, you could place something on the seat that has decent weight, you can try leaving the door slightly opened but still shut with your keys inside and if it’s really that important find something to keep the brake pressed down. If the break is pressed and keys inside it will not shut off for hrs

Or they figured out that it’s more efficient to skip the pre-battery heating and limit regen initially instead of preheating and having greater regen the first few miles. They did say the recent update would increase efficiency. Preheating the battery for a few miles of regen is probably not ideal from an efficiency perspective.