Debate regarding braking, regen, and brake light illumination.

[tls]

The behavior may be different in 2-pedal mode. If so, it will just approximate what a truck with a manual transmission would do when jake (engine) braking.

I will drive down the mountain after dark tomorrow (I am in the flatlands today) and find out.

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[hturnerfamily]

this is not correct unless i am misunderstanding what you are saying. Say i am on the highway at speed (one pedal driving) and i take my foot all the way off the accelerator, I can literally see my brake lights light up the instant my foot comes off. my tesla did this, every EV that has one pedal I believe does this. It would be so dangerous if they didn't.

correct, BUT, you are referring to ONE PEDAL mode, which ALWAYS applies the brakes, and REGEN, to bring the vehicle to a complete STOP. Of course, yes, the brake lights will illuminate.

I am referring to REGEN, only... it does not, and NEVER applies the brakes, no matter how fast, how slow, or even if you 'creep'.... ONLY you, the driver, will apply the physical brakes, in this mode, and only THEN will the brake lights illuminate.

TEST IT.

 

[hturnerfamily]

The behavior may be different in 2-pedal mode. If so, it will just approximate what a truck with a manual transmission would do when jake (engine) braking.

I will drive down the mountain after dark tomorrow (I am in the flatlands today) and find out.

good idea, as I've come 'down' many mountain ranges, such as west of Franklin NC, and north of Helen, GA, the Lookout Mt range in N Alabama, etc... the REGEN is a wonderful way to manage your speed, without brakes, and to have more of a 'controlled' descent... even with a camper in tow.

Try it in NORMAL mode, which will have a slight amount of REGEN,
then TOW mode, with a little more,
then with SPORT mode, for the most....

remember, too, that you are simply 'slowing', you are not applying the physical brakes, so there is no signal to any brake lights...

 

[LazyLightningATX]

good idea, as I've come 'down' many mountain ranges, such as west of Franklin NC, and north of Helen, GA, the Lookout Mt range in N Alabama, etc... the REGEN is a wonderful way to manage your speed, without brakes, and to have more of a 'controlled' descent... even with a camper in tow.
I am referring to REGEN, onlywhich will have a slight amount of REGEN,
then TOW mode, with a little more,
then with SPORT mode, for the most....

remember, too, that you are simply 'slowing', you are not applying the physical brakes, so there is no signal to any brake lights...

I am referring to REGEN, only

got it, so i was misunderstanding i have literally never turned one pedal off since i got the truck, so, this is not an issue for me.

but, ya, if you idle an ICE all the way through town at low speed and make slow turns, its brake lights will never come on either...kind of like what you described above.

i used to drive a manual golf-r and in traffic and i would see how long i could go without using the brakes!

 

[tls]

Just FWIW, not only Teslas but also many ICE cars will illuminate the brake lights at a decelleration threshold, whether the friction brakes are engaged or not. This all started decades ago with a recall of early BMW X-Drive vehicles which were getting rear-ended because the X-Drive cruise control could decellerate _hard_ using only engine compression, and not illuminate the brake lights...

 

[TaxmanHog]

the ONLY way brake lights illuminate is by PHYSICAL braking, not by Regen...never. TEST IT.

We've tested this before, and proved you wrong then , why perpetuate the farce?

 

[Joe.....Montana]

We've tested this before, and proved you wrong then , why perpetuate the farce?

You say potato I say patato....we can both hold onto our own realities....(heavy does of sarcasm).......

 

[Henry Ford]

"I reject your reality and substitute my own!"

- Adam Savage

 

[Henry Ford]

There should be a way to turn regen off then those who are confused by the system can have their basic brakes.

There's nothing to be confused about. The brake pedal always slows the vehicle down. Who cares why the brake pedal slows the vehicle down?

Letting off the accelerator pedal always* slows the vehicle down. The only difference between one pedal mode and two pedal mode is the rate at which the vehicle slows. Again, who cares why the vehicle slows down?

I don't need to know if my engine has six cylinders or eight to drive a car.

* Ignoring gravity

 

[TaxmanHog]

This thread contains posts originally found on the following thread

Truck accelerated from stop and rear ended car in front.

Please keep all posts regarding the braking functionality here while leaving the other thread for discussion about unintended acceleration while stopped in traffic.

 

[bmwhitetx]

I think when @hturnerfamily says REGEN Only, he means "Two-pedal mode".

