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Would you use battery heating if it were available?

Discussion in 'Model S: Battery & Charging' started by Andyw2100, Feb 8, 2015.

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Would you use battery heating if it were available?

This poll will close on Feb 7, 2017 at 7:28 PM.
  1. No. I have no interest in battery heating and I don't see why anyone would.

    11 vote(s)
    4.6%
  2. No. But I see the value in it for others, and think Tesla should make it available.

    21 vote(s)
    8.7%
  3. Yes, sometimes. This would be pretty useful to me.

    72 vote(s)
    29.9%
  4. Yes, very often. I would love this significant improvement!

    137 vote(s)
    56.8%
  1. Andyw2100

    Andyw2100 Well-Known Member

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    #1 Andyw2100, Feb 8, 2015
    Last edited: Oct 18, 2015
    Edit: I am updating this poll thread on October 18, 2015. I am hoping that if we make a concerted effort, we may be able to get Tesla to add some sort of traction pack pre-heating to version 7.1 or a later version, since they have added battery heating for performance reasons to version 7 with the "Max Battery Power" option.

    My plan is to write them again, mentioning the fact that they now have an option to heat the pack anyway, and also directing them to this poll.

    This ends the October 18, 2015 edit. The text below this was written on February 8, 2015.
    ---

    I recently started a thread that included a letter I sent to Tesla suggesting that they offer the ability to heat the battery pack as an option not tied to cabin heating. In the letter I asked for the ability to do this through the mobile apps, and independent of range mode. I also asked for the ability to schedule this heating, so that we could set a time when we wanted the battery pack warmed and ready to go.

    The benefits of this would be numerous. For starters, we would be able to heat the pack even if we forget to turn range mode off, which would allow us to leave range mode on all the time if we so desire. We would be able to heat the battery pack without needing to heat the cabin, which would save energy. We would be able to sufficiently heat the pack to so that we have regenerative braking available at the start of our trips. And we would be more easily able to use shore power to get the battery up to temperature, which could mean more range available for driving.

    You can see the thread, and comment here if you like:

    Suggestion for battery pre-heating and charge-end scheduling sent to Tesla

    There have been many positive comments in this thread.

    I decided to start this poll, in an attempt to demonstrate to Tesla just how much battery heating might help Tesla owners, and how many Tesla owners might want it.

    Please take a moment to vote in this poll, to let other TMC forum members, and I hope eventually Tesla know how you feel about battery heating as an option.

    Thanks.
     
  2. Jgdixon

    Jgdixon Member

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    Cross post
    In addition it is silly that when it is really cold we have to cycle the heat on at least twice through the app to get the pack warmed up so we have regen. Then you go out to a really hot cabin which is the waste. Many times I've opened the windows to cool the stifling hot interior on a cold winter day!
     
  3. Andyw2100

    Andyw2100 Well-Known Member

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    Exactly!

    I always lower the temperature as soon as I get to the car. Most of the time I probably wouldn't bother preheating the cabin at all, if I were able to preheat the battery without having to preheat the cabin. I bet there are many people doing exactly the same thing. So giving us separate battery warming would be one more thing Tesla would be doing to help the environment.
     
  4. wraithnot

    wraithnot Model S VIN #5785

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    I agree that this would be a really useful feature. In addition, I'd like to have a readout showing the current battery pack temperature. This would be helpful to make driving decisions BEFORE the yellow power limiter comes on as well as deciding when the battery pack is heated enough to leave on a trip.

    And while we're at it, I'd also like to see how well the main pack is balanced and see the exact voltage of the 12 V battery. If I'd known the state of the 12V battery, I could have made an informed decision about whether or not to limp to Tesla service rather than waiting for the tow truck.
     
  5. gpetti

    gpetti Active Member

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    I've been trying to work out why this was implemented the way it was and I'm thinking that maybe the object was simplicity. For example in an ICE people seem to understand the paradigm that warm engine = warm car interior. Maybe they felt that combining the pre-warming of the vehicle (battery in this case) as a result of warming up the car would be logical and would make things easier for people who aren't as detail oriented as some of us. Anyway, whatever the reason, I'm wholeheartedly in agreement with the principle that pre-warming or preconditioning of the battery should be independent of the climate control. Not sure if the new pre-conditioning feature is supposed to be a step in this direction - but again they may have tried to make it simpler leading to something that is not as functional (yet).
    I'm not going to specifically say they need to add a battery heater control as I believe Tesla is good at coming up with different ways to solve a problem but I think the basic requirement here is that we can have a car ready to drive with all necessary drive train components (I'm including the battery) at their optimum temperature for maximum range and performance, at a pre-determined time, or via remote control. We want this option to be independent of the climate control.
    Maybe they could have a "Car Pre-conditioning" option or "Ready Car for Driving". This could either be separate from climate control or perhaps it has an option to select climate control too. The other key being that even if the climate temp is reached, the battery keeps on heating until it has reached the required temperature.

