How to confirm 2nd inverter is dead? Generation has cut in half

[drnick5]

Hi all, I'll do my best to keep this short and just use bullet points where I can.
-12KW system, 4 powerwalls, 2 7.6KW Tesla inverters. (so I have 2x Powerwall+ and 2 x Powerwall 2's)
-A month ago get a text and email from Tesla saying my system was malfunctioning and to contact for support
-Call to schedule support, they tell me an inverter is showing Arc faults and isn't working. I check the last month of generation and notice I'm down approx 50% from the last month
-Techs come out, said they replaced some things but the inverter still won't turn on and that "Tesla needs to turn it on remotely", and if it doesn't, I need to call them.
-Techs then also said "We are pretty new to these systems"
-Call tesla support, after a 2 hour call they can't seem to confirm or deny if my system is working right, they ask me the standard questions "has it been cloudy? do you have trees shading your panels". which I understand they have to ask, but that wouldn't account for a 50% drop during the peak of summer. They also said my original ticket was closed (even tho the support techs told me the inverter still wasn't woring) The rep I spoke with opened a seperate ticket for low generation which I still haven't heard back on.

How can I verify if my 2nd inverter is working? (Or not working) I can log into the gateway on my network, but it just shows some generation, it doesn't show each inverter. I don't see any other tesla devices on my network. I've done a lot of digging and everyone says "just log into the inverter" but I haven't found info on how to do this when you have 2 inverters.

I opened each inverter and took pics, if its helpful. Inverter 1 seems to have a motherboard with a network jack at the top right, which I'm going to assume is the Gateway? But teh 2nd inverter doesn't have one. Both appear to have lights on inside

Inverter 1:

https://imgur.com/8sZbpId

Inverter 2:

https://imgur.com/qJJ8Mx6

Any help or suggestions on what to do would be most appreciated!

 

[cali8484]

Why don't you turn off the first inverter then see if there is any power production?

 

[Miata Head]

If you can do this and the capacity works, you could swap the wires on the panels and inverters to see if it's an inverter issue or a panel bank issue.

My non-Tesla inherited system had 2 panel banks, 2 inverters and years ago, lost one set of panels. Called the guy out and he looked at it, then ultimately just switched the panel/inverter connection. This clearly showed it was the inverter and not the panels. Since it was a plug connection, I felt kinda stupid calling him out, but an inverter needed replacing anyways, so it wasn't a wasted visit.

Also, suggest you stick with an inverter per panel bank, if you can. I ended up combining into a single inverter for both banks and that was a bad idea. One bank now has a ground fault error somewhere and it will cause the working panel to not generate. So now it is a pain to figure out what is wrong with that bank without affecting generation of the other.

 

[taphil]

You can get or borrow a clamp meter to measure AC output of the inverters. You can measure the solar input also.

 

[drnick5]

So to update, I finally figured out how to get more data from the inverter by downloading the Tesla Pros app and connecting to the inverter's wifi. When I logged in, I saw my 2nd inverter had an Arc fault, and it gave me the option to clear it. I did this, it ran some sort of self test, and now shows a Green checkmark. Unfortunately the next day, I'm still getting the same low production. I logged back in during the day in the afternoon when both sides of my roof are getting sun and found 1 inverter shows "generating" and shows the wattage being generated. the other just says "Standby" with 0W being generated... so its clearly still a problem.

I checked again this morning and took these pics.

Inverter not working :

https://imgur.com/BTQXk5d

https://imgur.com/3WOyjKg

Inverter that is working:

https://imgur.com/2JhEySD

https://imgur.com/pVETgeC

Main page showing whole system:

https://imgur.com/Gg4ZMXO

So I'm still at a standstill... I'm supposed to have techs coming out Monday, but it appears it will be the same crew as last time that didn't fix anything and left with the inverter still showing arc faults (I'm pretty sure they had no idea how to log in to clear the alert) so that worries me....

 

[Miata Head]

On my SunnyBoy inverter to totally clear a fault, I had to power it off and pull the physical disconnect for 30 secs and restart for it to function again.

 

[cali8484]

The inverter may working properly and there is actually arc fault problem in your system. If it was me, I would insist the techs inspect all wiring/insulation and connections from the panels to the faulting inverter to ensure safety. DC arc faults can start fires so I would not just clear them without understanding the root cause.

 

[drnick5]

The inverter may working properly and there is actually arc fault problem in your system. If it was me, I would insist the techs inspect all wiring/insulation and connections from the panels to the faulting inverter to ensure safety. DC arc faults can start fires so I would not just clear them without understanding the root cause.

They supposedly did this when they came out last month. They were there for 4 hours, including a few guys on the roof. He told me they replaced some MCCI's (I think thats what he said?) and tested all the wiring, saying its good. He also told me "Arc fault isn't as bad as it sounds, the inverer seems fine its not gonna spark and make a fire" (He specifically said that lol) But they didn't seem to know *sugar* about the actual tesla inverter saying "Oh tesla has to remotely turn it back on, it just says standby." So I'm a little worried about their knowhow with these systems. He did tell me "we're pretty new to working on these".

I'm a tech guy, and know enough to be dangerous but anything beyond using the app to look at info or restarting the inverters I'm leaving alone for fear I'd screw something up or void my warranty.

I did look at it more today after reading some other forum posts. Basically tried stopping the system and starting it again. When inverter 1 came back on, it did a self test that took about 3 min to complete. but when inverter 2 came on, it didn't do any of that. I then tested by disabling both inverters in the app, and putting them on 1 at a time. Same thing, inverter 1 (the good one) does a self test, but inverter 2 didn't. I'm guessing thats part of the problem.

