Not having regen after the last software update sucks

[SSedan]

The more I think about this I wonder if in a few weeks when we are seeing sustained sub-zero the lack of preheating the pack with the interior might affect my merging ability. I know I said 45mph drive above but I have to merge onto a short stretch of 55mph and am seeing the throttle limiting line fall with the temps. Hasn't been a hassle yet but in a few weeks when we get highs near zero I think it will be. I might have to set my charge amperage to 80 just to get some heat in the pack once a day.

Before someone who thinks 40degrees is cold, I am not a lead foot, rarely get deep into the pedal, but yesterday leaving work with a high of 10f the acceleration limit line was barely above my actual driving use.

 

[PhilDavid]

Maybe we are looking at it from the wrong angle. Maybe Tesla is optimizing the overall electric usage / improve efficiency. Reducing regen might sound counter intuitive to being more efficient but if they save energy by not/less heating battery, maybe the overall efficiency increases. I only have a 15min commute with 80% highway, so I can count the number of breaking on one hand. Im not a battery expert but wonder the efficiency loss/gain of driving the way I do with cold battery and reduced regen compared to using precious battery power for heating a 500kg battery for a 15min commute. On top of that knowing that regen is limited makes me drive more efficient as I want to avoid breaking and therefore slow down earlier when not on FSD I’m curious to learn how battery efficiency correlates to temperature compared to energy needed to heat battery to keep battery temperature up. If anybody as a link to an article/diagram would be appreciated. As mentioned earlier 3rd dimension of the diagram is battery life.

Honestly, I care more about the driving feel/experience than energy usage alone. I love slowing the car down with regen and one pedal driving, even if that's less efficient for whatever reason. I also like the planted feel I get when I take a turn with just regen. Somehow turning and friction braking does not feel the same -- sort of like the difference between engine braking and friction brakes.

Not having regen really has taken away part of the magic of driving my car in the winter and I would like to have regen back -- OR an option in the app to heat the battery using shore power so when I start driving the car I have regen would also work.

Not having regen for an entire season is not good.

 

[Babaron]

Since I went to 40.2.1, I’ve noticed a definite and marked improvement in regen. I mean to the point where regen is still full on with no limit even down to 27 degrees F. In fact, the only time I saw the yellow dashes was when it was parked outside in the cold for an hour or so. But taking it from my heated garage no longer limits regen. Before the update, even 50 deg outside would result in a limit, even from the garage.

 

[A-Wimoweh]

I've been noticing a reduction in regen even on 2019.36, back when it got cold back in the fall. I used to always get full regen back on the way home when driving home from work, now I don't. I've also noticed that preconditioning via the app does not preheat the battery anymore, and others have posted here that the battery heater does not work until you start driving.

This is speculation on my part, but I think that the battery heater is working all the time when parked, but very minimally, to keep the battery temp above a certain level.

They've definitely changed how it works since last year. I guess that's a good thing, they are still investing time in trying to optimize things.

 

[Max*]

Unlikely to mean anything but the battery heater was replaced 13 months ago.

I had mine replaced a few months ago. I also thought maybe it's related, until I saw this thread...

 

[Max*]

as of a recent update the battery no longer preheats when preconditioning from the app, could that be why you see a difference in regen? When I'm coming out of my warmed apartment garage I don't see any difference, but if I park outside overnight it takes a long time to get it back

No, this battery heating is a recent update (within the last year?). A lot of us have had 2-3+ winters with the car.

 

[Max*]

Random Google search on cold weather charging:

Ah yes, I get my online expertise from random Google searches too!

 

[beatle]

Since I went to 40.2.1, I’ve noticed a definite and marked improvement in regen. I mean to the point where regen is still full on with no limit even down to 27 degrees F. In fact, the only time I saw the yellow dashes was when it was parked outside in the cold for an hour or so. But taking it from my heated garage no longer limits regen. Before the update, even 50 deg outside would result in a limit, even from the garage.

