WOT Poll - How often do you use wide open throttle?

[PilotMark]

The HV contactors are shown in the snap below taken from Munro's Live video "Mach-E Battery Exposed." Potting the contactor electrodes in an Inert environment prolongs their life by preventing chemical reactions with corrosive elements in the environment and shortening their life.

Contactors are standard elements in motor control systems in industrial applications, so the tech isn't that unknown. You can readily find these components with a google search and you will find the coils and electrodes are potted in some type of polyethylene enclosure with the circuit terminals protruding.

Other than people's opinion, I've not read anything on this forum that definitively supports the conclusion that the problem is with the contactor electrodes.

As I have understood things, the contactors have failed in both the open and closed positions, which could point to issues with the coil circuitry, which is susceptible as well.

That not withstanding there will always be some measure of infant mortality in components such as these, and one reason for the QA side of any biz is to generate homework problems for undergraduate stem majors on calculating confidence intervals on a level of 1% failure in the wild, given the sample taken in house.

As for the battery pack details. I'd also suggest the accompanying episode on the "Battery Tray and Battery Cell Features." It tears down to the individual Li-ion cell level.

Munro has done at least 3 video teardowns on the Mach e battery. Yes I've watched them all and all the others on the entire Mache teardowns.
here is a link to one of the battery tear downs.

Almost as good at the TOP GUN movie.

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[Mach1E]

The HV contactors are shown in the snap below taken from Munro's Live video "Mach-E Battery Exposed." Potting the contactor electrodes in an Inert environment prolongs their life by preventing chemical reactions with corrosive elements in the environment and shortening their life.

Contactors are standard elements in motor control systems in industrial applications, so the tech isn't that unknown. You can readily find these components with a google search and you will find the coils and electrodes are potted in some type of polyethylene enclosure with the circuit terminals protruding.

Other than people's opinion, I've not read anything on this forum that definitively supports the conclusion that the problem is with the contactor electrodes.

As I have understood things, the contactors have failed in both the open and closed positions, which could point to issues with the coil circuitry, which is susceptible as well.

That not withstanding there will always be some measure of infant mortality in components such as these, and one reason for the QA side of any biz is to generate homework problems for undergraduate stem majors on calculating confidence intervals on a level of 1% failure in the wild, given the sample taken in house.

As for the battery pack details. I'd also suggest the accompanying episode on the "Battery Tray and Battery Cell Features." It tears down to the individual Li-ion cell level.

People keep saying “1% failure rate,” but that number is actually huge considering most Mach E’s on the road are less than a year old and most GTs are less than 6 months old.

And as the cars and components age, that rate may increase as well. But even if it doesn’t, that could put us at 8-16% failures during the 8 yr warranty period. That’s a huge number for a complete breakdown.

 

[Shayne]

The HV contactors are shown in the snap below taken from Munro's Live video "Mach-E Battery Exposed." Potting the contactor electrodes in an Inert environment prolongs their life by preventing chemical reactions with corrosive elements in the environment and shortening their life.

Contactors are standard elements in motor control systems in industrial applications, so the tech isn't that unknown. You can readily find these components with a google search and you will find the coils and electrodes are potted in some type of polyethylene enclosure with the circuit terminals protruding.

Other than people's opinion, I've not read anything on this forum that definitively supports the conclusion that the problem is with the contactor electrodes.

As I have understood things, the contactors have failed in both the open and closed positions, which could point to issues with the coil circuitry, which is susceptible as well.

That not withstanding there will always be some measure of infant mortality in components such as these, and one reason for the QA side of any biz is to generate homework problems for undergraduate stem majors on calculating confidence intervals on a level of 1% failure in the wild, given the sample taken in house.

As for the battery pack details. I'd also suggest the accompanying episode on the "Battery Tray and Battery Cell Features." It tears down to the individual Li-ion cell level.

They are rated for 500 amps? Do you know if that rating is continuous? I guess knowing the amps and the voltage you could calculate HP with no accessories? Calculate?

 

[RickMachE]

Doesn't everyone just pulse-width-modulate driving? (either 0% or 100%...no inbetween)?

I laughed reading this. That's how my grandmother drove. On gas, off gas, on gas, off gas. You would get seasick lurching back and forth. But she was surging from 25 to 40 and back again, on the interstate...

 

[mkhuffman]

They are rated for 500 amps? Do you know if that rating is continuous? I guess knowing the amps and the voltage you could calculate HP with no accessories? Calculate?

So many threads on this it is hard to keep track. Someone posted the spec is 500 Amps continuous for 7.5 minutes. It is rated much higher for shorter durations. It is rated for 2,000 Amps but I can't remember the duration. It is in another thread somewhere...

 

[Shayne]

So many threads on this it is hard to keep track. Someone posted the spec is 500 Amps continuous for 7.5 minutes. It is rated much higher for shorter durations. It is rated for 2,000 Amps but I can't remember the duration. It is in another thread somewhere...

Maybe you can summarize for me at what HP it becomes a problem. Or point me to the link that does. 90% efficient?

 

[gpgrim]

They are rated for 500 amps? Do you know if that rating is continuous? I guess knowing the amps and the voltage you could calculate HP with no accessories? Calculate?

I've tried to find info online and the specific part number does not get any hits, though it does present options of contactors from manufacturers like ETS.

