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:
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Regenerative braking at low temperatures has been improved.
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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:
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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,
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Tesla's Response:
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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,
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I am planning on following up, but not really expecting a much better answer.
--
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.
, 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 
