Updates on the HVBJB (22S41)

[mkhuffman]

Correct. But by adding just 2 milliseconds to the precharge, You can lower the contactor current 30%. It all depends on the health of the motor capacitor and specs.

If I understand what you are saying, you don't actually know they changed the precharge timing. You are guessing that is what they did. Right?

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[Fixbear]

Mach-lee; back when Scoopman had his second HVBJB failure, I really dug deep into this. I have worked in electrical engineering a bit and did years of plant electrical work. Even got into a battle for one of my customers over power with the electrical supply utility. I don't come in without knowledge. NIMO even provided correction equipment for their phase imbalance that they said wasn't possible. But their lawyers would no longer let meter and test personal talk to me. At least I solved the problem for my customer, but all the other 3 phase customers still are being damaged as they haven't to this day replace the sub-station transformer. And it's been 15 years since I help find it for them. $$$$

 

[Fixbear]

If I understand what you are saying, you don't actually know they changed the precharge timing. You are guessing that is what they did. Right?

It's the only thing I could find they could do with software. The actual contactors are still the same Eaton spec on the new board. A truly inexpensive but effective fix. Anything else would require fiscal replacement of parts. And when you look at the failed boards vs. the replacement ones, there is no major engineering change. Just a few resistors and a IC. So yes, I suppose you could say I'm guessing, but an educated guess.

 

[Mach-Lee]

It's the only thing I could find they could do with software. The actual contactors are still the same Eaton spec on the new board. A truly inexpensive but effective fix. Anything else would require fiscal replacement of parts. And when you look at the failed boards vs. the replacement ones, there is no major engineering change. Just a few resistors and a IC. So yes, I suppose you could say I'm guessing, but an educated guess.

What they added with the software was to monitor the voltage drop across the contactors as an early warning sign of failure. If the voltage drop value gets too high, it sets the contactor performance/SVS error. The previous software did not monitor the contactor voltage drop at all. There are voltage sense leads in the HVBJB on each side of every contactor so the BECM can monitor the contactor function and verify they open and close as commanded. They added software that looks at the voltage drop constantly while driving rather than just checking for function at key on and key off.

Precharge time should always be generous because there is no big hurry, an extra 100 ms isn’t much consequence when starting your car.

 

[Shayne]

They fixed it with software by changing the timing of charging of the capacitors? Appears to have worked as there has not been a single failure since?

My service informed me that they have been informed by Ford that it was corrosion of the contacts that created arcing and was due to no di-electric grease on the contacts? The grease fix would not help the original HVJB's however.

 

[Mach-Lee]

My service informed me that they have been informed by Ford that it was corrosion of the contacts that created arcing and was due to no di-electric grease on the contacts? The grease fix would not help the original HVJB's however.

That’s not correct either, the contacts are hermetically sealed in ceramic chamber filled with an inert arc-suppressing gas like SF6. It’s impossible for moisture to reach the contacts in the sealed chamber. Dielectric grease is not used in high voltage DC contacts.

Bad contact materials were likely used that couldn’t handle the heat under load without warping.

Watch the video on this page to see how the contactors work. We have a different brand, but they work the same way:

https://www.tdk-electronics.tdk.com/en/hvc_presentation

 

[Maquis]

They fixed it with software by changing the timing of charging of the capacitors? Appears to have worked as there has not been a single failure since?

My service informed me that they have been informed by Ford that it was corrosion of the contacts that created arcing and was due to no di-electric grease on the contacts? The grease fix would not help the original HVJB's however.

Dielectric grease is non-conductive and I’ve never heard of it being used on dynamic switches. I think that service person was misinformed.

 

[Regulus7]

@Fixbear are you saying that the “new replacement” HVBJB are basically the same part except for some minor capacitor or resistor timing changes?

 

[Fixbear]

What they added with the software was to monitor the voltage drop across the contactors as an early warning sign of failure. If the voltage drop value gets too high, it sets the contactor performance/SVS error. The previous software did not monitor the contactor voltage drop at all. There are voltage sense leads in the HVBJB on each side of every contactor so the BECM can monitor the contactor function and verify they open and close as commanded. They added software that looks at the voltage drop constantly while driving rather than just checking for function at key on and key off.

Precharge time should always be generous because there is no big hurry, an extra 100 ms isn’t much consequence when starting your car.

Yes I know they did that. That provided a warning method for them. And a way to determine degradation of contacts. But the only way they could prevent failure is to control/limit current through the contacts. Hence a simple timing adjustment.

