Car is back (yeah) and learned something about one-pedal drive

[MightyMike]

So I finally got my car back. By my calculations the car was in the dealer for about 11 weeks, of which only 1 week was 'active' service time. The rest was waiting for parts (3 parts, 2 weeks, 8 weeks, and 1 or 2 days). HVBJB replacement was standard, no problem. The surprise was the main battery harness. It needed replacing (still not sure why), and that part was back ordered for 8 weeks.

Once that came in we were slightly delayed due to a misunderstanding that the rear connector has to be replaced when you unplug the harness (apparently it is a one-time use part...good to know, because I don't think the ford documentation is clear on the one-use nature of the connector).

Either way that was sorted, and my car is (finally) back in my hands. I have to say my dealer has been excellent. Although I got hit by supply chain issues and there was nothing I could do, they kept me in the loop.

One final wrinkle occurred when I drove out of the lot. I heard a thump-thump-thump in the brakes. The car had sat for 12 weeks not moving, so some rust had built up. No problems. What was interesting was when I put it in one-pedal drive and got up to highway speeds and then let off the accelerator, and I heard the thump-thump-thump.

What that means to me is that one-pedal braking for speeds higher than 30 mph (it didn't happen at low speeds) does apply some physical braking even if you never touch the brake pedal. That was interesting I thought and figured I would pass it along.

Anyway -- So glad to be back!

Mike

Sponsored

 

[CurtW]

Maybe the "rust" is in the regen, not the disc brakes...? At highway speed, if this is build up on disc brakes, the frequency would be much higher, more of a vibration than a thump.

 

[JamieGeek]

Yup Ford confirmed that waaaay back before anyone got their cars. 1-P does engage the friction brakes.

 

[dtbaker61]

Yup Ford confirmed that waaaay back before anyone got their cars. 1-P does engage the friction brakes.

when ?

with all decelleration events at all speeds, or only if battery is full and cannot accept more regen?

 

[JamieGeek]

when ?

with all decelleration events at all speeds, or only if battery is full and cannot accept more regen?

Well way back when they simply said that 1-P uses the friction brakes. They didn't specify exactly when that happens (other than saying 1-P will bring the car to a complete stop with the brakes).

Ford hasn't exactly been that forthcoming with exact details on the cars operation so I would expect the same level of info about 1-P as they have provided about the other methods of operation (e.g. vague statements and assertations).

 

[JohnFoxeSheets]

Well way back when they simply said that 1-P uses the friction brakes. They didn't specify exactly when that happens (other than saying 1-P will bring the car to a complete stop with the brakes).

Ford hasn't exactly been that forthcoming with exact details on the cars operation so I would expect the same level of info about 1-P as they have provided about the other methods of operation (e.g. vague statements and assertations).

I believe that the use of friction brakes during 1PD driving is limited to situations where regen will not provide sufficient braking power (as determined by how hard the driver is pressing the brake pedal). I’ve read her on this forum that only regen breaking is used when the accelerator pedal is lifted, but ??‍

 

[Logal727]

Yes it’s always been blended braking in 1PD

 

[Blue PonyE]

I've had my rear brakes repaired twice (job 1 car) due to the brake pads "welding" to the disc when parked while wet after using the parking brake. In Seattle, who knew it rained?
Driving breaks off a piece of the pad causing a repeated grinding noise. The "welded" portion gets removed when driven. There is a TSB for this.

Your noise may be due to the length of time the vehicle was parked. Have your pads inspected.

 

[SnBGC]

Well way back when they simply said that 1-P uses the friction brakes. They didn't specify exactly when that happens (other than saying 1-P will bring the car to a complete stop with the brakes).

Ford hasn't exactly been that forthcoming with exact details on the cars operation so I would expect the same level of info about 1-P as they have provided about the other methods of operation (e.g. vague statements and assertations).

I agree. The 1PD programming is something that Ford protects as proprietary information. As such, don't expect to hear many details as to when and why.

As to the OP's question...
There are times where Ford thinks it is best to conserve the kinetic energy in the rotor and use the friction brakes instead. This situation is more likely at higher speeds.

Many manufacturers have similar programming ideas. Which isn't surprising since many manufacturers share tier 1 suppliers for EV components including the base programming.

 

[superdave80]

Maybe the "rust" is in the regen,

Isn't the regen just using the motor as a generator? What would not be used that would 'rust'?

 

[superdave80]

I believe that the use of friction brakes during 1PD driving is limited to situations where regen will not provide sufficient braking power (as determined by how hard the driver is pressing the brake pedal). I’ve read her on this forum that only regen breaking is used when the accelerator pedal is lifted, but ??‍

If you are using 1PD, braking is engaged the moment you let off the accelerator, so there is no 'how hard the drivers is pressing the brake pedal' to determine anything.

 

[AllenXS]

The key thing is that brakes are applied and you stop in time!
Great to have your car back.
Wondering if they hurt the battery frame when taking the battery off, but if so that’s part of their learning curve and they get it right next time.

 

[CurtW]

Isn't the regen just using the motor as a generator? What would not be used that would 'rust'?

I don't know much about how the regen functions, but I know letting off the pedal does not engage this unless you are in 1P mode, so there is something that engages, etc. My main point is at different speeds, the brakes would not thump at the same rate. The original post made me think the thump was same, slow or fast.

 

[BigMach-E]

When you had failure, what was the situation? Ambient temp, DCFC, elevation change, distance traveled, current mileage?

 

[Chainspell]

Did you try turning off 1PD and seeing if the noise persisted?

Sponsored