 

[DarylLafferty]

Hi all, I'll do my best to keep this short and just use bullet points where I can.
-12KW system, 4 powerwalls, 2 7.6KW Tesla inverters. (so I have 2x Powerwall+ and 2 x Powerwall 2's)
<snip>
-Call to schedule support, they tell me an inverter is showing Arc faults and isn't working.
<snip>
-Call tesla support ... they ask me the standard questions "has it been cloudy? ... They also said my original ticket was closed
<snip>

Any help or suggestions on what to do would be most appreciated!

I am in the middle of a very similar situation.

I have had 8kW from another company for about 10 years. In March Tesla installed another 4.8 kW, 2 PWs and another inverter, so I have my "legacy" inverter and a Tesla inverter, all connected through the "inverter combiner" and the Gateway.

Almost immediately after installation, I noticed incidences when the Tesla inverter completely shut down, then about 30 minutes later would start back up again. Since I can separately monitor the output from my legacy inverter, I can show definitively that only the Tesla inverter is shutting down, and that it's not clouds. Clouds wouldn't act differently on solar panels a few feet apart.

These shutdowns would happen anywhere from 1 to 4 times a day. Then one day, the inverter shut down and failed to come back up. After about a week of support chats, Tesla agreed that the inverter was down and scheduled a service visit 5 weeks later. So my Tesla-added system was totally down for 6+ weeks.

During the service visit the techs said that the inverter showed Arc faults which they cleared, and they trimmed some wires that might have been too close to a ground point. They also replaced units on the solar panels. I don't have any complaints about their apparent competence, though I was disappointed that they didn't just replace the inverter.

Almost immediately the system has returned to it's previous status, shutting down multiple times a day for about 30 minutes at a time.

Currently, multiple chats with support have confirmed that there is a problem (I've had the system go down while in a chat, and they can see the status), but they refuse to schedule a service call. They claim that the problem should be fixed by a firmware update to be delivered "sometime".

My take-away from this and reading your comment is that the "Arc fault" is a problem not necessarily caused by arcing that they are seeing in multiple inverters, and that they are working on a solution. I hope that's it. If not, and it is truly a hardware problem, they need to replace these defective units as soon as possible.

Tesla was very responsive until they got my money. After activation tech support has been very poor.

 

[Wahiawahi]

I am in the middle of a very similar situation.

I have had 8kW from another company for about 10 years. In March Tesla installed another 4.8 kW, 2 PWs and another inverter, so I have my "legacy" inverter and a Tesla inverter, all connected through the "inverter combiner" and the Gateway.

Almost immediately after installation, I noticed incidences when the Tesla inverter completely shut down, then about 30 minutes later would start back up again. Since I can separately monitor the output from my legacy inverter, I can show definitively that only the Tesla inverter is shutting down, and that it's not clouds. Clouds wouldn't act differently on solar panels a few feet apart.

These shutdowns would happen anywhere from 1 to 4 times a day. Then one day, the inverter shut down and failed to come back up. After about a week of support chats, Tesla agreed that the inverter was down and scheduled a service visit 5 weeks later. So my Tesla-added system was totally down for 6+ weeks.

During the service visit the techs said that the inverter showed Arc faults which they cleared, and they trimmed some wires that might have been too close to a ground point. They also replaced units on the solar panels. I don't have any complaints about their apparent competence, though I was disappointed that they didn't just replace the inverter.

Almost immediately the system has returned to it's previous status, shutting down multiple times a day for about 30 minutes at a time.

Currently, multiple chats with support have confirmed that there is a problem (I've had the system go down while in a chat, and they can see the status), but they refuse to schedule a service call. They claim that the problem should be fixed by a firmware update to be delivered "sometime".

My take-away from this and reading your comment is that the "Arc fault" is a problem not necessarily caused by arcing that they are seeing in multiple inverters, and that they are working on a solution. I hope that's it. If not, and it is truly a hardware problem, they need to replace these defective units as soon as possible.

Tesla was very responsive until they got my money. After activation tech support has been very poor.

I have a very similar situation. 9.6kw system with 2 PW, one of those is a 7.6kw Powerwall +. System was installed October 2022, we got PTO June 26, 2023. July 14th we had an electrical fire in the same wall as our powerwalls and inverter. Half our house was damaged by either fire or smoke. Tesla came out after the fire and said their system was fine according to their diagnostic check.
August 14, 2023 as I’m checking my Tesla app for the hundredth time that day, I realize our solar production went from clipping at 7.7kw to flatlining at 0kw.
We went through the troubleshooting process from the app, and then put in a service order. It took Tesla an entire month to finally send me an email to schedule service. I spoke to them yesterday and they mentioned something about arching when I brought up the fact that I’ve been seeing a problem with the Powerwall+ inverters failing in the Tesla Forum. I asked to speak with a manager, and today a supervisor emailed me apologizing that this was their busy season. I messaged back and told him that taking 12 weeks to send a technician out to my house is ridiculous. The soonest they can even look at my system in person is November 3rd. This is unacceptable to me. I wonder how many other people are going through this and don’t know about this site. Tesla needs to get their crap together and fix this. I’m sick of paying HECO and also paying Tesla. I expected my system to work more than 6 weeks after PTO. Why are the Powerwall+ inverters arching and failing?

 

[BGbreeder]

I feel your pain and it is annoying to have the service process be so spotty and prolonged. I hope that your home is getting repaired on a more timely basis.

Maybe it is just me, but I feel that these days there is enough data out in the public view to show that Tesla is not particularly good at customer facing post sales service or support. Personally, I've have tried to make peace with that lack of resources/service as being part of the price (or discount depending on how you look at it) for my buying into the Tesla ecosystem.

Not to say that Tesla shouldn't know what they are doing, but salt air is hard on electrical devices and electronics generally.

All the best,

BG