Terminal block melted on HPWC Gen 2

[SYLotusElise]

Not sure what part you need but here is a link to ebay person who repairs terminal blocks for $85 Picture he shows should allow you to see if it is the same part you need.

Tesla Gen 2 A/C in Connector repair | eBay

I can repair the connector for you.

www.ebay.com

That's it! THANK YOU!!!

So this morning, I went to two shops to see if they might be able to fix this. The guy at the TV repair store looked at it and said this was the kind of stuff that interests him - novel problems. But he said he's so backlogged that it would take him 2mo to get to it. Oops.

At any rate, the missus (it's her car) said she wants to order a new one, and I can try this eBay bit.

Again, thank y'all so much for all your guidance and help!

 

[Tomin8or]

I love my Model X, but I'm starting to grow tired of little issues that I never experienced with ICE vehicles in the fist year of ownership. Last night my app popped up a message that stated the charging was interrupted. I immediately went outside to find that the vehicle had stopped charging and showed "Charge Cable Fault" and "No wall Power" messages on the digital dash. I can't tell you the particular light sequence on the charge port or the HPWC, but red was prevalent. I unhooked the charge head and placed it back in the HPWC receptacle. I reset the wall charger and hooked it back up to the vehicle. The vehicle wouldn't get pass 60 amps and then dropped to 30. I reset again. The charging sequence got up to the normal 72 amps and I went in the house thinking everything was good. A few seconds later I heard a pop in the garage. I went out to find the HPWC was dead. I checked the breakers which seemed fine and got around to popping the cover on the HPWC to find that a terminal block had melted. This charger has been installed since January and was done by a Tesla approved electrician. I've always charged at 72 amps without issue with voltage typically being in the 235-240 range. Maybe I just got a unit that bit the dust early, but I have to be honest when I say I'm tired of issues like this. It's not the end of the world, but it surely does change the family routine this week with the kids as we look to utilize Superchargers until this is remedied.

I see that this is an older thread, but I have found something interesting. We have been a certified installer of Tesla HPWC's since 2015. In that time, we have had 3 failures of the same type. We have always torqued the terminals to spec. The thing that I find interesting is that the OP had terminal 1 (left) fail. In all three instances of our failures, it has been terminal 1. We have installed around 100 of these HPWC's. I just find it odd that all of these have involved the left terminal. It could be an installer error, I just find it odd...

 

[brainhouston]

Possibly same issue as Gen3 -F versions, where one phase starts to conduct more current vs 50/50?

 

[mspohr]

Possibly same issue as Gen3 -F versions, where one phase starts to conduct more current vs 50/50?

One phase. No neutral. Everything that goes into L1 comes out L2.

 

[brainhouston]

One phase. No neutral. Everything that goes into L1 comes out L2.

ah right, i need to brush up on my high voltage theory

 

[Rocky_H]

Possibly same issue as Gen3 -F versions, where one phase starts to conduct more current vs 50/50?

One phase. No neutral. Everything that goes into L1 comes out L2.

Well, that's incorrect because it wasn't phrased right. It's true that the two sides of the circuit must have the same current because it's a loop, but I remember what you're thinking of, and it's close.

Gen3 HPWC disassembly, with overheating issues explained!

Caution: Wall of text ahead! So, I got a secondhand Gen3 HPWC (TPN:1457768-01-F) that had known issues at full power and of course ran it right up to 48 amps to see what she'd do(note it had updated firmware). For a little while it did 48 amps, but after a half hour in my 20f garage, it...

teslamotorsclub.com

That thread shows a detailed disassembly and investigation that found what the problem was with the early versions of the Gen3 wall connector that were having this overheating problem. Internal to the wall connector, it tries to split current in parallel through two 24A relays, assuming they will conduct exactly equally to pass the 48A of current, but they don't. Here's the paragraph describing this, where he is just referring to L1 & L2 as the parallel split paths of one incoming side of the circuit:

"Those two big dark brown things are each two-pole relays, one relay for L2, and the other relay for L1. Tesla's hope seems to be that the two poles(called A and B in the pictures, in small blue font) of each of the two relays will take 24 of the 48 amps of that 120V leg. That hope is more of a dream, but I was surprised by how it happened."

Basically those parallel paths used some unequal wire sizes and lengths and unequal traces on the circuit board that caused uneven resistance between the two paths, which started to shift the current hard toward one side. He did some testing and was seeing the 48A split about 44 to 4, rather than half and half.

"IMHO, the design is flawed because it relies too heavily on balanced currents with nothing to really balance them, and it seems that even though there's enough electronics to monitor the imbalance, the logic doesn't seem to do much with that information. As a result, while its great to have redundancy, both paths through each relay should have been designed to be able to handle the full 48 amp load continuously without overheating."

 

[mspohr]

Well, that's incorrect because it wasn't phrased right. It's true that the two sides of the circuit must have the same current because it's a loop, but I remember what you're thinking of, and it's close.

