Awful regen since 2020.8

[Galinette]

Hi,

A lot of people complained of bad regen with late 2019 and 2020.4 firmwares, while mine was perfectly ok even by mildly cold weather. Then I upgraded to 2020.8 last week and got this! (Pictures attached) 14°C is approx 57°F. This lasts about 20 minutes...

Am I alone? Why are these regen limitations random across cars and firmwares?

I have a 100D from 03/2018, with only 35000km / 20000mi...

 

[aerodyne]

No, if the car battery is below 65 deg. F, you won't get full Regen.

You can improve the situation by adding a few KWh before you drive.

If you have a Canbus adapter, and a app like Scan my Tesla (SMT) you can see the behavior yourself on your phone as you drive.

 

[Ande]

Yes, they destroyed regen at low temperatures lately.
It's so bad, that this kind of destruction of driving experience well after purchase is what to makes me it unsure if I will buy a new Model S this year or... Ever

 

[aerodyne]

I was not happy at first, but I think destroyed is overstating the problem. It can be solved by heating the batt slightly by charging.

I plan to keep the car out of warranty, so if reduced Regen at low temps helps, I am Ok with that...

Reduced SuC rates? Not happy about that.

 

[GeorgeAlma]

Hi Guys. New here...

I noticed the same thing. My 2019 MS shows about half of regen not available and it's 75 degrees today. It never did that last summer. In fact, it had to get below 55 degrees to start limiting regen.

 

[mongo]

Hi Guys. New here...

I noticed the same thing. My 2019 MS shows about half of regen not available and it's 75 degrees today. It never did that last summer. In fact, it had to get below 55 degrees to start limiting regen.

It may be 75 right then, but how cold was it last night (and in the past few days)?

 

[GeorgeAlma]

Definitely not 75, but yesterday was 64 and the car is garage kept, heated and well insulated. Still though, this is unlike last year's regen levels. We'll see how it goes when the warmer temps are more consistent.

 

[aerodyne]

The important thing is what is the batt temp?

When I interogate the Canbus, it tells me when the min cell temp is over 65 deg, I get full Regen.

Well worth the 70 or so bucks for the App, adapter cable and canbus reader to answer thus question.

 

[GeorgeAlma]

Good idea. Time to spend more money!

 

[aerodyne]

If you search here on TMC using Regen, you will find a graph of exactly when the Regen is limited now compared to before. It only is 5 degrees change.

 

[fbitz777]

If you search here on TMC using Regen, you will find a graph of exactly when the Regen is limited now compared to before. It only is 5 degrees change.

5 degrees Celsius?

In 2017 I remember 8C was the magic battery temp now you are talking close to 20C

For us NorthEast and given the nights being cool Regen is now limited probably for 8 months of a year.
And suggesting to keep wasting about 3kwh each time you need to condition the battery adds up (and is not counted in Telsa Wh/mi display)

 

[aerodyne]

I suggested to charge the batt, adding a few KwH to the state of charge prior to driving. I did not suggest to condition the car. The charging energy will be mostly used on the drive, not wasted.

 

[Barry]

I think destroyed is overstating the problem.

That's because you live in LA. My car was unusable for part of the winter for ski trips. Coming upon a 40 mile long down hill with no engine braking is dangerous. Many cars and trucks have burned out their brakes and crashed on this stretch of road (I-70).

 

[aerodyne]

Drove to Reno last winter via 395. And cross country in the fall of 2018. 7k miles.

I will admit I have never parked outside in the teens without charging the car. If you are forced to do that, then you have to be cautious. I expect the MS brakes are up to the task if needed.

 

[fbitz777]

I suggested to charge the batt, adding a few KwH to the state of charge prior to driving. I did not suggest to condition the car. The charging energy will be mostly used on the drive, not wasted.

if you charge the battery just prior to driving some of the charge (almost half on L2) will be diverted to heating up the battery (assuming it is cold)! But again you don't live in a cold climate like us so you might not have been subjected to it.

 

[aerodyne]

Don't live in one, but drove through a few. One example... Stayed in Minden with car outside parked overnight. Temps in low 20's. Charged at slow rate with NEMA 5-20.

Regen was limited, but not severely.

If you have to park outside half the year with temps below 40, get a Volt/Bolt. Nothing wrong with that..

 

[fbitz777]

Don't live in one, but drove through a few. One example... Stayed in Minden with car outside parked overnight. Temps in low 20's. Charged at slow rate with NEMA 5-20.

Regen was limited, but not severely.

If you have to park outside half the year with temps below 40, get a Volt/Bolt. Nothing wrong with that..

I have a Bolt and yes it has GREAT Regen even in cold temps. It even has Regen (50 percent of max) when battery is full.
Most days I just take the Bolt to run errands as I can't deal with total lack of Regen on my X.

 

[P100D_Me]

Coming upon a 40 mile long down hill with no engine braking is dangerous

That is a VERY valid point, anyone that has any clue about mechanics and how to drive properly knows you don't ride the brakes on steep descents for miles and miles.

 

[Ande]

Yes, when I say DESTROYED the driving experience, I mean it.
Last summer they made a bug(or experiment) that did not preheat the battery when preheating car. We had no effective
regen for the first 0...20 min of the drive from November till January when 20.4.1 fixed this issue.
So now, if I just don't want to drive somewhere, but have AMPLE TIME to preheat.. I still have no regen for the first 0..20min, (which can be the whole trip.)

Tesla's "californians" apparently do not know winter. Here in northern Norway we still have winter, icy roads and snow, see Weather observations, weather cameras, UiT The Arctic University of Norway, Department of Computer Science, campus Tromsø, Breivika - we also have PLENTY of hills & mountains.

So changing the effect of "lift your foot from the pedal" down a slippery hill, or a slippery turn, is equally DANGEROUS as if any car changed it breaking power and breaking threshold on the pedal, or changed it's engine breaking force by temperature !

Yes, I love the car, and YES I AM DAMN ANGRY with TESLA for not understanding basic car use in cold-weather!
The fact they fcked around and took half a year to fix battery preheating is HORRIBLE and for the first time I understood all those that refused updates.

 

[Chaserr]

It isn't that they "don't know winter" - thermal and charging settings in tesla battery behavior has been drastically changed in the last year to try and limit long term accumulated damages that wound up causing fires in older cars. Everyone sees less regen, most are seeing less supercharging speeds, and some are seeing less range and horsepower. They didn't want to do all of this, but there was a still-secret fundamental problem they discovered that has something to do with charging and temperature based on all of these simultaneous downgrades that started about a year ago.