Preheating battery in cold weather use.

[evJOULE]

Found this gem that was posted a while back...

Source: Model3OwnersClub

Consensus seems to be:

• As long as the ambient temperature doesn't drop below -30C for longer than 24 hours, the car will take care of the battery itself. Otherwise, find somewhere warmer to park it.
• If you don't pre-heat the battery, you will definitely have reduced range or much slower charging until the battery warms up.
• If you want to pre-heat the battery, just switch on cabin control at least an hour before you head out, preferably hooked up to "shore" power.

Battery chemistry is virtually the same. It's still NCA, but with further reductions in cobalt. Source: Two Bit da Vinci via InsideEVs

Also, I think you took @Rocky_H's post a bit too personally. He (or she) wasn't attacking you. Basically his argument, extrapolated, was a generalization is that Tesla is building vehicles for the mass consumers and it should be as simple or easier than owning an ICE vehicle, or actually even worry less than one. We're all here to help each other and answer to the best of our abilities. Here are some of the questions you asked:



He (or she) is basically pointing out that you shouldn't have to worry about any of these conditions other than what was stated in the manual of extreme temperature. To answer your second question, yes. Preheating the cabin will also activate the Model 3 heater, if the BMS determines it is needed as you can see from the image above.

3rd question is answered in the manual on Page 44 for the Model 3. It has the same verbiage as the Model S/X owner's manual:

4th and 5th question, it would be the same for any of the Tesla models. It's up to the BMS to make sure the battery stays healthy. But back to Rocky_H's extrapolated point of "K.I.S.S.", the manual says as long as the vehicle is in an ambient temperature higher than -30C, the vehicle should be fine. I've left my car at an airport for 5 days, unplugged in very cold weather, and it was fine when I got back minus a bit of vampire drain. Does leaving a lithium battery in cold weather affect the longevity? From my previous academics, it's negligible until certain extremes (i.e. colder than -30C for Tesla) and mostly occurs if you try to PULL or PUT too much into the battery (hence the no regen, slow charging, power-limited/slow acceleration). If the battery is basically not being used, there should be little to no degradation, in terms of longevity, at all to it.

Hopefully, some of this will help put your mind at ease and not to sweat it too much. And if there are any more definite answers to your questions, I'm sure they will surface up and provide more information.

Cheers.

Thanks again for your valued input. It looks like the attached screen shot you provide is from the mobile app for Model S. My mobile app looks slightly different, so I will have to wait till it gets a little colder to see if it displays the icon for battery heating. The image shows an interior temp of -8, I am about +10 at the moment. Anyway, thanks for the tip on page 44. I must have passed over that. In regards to the Model 3 battery, I read over the section starting on page 109. No where does it state one way or another that the battery will be kept at some temperature level when unplugged, or that the battery heating will be activated by turning on climate control when unplugged. On page 44, it states that you can preheat the battery using wall power when plugged in, but does not mention what happens when unplugged. On page 111, it mentions that a 1% drain to power the onboard electronics is normal when not plugged in, and recommends that the user should ensure enough charge level to account for this when leaving Model 3 unplugged for extended periods of time, such as at an airport. Taking both of these information sources together, I have to believe that when the car is left unplugged, there is no active heating of the battery, even when climate control would be turned on. Otherwise, the 1% battery drain would be much higher depending on the time of year and at which airport your car is parked. JNU, or LAX. Given the extreme temperature dips here in the cold white north, this may even extend concern to anyone having to leave their car outside unplugged while at work for 8 to 12 hours. I am not saying it is, or will be, I am just opening discussion on something I feel is important as an advocate of EV's... hence all the questions.

In terms of what is, or isn't good for a batteries life, I am certainly not the go to person... hence all the questions on a users forum. But in your brief explanation of why you think cold weather is not a factor worth concerning about, it seems to me that you give at least one good reason why a Canadian Model 3 owner maybe should be at least interested to ask. If battery degradation occurred at extremes, and mostly when you try to pull or put too much energy into the battery, wouldn't it then make sense to avoid cold soaking the battery in -25C weather for both longevity and performance issues? I think it is reasonable to expect that the driver might need to pull/put high amounts of energy out of/into the battery when they start driving. And remember, the questions raised in this thread are in the context of extreme cold weather up here in Canukville. So while we all learn from the collective experience here, it seems counter productive to discourage the inquisitive nature that underpins the purpose of an internet user forum.

