Where do you get that the contactors are rated for 1/2 of what the car is capable of?
There's a handful of threads that go into their specifics.
I have never seen that posted anywhere. Can you please provide a link? Some pdf on the internet is no proof that we have that in our cars.
It is understandable they didn't replace the problem part due to greed and the bottom line? It was not manufactured wrong it was undersigned and specified like that in the first place. Ford would have thrown the cost on the manufacturer/supplier if it was something they did wrong. It was Fords mistake and therefore no part for you. Which is understandable? It is not the problems with the car as an EA that was expected it is how the problems get fixed (or ignored and don't) that have turned some off.
He's right, from my HVBJB teardown I also concluded they are most likely 500A contactors that are pushed to 1000A (which is okay for short period only). The contactors are not fully heat sinked enough to do 500A continuous IMO, the max safe continuous on the HVBJB is about 350A.
Then his comment is incorrect. Most contactors that are rated at 500A continuous are rated for a max of 2k. Therefore, it's not exceeding the amperage rating. It's designed to take over 500A, just not for a continuous time. As for continuous 500A... It's all a guessing game. There's no doubt that Ford designed the part incorrectly. Based on the data I collected most of the failures happened in/and around the 500A mark. As for what they've done to fix this, I have no idea, but I have a feeling that if it wasn't designed to handle 1000A then they would have power limited the car to prevent that from happening instead of replacing it without any software to neuter the vehicle.
Read the charts, the higher the amperage, the shorter the life. The failure and when it actually presents aren't the same thing. Post failure it could take any number of amps before it's realized. The damage is gradual and the actual POF isn't instantaneous.
I understand that. This is why we get jail bars. My point is that Ford replaced the contactors with something "new". What they've done, I personally don't know. But if it was purely based on the contactors exceeding 500A then they would have modified the software in the car and neutered it, which they didn't. So, what caused it in the original contactors? I don't think anyone other than a Ford battery systems engineer can answer that question.
You are correct that only the Ford engineers probably know for sure. My guess though is there was a bad batch of contactors and by that I mean they barely met their rating. We had 12kV insulators from a major supplier that started failing. They just had a batch that did not meet their manufacturing tolerances. We sent all the ones back in our warehouse but had to deal with the ones that failed in the field as they occurred. Not all of them failed but they did take back all that were in inventory. I could see the contactors working fine but slowing taking damage at their higher momentary ratings until enough damage took place that they failed at their continuous rating level. Just my thoughts on what occurred.
Wrong. That is not what the recall says read it again and see what they say for sure. Under designed is right there in black and white. Tolerance and specifications comes from the designers the manufactures just comply.
The report states design and part to part tolerances. The report also states the damage is caused by DCFC and repeated WOT occurrences and we know that is not accurate as many have failed that were never DCFC’d or driven aggressively. If all the HVBJB were going to fail what benefit is it to Ford to go the software route versus change them all out? I do not drive with any anxiety regarding potential failure but I do wish it would have been a recall or the part and not a software patch.
Agreed! I looked at the chart and came back with the same conclusion. I just do not know if they replaced the contactor with something with a slightly higher rating or somehow limited the instantaneous current.
The report states:
Someone has cut open many of the failed units and does in-fact know definitively. Additionally contactors aren't new or novel, they've been used for more than 100 years in industrial automation and control. The weak point will always be the mating surfaces. Tesla had a similar problem early on and resolved it. They still have 400v architectures with up to 1000hp and no issues. Contactor failure isn't new, novel, special, nor unique.
