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HPWC kapoooooooot!

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I was charging my nearly dead battery this evening, and noticed, a few hours into charging I checked the app and it said not charging. I checked the HPWC and there's no power, and it was EXTREMELY warm. Checked the breaker and it did not trip.

I'm thinking that perhaps the internal fuse is blown, though i thought my HPWC was the newer version without the fuse problem.

Anyone have suggestions ?
 
I would still think one of the internal fuses is "blown". Are you sure you have the new JJN-200 fuses?

Turn the breaker off. Open the HPWC and see which ones you have. If they are the old TJN-100 fuses, then more than likely that is the problem. Remove the fuses and measure the resistance. Of hand I forgot the values but can tell you tomorrow. Now if you have the JJN-200 fuses with the bus bar design, than all bets are off....
 
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Why does the HPWC even have its own fuses? Seems silly to me, especially since the HPWC will be on a 100 AMP breaker. If you find this to be an internal fuse issue, I would probably look into bypassing the internal fuses. What purpose do they serve if the HPWC connection is already on a 100A breaker? I'm not an electrician, but it seems like adding a redundant set of fuses leads to unnecessary problems.
 
Why does the HPWC even have its own fuses? Seems silly to me, especially since the HPWC will be on a 100 AMP breaker. If you find this to be an internal fuse issue, I would probably look into bypassing the internal fuses. What purpose do they serve if the HPWC connection is already on a 100A breaker? I'm not an electrician, but it seems like adding a redundant set of fuses leads to unnecessary problems.
A fuse acts faster than a breaker. It's better to replace a fuse than the whole HPWC when something happens. That's probably why most higher power EVSEs have internal fuses.

Also, Tesla can't really control what you connect your EVSE to. Even though NEC 625 is designed to make this illegal (assuming your local code adopts it), it's still possible for a person to connect the EVSE to a shared circuit or one with a different rating. The fuses will prevent something bad from happening in that case.
 
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If you were charging at greater than 60 amps and you have vertical fuses in your HPWC (old style) you have blown your fuses. This is exactly what the pop-up warns you of when you go over 60 amps without having the updated horizontal fuses.

Call your nearest service center and have them send a Ranger out with a set of fuses. Ask them if they have a upgraded horizontal fuse retrofit kit in stock, if not have them bring out a direct replacement set of the old style vertical fuses. If you get the vertical old fuses, limit your charging current to 60 amps or less until you can get the updated fuses.
 
If you were charging at greater than 60 amps and you have vertical fuses in your HPWC (old style) you have blown your fuses. This is exactly what the pop-up warns you of when you go over 60 amps without having the updated horizontal fuses.

Call your nearest service center and have them send a Ranger out with a set of fuses. Ask them if they have a upgraded horizontal fuse retrofit kit in stock, if not have them bring out a direct replacement set of the old style vertical fuses. If you get the vertical old fuses, limit your charging current to 60 amps or less until you can get the updated fuses.

Uhhhh.....it's not necessarily the fuses. My HPWC stopped working today (no lights on; nobody home). I opened it up and checked for voltage from the breaker. All OK. Then, assuming it was probably the fuses, I checked for voltage downstream of the fuses. Also, all OK. Then checked for voltage on the other side of what appears to be a relay (at top of HPWC). No power there. So, for some reason the relay has decided not to close. It's NOT the fuses.

Called Tesla. They indicated that the local service center would contact me and send out a ranger to evaluate the problem. Sure hope it doesn't take long. Charging on a 110VAC circuit is SOOOO slow.
 
Uhhhh.....it's not necessarily the fuses. My HPWC stopped working today (no lights on; nobody home). I opened it up and checked for voltage from the breaker. All OK. Then, assuming it was probably the fuses, I checked for voltage downstream of the fuses. Also, all OK. Then checked for voltage on the other side of what appears to be a relay (at top of HPWC). No power there. So, for some reason the relay has decided not to close. It's NOT the fuses.

Called Tesla. They indicated that the local service center would contact me and send out a ranger to evaluate the problem. Sure hope it doesn't take long. Charging on a 110VAC circuit is SOOOO slow.

A blown fuse in the HPWC can/will show proper voltage. Only a resistance measurement will tell you if it is really blown. I am not saying that it could not be the relay but statistically the fuse has a higher probability.
 
