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This is a new one...reduced acceleration, warm battery, high SOC

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
Happened for the first time since I’ve owned the car. Left work tonight. It’s 32F and car sat for a couple hours after I ran out for dinner. It was misting and kind of freezing on the cars so I defrosted/pre-heated the car for about 5 mins prior to going outside. When I departed work I noticed that I had reduced power dots on the power bar. I did not have any reduced regen dots which always pop up when the battery is cold. As you can see in the picture, My SOC isn’t a problem. I’ve only ever seen reduced power dots when the battery gets extremely cold and basically all regen is lost or when the SOC drops under 25-30%. Anyone ever seen this before or have any idea why the car would be reducing power?

B8A7A190-596C-426C-B5B6-7E070CDAF4C3.jpeg
 
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Gasaraki

Active Member
Oct 21, 2019
1,668
1,070
Syracuse, NY
You get reduced power when the battery is cold also. But that usually happens when the state of charge is low AND it's cold.

I'm assuming that went away after a few minutes...
 
Last edited:

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
You get reduced power when the battery is cold also. But that usually happens when the sate of charge is low AND it's cold.

I'm assuming that went away after a few minutes...


I know. Battery wasn't cold, as I didn't have any reduced re-gen. That always goes first and acceleration goes second. This did not go away after a few miles. It was the same for my whole ride home. I posted this because I've never seen reduced power when I didn't have reduced regen unless the battery was warm and at a low SOC. All that said, the situation seems to have resolved itself. I charged to 90% overnight in my garage (60F) and now I'm showing 8 regen dots and zero power dots.
 

Gasaraki

Active Member
Oct 21, 2019
1,668
1,070
Syracuse, NY
I know. Battery wasn't cold, as I didn't have any reduced re-gen. That always goes first and acceleration goes second. This did not go away after a few miles. It was the same for my whole ride home. I posted this because I've never seen reduced power when I didn't have reduced regen unless the battery was warm and at a low SOC. All that said, the situation seems to have resolved itself. I charged to 90% overnight in my garage (60F) and now I'm showing 8 regen dots and zero power dots.
Weird.
 

GtiMart

Member
Nov 13, 2019
854
698
Quebec City, Canada
2021.4.11 brought along changes to regen on a cold battery. We now get more regen at low temps than before. Now you might have full regen (85kW) with a 13C battery whereas before it would have required 21C. Maximum battery "output" continuously varies depending on SOC and battery temp, among other things. Historically that energy bar has not been very precise. My AWD+ should output something like 330kW max but even with a 250kW max output value in ScanMyTesla, I normally see no dots on the acceleration side.
You're at 68% SOC, your maximum power output is lower than if you were at say 90% SOC. Maybe they have changed the rendering of the power bar so it more closely matches reality? I'll try to check mine if I use my car soon.
 
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M109Rider

Active Member
Apr 8, 2018
1,541
1,585
Kitchener, Ontario
2021.4.11 brought along changes to regen on a cold battery. We now get more regen at low temps than before. Now you might have full regen (85kW) with a 13C battery whereas before it would have required 21C. Maximum battery "output" continuously varies depending on SOC and battery temp, among other things. Historically that energy bar has not been very precise. My AWD+ should output something like 330kW max but even with a 250kW max output value in ScanMyTesla, I normally see no dots on the acceleration side.
You're at 68% SOC, your maximum power output is lower than if you were at say 90% SOC. Maybe they have changed the rendering of the power bar so it more closely matches reality? I'll try to check mine if I use my car soon.

I’ve definitely seen a change in the battery preconditioning. I haven’t exactly been able to figure out how it determines when to precondition though. Time will enlighten me I’m sure.
I suspect your scenario (reduced power dots) has something to do with it. This is a pretty new change, so it could be just a bug as well.
I’m sure it’s methods will eventually make more sense as we move along.
I do like the new change though.
 