    - - - Updated - - -

    I would personally like these features too but I would say that it is important to put them somewhere that only geeks will go, maybe even an advanced tab. At some point the car becomes like an aircraft cockpit - probably welcomed by many people here (as we seem to have a lot of pilots) but I'm guessing my wife would not be remotely interested in this information and if there was too much of this type of information she might not go looking for some of the more useful tabs.
     
  6. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I'm not sure which one to answer. I'd very seldom want battery heating without cabin heating. Heat soaking the cabin when it's cold goes a long way to mitigating range loss--as does heating the battery, but that's easy to do by setting the start time so that it ends around the time you start driving.
     
  7. Andyw2100

    Andyw2100 Well-Known Member

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    #7 Andyw2100, Feb 9, 2015
    Last edited: Feb 9, 2015
    Or better yet, start the battery heating first, since it's going to take longer, and only start the cabin heating at the point that it needs to start so that it's finished at the same time that the battery is ready, which is the time designated as the departure time



    There are so many cool things that could be on an advanced tab. I agree that if things get too complicated for those that don't want the level of detail many of us find useful, that would be a negative. But there is just so much possible that advanced user options almost scream to be added. At some point. For now, I'll take some more basic ones.




    There are a couple of issues here. The first is even if you like your cabin toasty and heat soaked, doesn't it get that way a lot quicker than the battery warms up? In other words, if you weren't also charging the battery, and were limited to warming it via preheating, wouldn't you wind up having to overheat the cabin in order to adequately heat the battery?

    Another issue is that while for many of us it may be relatively easy to time the battery charging to complete when we want to start our trip, so that it is warm, for some people that may not be the case. And even for the technically inclined and knowledgeable, there are still times that this method alone won't work.

    As an example, let's say you haven't run the battery down much at all, and don't need to charge it much or any, but still would like to preheat the battery. This is a typical situation for me, say, on a weekend. Another situation might be if you want to go out a time that is not in sync with when you'd like to charge, because of night time charging rates.

    Finally, perhaps this was a one-off situation, but I had an issue the other night where somehow I failed to adjust for how cold it was, and because of that, had I not happened to be up late, the car would not have been charged enough for my wife the next morning. I typically charge at 56 amps (so as not to stress any of the components in any of the systems) which gets me about 38 miles per hour. I believe I was trying to charge from about 70 range miles remaining to the 229 or so 90% charge, so roughly 160 miles, or roughly four hours. My wife was planning on leaving at 6:00 the next morning. I had set the charging to start at 1:15AM, thinking that it should end at around 5:30AM, and there'd be a little wiggle room. I was up late reading TMC and at around 2:15AM or 2:30AM checked the app to find the battery charging at the rate of 17 miles per hour. The temperature was 2 degrees Fahrenheit. I went out to the garage and kicked up the amperage to 72, I believe, and the car was charged to 227 when my wife left the next morning, but was not completed. (I was slightly annoyed she didn't wait for the charge to complete. I was watching the app, in bed, sure she wasn't going to unplug and stop charging so close to completion, but off she went!)

    My point is that I had successfully timed the battery charging to end appropriately several times before that incident, but the cold really threw me off.

    Scheduled end time charging, with Tesla in control, can account for that easily. More importantly, it would make things simple and easy for people who don't want to be bothered thinking about this stuff.
     
  8. mknox

    mknox Well-Known Member

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    Weird. I usually pre-heat for about 15 to 20 minutes in the morning and find that is plenty. I still have a bit of re-gen limit, but nothing that I really notice in day to day driving.
     
  9. David99

    David99 Active Member

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    Where I live we don't need pre-heating ever but I agree, it's a feature that should be available. As for implementation, though, I think it should be just be a part of a smarter timer. What I mean is you want to be ready to leave at say 8 am. All you do is tell the car that one thing. The car is smart enough to know when to start charging so it's finished charging at 8 am. It knows the outside temperature and battery temperature to figure out when and how much battery and cabin heating is necessary.
    As someone else said, the majority of people don't know and don't want to know what the car needs to run best. All they want is a car that is ready to go at the time they say. Everything else can be done automatically.
     
  10. ToddRLockwood

    ToddRLockwood Active Member

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    I made a similar suggestion to Tesla engineering a couple months ago. A dashboard display of the pack temp and an estimated time-to-nominal-temp would be very helpful. At the moment, the best solution I've found is to turn on climate with the phone app and set the interior temp to 76. This will take the pack from a temp cold enough to disable regen, to a temp that gets rid of the regen limiter in about 45 minutes. Question is: is the pack heater finished when that dotted line finally disappears? It would be nice if there was at least an indicator on the dash to let you know when the pack heater is functioning.
     
  11. RiverBrick

    RiverBrick Active Member

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    I definitely would like to be able to activate the battery heater remotely.

    Also, when preheating while not plugged in, is the battery heater engaged? If not, I'd like the option to change that as well.
     