Depends on where you measure it to/from. A bad fuse in the HPWC will show zero voltage when measured from the top of one fuse to the top of the other fuse.

The contactor only closes when the car modifies the voltage on the J1772 pilot pin; so measuring across the NO contactor contacts only shows voltage if everything else is working. If the HPWC's circuit board, or the pilot signal line to the car has a failure somewhere, the contactor will never get the voltage required to close and you'll never see voltage north of those contacts.

If you have voltage between the two north ends of both fuses, but no lights, then you likely have an HPWC circuit board failure of some type.
 
Well, color my face red! Tesla Ranger came to look at HPWC the other day. Told me he would try replacing the fuses as a first step. I confidently informed him the "fuses are not the problem." Of course, he had to replace them anyway, as that's the protocol. And, of course, that solved the problem! Talk about feeling like an idiot. Other than that, a very positive first experience with Tesla service.
 
My house has two breaker panels. The main panel gets the 200A circuit into the house - and there's a 125A breaker/line to the second panel.

When my HPWC was first installed - the breaker for the HPWC was installed opposite the 125A breaker to the second breaker panel.

After a few months, the 100A HPWC breaker melted and the HPWC lost power. The breaker shouldn't have melted - so it's possible the breaker was defective (and could have caused a fire).

However, it's also possible there was too much power going through the breaker panel at the same place - and the heat of transferring that much power - at about the same place in the breaker pane, might have caused the breaker failure.

So word of caution - when installing the HPWC 100A breaker - look at the breakers that are adjacent in the panel - and don't install it near another high amp breaker - just to be safe...
 
My house has two breaker panels. The main panel gets the 200A circuit into the house - and there's a 125A breaker/line to the second panel.

When my HPWC was first installed - the breaker for the HPWC was installed opposite the 125A breaker to the second breaker panel.

After a few months, the 100A HPWC breaker melted and the HPWC lost power. The breaker shouldn't have melted - so it's possible the breaker was defective (and could have caused a fire).

However, it's also possible there was too much power going through the breaker panel at the same place - and the heat of transferring that much power - at about the same place in the breaker pane, might have caused the breaker failure.

So word of caution - when installing the HPWC 100A breaker - look at the breakers that are adjacent in the panel - and don't install it near another high amp breaker - just to be safe...


When I saw this, I sent the link to this post to my electrician with the question, "Have you ever seen anything like this?"

His response:
Yes. Heat build up can be an issue and wreak havoc. I usually notice an imbalance of some sort, whether its a load on one phase or a poor connection somewhere in the system. These chargers are taxing on residential systems, which is why i installed bolt down breakers in your house. I would blame his breaker spades not engaging the bussing adequately and maybe arcing a bit, causing molten metal to damage the case, not just melt like taffy.

Bolt down breakers could be good insurance.
 
So word of caution - when installing the HPWC 100A breaker - look at the breakers that are adjacent in the panel - and don't install it near another high amp breaker - just to be safe...

If your breaker melts, it's not due to adjacent breakers and "heat build-up", it's almost certainly due to a bad connection that is causing a higher resistance. It could be (as Cottonwood's electrician friend mentions) the lack of a tight grip (especially if used breakers were snapped in place) on the busbar, it could be the panel's bus bars were corroded or pitted or previously damaged due to overloads. More often than not, though, it's an improper placement of the wire and torque on the screws in the breaker. When the wire is placed into the breaker and the bolt tightened, it should cause the strands of the wire to fan out and create a broad, flat connection. If you don't tighten the screws with enough torque, the wire will still remain round and the surface area will be reduced. This, in turn, creates a higher resistance, and some serious heat, enough to melt breakers.

As for bolt-down breakers, they provide extra insurance, but a bolt is adding suspenders to the belt. If the breaker doesn't securely snap onto the bus in the first place, a bolt won't eliminate heat. Both are likely to fail in that case. I see this frequently on older panels, where the panel is simply plum worn-out.
 
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> I checked for voltage downstream of the fuses. Also, all OK. [Borgie]

Are you sure you were 'downstream'? Fuses only have one failure mode = blown. If they just melt a tad, then they still conduct and thus are still fuses. I prefer to draw actual current using a pair of 60 watt light bulbs in series as a 'tester'. No false positive readings.
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