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
2021.4.11 brought along changes to regen on a cold battery. We now get more regen at low temps than before. Now you might have full regen (85kW) with a 13C battery whereas before it would have required 21C. Maximum battery "output" continuously varies depending on SOC and battery temp, among other things. Historically that energy bar has not been very precise. My AWD+ should output something like 330kW max but even with a 250kW max output value in ScanMyTesla, I normally see no dots on the acceleration side.
You're at 68% SOC, your maximum power output is lower than if you were at say 90% SOC. Maybe they have changed the rendering of the power bar so it more closely matches reality? I'll try to check mine if I use my car soon.
I'll watch it again today, but I doubt it does it again the same way. It's been a while since I last updated and I've had the SOC down to about 40% and haven't seen reduced power indicated in the power bar at all until last night. I'm guessing it's a bug.
 

GtiMart

Member
Nov 13, 2019
854
698
Quebec City, Canada
I've gone for a drive today and I have not witnessed what you are showing here. Initially I had no regen and limited power as my battery was at -5.5C (outside temp was -4C). I had only 92kW of maximum discharge power, which equates to around 120hp. Let's just say the car was slow. As battery temp rose, regen came back and power went up. At 70-74kW of regen, all the regen dots had disappeared. Note that max regen on my car is 85kW so the display tricks us a little. On the power side, dots disappeared as I reached ~200kW of max discharge. I'm not sure what the theoretical max discharge is at ~70% battery, I'll need to look that up. I know at best I can output ~330kW. You can see that here too, the power bar tricks us...
Still, I have not see dots on power without dots on regen.
 

Phlier

Bluebird
Jun 12, 2019
1,475
1,852
Utah
Battery wasn't cold, as I didn't have any reduced re-gen.
That's not quite right....

Reduced regen if a function of battery temp AND state of charge. The higher the battery charge, the higher the temperature at which you'll get reduced regeneration. The lower the battery charge, the lower the temperature at which you'll get reduced regeneration.

I've gotten into my car on very cold mornings (temperature around 20F), with a battery at a low state of charge (mine was 20% that morning) and had zero regen dots.

You gotta remember the BATTERY STATE OF CHARGE and not just the temperature when thinking about reduced regen.

You were at a relatively low battery SoC in the picture (68%). With the combination of temperature and SoC you had, you got the exactly appropriate display: Warm enough battery with a relatively low state of charge to not get regen dots, and also a low enough battery temperature and state of charge to get reduced power.

Your picture shows a perfectly healthy and correctly functioning car.
 

KenC

Active Member
Sep 4, 2018
3,553
3,217
Maine
That's not quite right....

Reduced regen if a function of battery temp AND state of charge. The higher the battery charge, the higher the temperature at which you'll get reduced regeneration. The lower the battery charge, the lower the temperature at which you'll get reduced regeneration.

I've gotten into my car on very cold mornings (temperature around 20F), with a battery at a low state of charge (mine was 20% that morning) and had zero regen dots.

You gotta remember the BATTERY STATE OF CHARGE and not just the temperature when thinking about reduced regen.

You were at a relatively low battery SoC in the picture (68%). With the combination of temperature and SoC you had, you got the exactly appropriate display: Warm enough battery with a relatively low state of charge to not get regen dots, and also a low enough battery temperature and state of charge to get reduced power.

Your picture shows a perfectly healthy and correctly functioning car.
Interesting, I'll keep a closer eye on my car, but I set my SOC for 60%. This winter, fairly cold, I've always gotten maximum regen dots, unless I precondition, then I only get 5 to 7 dots. Never seen the reduced power dots.
 

Phlier

Bluebird
Jun 12, 2019
1,475
1,852
Utah
Interesting, I'll keep a closer eye on my car, but I set my SOC for 60%. This winter, fairly cold, I've always gotten maximum regen dots, unless I precondition, then I only get 5 to 7 dots. Never seen the reduced power dots.
The reduced regen and reduced power logic vary according to model. I see the no regen dots but reduced power dots semi-frequently in my stealth Performance.

The LR AWD is capable of pulling more power than the single motor cars, and the Performance cars can pull more power than the LR AWD cars. Hence you will get reduced power sooner in the Performance cars before you would the LR AWD, and in the LR AWD before the single motor variants assuming the same conditions for each.
 