In terms of Rocky_H, I respect his opinion and welcome it quite frankly, but when his opinion is that other's don't have one, it is less appreciated.

Cheers!

 

[evJOULE]

Another good source to include in this discussion.

Teslas in Cold Weather

 

[Rocky_H]

In terms of Rocky_H, I respect his opinion and welcome it quite frankly, but when his opinion is that other's don't have one, it is less appreciated.

You are badly misinterpreting what I said and making up things I did not say. I said that Tesla has good reasons why they would not want to present such a finely detailed list of care instructions for the battery.

(And you needn't worry about me. I did read the manual all the way through the very day I got the car, because I'm an electrical engineer, and I find it fascinating, but that's not necessarily helpful for the mass market. The car does need to be easily usable even if people don't choose to read the manual.)

 

[Zidarich]

Anyone know if acceleration is also decreased when regen is decreased in the cold?

 

[SSedan]

Regen is reduced at warmer temps than acceleration is computer limited, in my S there will be dashed yellow lines denoting the computer imposed limits of each.

That said, you can feel cold reduce acceleration just based on slowed chemical reaction within the battery before the computer limiting occurs, car is still plenty quick but there is a difference.

 

[David99]

... It was more about preheating the battery in the Model 3, and if there are any recommendations for extreme cold weather use. The reason I was asking is because the Model 3 uses a different method to warm the battery then the Model's S and X, and I live a little bit North of Orange County, California if you know what I mean.

The Model 3 uses the motor as a heating element instead of a dedicated heater. The method is different, the result is the same. The coolant going though the battery is warmed up to heat the battery. The cell size on the Model 3 is different, but the chemistry is not different than the latest Model S/X. Maybe minor tweaks. It's not like the Model 3 uses an all new different battery that requires different treatment. What we and mostly Tesla learnt from the years with the Model S and X is all true for the Model 3.

We can use the first Gen Leaf as the case study in what happens when you don't use good thermal regulation, and I think it is safe to say that goes for both high and low temps.

The Leaf used different chemistry and had had poor battery management and no thermal management. Has nothing to do with the Model 3. Again, I think looking at the experience with the Model S/X is the best best to predict what the Model 3 battery will do. Driving in cold climate is just fine. The car won't allow you do draw more power than safe out of the battery when it's cold. Asked about battery longevity Elon once said when driving in Alaska the battery will last 'forever'. Cold temperatures are good for longevity. Looking at battery degradatin from people living on cold climates vs people living in warm climates shows the same. The cooler, the slower the degradation. Many studies done in labs have shown this as well.

There is really no benefit trying to find a way to manually heat the battery on your Model 3. Let Tesla's BMS do it's job and don't worry. Your battery will not last longer or age slower if you preheat the battery before driving. If, for whatever reason, you insist on doing it, you can use the app I mentioned previously. It will time the charge process automatically just before you drive. Charging warms up the battery as a side effect, so you get what you want for free.

There is nothing you can do on your end that would greatly affect battery degradation other than charging the car up to 100% every day. Just avoid charging to 100% all the time and you are good. Everything else is making very little difference and isn't worth worrying about.

 

[David99]

Anyone know if acceleration is also decreased when regen is decreased in the cold?

The max power the battery is able to output depends on the temperature for sure. The car actually reports what this value is (on the CAN bus) and it decreases with temperature. A cold battery can output less power than a warm one. That's why Tesla has a 'max power' setting in the P100D cars which warms up the battery to reach it's peak output. The max output also varies with state of charge. A charge level of 30% has a lower max output than one with 90%. On the CAN bus you can see how the max power value changes all the time depending on different conditions. But only when it falls under a certain value will it show the driver as the dotted line.

BTW, the max output power of a Lithium battery is not at 100% SoC but at a little over 90%. That's where the impedance is the lowest (internal resistance).

 

[evJOULE]

You are badly misinterpreting what I said and making up things I did not say. I said that Tesla has good reasons why they would not want to present such a finely detailed list of care instructions for the battery.

(And you needn't worry about me. I did read the manual all the way through the very day I got the car, because I'm an electrical engineer, and I find it fascinating, but that's not necessarily helpful for the mass market. The car does need to be easily usable even if people don't choose to read the manual.)

