Need some advice...

[OON7]

Man, it's Vegas. Gotta gamble right??

In all reality, would make sure if you take it you are prepared in case you get stuck. On the flip side, if you do tempt fate and it fails, you'll be on the fast track to getting this faulty part out of your car and hopefully putting your mind at ease for the next trip.

Tough call honestly, not sure what I'd do in your shoes.

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[Mach-e4x]

At first thought, one would not think ambient temps will contribute to contactor failure, but then, since we don't know actual component operational temperature data, it is hard to say.

Here is the conundrum, it is now clear that under the right circumstances, the contactors can overheat and in some cases actually melt, weld, etc. However, how hot does the contactor and surrounding circuitry get when operational and the vehicle is pulling a lot of amps?

Based on my experience with replacing failed electrical contractors used in high voltage, high amperage systems, here are some thoughts:

Pulling long a hill/incline or jamming the accelerator a lot or using a DC fast charging will move a lot of power through the contactors. When you draw high amperage, you generate heat. When you generate heat, you should get rid of it so the electrical system components do not suffer potential heat related collateral damage. I believe the MME has design provisions to open the front louvers, let in ambient air, to cool components and that would make engineering/design sense. What we don't know is what the design criteria is for the heat sensor threshold and software parameters. i.e. what is the normal operating temps?

What I do know, for a fact, is that when I charge my MME in the garage, @ 40 Amps, the power cables heat up to about 120F to 130F. This temp is not a problem since it is well within the temperature design thresholds of the cables,materials, plugs, etc. I also know the cable temps are higher in the summer than the winter, I have tested/measured the temps. The rate at which heat from the cables escapes into the surrounding air is related to the ambient temperature. i.e. the warmer the ambient, the slower the heat transfer to the ambient air is, AND if I were to insulate those cables, and reduce the rate of "heat rejection"/ transfer, they would get very hot, quickly. I also know that if I directed air flow over the cables, I could drop the temps. These are the the basic principles of thermodynamics.

Regarding collateral damage to electrical system components. Just because you had a high amperage draw session at a given time, it doesn't mean you will have a failure during that event. With electrical components, collateral heat damage can be cumulative. i.e. what happens today, may lead to failure hours, days, weeks, months later. Why? Because thermal cycling, ( constant raising and lower temps.) can be detrimental to electric system components and every thermal cycling event poses some risk of collateral damage. The risk is proportionate to heat levels, duration time, frequency and component design temperature thresholds.

This means you may have driven up the "grapevine" in California one day, experienced some system collateral damage but the MME operated fine and you had no reason to be concerned. Then the next day, while driving on flat terrain in the San Joaquin Valley, you experienced total system failure.

I have read that the contactors are "hermetically sealed". If true, that would make good engineering/design sense because contactor components operated in an inert gas atmosphere would have significantly extended contactor life by minimizing the negative impact of the electrical arc created during normal contactor component operation. In a regular oxygen atmosphere the electrical arc would create ozone, leave a carbon trail, and create other highly corrosive electrical circuit compromising "nasties" that will NOT go away. . . . . ever, unless you replace the component.

A hermetically sealed contactor has heat design limits too, just like any other electrical device. What are those design limits? I don't know, but I do know, that after repairing dozens and dozens of high amperage/heat voltage systems, heat is your enemy. Whenever there is to much for to long, it makes things loose, leak or melt and failures happen. I also know that I have never seen a contactor that lasts forever. At some point, they all fail, it is to be expected.

In my opinion if anyone suggests this problem is solved with software is full of BS. Furthermore to design this vehicle with contactors buried in the battery pack is a basic, design error. It would be about the same as designing a car where you had to take off the fenders to change a tire. Kinda dumb. . . .

WEBER STATE UNIVERSITY DAVIS

Here is a great video all about the HVBJB - WeberAuto.

 

[heisnuts]

Hi -I have a couple of questions.
5 hours on the highway without stopping? Hours of fast driving then fast charging right after is something I haven't done yet.
How long and how often are your "wide open throttle events"?
I don't think I ever put the pedal to the floor.
Three HVBJB's?
How long does the service take to replace the HVB Junction Box?

The short answer is I have a lot of wide open throttle events that occur over usually a 2 to 3 hour time period at highway speeds. The first time the dealer does the repair it will probably take a tech most (if not all) of the day to complete the repair, but after they have done a few of them, I am sure they will get close to (or even beat) the 7 hours of labor time that Ford pays the dealer to complete the repair.

I am by no means the typical MME driver. I live about 5 miles from wide open country back roads that literally go on for hundreds of miles with open 2 lane highways going through farm lands and a lot of sections with tight turns that can go on for miles as well. Even before the MME, I have spent a lot of my time out in those roads enjoying my sport bikes and Corvettes (the current one is a 2021 Stingray). My typical loop is over 70 miles long, but there are so many other side routes that I usually always end up taking at least one or more that before I know it I am 3 hours in, getting hungry and stopping in at one of the rural mom & pop places for some food and restroom break.