Gen3 HPWC disassembly, with overheating issues explained!

Caution: Wall of text ahead! So, I got a secondhand Gen3 HPWC (TPN:1457768-01-F) that had known issues at full power and of course ran it right up to 48 amps to see what she'd do(note it had updated firmware). For a little while it did 48 amps, but after a half hour in my 20f garage, it...

teslamotorsclub.com

That thread shows a detailed disassembly and investigation that found what the problem was with the early versions of the Gen3 wall connector that were having this overheating problem. Internal to the wall connector, it tries to split current in parallel through two 24A relays, assuming they will conduct exactly equally to pass the 48A of current, but they don't. Here's the paragraph describing this, where he is just referring to L1 & L2 as the parallel split paths of one incoming side of the circuit:

"Those two big dark brown things are each two-pole relays, one relay for L2, and the other relay for L1. Tesla's hope seems to be that the two poles(called A and B in the pictures, in small blue font) of each of the two relays will take 24 of the 48 amps of that 120V leg. That hope is more of a dream, but I was surprised by how it happened."

Basically those parallel paths used some unequal wire sizes and lengths and unequal traces on the circuit board that caused uneven resistance between the two paths, which started to shift the current hard toward one side. He did some testing and was seeing the 48A split about 44 to 4, rather than half and half.

"IMHO, the design is flawed because it relies too heavily on balanced currents with nothing to really balance them, and it seems that even though there's enough electronics to monitor the imbalance, the logic doesn't seem to do much with that information. As a result, while its great to have redundancy, both paths through each relay should have been designed to be able to handle the full 48 amp load continuously without overheating."

Well, that looks like a bad design.
I can understand why they have separate relays on L1 and L2... so that both live wires will be disconnected when the unit is off.
In this arrangement, the current must travel out one arm and back the other. Same current through both.
However, these should be 48 amp relays if the unit is designed to deliver 48 amps since they both will be handling the same high current.

 

[mongo]

Well, that looks like a bad design.
I can understand why they have separate relays on L1 and L2... so that both live wires will be disconnected when the unit is off.
In this arrangement, the current must travel out one arm and back the other. Same current through both.
However, these should be 48 amp relays if the unit is designed to deliver 48 amps since they both will be handling the same high current.

It's not out and back on the same relay, each relay's contacts are in parallel, L1A&L1B on one and L2A&L2B on the other. In an ideal world, the contacts would only need a 24A rating (48A for the pair in each housing), but the world isn't...

 

[Rocky_H]

Well, that looks like a bad design.
I can understand why they have separate relays on L1 and L2... so that both live wires will be disconnected when the unit is off.
In this arrangement, the current must travel out one arm and back the other. Same current through both.
However, these should be 48 amp relays if the unit is designed to deliver 48 amps since they both will be handling the same high current.

No, you misunderstood the thread and how I described it. I knew that the L1 L2 terminology would be confusing, because you were thinking of it as the two sides of the circuit, so I specifically said in advance:

"he is just referring to L1 & L2 as the parallel split paths of ONE incoming side of the circuit:"

This is on ONE side of the circuit that is supposed to be able to handle 48A. But they thought they could do it cheaper(?) maybe(?) by splitting it in parallel with two smaller 24A relays and assuming it would parallel split evenly half and half, and that didn't work because of uneven resistance.

 

[mspohr]

No, you misunderstood the thread and how I described it. I knew that the L1 L2 terminology would be confusing, because you were thinking of it as the two sides of the circuit, so I specifically said in advance:

"he is just referring to L1 & L2 as the parallel split paths of ONE incoming side of the circuit:"

This is on ONE side of the circuit that is supposed to be able to handle 48A. But they thought they could do it cheaper(?) maybe(?) by splitting it in parallel with two smaller 24A relays and assuming it would parallel split evenly half and half, and that didn't work because of uneven resistance.

There are two relays. One relay for L1 and one for L2. These disconnect both "hot" sides of the supply. All of the current (48amps) goes out through one relay and comes back through the other.
I can't find the specs for the relay and it's not labeled so don't know the contact amp rating.

 

[Rocky_H]

There are two relays. One relay for L1 and one for L2. These disconnect both "hot" sides of the supply. All of the current (48amps) goes out through one relay and comes back through the other.
I can't find the specs for the relay and it's not labeled so don't know the contact amp rating.

I still don't think you're getting it. Each of those relays is internally parallel. It has A and B inputs and outputs, and has two switches inside in parallel. They are each supposed to handle 24A of the 48. Here, this comment shows a circuit diagram of the inside of that relay piece, showing the two parallel paths inside the relay. Read more of that thread.

Gen3 HPWC disassembly, with overheating issues explained!