No actually, I'm not making up things you did not say! That is actually exactly what I have been thinking since you entered this thread. I knew you were answering to my posts because you were quoting them, but from the responses you gave, it was almost like you were having a conversation with someone else at times.

If you go back and read the history of both our posts, you entered the discussion by wanting to make sure that I understood the Model 3 has a way of heating the battery, when I had just stated I understood that point in my initial post. Then you mistakenly claimed that I was comparing the battery in the first Gen Leaf with the thermally regulated battery in a Tesla car which I was not. Then you actually tell me that I have "some really weird perception about something" that you disagree with, and claim that I was suggesting people were throwing their hands in the air and calling a cab because their cars don't work. How you came to that conclusion, I have no idea, but then you go on to cite information regarding the EV growth rate in Norway as if it was proof that warming the battery in cold weather conditions has no benefit. And finally, you claim that I have somehow suggested that we should all be following several pages of detailed instructions to properly care for the batteries in our cars. This is a concept you put in your own head, and not something I actually posted. If you go back and read what I posted, not what you want to understand, but what I posted, I basically said that I would like to see Tesla further clarify how their system works in the form of an addition to the owners manual, which by the way is something Tesla encourages its customer base to actively participate in. And I fail to see how adding more or new information to the owners manual will detract from, or have an impact on Model 3's ease of use. Just as an example, you seem to think that the BMS will activate to warm the battery in cold climates when the car is unplugged. You may or may not be right, but after being pointed to the information on page 44, I seriously doubt that is the case. The more I think of it, the more sense it makes, because it is the lesser of two evils. Having a cold battery with energy still stored in it I imagine far outweighs a cold dead battery with no energy left in it.

I am glad that as an electrical engineer, you find the Model 3 owners manual fascinating, but I hope you can see after having read it, that it has no real impact on how easy and simple the Model 3 is to operate.

 

[evJOULE]

The Model 3 uses the motor as a heating element instead of a dedicated heater. The method is different, the result is the same. The coolant going though the battery is warmed up to heat the battery. The cell size on the Model 3 is different, but the chemistry is not different than the latest Model S/X. Maybe minor tweaks. It's not like the Model 3 uses an all new different battery that requires different treatment. What we and mostly Tesla learnt from the years with the Model S and X is all true for the Model 3.

The Leaf used different chemistry and had had poor battery management and no thermal management. Has nothing to do with the Model 3. Again, I think looking at the experience with the Model S/X is the best best to predict what the Model 3 battery will do. Driving in cold climate is just fine. The car won't allow you do draw more power than safe out of the battery when it's cold. Asked about battery longevity Elon once said when driving in Alaska the battery will last 'forever'. Cold temperatures are good for longevity. Looking at battery degradation from people living on cold climates vs people living in warm climates shows the same. The cooler, the slower the degradation. Many studies done in labs have shown this as well.

There is really no benefit trying to find a way to manually heat the battery on your Model 3. Let Tesla's BMS do it's job and don't worry. Your battery will not last longer or age slower if you preheat the battery before driving. If, for whatever reason, you insist on doing it, you can use the app I mentioned previously. It will time the charge process automatically just before you drive. Charging warms up the battery as a side effect, so you get what you want for free.

There is nothing you can do on your end that would greatly affect battery degradation other than charging the car up to 100% every day. Just avoid charging to 100% all the time and you are good. Everything else is making very little difference and isn't worth worrying about.

Again David, it seems that this discussion is constantly being misquoted. The question was not about how the Model 3 generates heat to warm the battery, it was more about how effective this new method was. In other words, is it as capable as the system in the Model S and X, because I thought I was getting something similar when I made my reservations. If you go back to the start of this thread, including what was already posted in other threads at that time, you should see that other people were suggesting that the battery warming capabilities in the Model 3 appear to be a little weak. Now this is not hard fact, but more simply the experience of a few owners. My concern comes from the fact that I will have to park my car outside in temperatures much lower then what had been reported back when I started this thread. So I am not doubting Tesla's experience, I was reaching out to the broader community here to get a sense of how well the Model 3 can handle cold climates, and if there is anything we should know or do to help optimize things.