What are your pack temperatures? In my experience, regen has been nerfed until the pack reaches 66-67F. My garage drops to the low 50s, but with scheduled departure, I experience no loss of regen when setting out even in sub-freezing temperatures. This is with 40.2 and 40.2.1. I have another update coming tonight beyond 40.2.1 so I will see how it goes, but I am not expecting more regen.

 

[Battpower]

I love slowing the car down with regen and one pedal driving, even if that's less efficient for whatever reason.

Me too. But if those high current charge spikes at low temperatures are going to risk trashing the battery......? We'll get it back when it's warmer, right?

Since I went to 40.2.1, I’ve noticed a definite and marked improvement in regen. I mean to the point where regen is still full on with no limit even down to 27 degrees F.

So, since you're bucking the trend, how are you measuring temp? Is that battery pack, coolant, ambient, cabin? Is it a Raven?

How about: Tesla concerned about increasing evidence of battery issues (batterygate stuff) has to limit charge (regen / sc..... whatever) especially when cold. To mitigate, they push the battery harder when it's safe to do so giving faster s/c specs and increase in range / performance for some cars as announced a month or two back.

So you are keeping your car fairly warmed through. The battery won't go cold so quickly when you take it outside, especially if you are driving and Re-genning. This is what precon should do, but Tesla may have seen that for many / most cars, more energy is used preheating than is clawed back by subsequent regen, so decided (statistically) no point doing that.

Downside, as a group some suffer because thay may have been one of the few who had a small net gain from Regen. Over all, better battery life seen as more value than keeping regen on just for a few use cases, and net energy use of the car fleet is reduced.

Again, communication from Tesla would help massively.

 

[SSedan]

I think you are too optimistic in the reduced regen being separate from batterygate. If it was an energy thing it would have rolled out sooner.

On the new heater I really don't think it related I more brought it up to say mine is good and up to date, last winter it worked as it had the year before.

If the new heater is a factor I would wonder if again an inferior part and the change was to limit warranty claims.

 

[ucmndd]

So are you suggesting something is wrong with the regen profile we have had in the Model S for 7 years from 2012 to 2019 that it necessitates taking away regen in the winter?

I think what I said in my original post, that Tesla has been tweaking this continuously (almost exclusively downward) since 2012 and this latest update is no different.

 

[sd_tom]

for me it started with 36.2.1.. coinciding with scheduled departure. i live in san diego.. it has yet to get below 40F this year ever. my non data backed impression is cold soaks at 55F or below is when i get limited regen given all the highs and lows I've been experiencing compared to yellow dashes. 4 dashes in morning is typically when the over night low is upper 40s to low 50s. last two mornings the overnight low was lower 40s (42 at this moment) and get like 6-8 dashes. parked outside
- i have tried having it plugged in or not - no difference*
- i have tried turning on/off energy saving modes.. no difference
- i have never operated the car in range mode

*i have not tried scheduled departure.. i am sure that will help, i still have it on the old start charging when super off-peak rates kick in at midnight. i dont like how they have scheduled departure setup currently.

i have not had my car through a winter before though, so feel free to discount my experience. 2016 90D AP1 refresh

 

[TIppy]

The battery heater on the Model S is 6kw, so it takes a long time to heat the battery. If you are in a hurry to heat the battery, just do a few full pedal accelerations. A ludicrous launch on a P100D causes a 90 volt drop across the battery at 1850 amp. That's 166kw. Plus you get the additional i squared r losses across the motor and inverter. Even a much more moderate acceleration of a non-performance Model S will have a 60 or 70 kw drop across the battery. As the battery begins to warm, regen will also heat the battery.

This is no more wasteful than heating the battery slowly with the 6kw heater. It's just faster.

Preconditioning might be a better choice, though, except for return trips.

 

[Battpower]

If the new heater is a factor I would wonder if again an inferior part and the change was to limit warranty claims.