Caution: Wall of text ahead! So, I got a secondhand Gen3 HPWC (TPN:1457768-01-F) that had known issues at full power and of course ran it right up to 48 amps to see what she'd do(note it had updated firmware). For a little while it did 48 amps, but after a half hour in my 20f garage, it...

teslamotorsclub.com

Sorry that I did mix up his terminology. It's the A and B that he's mentioning that are the parallel paths where the current is supposed to be split evenly.

 

[mspohr]

I still don't think you're getting it. Each of those relays is internally parallel. It has A and B inputs and outputs, and has two switches inside in parallel. They are each supposed to handle 24A of the 48. Here, this comment shows a circuit diagram of the inside of that relay piece, showing the two parallel paths inside the relay. Read more of that thread.

Gen3 HPWC disassembly, with overheating issues explained!

Caution: Wall of text ahead! So, I got a secondhand Gen3 HPWC (TPN:1457768-01-F) that had known issues at full power and of course ran it right up to 48 amps to see what she'd do(note it had updated firmware). For a little while it did 48 amps, but after a half hour in my 20f garage, it...

teslamotorsclub.com

Sorry that I did mix up his terminology. It's the A and B that he's mentioning that are the parallel paths where the current is supposed to be split evenly.

That would only matter if the contacts weren't rated for 48amps or more.
What are the specs for the contacts?

 

[Rocky_H]

That would only matter if the contacts weren't rated for 48amps or more.
What are the specs for the contacts?

They weren't--that's the point! I don't know the specifications of any part of this, but it had two paths along some solder connections to the circuit board and metal traces along the circuit board, and the sizing of those seemed to have been made with the naïve assumption that each would only need to handle 24A at most. But since these paths were different, current starts shifting heavily toward the one with lower resistance, and goes up farther than it was designed to handle.

The extra experiments were interesting as @Sophias_dad built some big external bussing to try to conduct the current better and more evenly and was able to get it operating better.

 

[mspohr]

They weren't--that's the point! I don't know the specifications of any part of this, but it had two paths along some solder connections to the circuit board and metal traces along the circuit board, and the sizing of those seemed to have been made with the naïve assumption that each would only need to handle 24A at most. But since these paths were different, current starts shifting heavily toward the one with lower resistance, and goes up farther than it was designed to handle.

The extra experiments were interesting as @Sophias_dad built some big external bussing to try to conduct the current better and more evenly and was able to get it operating better.

So, nobody knows the specs but is just assuming they are 24a and that Tesla engineers are stupid?

 

[Rocky_H]

So, nobody knows the specs but is just assuming they are 24a and that Tesla engineers are stupid?

No. Are you ever actually going to read that thread where this is broken down in extreme detail and explained thoroughly? @Sophias_dad measured the current on the two paths that go to the relay, and it was a very uneven split of 44A on one side and 4A on the other side, and the side that was getting an extreme majority of the current was showing burnt brown spots on the connection points on the circuit board of that current path.

So, no, it's not "assuming". Stop being like that. This was demonstrated and observed fact that it operated in a way that they didn't anticipate, and it failed because it was demonstrably underbuilt for how it operated in reality.

Specification numbers are not the relevant point. And no, we are not "assuming" it only had margin for exactly 24A. They probably did have some overage margin in there. But the simple fact is that however much extra room they left, in operation, it went over what they allowed for.

And no, we are not saying that "Tesla engineers are stupid". That's a claim you made up. It's just a fact that they are human. Humans can overlook or miss things sometimes. It happens. Mistakes happen.

 

[mspohr]

No. Are you ever actually going to read that thread where this is broken down in extreme detail and explained thoroughly? @Sophias_dad measured the current on the two paths that go to the relay, and it was a very uneven split of 44A on one side and 4A on the other side, and the side that was getting an extreme majority of the current was showing burnt brown spots on the connection points on the circuit board of that current path.

So, no, it's not "assuming". Stop being like that. This was demonstrated and observed fact that it operated in a way that they didn't anticipate, and it failed because it was demonstrably underbuilt for how it operated in reality.

Specification numbers are not the relevant point. And no, we are not "assuming" it only had margin for exactly 24A. They probably did have some overage margin in there. But the simple fact is that however much extra room they left, in operation, it went over what they allowed for.

And no, we are not saying that "Tesla engineers are stupid". That's a claim you made up. It's just a fact that they are human. Humans can overlook or miss things sometimes. It happens. Mistakes happen.

I understand that he measured uneven current. Doesn't matter as long as each contact is rated for max current.
What are the specs for the relay?

 

[Sophias_dad]

I understand that he measured uneven current. Doesn't matter as long as each contact is rated for max current.
What are the specs for the relay?

The relays in a Gen3 are not generally available, but since the units with the defective relays would hover right around 32 amps continuous, I'm wagering they are rated for(or at least capable of) maybe 30 amps on each path, assuming the 'weak' path is supplying the other 2.