Regarding Nissan, if you go back and read my post where it is mentioned, you will see that you are posting a one-sided argument, because I never suggested that the Leaf and Model 3 are comparable, or are related in anyway. The relevant point being made by mentioning the Leaf, is that it is a good case example of what happens when you don't use a thermal regulation system with the battery. If Tesla didn't have a thermal regulation system on their batteries, they would likely face similar problems as Nissan. And I guess the way we all have our own way of interpreting things is what makes internet forums such interesting places. I am not trying to find a way to manually warm the battery in my car. What would give you that impression. I said at some point that I would like to be able to control that function via a software setting in the mobile app, but I have no interest in manually warming the battery, and I find it bizarre that you suggest I do. Other then that, what I really wanted was to just get all the information straight in terms of how everything works.

 

[evJOULE]

The max power the battery is able to output depends on the temperature for sure. The car actually reports what this value is (on the CAN bus) and it decreases with temperature. A cold battery can output less power than a warm one. That's why Tesla has a 'max power' setting in the P100D cars which warms up the battery to reach it's peak output. The max output also varies with state of charge. A charge level of 30% has a lower max output than one with 90%. On the CAN bus you can see how the max power value changes all the time depending on different conditions. But only when it falls under a certain value will it show the driver as the dotted line.

BTW, the max output power of a Lithium battery is not at 100% SoC but at a little over 90%. That's where the impedance is the lowest (internal resistance).

This is all interesting stuff David, I am hoping that I am able to access the CAN bus on the Model 3 in a similar way. But the fact that you see this performance drop with temperature implies that the battery is probably better off when it is kept at some ideal temperature value. I think the best I can do is follow Tesla's recommendation and have the car plugged in each night, Preheat the battery before departure by activating the cabin heat, charge the car to no more then 80% at the end of each day while the battery is warm, and avoid hard accelerations until the battery is fully warm.

 

[David99]

This is all interesting stuff David, I am hoping that I am able to access the CAN bus on the Model 3 in a similar way. But the fact that you see this performance drop with temperature implies that the battery is probably better off when it is kept at some ideal temperature value. I think the best I can do is follow Tesla's recommendation and have the car plugged in each night, Preheat the battery before departure by activating the cabin heat, charge the car to no more then 80% at the end of each day while the battery is warm, and avoid hard accelerations until the battery is fully warm.

I do agree, when the battery is very cold it's probably a good idea to accelerate moderately and avoid full power.

Battery temperature is a double edged sword. One one hand it is good to have a warm battery as the chemical processes are working better, the internal resistance is lower, thus the battery performs better and more efficient. On the other hand the bad chemical reactions, that cause degradation are also working better making the battery age faster.
In normal driving conditions we don't push the battery to it's extreme. Normal acceleration is 1/4 to 1/8 of peak power. In winter conditions you are also rarely accelerating at full power due to road conditions. I think that's why Tesla isn't too worried about keeping the battery warm. I guess what I'm saying is that both the theory and the experience from Teslas driving in cold regions the battery is doing actually better than cars that are in hot regions. My conclusion is that the relaxed battery heating is intentional and helps the battery last longer.

 

[evJOULE]

I do agree, when the battery is very cold it's probably a good idea to accelerate moderately and avoid full power.

Battery temperature is a double edged sword. One one hand it is good to have a warm battery as the chemical processes are working better, the internal resistance is lower, thus the battery performs better and more efficient. On the other hand the bad chemical reactions, that cause degradation are also working better making the battery age faster.
In normal driving conditions we don't push the battery to it's extreme. Normal acceleration is 1/4 to 1/8 of peak power. In winter conditions you are also rarely accelerating at full power due to road conditions. I think that's why Tesla isn't too worried about keeping the battery warm. I guess what I'm saying is that both the theory and the experience from Teslas driving in cold regions the battery is doing actually better than cars that are in hot regions. My conclusion is that the relaxed battery heating is intentional and helps the battery last longer.

Yeah I am starting to get that David thanks. Out of interest, I will be posting my experience here as the winter wears on. At the moment, I am hovering between 0 and +10C so no big surprises at this point that Model 3 is performing admirably as expected.

 

[David99]

I'm really hoping someone will come up with a reasonable way to read the CAN bus on the Model 3. Without it, so much is guesswork. I learned so much once I was able to read the data from my Model S.

