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Regenerative braking at lower temps?

DeltaOne

Member
Mar 19, 2021
54
33
Mount Airy, MD
New Model 3 owner since Friday. Our overnight temps bottomed out at 40° F. Around 10 am it was 45° F and I left to run an errand. I had no regenerative braking for the first two stops. Regenerative braking started working on the third stop, about a mile in to the trip.

Does something in the car need to warm up a bit for regenerative braking to start working?
 

5150

Member
Apr 26, 2020
70
16
San Diego
The battery needs to warm up. Cold batteries do not like to charge well.

You'll notice too, the amount of gray dots is more when regen not working, or not working as well. The less dots better regen.
 

5150

Member
Apr 26, 2020
70
16
San Diego
I'm in San Diego, and I've only had it tell me once that regen is reduced since I've owned it this past year. My M3 is always garaged though too. When it did notify me, it was something in the low 50's when I began to drive, I believe. My garage temperature may have been low 60's? And, I believe that is what the battery temperature was at, and didn't matter so much what the outside temperature was while driving.

Someone else may have hard numbers to go by, as I've only experienced once.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,712
8,499
Riverside Co. CA
I'm in San Diego, and I've only had it tell me once that regen is reduced since I've owned it this past year. My M3 is always garaged though too. When it did notify me, it was something in the low 50's when I began to drive, I believe. My garage temperature may have been low 60's? And, I believe that is what the battery temperature was at, and didn't matter so much what the outside temperature was while driving.

Someone else may have hard numbers to go by, as I've only experienced once.

It may not have told you with a snowflake, but I bet if you actually looked at the regen dots you would have lower regen every morning. I park in a drywalled covered garage too, and have never had the snowflake while parked in my garage, yet every morning from roughly november to march ish, when the garage is in the 60s and you get it in it in the morning, you will see the grey regen limited dots (which means the battery is cold).
 

5150

Member
Apr 26, 2020
70
16
San Diego
It may not have told you with a snowflake, but I bet if you actually looked at the regen dots you would have lower regen every morning. I park in a drywalled covered garage too, and have never had the snowflake while parked in my garage, yet every morning from roughly november to march ish, when the garage is in the 60s and you get it in it in the morning, you will see the grey regen limited dots (which means the battery is cold).
Correct, no snowflake, and more dots on the colder mornings that I drive. I work from home, both pre and post pandemic, so not too many earlier mornings do I drive somewhere. Only one time though that I received the warning/message.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,712
8,499
Riverside Co. CA
Correct, no snowflake, and more dots on the colder mornings that I drive. I work from home, both pre and post pandemic, so not too many earlier mornings do I drive somewhere. Only one time though that I received the warning/message.

We dont get cold enough for the snowflake out here in southern california very often, but we do get cold enough to limit regen braking due to the battery being cold, so thats what I was trying to express to @Kimmi.

Pre covid, I drove 40 miles 1 way to work (from temecula to North county SD) and each morning, I would have limited regen for about the first 20 ish miles of the drive, despite driving on the 15 freeway at 80 MPH from temecula to the 76. Someone with scan my tesla or something could tell you the numbers the battery gets warmed to (I read em here somewhere at one point). I think its more than 100 degrees though, and the battery has a LOT of thermal mass to warm, and warms up pretty slowly.

There isnt much waste heat in a tesla, which is why heating the cabin can suck battery range.
 

Tennislover9

New Member
Mar 15, 2021
2
1
Boca Raton
Sorry to piggy back off this thread. New Tesla owner. I haven't used the break at all. My question is ive just coasted into the light taking my foot off the accelerator. My question is do the tail/break lights come on by doing this? My concern is someone is going to rear-end because they don't realize im slowing down with hitting the break pedal.
 

