[UPDATED with Ford Norway's Response] Reports of Steep Downhills / Descents Overheating Mach-E

[DanCoon]

I don't know, but there has been at least one report that shifting to neutral while coasting downhill keeps the regen from engaging, and they didn't have problems with the long, hot descent.

Like Tim, I'm on the east coast, and while I've got a mountain range to cross to get to civilization, it's a very tiny mountain range in comparison. Won't be an issue for me, I'm sure.

I used this technique to get from Phoenix to Las Vegas, and Las Vegas through Death Valley... shifting from N to D to maintain a good speed while also taking advantage of regen. I didn't run into any problems. For reference, on the steepest downhill I encountered in Death Valley I was able to regen 6%. I was in Engage mode with 1 pedal turned off.

It's my assumption that regen isn't engaged while in Neutral because any time you use the brake peddle I can feel the pads grip the rotors.

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[AZBill]

The most likely cause of this is that regen going down the hill is overheating the motor(s), nothing to do with brakes. Turn off low gear and one-pedal and it will have less regen, thus less KW through the motor, thus lower heat levels. Also I recommend whisper mode for highway driving, especially in hot temperatures like here in Arizona.

The battery is designed to take sustained high KW power for fast charging. The motors are not designed to provide that high KW power for long periods. Once you accelerate a car and get it to a steady speed it drops the power consumption.

 

[Shayne]

The most likely cause of this is that regen going down the hill is overheating the motor(s), nothing to do with brakes. Turn off low gear and one-pedal and it will have less regen, thus less KW through the motor, thus lower heat levels. Also I recommend whisper mode for highway driving, especially in hot temperatures like here in Arizona.

The battery is designed to take sustained high KW power for fast charging. The motors are not designed to provide that high KW power for long periods. Once you accelerate a car and get it to a steady speed it drops the power consumption.

Where they were descending the speed must be minimal as it looks like a ride your brakes descent and not at speed. You would think 30 mph down this mountain can't generate to much heat? I know the brake pads/rotors could get red hot in these conditions and I guess the motors are the brake pads in this case.

 

[EVmodeler]

Where they were descending the speed must be minimal as it looks like a ride your brakes descent and not at speed. You would think 30 mph down this mountain can't generate to much heat? I know the brake pads/rotors could get red hot in these conditions and I guess the motors are the brake pads in this case.

Brakes turn mechanical power into heat 100%. Motors as generators turn mechanical power into 90+% electric power to the battery and less 10% into heat. So this may be a battery power acceptance problem, but as noted the system is designed for DCFC power levels.
The motors are not brake pads.

 

[JoeDimwit]

Ford needs to start releasing these bug fixes OTA to fix all of these issues with this car. When it bricks the car that should be an emergency release.

And if the emergency “fix” accidentally bricks other cars? They need to take a minute or two to insure they don’t turn a thousand cars into fancy paperweights.

 

[jlauro]

And if the emergency “fix” accidentally bricks other cars? They need to take a minute or two to insure they don’t turn a thousand cars into fancy paperweights.

Exactly, they don't want to rush the job and turn a problem that impacts 0.1% of vehicles to something that impacts 10%.

 

[mr_raider]

Whisper mode has very little regen. That with one pedal off should do it.

 

[Kamuelaflyer]

yikes. thank goodness most of NJ is flat

Gives me pause to think about the drive to Kona where I’m averaging 7.1 or higher.

 

[dbsb3233]

Whisper mode has very little regen. That with one pedal off should do it.

Unless you touch the brake pedal. Which you probably will be if it's a steeper downhill than coasting grade.

At least that's my understanding - that the brake pedal still uses regen first, and only adds on friction braking if you max out regen (regardless of drive mode).

 

[Shayne]

Brakes turn mechanical power into heat 100%. Motors as generators turn mechanical power into 90+% electric power to the battery and less 10% into heat. So this may be a battery power acceptance problem, but as noted the system is designed for DCFC power levels.
The motors are not brake pads.

Kind of what I thought also. Wire size, fried a board/module? I hope it reveals that there is a software fix as the article noted and the car was smart enough to shut itself down prior to any damage. I understand it was/is an inconvenience for those effected right now but motors or other damage would be worse on top of being stranded. 6 all the same place at least we know they are all designed and running the same as they behaved all the same way. I guess you can not point at the driver when there were 6. Most likely this condition was not tested. It is hard to run a vehicle through every condition possible prior to releasing it. It is hard to come up with every possible condition even if you wanted to. Few bumps but ford reacted quickly to a 12V and I think we will see the same here. A SSM will come out months after those effected are fixed maybe? Do SSM happen as often when OTA is up and running?

Still would be good to know exactly what happened and if user input (best practices) can help minimizing it. Like take 1P off or something? Understood that just regens with the brake pedal and not the accelerator? Different pedal same outcome?

Gives me pause to think about the drive to Kona where I’m averaging 7.1 or higher.

But what is it coming back? Most likely down hill both ways for the lucky Hawaiian's.

 

[Frankie]

The most likely cause of this is that regen going down the hill is overheating the motor(s), nothing to do with brakes. Turn off low gear and one-pedal and it will have less regen, thus less KW through the motor, thus lower heat levels.

"Turn off 1PD and there's less regen" isn't true in this scenario.

If you're going down a hill that requires say 5 kw of regen to maintain a given speed, it does not matter whether that regen is applied with 1PD or by using the brake pedal. The Mach e is not a Tesla, the brake pedal increases regen unless you step on it so hard that it engages the friction brakes.

Similarly if you're "coasting" down the hill i.e. not regening at all, it also doesn't matter whether you do it via being in 1PD and feathering the throttle, or not being in 1PD and just not touching the brake.

 

[Frankie]

Understood that just regens with the brake pedal and not the accelerator? Different pedal same outcome?.

Exactly.

 

[Kamuelaflyer]

But what is it coming back? Most likely down hill both ways for the lucky Hawaiian's.

Uphill both ways.

Regen on the descent results in miles per kWh ranging from the 7’s to as high as 10.1. I usually lose about 3% soc in the first 4 Mike’s of a trip to Kona. By the time I get to the bottom of the cross island highway, I’ve regained all of that loss. If I’m driving close to the speed limit, there’s enough rolling hills trending downwards that the 40 mile drive results in a loss of 6 to 7%.

The return? 2.1 to 1.6. This is why the GOM is stuck at 220.

 

[Christina]

This was a pretty interesting article and reveals a similar issue to some of our friends in the West on steep mountain descents. Apparently in the last 14 days, six Mach-Es have bricked themselves from the heat generated during long downward slopes in this one little town. Ford has said that a patch will fix it, but it's currently only available at service centers and won't be OTAed until Sep/Oct.

https://translate.google.com/translate?hl=&sl=auto&tl=en&u=https://motor.no/bil/slik-skal-ford-fikse-mustanger-som-matte-berges-i-bakkene-ned-til-geiranger/204431

I'm in California. Should I call my local dealer and ask for a service appointment?

 

[DenverDan]

Just did a mountain trip up 285 and I-70 over 3 different passes with no issues. Car was great the whole time. Regen was exceptional on downhills used only 12% battery to go from Frisco to Denver. I had the car in the following settings one pedal, adaptive cruise, lane keeping, and was in unbridled.

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