 

[hoang51]

Not sure this is relevant but yesterday mornin the outside temp was 59 degrees and had been about 50 overnight. In the morning we drove about a mile to the supercharger. At 52% charge level we started to charge at 32 kW and very quickly dropped to 28 kW. Long story about moving to different stalls, rebooting, calling Tesla, etc but the charge level did not change until about 80% level. Then the charge level dropped to 26 kW.

Later that same day, after driving about 150 miles and charging at a destination charger we returned to the same supercharger. The charge level was normal at about 100 kW.

We had charged normally at this same supercharger two days earlier.

I had a similar charging situation like you did. I normally get nearly 120 kWh for charging at a Supercharger station in the 70s and 80s F weather. Then came the season change with drop in temperature real quick (fall). I was charging in temperatures from low/mid 50s F, while having about 1xx miles of rated range left, and my Model 3 didn't receive higher than 64 kWh. The Supercharger also reduced the power even further as the battery progressed to 80% SOC. Good thing I was shopping while having the car charging. I see that the battery got cold that prolonged the charging.

 

[Kermee]

I had a similar charging situation like you did. I normally get nearly 120 kWh for charging at a Supercharger station. Then came the season change with drop in temperature real quicj

Yeah. This is starting to look like if the Model 3s, half-ton of battery mass is soaked at around the low 50's (10C), it's very unhappy at taking higher Supercharger rates until it warms up considerably. And since there's no dedicated battery heater to pre-condition the battery for charging unlike the Model S/X, if you start charging at around 50%, by the time the battery probably gets warm enough due to charging, you're already at an SoC where charging rate rapidly tapers off anyway.

I think the recommendation at this point is in colder weather, do your charging after a long trip (while your batteries are still relatively "warm") before you turn in for the day vs. if you were planning to charge the next morning if you want to spend the least amount of time Supercharging.

EDIT: On the bright side, there should be an assumption that the talented Tesla engineers who developed the BMS would allow the "fastest" charging rate for the Model 3 if the battery was "cold soaked" to avoid degradation or damage to the batteries. I don't have the link I saw for the article handy, but the Munro & Associates teardown of the Model 3, which included the battery pack... They stated out of the entire Model 3 teardown they did, they were most impressed with the battery pack and the BMS that was "light years" ahead of the competition. That's at least reassuring to me as the weather gets colder and colder, and for some, to the extremes.

 

[NickFie]

Dumb question here:
How does one precondition/heat the battery?
Do you just turn on the car heater to max?

Charging warms the battery. Our cars are parked outside. Last winter, with the S, I timed charging so it would complete about the same time the car would be used in the morning.
- Start time
- Charge rate
- Target charge level. 90%, but there's no problem if we only reach 70%.

This meant the battery would be warm when my wife disconnected HPWC cable and left. Also, the battery heat warms the cabin.

If you want to pre-heat your battery, in the S we turn on cabin heat. In the iPhone app, a red icon in the console lights up, showing that the battery is being heated. Cabin heat should be your target temperature, doesn't have to be full blast.

We got the 3 last month, haven't explored its cold weather options.

 

[MP3Mike]

And since there's no dedicated battery heater to pre-condition the battery for charging unlike the Model S/X

Why does there have to be a dedicated battery heater. The Model 3 can use the motor to heat the pack even when the vehicles is parked. And it can probably generate way more heat then the dedicated pack heater in the S&X.

 

[NickFie]

Based on that route I believe there is another Tesla supercharger in New Rochelle, NY. I would recommend you consider stopping there before heading into the City just in case you hit a lot of traffic or other situations, busy chargers etc.. Have not visited any of the chargers in NYC Manhattan area, but from the map, it only looks like there are two supercharging stations in lower Manhattan, NY. One has only two chargers and the other has only two. Not a lot for a large congested city in lower Manhattan.

Many NYC parking garages have HPWC for Tesla. They're visible in PlugShare.com and SpotHero. If you plan to recharge in NYC garage, book it through SpotHero.

 

[hoang51]

...
We got the 3 last month, haven't explored its cold weather options.

Wait until the temperature dips below 60 degrees F an you'll know what's going on. Best thing that I know is to Supercharge either during day time when the sun is shining or after driving around for a while.

 

[NickFie]

Yeah I am starting to get that David thanks. Out of interest, I will be posting my experience here as the winter wears on. At the moment, I am hovering between 0 and +10C so no big surprises at this point that Model 3 is performing admirably as expected.

Here's another way to warm up your battery after a very cold night.