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GtiMart

Member
Nov 13, 2019
854
698
Quebec City, Canada
Makes sense @Phlier . I'll just emphasize that the "energy bar" with the dots is not a precise indication. In my AWD+boost which might have a max of ~330kW output, dots start appearing only when under ~200kW of max discharge power. I can get under 200kW easily with low temperatures, but I could also get there from a low SOC indeed. With that said, 68% is not low, that's where I was at lunch today, and the situation indicated here didn't happen.
 

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
That's not quite right....

Reduced regen if a function of battery temp AND state of charge. The higher the battery charge, the higher the temperature at which you'll get reduced regeneration. The lower the battery charge, the lower the temperature at which you'll get reduced regeneration.

I've gotten into my car on very cold mornings (temperature around 20F), with a battery at a low state of charge (mine was 20% that morning) and had zero regen dots.

You gotta remember the BATTERY STATE OF CHARGE and not just the temperature when thinking about reduced regen.

You were at a relatively low battery SoC in the picture (68%). With the combination of temperature and SoC you had, you got the exactly appropriate display: Warm enough battery with a relatively low state of charge to not get regen dots, and also a low enough battery temperature and state of charge to get reduced power.

Your picture shows a perfectly healthy and correctly functioning car.
I understand that re-gen is a factor of both temp and SOC (though besides @ 85%+ the battery level doesn't affect regen in my experience) 68% is NOT a low SOC. When I left work it was @ 72% SOC and already had the power dots but no re-gen dots. My point was that my car has never behaved like this before. I've never seen reduced power dots anywhere above 30% SOC unless the battery we extremely cold also resulting in basically zero re-gen. There is nothing "normal" about nerfed power output at around 70% SOC with a battery that isn't freezing cold.

To add to that, I ran basically the same situation tonight. I just left work a bit ago. Ambient temps were about 3 degrees warmer than last night (36F) and car was at 73% SOC. In contrast to last night, tonight I had 5 re-gen dots that did not disappear the whole way home and zero power dots down to 69% SOC.

So the car behaved completely differently in nearly identical situations. What happened tonight is what has consistently happened since I purchased the car in 2019. Last night was the aberration.
 

Phlier

Bluebird
Jun 12, 2019
1,475
1,852
Utah
@vogz Also keep in mind that Tesla is always messing around with the trip points for pulling power and regen. It seems like the latest few firmware revisions have had revisions to the logic used for regen and power pulling. You're bound to see different indications in similar conditions with these changes.
 

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
@vogz Also keep in mind that Tesla is always messing around with the trip points for pulling power and regen. It seems like the latest few firmware revisions have had revisions to the logic used for regen and power pulling. You're bound to see different indications in similar conditions with these changes.
Understood. Just weird that it only happened once.
 

Candleflame

Active Member
Mar 9, 2015
2,768
1,282
QLD, Australia
I know. Battery wasn't cold, as I didn't have any reduced re-gen. That always goes first and acceleration goes second. This did not go away after a few miles. It was the same for my whole ride home. I posted this because I've never seen reduced power when I didn't have reduced regen unless the battery was warm and at a low SOC. All that said, the situation seems to have resolved itself. I charged to 90% overnight in my garage (60F) and now I'm showing 8 regen dots and zero power dots.

you still have reduced power even if you have full regen. nothing unusual here.
 

vogz

Member
Dec 5, 2019
258
341
Batavia, IL
you still have reduced power even if you have full regen. nothing unusual here.

In 10K miles of driving this car in weather conditions from -5F to 98F I've never had the above situation happen. I know you can have reduced power if you have full regen. That situation has only happened to me if the SOC is UNDER 30%. (I also know that full power above 60mph reduces in a linear manner as the SOC drops. That wasn't what happened) I understand how battery temp, SOC and regen/power output work these cars and the situation I had cut against everything that I'd experienced for a year plus of ownership. That's why I posted about it. All that said, it hasn't happened again. Since that night, I haven't had any reduced power indication on the power bar in any situation all the way down to 40% SOC so it clearly was unusual.
 

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