In the present app, I don't see anything specifically about battery heating. Am I missing something? Since battery, external ambient, cabin and internal battery temps are potentially very different and have different significance, is battery temp / available power / regen actually visible through any standard Tesla means (without resorting to teslascan / ODB etc)

I think it's more likely any change to battery heating is because it had no overall energy saving fleet wide rather than to save replacing crappy battery heaters, but you never know!

 

[Battpower]

The battery heater on the Model S is 6kw, so it takes a long time to heat the battery. If you are in a hurry to heat the battery, just do a few full pedal accelerations. A ludicrous launch on a P100D causes a 90 volt drop across the battery at 1850 amp. That's 166kw. Plus you get the additional i squared r losses across the motor and inverter. Even a much more moderate acceleration of a non-performance Model S will have a 60 or 70 kw drop across the battery. As the battery begins to warm, regen will also heat the battery.

This is no more wasteful than heating the battery slowly with the 6kw heater. It's just faster.

Preconditioning might be a better choice, though, except for return trips.

You beat me to it. I didn't know the numbers, but exactly - just drive hard and you at least 'get something useful' (the car moves) in return for heating the battery. Also that i^2 heat is generated right inside the cells so should work quicker.

 

[SSedan]

In the present app, I don't see anything specifically about battery heating. Am I missing something? Since battery, external ambient, cabin and internal battery temps are potentially very different and have different significance, is battery temp / available power / regen actually visible through any standard Tesla means (without resorting to teslascan / ODB etc)

I think it's more likely any change to battery heating is because it had no overall energy saving fleet wide rather than to save replacing crappy battery heaters, but you never know!

How long have you been a Tesla owner?

The pack heater used to activate during cabin preheat, we could see this by miles consumed and the regen we had compared to if we didn't preheat the cabin.
I am sure a lot of us discussing this have more time in colder climates with our cars than you do.
If it was an energy savings thing wouldn't Tesla be proud of it? They don't seem to be and there are some reports a fix is coming which doesn't support the energy savings koolaid you are pushing.

 

[Battpower]

How long have you been a Tesla owner?

The pack heater used to activate during cabin preheat, we could see this by miles consumed and the regen we had compared to if we didn't preheat the cabin.
I am sure a lot of us discussing this have more time in colder climates with our cars than you do.
If it was an energy savings thing wouldn't Tesla be proud of it? They don't seem to be and there are some reports a fix is coming which doesn't support the energy savings koolaid you are pushing.

No koolaid. Playing devil's advocate to try and understand what's going on.

Not long.... To answer your question.....

I totally agree with you that from our perspectives as owners, this is Tesla reducing the performance of our cars. No question.

I am also trying to appreciate if there is any other possibly valid way of seeing this from a different perspective, even if I don't agree with it. Any comment I have made about possible 'Energy Saving' is purely comparing energy use to pre-heat vs energy recouped from subsequent regen. Not related to any other aspect of the discussion.

 

[RiverBrick]

Battery heating from the app was a thing for about two years until it stopped working for me when I "upgraded" to 40.2

Since then I've gotten 40.2.1 and 40.2.3 and it still doesn't work.

If the car is in Park the battery heater will run. So, to pre-heat the battery you need to start the car, then leave a weight on the driver's seat to fool the vehicle into thinking you're still there after you exit

 

[BrownOuttaSpec]

Would a change of the threshold of what is considered a "cold battery that needs to be warmed" be consistent to what we are seeing?

Say the old battery temp threshold pre-2019.36 was 55°F and the new threshold is 65°F, therefore the battery would need to be warmed up longer/more before regen is back to normal. I wish the patch notes would mention something like this if it were the case so we would have better expectations of how our cars would perform after an update but maybe its a legal thing so there isn't documentation that they are slowly nerfing our cars in the name of longevity (and potential warranty claims against them).

 

[Battpower]

The pack heater used to activate during cabin preheat, we could see this by miles consumed and the regen we had compared to if we didn't preheat the cabin.

This is what I understood but have not seen myself. That's why I asked the question.