If so, then all of you are in violent agreement. Like the ICE F-150, two-pedal mode does not turn on the brake lights unless the brake is pressed (or when Auto-Hold engages).

 

[RocketGhost]

correct, BUT, you are referring to ONE PEDAL mode, which ALWAYS applies the brakes, and REGEN, to bring the vehicle to a complete STOP. Of course, yes, the brake lights will illuminate.

I am referring to REGEN, only... it does not, and NEVER applies the brakes, no matter how fast, how slow, or even if you 'creep'.... ONLY you, the driver, will apply the physical brakes, in this mode, and only THEN will the brake lights illuminate.

I think there's been miscommunication and people have been talking about two different things while others think we're talking about the same thing.

One-pedal is a regen mode. That's how it slows the vehicle down. Regen also happens, sometimes, when coasting in two-pedal mode. When OP is talking about "regen" he's talking about when coasting in two-pedal mode (I think).

Coasting in two-pedal mode does not always perform regen. I just went for a drive and paid attention to the power meter. At times I coasted and no regen was taking place. In my observations it depends on speed and inertia and maybe other factors.

Coasting in two-pedal mode when regen is happening probably never activates the brake lights. In one-pedal mode the truck will activate the brake lights if deceleration is above a threshold. If you slightly let off the pedal and slowly decelerate the lights won't come on. I say the lights "probably" won't activate when coasting and regenerating in two-pedal mode because 1) the truck is programmed to only activate the lights upon pressing the brake pedal in two-pedal mode, and/or 2) the regen force is never enough to decelerate above the activation threshold.

When pressing the brake pedal the truck uses blended braking. It uses a combination of regen drag and friction brakes to slow the truck. However, I do not know if pressing the brake pedal always uses friction brakes. Maybe slightly pressing it only uses regen to slow the truck. Without confirmation from Ford there's really no way to know. The brake lights will come on when the brake pedal is pressed in all situations. Just because the light comes on doesn't mean the friction brakes are being applied. We can't feel or watch the friction brakes. If you slam the brake pedal you know the friction brakes are being applied because intuitively we know regen alone can't stop the truck that quickly. But barely pressing the pedal? We don't know.

In one-pedal mode, we likewise don't know for sure that friction brakes are always applied. The brake lights come on when deceleration is above a threshold. If friction brakes are applied the lights will almost certainly come on because that means you are decelerating faster. But it's not necessarily true that one-pedal always uses friction brakes, and I highly suspect that it's not. It wouldn't make sense for the friction brakes to be applied when slightly letting off the go pedal if regen alone can slow the truck just a little bit as the driver intends. And regen alone may provide an intended deceleration that activates the brake lights but not the friction brakes.

 

[hturnerfamily]

Coasting in two-pedal mode when regen is happening probably never activates the brake lights.

When pressing the brake pedal the truck uses blended braking.

...pressing the brake pedal always uses friction brakes. Maybe slightly pressing it only uses regen to slow the truck. Without confirmation from Ford there's really no way to know. The brake lights will come on when the brake pedal is pressed in all situations. Just because the light comes on doesn't mean the friction brakes are being applied. We can't feel or watch the friction brakes. If you slam the brake pedal you know the friction brakes are being applied because intuitively we know regen alone can't stop the truck that quickly. But barely pressing the pedal? We don't know.

In one-pedal mode, we likewise don't know for sure that friction brakes are always applied. The brake lights come on when deceleration is above a threshold. If friction brakes are applied the lights will almost certainly come on because that means you are decelerating faster. But it's not necessarily true that one-pedal always uses friction brakes, and I highly suspect that it's not. It wouldn't make sense for the friction brakes to be applied when slightly letting off the go pedal if regen alone can slow the truck just a little bit as the driver intends. And regen alone may provide an intended deceleration that activates the brake lights but not the friction brakes.

I've corrected your assumptions. TEST IT.

 

[RocketGhost]

I've corrected your assumptions. TEST IT.

As I discussed, whether friction brakes are applied cannot be tested by a driver. The only way to know, for sure, is to have knowledge directly from Ford on the design and programming of the truck, or set up some sort of experimental condition that directly monitors the physical movement of the friction brakes (e.g. a camera, sensor, etc.). There may also be ways to read braking information in real-time with a diagnostic tool.

How do you know, with absolute certainty, that 1) applying the brake pedal always uses friction brakes, and 2) one-pedal always applies friction brakes? What was your test method?

 

[TaxmanHog]

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