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Regenerative Braking Improvement At Low Temperatures Means What Exactly?

Discussion in 'Model S: User Interface' started by Andyw2100, Mar 1, 2016.

  1. Andyw2100

    Andyw2100 Well-Known Member

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    Recent versions of the 7.1 firmware update, including the widely distributed version 7.1.2.12.126 have included a note under "Additional Improvements" that reads:

    --
    Regenerative braking at low temperatures has been improved.
    --

    I wrote to [email protected], to ask just what this meant. I want to make sure that my wife and I are doing whatever we need to do settings-wise to best take advantage of this improvement. Unfortunately the response I received doesn't answer the question.

    Below is a copy of the message I sent, followed by the response I received.

    I am hoping in time we may get more information from Tesla, or we may be able to figure out ourselves what has changed.


    My email message to Tesla:

    --
    In the release notes of the firmware update my Model S received last Friday I noticed the following line under “Additional Improvements:”

    “Regenerative braking at low temperatures has been improved.”

    I’m wondering if you might be able to shed some more light on this and let me (and my wife) know in what way it has been improved? Is the regenerative braking limit likely to go away sooner, and if so is that true with both range mode on and range mode off? Or is the limitation likely to be less of a limitation in the first place?

    I ask because in the limited amount of time we have driven the car since receiving the firmware update, all of which has been with range mode on, we have not noticed a difference. We’d like to know what we should be looking for, and also what changes we might want to make to maximize the benefits of the changes Tesla has made.

    Thanks very much.

    Sincerely,

    --


    Tesla's Response:

    --
    Thank you for contacting Tesla Motors Technical Support.

    Unfortunately we do not have any specifics on the actual expectation for what you should experience. Range mode could affect this, as it limits the heating power the vehicle uses both in the cabin and for the battery. The battery will always stay at a safe level for reheating but will take some time to heat up to optimal operating temperature.

    Also because of the variables that do go into this that can be very different every single drive the vehicle is on (original battery temperature, exterior temperature, driving style), it may be difficult to see a direct improvement in one certain number for this system.

    Have a good day,
    ---


    I am planning on following up, but not really expecting a much better answer.
     
  2. apacheguy

    apacheguy Sig 255, VIN 320

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    My guess would be they've modified the algo that determines how much power can go into the battery at low temps. This benefits both SpC and regen.
     
  3. BertL

    BertL Active Member

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    I wondered what this was as well, but guess we won't know the answer. Thx for trying.

    Seems to sort of be the way Tesla is electing to operate... Provide only very broad description of most capabilities. Autopilot seems to get the most. I could say perhaps they take that approach trying to keep it simple for customers ;), but my more sarcastic side would say they do it to maintain wiggle room as to what they do and don't actually provide, and it allows them to keep modifying things as time goes on without customers being able to complain or pin them down if something were changed or taken away one day. Tesla Owners manual is <200 pages; my former Lexus was in excess of 700. While many complained about how big the Lexus (or MBZ or BMW) manuals were, one could generally find detail as to what each capability was for, the constraints it was designed to operate within, supported specs where that made sense (e.g. Supported media player devices, formats, bitrates, etc), and even some FAQ-like usage suggestions. Like you I believe, I appreciate there are a myriad of variables, and one size does not fit all, but if Tesla provided a combination of a broader description and a general example or two discussing the design intent of some of these features and improvements -- it would be invaluable for Owners to make more use of various functions we are provided. While TMC can drive me a bit mad at times with sarcasm and sometimes wondering if a person really means what they say or if it's in jest because they didn't put in a wink emoticon ;)... without TMC and some key owners sharing their own research and observations, I wouldn't know about or be using a huge percentage of what my MS is capable of.
     
  4. Max*

    Max* Autopilot != Autonomous

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    This is a typical tier 1 customer support answer.

    I understand why Tesla has a Tier 1 customer support team, but at the same time, I would expect as a tech company their Tier 1 would be more knowledgeable about the tech product.

    I'd also reply and escalate it. Though when you escalate the response is "we'll send it off to engineering...." and you never hear back.
     
  5. Andyw2100

    Andyw2100 Well-Known Member

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    Well, my response actually asked them to query engineering, so I guess that plays right into their standard second response. :)

    My response:

    --
    Thanks for the response.

    I’m familiar with the basic effects range mode has on heating the battery and the cabin which is why I specified that we had been driving with range mode on when I noted that we had not noticed a change.

    Since you don’t have any specifics on what we might expect, or on what the improvement is, I’m wondering if you might be able to forward my question to engineering.

    Thanks again.

    Sincerely,
    --
     
  6. AWDtsla

    AWDtsla Active Member

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    Seems like a less sh**** ramp when partially regen limited. Before it would seem like if the regen was cut in half, the regen ramp as also cut in half, which is pretty dumb. If I only have 15kW of regen, I want it all *now*. So I haven't looked in detail, but my gut feeling is that the ramp is now the same regardless of regen being limited, and possibly less delay before regen kicks in. There was quite a noticeable latency before. I appear to be getting better energy usage around the city, but it's also been slightly warmer. This is only from a few short drives with regen ~15kW, so I may revise my opinion.