 

[DevSecOps]

But the only way they could prevent failure is to control/limit current through the contacts. Hence a simple timing adjustment.

That's just it, they aren't preventing failure with software alone, at all. The recall is not what stopped this from happening. It was the re-designed HVBJB. Do you suppose they just re-designed it for fun?

I think the point everyone is making is that you have told people something implying it's factual without actually having the facts to back it up. Some of us have even had Ford engineers tell us that the recall is not a "fix".

Now, we have multiple people on this forum who think what you said is true. It's cool that you're educated and all, but no one has ever confirmed the software doing anything other than what @Mach-Lee described and your first post was written with a lot of confidence.

 

[Mach-Lee]

Yes I know they did that. That provided a warning method for them. And a way to determine degradation of contacts. But the only way they could prevent failure is to control/limit current through the contacts. Hence a simple timing adjustment.

The limiting only happens after a voltage drop is detected and “Service vehicle soon” is active. Then you get a big power limit. Before that happens there is no added limiting (confirmed by testing). HVBJBs are still failing daily with the new software, all it did was make the failure mode “safer” (to satisfy NHTSA, not customers) by providing an earlier warning and power limit as damage control until a replacement with the revised part is installed.

It’s a hardware problem. The bad HVBJBs are going to fail eventually, regardless of software. Mine had the recall software put on with less than 1500 miles and it still SVSed at 7k with me being mostly careful not to floor it unless necessary. For comparison, I drive my Fusion way harder than the Mach-E and that’s survived 130k with zero mechanical failures.

 

[Pushrods&Capacitors]

It blows my mind that Tesla has been building cars for 10 years and, as far as I know, they have no issues comparable to this HVBJB fiasco. Couldn’t/ shouldn’t Ford have just torn down a Tesla and copied it the EV part? The MME has many advantages but getting from point A to B is most important.

My man. Tesla sends vehicles out to this day with:

1. Steering wheels that fall off
2. Mismatched summer/all-season tires
3. Brake calipers……….minus the pads
4. Auto pilot with phantom braking issues that scare drivers shitless.

Next level shit.

 

[Pushrods&Capacitors]

And to the commenter who praised Ford and called this merely an inconvenience, Ford sends their love, you’re their most favorite customer. Glad yours was replaced in 6 days. Ours took 29 days for various reasons. The only thing that salvaged the relationship with Ford for us was the BEV team bending over backwards to help out and cover rental costs etc.

 

[Shayne]

That’s not correct either, the contacts are hermetically sealed in ceramic chamber filled with an inert arc-suppressing gas like SF6. It’s impossible for moisture to reach the contacts in the sealed chamber. Dielectric grease is not used in high voltage DC contacts.

Bad contact materials were likely used that couldn’t handle the heat under load without warping.

Watch the video on this page to see how the contactors work. We have a different brand, but they work the same way:

https://www.tdk-electronics.tdk.com/en/hvc_presentation

I did not say it was correct I said that is what I was informed. Kind of explains how misinformation may get around.

Dielectric grease is non-conductive and I’ve never heard of it being used on dynamic switches. I think that service person was misinformed.

Yes I know I have a tub of Di-electric sitting in my shop. Since I have seen in video they are in a closed cylinder it would need to be done before the part was sealed and before Ford every saw the part ?‍ Still does not help the fact that Ford continues to let people drive a vehicle that can suddenly loose power at any time and as such can create an unsafe dangerous condition. This they know and continue to do.

Yes I know they did that. That provided a warning method for them. And a way to determine degradation of contacts. But the only way they could prevent failure is to control/limit current through the contacts. Hence a simple timing adjustment.

Whatever they did with their software the bottom line is it appears it did not work at fixing anything. 140 pages can not be wrong link

 

[Maquis]

I did not say it was correct I said that is what I was informed. Kind of explains how misinformation may get around.


Yes I know I have a tub of Di-electric sitting in my shop. Since I have seen in video they are in a closed cylinder it would need to be done before the part was sealed and before Ford every saw the part ?‍ Still does not help the fact that Ford continues to let people drive a vehicle that can suddenly loose power at any time and as such can create an unsafe dangerous condition. This they know and continue to do.


Whatever they did with their software the bottom line is it appears it did not work at fixing anything. 140 pages can not be wrong link

My point was simply that dielectric grease is not used on electrical contacts. Lack of it in the contactors is not part of the problem.

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