One pedal mode uses the brakes?

[WilliamG]

How do you differentiate providing power to slow down the motor vs regen braking power?

My video earlier in this thread shows it pretty damn clearly. On a downhill slope at least the car can't generate enough regen to slow the car down further, so it uses it expends energy to slow the vehicle via the motor.

Now, if you're asking how I can personally tell the difference between the two without seeing the regen bar? I can't.

 

[derotam]

It was about 20 deg over night. The dotted line was full up to the middle of the bar, and when coasting at speed, there was zero green showing no regen. Someone on here did mention that if I had the heat on (which I did) it could have possibly negated any actual regen to make it look like nothing, it's hard to say for sure.

Ok, yeah the heater could cancel out the visual. I have test data comparing full regen available power curve to a limited regen power curve. I think I had about half dots but I didn't make a note more detailed than that. Even in the limited regen data it showed regen at slower speeds. Graph here

 

[derotam]

My video earlier in this thread shows it pretty damn clearly. On a downhill slope at least the car can't generate enough regen to slow the car down further, so it uses it expends energy to slow the vehicle via the motor.

Now, if you're asking how I can personally tell the difference between the two without seeing the regen bar? I can't.

Got it, watched the video. So yes that looks like it shows using power to fight gravity. Now what we don't know in a non gravity induced scenario, is whether there really is a cold weather limited regen scenario where there is actually NO regen. From the OP's scenario of the car in >20F temps, even =20F, I am going to say that there will still be regen available at less than 10mph. I really wish I had colder temps to look at this right now.

 

[SageBrush]

So far I am loving the one pedal driving mode that is now available. But this weekend I noticed something interesting. My car had been outside all night in the cold, and when I got in to drive there was literally no regen since the battery was all cold. So driving along at normal speeds would result in coasting, as expected. However I found that if I was coasting below 7mph or so, the car would still slow to a stop.

Since the battery is too cold for regen, I assume that this slowing to a stop is being done with the brakes. I just found it interesting and a little unexpected.

I saw the brake pedal move by itself. I thought it as pretty cool

 

[RSL2020]

The “old mode” is still there - labeled as ROLL, which I prefer.

Yeah I tried that pretty quickly, but, it seemed that the previous brake-actuated "hold" function would not engage. I've used the hold feature so long that I don't even think about it... which means I may forget its not active anymore. So I set it back to 1-pedal mode.

Does the hold function work for you on "roll" mode?

 

[Big Earl]

I would not assume that at all. The motor is definitely capable of reducing power to slow the car down to 0, even on a slope. I demonstrated this in a video last week. This consumes energy at low mph.

That's even less efficient than using the brakes. Interesting.

 

[eladts]

That's even less efficient than using the brakes. Interesting.

Unless you want to generate heat in the motor to warm up the battery.

 

[WilliamG]

That is incorrect. It uses the brakes at approximately 7 miles an hour

I just tested again. It does not appear to use the friction brakes at any point until it enables Hold.

you go stick your foot behind the brake pedal using one pedal driving on the accelerator pedal and you tell me if you don’t feel the pressure before hitting zero. You will feel it the brake pedal pushers itself down long before you hit zero

No. I don’t feel any pedal movement until it enables Hold. I’m out right now and testing this over and over on flat roads and hills. It uses the regen + motor (non-regen) to slow down on downhill slopes, and just regen and no motor (that I can tell) on flat surfaces/uphills. There is no friction braking at any point that I can feel through the pedal, until Hold enables, which is really easy to feel.

 

[nvx1977]

I also tested the brake pedal while coasting to a stop and felt absolutely no movement.

 

[WilliamG]

I also tested the brake pedal while coasting to a stop and felt absolutely no movement.

And yet I have so many dislikes to my first post where I stated this. Go figure.

 

[HelixSpiral]

Yeah I checked this on my way home tonight. Stuck my foot behind the brake pedal and held the pedal up. Car stopped with regen only and the pedal didn't try to move until Hold activated at 0 mph.

 

[timk225]

Even if it is using the brakes for the last little bit of coming to a stop, so what? That's a lot less brake wear then bringing it down from 40 or more mph all the way to zero.

 

[RSL2020]

Yeah I tried that pretty quickly, but, it seemed that the previous brake-actuated "hold" function would not engage. I've used the hold feature so long that I don't even think about it... which means I may forget its not active anymore. So I set it back to 1-pedal mode.

Does the hold function work for you on "roll" mode?

Update, hold does work on "roll" mode just as before. Sorry for the misinfo.

 

[PalmBeachPaul]

I have to say I like the one pedal feature for normal driving but hate it for backing up. When I pull out of my garage, I need to navigate around another car in my driveway, I miss the coasting and braking of the original mode compared to this. Assuming we get 0.0001% regen from backing up, it would be nice if it used traditional braking in reverse. Does anyone else agree or is it just me?

 

[destructure00]

It also doesn't say whether there is any blending of regen and physical brakes.

It's right there on the screen.

 

[noicepls]

I have to say I like the one pedal feature for normal driving but hate it for backing up. When I pull out of my garage, I need to navigate around another car in my driveway, I miss the coasting and braking of the original mode compared to this. Assuming we get 0.0001% regen from backing up, it would be nice if it used traditional braking in reverse. Does anyone else agree or is it just me?

Agreed. "Hold" mode should be disabled momentarily during reverse/backup movements. As it is currently, the car fights with normal progression, instead of helping it

 

[gavine]

My video earlier in this thread shows it pretty damn clearly. On a downhill slope at least the car can't generate enough regen to slow the car down further, so it uses it expends energy to slow the vehicle via the motor.

Now, if you're asking how I can personally tell the difference between the two without seeing the regen bar? I can't.

The energy meter showing power usage could be the cabin heater which can get over-ridden by regen which is why it looks like you're using power when you get below a certain speed. Or, if you are navigating to a supercharger, the battery preconditioning will also show power usage on the meter. I would be VERY surprised if the car is using energy to slow the car when it can easily use the friction brakes instead.

 

[derotam]

It's right there on the screen.
View attachment 479070

First, what you quoted from me was in response to what is in the manual so lets keep context of quotes in tact please.

Second, in response to your picture, it says it blends the brakes to HOLD the vehicle. That does not indicate blending to SLOW the vehicle from say "7mph" as per the OP.

 

[derotam]

The energy meter showing power usage could be the cabin heater which can get over-ridden by regen which is why it looks like you're using power when you get below a certain speed. Or, if you are navigating to a supercharger, the battery preconditioning will also show power usage on the meter. I would be VERY surprised if the car is using energy to slow the car when it can easily use the friction brakes instead.

It could but first, I don't think that much black could be attributed to cabin heat especially the amount he was even possibly using in the video(54F outside temp, HVAC on manual 68F, and 1 bar of driver seat heat). Second, the power indication went away after the car stopped, the cabin heater doesn't just go off and on like that...normally.

 

[lolder]

The energy meter showing power usage could be the cabin heater which can get over-ridden by regen which is why it looks like you're using power when you get below a certain speed. Or, if you are navigating to a supercharger, the battery preconditioning will also show power usage on the meter. I would be VERY surprised if the car is using energy to slow the car when it can easily use the friction brakes instead.

I think the last few mph the car may be using reverse "regen" to slow the car and then put on the rear brakes for hill hold when completely stopped. That would explain strange wrong direction behavior reported on steep hills.