Debate regarding braking, regen, and brake light illumination.

[RLXXI]

I was watching my brake lights this am on the way to work and using 2pd it never turned the brake lights on until I pressed the brake pedal, with it in 1pd just barely lifting pressure off my foot yet still pushing on the pedal, the brake lights came on immediately.

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[hturnerfamily]

exactly

Normal driving uses NO braking when simply coasting and regenerating

ONE PEDAL, though, ALWAYS uses physical braking, even at high speeds, to slow you almost abruptly, unless you 'feather' the GO pedal to minimize the effect...


thanks for the tests

 

[molsonmatt]

 

[tls]

OK as promised I did the down-the-mountain test. I was lucky enough to get a friend to drive in front of me who didn't mind a little tailgating. We did it twice.

I couldn't get the brake lights to come on from regen in 2-pedal mode without using cruise control, which is cheating. The display clearly showed the truck was regenerating, and it sped ip much more if I shifted to neutral.

Then we did 1-pedal mode. Sure enough, easing off the gas pretty much immediately slowed the vehicle and illuminated the brake lights. But I don't think it engaged the friction brakes. The displayed regen shot way up as the vehicle slowed but I never felt or heard anything that would suggest the discs and pads were involved.

To try to to get a better feel for it I set the cruise control to maximum follow distance, then overrode it with the gas pedal and got very close to my buddy. When I released the pedal, the car definitely applied the friction brakes as well as maximum regen. There was a very different feel and sound. I also tried neutral and very gently applying the brake pedal. As soon as the pedal was even slightly engaged, I could feel it in the ride of the truck and even hear it a little in the road sound. I did not detect any of this in 1-pedal mode until reaching very low speed or forcing the car to brake hard with the other experiment.

My conclusion is that the truck _can_ apply the friction brakes in 1-pedal mode but usually doesn't, and that the brake lights do come on when decellerating hard enough even just with regen. But in 2-pedal mode I couldn't cause a hard enough regen to actually trigger it.

It might be possible to know for sure using the OBD port. I don't think I care enough to try.

 

[Henry Ford]

This thread should be closed. Anyone capable of critical thought can figure out how the brake lights work in a Lightning based on this thread. There's some misinformation, but the source is pretty obvious.

 

[RocketGhost]

exactly

Normal driving uses NO braking when simply coasting and regenerating

ONE PEDAL, though, ALWAYS uses physical braking, even at high speeds, to slow you almost abruptly, unless you 'feather' the GO pedal to minimize the effect...


thanks for the tests

Which tests are you referring to? The poster above you tested brake light operation, but they didn't test or report on physical friction brake operation.

 

[Mal106]

While I can't say for sure how Ford works, I went to great lengths testing this in a Niro PHEV even to the point of extended downhill in cruise and not then measuring brake temperature.

Again, I can't say how Ford works but, without reservation, I can say how it should and thus may work. I know it has the sensors to do so. One pedal, two pedal or cruise should not matter. Braking should be regen until max regen cannot meet stopping requirements; then and only then would friction brakes are added.. Brake lights come on when deceleration is beyond the threshold of an ICE car releasing the accelerator.

I can say the brake lights work that way with the addition of the brake pedal immediately lighting the brake lights regardless.

The two common misconceptions are that the brake lights don't operate without friction lights or the pedal and that the brake pedal will not use regen.

I really wish I had a friction brake indicator from the pads themselves and a brake light indicator. Obviously need stuff that doesn't really matter.

 

[Joe.....Montana]

exactly

Normal driving uses NO braking when simply coasting and regenerating

ONE PEDAL, though, ALWAYS uses physical braking, even at high speeds, to slow you almost abruptly, unless you 'feather' the GO pedal to minimize the effect...


thanks for the tests

Several other members have shown that 1 pedal does not result in physical breaking...they did this by sharing "charging" data for 2 pedal vs 1 pedal...clearly Ford built the truck so taillights will illuminate instantly in 1 pedal...my guess would be due to 1 pedal regen "braking" far more aggressively than 2 pedal...

 

[P-38]

How does charging = not braking?

 

[Joe.....Montana]

How does charging = not braking?

Some members put their truck in different modes and pulled the data on how each mode provided different charging rates with regenerative braking.

 

[P-38]

Right but different regen rates in different modes does not mean no mechanical brakes applied

 

[Joe.....Montana]

Right but different regen rates in different modes does not mean no mechanical brakes applied

But touching brake pedal in two pedal mode also doesn't mean brakes applied...thus the brake coach informing you % returned.

 

[P-38]

Right.

I'm still confused as to how increased Regen proves no mechanical braking, you still regenerate while mechanical are engaged (assuming moving fast enough)

 

[RLXXI]

Right.

I'm still confused as to how increased Regen proves no mechanical braking, you still regenerate while mechanical are engaged (assuming moving fast enough)

Theoretical at this point. I plan to investigate this in a way that will remove all doubt, stay tuned.

 

[mr.Magoo]

I couldn't get the brake lights to come on from regen in 2-pedal mode without using cruise control, which is cheating. care enough to try.

I'm sure you could if you switch to sport mode which has a more aggressive regen profile, and thus deceleration, much like the one in 1-pedal mode.

Also worth noting is that enabling cruise-control will aslo enable 1-pedal mode (silently, you won't see it on the dash, but if you run an OBD logger you'll see it switch).
Now, I haven't verified that it still does this with BC and adaptive cruise OFF, but it definitely does it with them ON.

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