  12. Andyw2100

    Andyw2100 Well-Known Member

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    #12 Andyw2100, Feb 10, 2015
    Last edited: Feb 10, 2015
    I have a couple of questions for you on this.

    For starters, does your preheating stay on continuously for 45 minutes? I'm not sure how long ours stays on, but I know it's not close to that long. I think it's probably about 15 minutes. We're constantly having to check and turn it on again.

    Also doesn't the pack take longer to heat up than the cabin? What I'm getting at is if 76 happens to work for you, isn't that just a somewhat random combination of how cold your battery usually gets and other conditions? I mean, since the pack and cabin heat at different rates, if someone's pack started out warmer than yours usually does, they'd probably use a lower cabin temperature to reach the same point with the pack temperature, and similarly, if their pack started out colder than yours usually does, it would take a higher cabin temperature before their pack reached the same temperature as yours.

    Or am I missing something? I very well may be.

    - - - Updated - - -

    Whether the battery heating is engaged when you are preheating is currently not dependent on whether you are plugged in or not, but rather on whether you have range mode enabled or not. That, to me, is one of the major issues here. If you have range mode enabled, you won't currently be preheating the battery, even if you are plugged in.

    And to the people who say "we don't need separate battery preheating. Just heat the battery even if range mode is on when plugged in, and don't heat the battery when not plugged in", I say that doesn't meet everyone's needs. Some people may be trying to charge quickly, away from home, and may not want the battery heating while they charge, preferring to just charge and go, rather than spend the extra time. Others might choose to warm the battery even when on battery power, but still want to be able to leave range mode on all the time, out of convenience.

    While I agree the car and the interface should not become overly complicated, the option of heating the battery separate from the cabin does not have to be overwhelming for anyone. For those easily overwhelmed, the ability to not avail themselves of that option should be easily selectable.
     
  13. Brass Guy

    Brass Guy Member

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    Several posts above reference heating the cabin hotter than comfortable. I think you can set the heat to a reasonable temperature, and it will maintain that temp and continue preheating the battery until the preheat cycle ends.

    According to the release notes, the battery gets preheated when the car is plugged in. I'm reasonably certain that this is the case, and not when unplugged. The battery heater uses a significant amount of power. Definitely more than the cabin heater. That is probably why it's set up this way. I can imagine loosing upwards of 15 miles heating the battery from freezing temps.
     
  14. liuping

    liuping Active Member

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    I chose "sometimes" because I live in San Diego and only would using when on ski trips, etc. But I still think it would be a significant improvement. :)
     
  15. Jgdixon

    Jgdixon Member

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    The problem is quite often the app will time out after 30 minutes and the cabin or battery isn't up to temperature.
     
  16. Andyw2100

    Andyw2100 Well-Known Member

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    Unfortunately that's not how it works. When the temperature is reached or when the time limit is reached, the heat shuts off.



    Can you please post a reference to the exact release notes you are talking about.

    The battery will not preheat with cabin preheating when in range mode. The battery does heat enough to be charged when plugged in, because a battery can't be charged when it is cold-soaked. But that's not what we're talking about here. And as long as the car is not in range mode, the battery does preheat from battery power when the cabin in being preheated. There is some loss of range miles. That's the price we're paying to not start our trips with no regenerative braking.

    Note that the proposed battery heating options wouldn't be taking options away from anyone, or forcing anyone to behave differently than they are now. They would just give those of us that want them additional options and additional flexibility.
     
  17. mknox

    mknox Well-Known Member

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    I thought I read or heard somewhere that the cabin heater and the battery heater were each 6 kW max. I have a separate real-time meter on my car's charging circuit and I do see the power draw go down as the car warms up. After about 20 minutes, my car is only pulling about 1 kW from the wall (in a garage, but at sub-freezing temperatures).

    I will pre-heat my car after work for about 5 or 10 minutes before departing. According to the app, I will lose about 3 to 5 miles of Rated Range, but the car is nice and toasty inside.

    - - - Updated - - -

    Mine doesn't. As pointed out above, it will throttle back, but it keeps on running. It will time out if started by the app, however.
     
  18. Andyw2100

    Andyw2100 Well-Known Member

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    Then perhaps I've always seen it time out. All of my answers were based on starting preheating with the app. I wasn't thinking about someone physically walking to the car and turning on the heat that way, though apparently that is possible, and I guess people do that too.
     
  19. N4HHE

    N4HHE Member

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    A year ago with probably 5.8 firmware temperatures here got down to the teens and my Model S 85 displayed "heating battery" on the speedometer.

    My question when I don't readily see an answer for is, "Why do I care?" Yes, regeneration, but I'm not going to regenerate as much as warming the battery consumes. When really cold acceleration was limited as well but not so much that it affected my commute.
     
  20. mknox

    mknox Well-Known Member

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    Interestingly, if you go out to the car and turn the heat on, it will shut off as soon as you close the door. For those of us who had cars before the app was released, it was a common "trick" to leave the door slightly ajar so that the heat would stay on!
     

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