    While we're on the topic, I believe Tesla has the ability to make regen even more aggressive, you can see this with the "downshift" like behavior when slowing down, it makes regen more aggressive with a tiny blip at low speeds. Why it isn't more aggressive all the time, I don't know. There's only small sections of speeds where regen is significantly more drag than a downshifted manual transmission ICE car.
     
  7. travwill

    travwill Member

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    not scientific here either, but i want to say since having this update a while; 1) full regen comes faster now (main notice), and 2) more regen is still enabled at very cold temps - e.g. where used to be like 20% avail, more like 40% to start.
     
  8. mspohr

    mspohr Active Member

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    Having developed and maintained software, I have experience with this... You can try explain in detail the who,what,why and wherefore of every change but this usually leads to a never-ending cycle of of questions and unhappiness all around. I adopted the same stance as Tesla (and most software companies) which was to give a general description of the changes. You can drive the engineers crazy having them explain the entire system and the rationale for the changes.
    I think the Tesla description is perfect.
    "Regenerative braking at low temperature has been improved"
    Relax and enjoy the car. You don't need to do anything. The car will take care of it.
     
  9. Andyw2100

    Andyw2100 Well-Known Member

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    Are you driving with range mode on or off?
     
  10. AWDtsla

    AWDtsla Active Member

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    With proper design there are really no such questions. Which also means with bad design there are a ton of questions. Good design means that things work well and are self explanatory. Take the most discussed features of the car and you can tell where the worst parts are.

    A lot of people see room for improvement so they want to know what happened.
     
  11. Andyw2100

    Andyw2100 Well-Known Member

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    I'm sorry, but that's not an answer that is acceptable with respect to a six-figure piece of technology.

    If some people are satisfied with that answer, that's fine for them. Many of us are interested in the finer points of our cars, and in maximizing what we can get out of them. In this case I'd like to be able to maximize my regenerative braking ability, which means minimizing the regenerative braking limits whenever possible. Tesla just announced that they have done something to improve this system, but without more detail than that, I don't know if it affects me or not.

    Perhaps it only works when range mode is off. I drive with range mode on. If driving with range mode off for five minutes would completely eliminate the regenerative braking limit, I might choose to do that, but unless I'm told that the improvement just made works with range mode off, but not with range mode on I have no reason to experiment with that, since I'd be giving up some of the torque sleep benefits in the process. Or perhaps the improvement is that now the battery will heat when the cabin does whether range mode is on or not. If that's the case I can stop toggling range mode off when I get home, and on before I leave just so that I get the battery heating benefits when I heat the cabin.

    Give me information so I can make intelligent decisions with it. Don't keep me in the dark because some customers don't want to be bothered with the details.
     
  12. mspohr

    mspohr Active Member

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    Which part of "Regenerative braking at low temperature has been improved" don't you understand?
    You don't need to do anything or make any decisions. Just drive. The car is getting better.
     
  13. Andyw2100

    Andyw2100 Well-Known Member

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    I don't know if it has been improved for the way I drive or not. I want some specifics. What part of that don't you understand?
     
  14. mspohr

    mspohr Active Member

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    Regenerative braking at low temperature has been improved for the way you drive.
     
  15. S4WRXTTCS

    S4WRXTTCS Active Member

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    With all the people getting the CAN bus analyzers I'm surprised there isn't comparisons graphs of battery heating vs. regen between the different levels of firmware.

    My experience has been that more re-gen is allowed sooner than before. Although I wouldn't expect this to happen with range mode on.

    Of course my experience can also be explained by it simply being warmer out.
     
  16. Johann Koeber

    Johann Koeber Member

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    As a Tesla enthusiast I am happy with any improvements to the car. Just make sure it is really an improvement.

    Not being an engineer, I don't care about the specifics. Unless I need to do something, which here clearly is not the case.

    So I am just happy and enjoy. For me it yould have been ok not even to mention it. Do you guys and gals really think they are informing you about each and every update to the car? Elon said they change 10 to 20 things a week. They won't tell you and they don't need to.

    Maybe Tesla could offer info to the technically inclined. Got to find a proper platform for that (a TMC talk?). I can understand some users craving for more details and more technicals. But equally I understand the company not handing those out - for a thousand reasons.

    But please don't bug me with more information than I need.
     
  17. mkjayakumar

    mkjayakumar Active Member

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    I didn't even bother to read through the entire release notes, and didn't realize there is a blurb about this.

    Improved regen at low temps? Great, now let me just drive.
     
  18. doctorwho

    doctorwho Member

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    why not drive the car and see if you can work out what is different?
     
  19. svp6

    svp6 Member

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    My initial impression is that efficiency improved. I typically see 500-700 Wh/mi in my very short commute. The morning after the download I saw 400-500 Wh/mi in similar weather. I suspect the impact will be maximal for short trips.
     
  20. cynix

    cynix Member

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    In the v7.1.1 release notes now available in My Tesla, this particular entry reads:

    What is an "ESP2 vehicle"?
     

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