DeltaOne

Member
Mar 19, 2021
54
33
Mount Airy, MD
Sorry to piggy back off this thread. New Tesla owner. I haven't used the break at all. My question is ive just coasted into the light taking my foot off the accelerator. My question is do the tail/break lights come on by doing this? My concern is someone is going to rear-end because they don't realize im slowing down with hitting the break pedal.
I wondered the same thing. My wife followed me home the day we picked up our Model 3. I called her...asked if the brake lights were coming on. She said yes...the brake lights were working as she thought they should be.
 

yyzbig6

Member
Jan 21, 2018
103
148
Toronto
I wondered the same thing. My wife followed me home the day we picked up our Model 3. I called her...asked if the brake lights were coming on. She said yes...the brake lights were working as she thought they should be.
If you look closely on your screen rendering of the car, the brake lights will also light up. It's very hard to tell though since it's so small. Tesla should really exaggerate the rendering.
 

GtiMart

Member
Nov 13, 2019
665
538
Quebec City, Canada
The regen curve has changed in recent software updates. Prior, you would have had zero regen below freezing and it would have slowly ramped up until your battery reached around 20-21C. The latest software update has helped in that regard. There is still no regen under freezing. However, once you pass that point, the regen curve goes up quickly and reaches full at around 10-11C. The "power bar" at the top of your screen should show dots on the left side if you don't have full regen.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,712
8,499
Riverside Co. CA
Sorry to piggy back off this thread. New Tesla owner. I haven't used the break at all. My question is ive just coasted into the light taking my foot off the accelerator. My question is do the tail/break lights come on by doing this? My concern is someone is going to rear-end because they don't realize im slowing down with hitting the break pedal.

Yes, they (brake lights) come on. As mentioned, you can see it on the representation of the car on the screen as well. In fact, I would say that whatever algorithm tesla uses to decide when to turn on the brake lights when decelerating because of regen braking is pretty darn aggressive. You likely are displaying brake lights more than you used to (every time you take your foot off the accelerator) and if you are a person who learned how to drive by "pulsing" the accelerator you are constantly "brake checking" people behind you.
 

DeltaOne

Member
Mar 19, 2021
54
33
Mount Airy, MD
You likely are displaying brake lights more than you used to (every time you take your foot off the accelerator) and if you are a person who learned how to drive by "pulsing" the accelerator you are constantly "brake checking" people behind you.
One time when my wife was driving behind me she said the brake lights were fluttering on and off. Probably because I was feathering the accelerator pedal.
 
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Gasaraki

Active Member
Oct 21, 2019
1,453
976
Syracuse, NY
New Model 3 owner since Friday. Our overnight temps bottomed out at 40° F. Around 10 am it was 45° F and I left to run an errand. I had no regenerative braking for the first two stops. Regenerative braking started working on the third stop, about a mile in to the trip.

Does something in the car need to warm up a bit for regenerative braking to start working?
No regen at all? As a new owner, I think you're just confused. It might be weak but 40 degrees is not cold enough to not have any regen.
 

Gasaraki

Active Member
Oct 21, 2019
1,453
976
Syracuse, NY
Sorry to piggy back off this thread. New Tesla owner. I haven't used the break at all. My question is ive just coasted into the light taking my foot off the accelerator. My question is do the tail/break lights come on by doing this? My concern is someone is going to rear-end because they don't realize im slowing down with hitting the break pedal.
Yes. You can see your brake lights come on when you look at the picture of your car on the screen.
 

DeltaOne

Member
Mar 19, 2021
54
33
Mount Airy, MD
No regen at all? As a new owner, I think you're just confused. It might be weak but 40 degrees is not cold enough to not have any regen.
You're right...the regen was reduced for a few miles. And, as a new owner, I had not yet learned about the "power bar" thing on the display...but now I know to look there and how to interpret what it's showing me.
 
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Marty3SR+

Member
Jan 16, 2021
27
9
Pleasant Hill, CA
I'm curious about this. I live in the SF Bay Area, but in Contra Costa County where it does freeze often during the winter. However, only recently, since it's warmed up a bit, I've been seeing the reduced regen warning for the past several days. Normally, I never saw warnings at all. Oddly enough, I also got a warning about the USB drive getting full, but it won't allow me to reformat it no matter what I did, so I had to remove it and use my desktop. It's almost as if the car didn't think the regen warning was important enough, but added to the USB warning, decided to let me know. :)
 

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