What is destructive for a properly designed and functioning contactor is not the load current, per se, but the process of opening and closing. At the moment just before circuit is closed/opened, the electric field between the contactors gets quite high, which produces an arc. That arc will erode some of the electrode and is one aspect of the wear and tear that limits the life of the contactor.

 

[DYohn]

I've tried to find info online and the specific part number does not get any hits, though it does present options of contactors from manufacturers like ETS.

What is destructive for a properly designed and functioning contactor is not the load current, per se, but the process of opening and closing. At the moment just before circuit is closed/opened, the electric field between the contactors gets quite high, which produces an arc. That arc will erode some of the electrode and is one aspect of the wear and tear that limits the life of the contactor.

And you've described the reason whey high current loads can be problematic for contactors - and the likely reason why WOT can cause issues. It's not the load while the contactor is closed - unless it is high enough to exceed the heat capacity of the system. It is rapid lifting off the WOT. Breaking the connection at high current load will cause an arc and apparently in the MME contactors can damage and or weld them together. This is why Ford thinks they can mitigate with software. If they can sense a potentially dangerous loading they can reduce the load before opening the contactor. It will be interesting to see how or if this impacts the driving experience for those who like to use WOT.

 

[breeves002]

And you've described the reason whey high current loads can be problematic for contactors - and the likely reason why WOT can cause issues. It's not the load while the contactor is closed - unless it is high enough to exceed the heat capacity of the system. It is rapid lifting off the WOT. Breaking the connection at high current load will cause an arc and apparently in the MME contactors can damage and or weld them together. This is why Ford thinks they can mitigate with software. If they can sense a potentially dangerous loading they can reduce the load before opening the contactor. It will be interesting to see how or if this impacts the driving experience for those who like to use WOT.

The contactors don't open when you lift off after going WOT. They only open when the car is turned off or the battery needs to be isolated. Yes arcing is the issue that destroys contactors over time but you don't have arcing in any driving situation as they stay closed the entire time the car is on.

 

[Shayne]

I've tried to find info online and the specific part number does not get any hits, though it does present options of contactors from manufacturers like ETS.

What is destructive for a properly designed and functioning contactor is not the load current, per se, but the process of opening and closing. At the moment just before circuit is closed/opened, the electric field between the contactors gets quite high, which produces an arc. That arc will erode some of the electrode and is one aspect of the wear and tear that limits the life of the contactor.

This that has been floating around is not accurate?

Where did you confirm this from? Are there any specs on it? From what I've read online they could be or might not be. Several manufacturers do not seal them because sealed means there is no where for the hot gas to transfer the heat away from the contactor. Sealing them really is only to dampen the arc during shut off from my understanding. Now the entire battery case is sealed for sure but I don't know about the actual contactors.

Edit: Finally found it here https://www.macheforum.com/site/thr...f-the-hv-battery-contactors.19114/post-452630

Here's a link to the general product offering for these contactors: https://www.te.com/usa-en/products/...ge-contactors-evc-500-500l.html?tab=pgp-story
And a link to one of the specific part numbers that are used in the car, with a technical datasheet drawing: https://www.te.com/usa-en/product-2342963-4.html

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And you've described the reason whey high current loads can be problematic for contactors - and the likely reason why WOT can cause issues. It's not the load while the contactor is closed - unless it is high enough to exceed the heat capacity of the system. It is rapid lifting off the WOT. Breaking the connection at high current load will cause an arc and apparently in the MME contactors can damage and or weld them together. This is why Ford thinks they can mitigate with software. If they can sense a potentially dangerous loading they can reduce the load before opening the contactor. It will be interesting to see how or if this impacts the driving experience for those who like to use WOT.

Really I envisioned you power it on the contacts close (small pos neg big pos) and that is it until an accident or powered off. You are saying it opens and closes every time you hit the accelerator? Software that does not open and close them so much may help.

 

[breeves002]

Really I envisioned you power it on the contacts close (small pos neg big pos) and that is it until an accident or powered off. You are saying it opens and closes every time you hit the accelerator? Software that does not open and close them so much may help.

No, they don't do this. They stay closed when the car is on and open when it is off or the battery needs to be isolated (like in an accident).

 

[mwtechy]

They are rated for 500 amps? Do you know if that rating is continuous? I guess knowing the amps and the voltage you could calculate HP with no accessories? Calculate?

Thank everyone in this thread for this convo, this is what I was missing. Many on this forum just keeps running around screaming the part is melting the part is melting assuming everyone else has the correct back story and industry knowledge. This is what I was missing and now it's adding up more correctly in my head. Now I just wish we had proper specs of the actual part and the newer part to understand the differences better and why the new part might not be the proper solution even though many on here believe it is even without such info...which is also mind boggling to me.

 

[DYohn]

No, they don't do this. They stay closed when the car is on and open when it is off or the battery needs to be isolated (like in an accident).

Good to know, thanks. So how is the contactor being damaged?

 

[Shayne]

No, they don't do this. They stay closed when the car is on and open when it is off or the battery needs to be isolated (like in an accident).

Thanks; maybe you can help me understand a bit better. I understand that there is a contact for motors and one for DCFC. What is the difference DCFC with the car powered on and with it powered off and which is better. Would two sets of contacts be closed when powered on and DCFC and only one when powered off DCFC?

 

[macchiaz-o]

Good to know, thanks. So how is the contactor being damaged?

Heat

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