I can go miles without seeing another car and since there are several intersections with just a stop sign, I will have several 0 to 60 runs for those and then the curvy sections where I will be entering the turns at a somewhat slower speed and then full throttle coming out of them. I originally never thought I would be using the MME out in the country since I have the sport bike and Corvette, but in the 7 months I have had the MME now, I find I spend most of my time in the MME. It was actually kind of nice to have the MME waiting for parts over the weekend which put me back in the Corvette and bike for the Labor Day holiday, which was a lot of fun. Even after years of doing the same roads over and over and over again it has never gotten old. I almost always come back with a huge grin on my face feeing so appreciative of being able to have that kind of enjoyment.

 

[Mach-e4x]

The short answer is I have a lot of wide open throttle events that occur over usually a 2 to 3 hour time period at highway speeds. The first time the dealer does the repair it will probably take a tech most (if not all) of the day to complete the repair, but after they have done a few of them, I am sure they will get close to (or even beat) the 7 hours of labor time that Ford pays the dealer to complete the repair.

I am by no means the typical MME driver. I live about 5 miles from wide open country back roads that literally go on for hundreds of miles with open 2 lane highways going through farm lands and a lot of sections with tight turns that can go on for miles as well. Even before the MME, I have spent a lot of my time out in those roads enjoying my sport bikes and Corvettes (the current one is a 2021 Stingray). My typical loop is over 70 miles long, but there are so many other side routes that I usually always end up taking at least one or more that before I know it I am 3 hours in, getting hungry and stopping in at one of the rural mom & pop places for some food and restroom break.

I can go miles without seeing another car and since there are several intersections with just a stop sign, I will have several 0 to 60 runs for those and then the curvy sections where I will be entering the turns at a somewhat slower speed and then full throttle coming out of them. I originally never thought I would be using the MME out in the country since I have the sport bike and Corvette, but in the 7 months I have had the MME now, I find I spend most of my time in the MME. It was actually kind of nice to have the MME waiting for parts over the weekend which put me back in the Corvette and bike for the Labor Day holiday, which was a lot of fun. Even after years of doing the same roads over and over and over again it has never gotten old. I almost always come back with a huge grin on my face feeing so appreciative of being able to have that kind of enjoyment.

The service department should get better at the MME repairs each time.
That kind of driving sounds like fun.
I think Ford should hire you to test out the MME for those kind of conditions.

 

[heisnuts]

The service department should get better at the MME repairs each time.
That kind of driving sounds like fun.
I think Ford should hire you to test out the MME for those kind of conditions.

Yeah, that’s how I look at it too. The parts department just told me the part is here now and it is the “C” version. Now just waiting to see when there will actually be time with the tech to install. Since tomorrow is his Friday I don’t have much hope for this week, but we will see.

I also consider myself a volunteer test driver for Ford. So far it has not gotten old so after this install I see lots of the same driving out in the country to continue testing the latest and greatest HVBJB. I guess we will see in another 6,000 miles if it is fixed or still a 6,000 maintenance item.

 

[Mach-e4x]

Yeah, that’s how I look at it too. The parts department just told me the part is here now and it is the “C” version. Now just waiting to see when there will actually be time with the tech to install. Since tomorrow is his Friday I don’t have much hope for this week, but we will see.

I also consider myself a volunteer test driver for Ford. So far it has not gotten old so after this install I see lots of the same driving out in the country to continue testing the latest and greatest HVBJB. I guess we will see in another 6,000 miles if it is fixed or still a 6,000 maintenance item.

Hope the C version is better! Keep on testing man.
Do you know if the HVBPJ is covered under the 36k or 80k warranty?

 

[4sallypat]

While I await my pushed back 2022 MME order; my Lightning EV truck at 117 degrees all week has been running just fine.

 

[heisnuts]

Hope the C version is better! Keep on testing man.
Do you know if the HVBPJ is covered under the 36k or 80k warranty?

As I understand it, the HVBJB is part of the high voltage battery warranty coverage, which is 8 years or 100,000 miles (whichever comes FIRST). I also believe there are some states (like California) that require longer warranty on the battery. I believe in California it is 10 years or 150,000 miles.

 

[Mach-e4x]

As I understand it, the HVBJB is part of the high voltage battery warranty coverage, which is 8 years or 100,000 miles (whichever comes FIRST). I also believe there are some states (like California) that require longer warranty on the battery. I believe in California it is 10 years or 150,000 miles.

Right! I meant to say 100,000. Thanks.

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