Tesla Powerwall Plus Inverter failure

[Brian Mann]

My Solar system with Powerwall plus was installed in may of 2022. Installers broken over a dozen rafters during install. In order to fix this, the solar array had to be removed, rafters fixed, then roof fixed, then panels reinstalled. system got commissioned and PTO around November of 2023. In April the inverter start cycling on and off. After having 3 service calls. They finally replaced the Invertor towards the end of May. Now only a little over a month with a new invertor the new invertor has failed and is now leaking coolant, just like the first one.
What is the deal with these Invertors failing? Why has this problem not been remedied yet? Why is Tesla using cheap parts? I

 

[charlesj]

Welcome.

I feel your pain. No idea what and why. How did they break the rafters, multiple ones? Are they part of a truss system up there. Just curious.

 

[Brian Mann]

Welcome.

I feel your pain. No idea what and why. How did they break the rafters, multiple ones? Are they part of a truss system up there. Just curious

When they were drilling the pilot holes for the pucks to be installed. they couldnt drill straight, then they just send the 5 inch lags sideways into the rafters, causing the rafters to split. out of a 24 panel aray, they might been less than a 1/4 of the lags secured properly.

 

[elektrikuser]

In the same boat as you. New 9.6KW solar system with powerwall+ installed in Sep 22. The inverter failed in may 23.. they replaced the inverter on July 6, 23.. it started leaking coolant from July 8th and failed again on July 10th.. since then my "hardware concern" is "pending parts"

 

[preilly44]

I have a 34KW, 5PW, 3PW+ system (so 3 PW+ inverters) that was installed in July '22. They have replaced 5 inverters so far and are coming out on Monday to replace a 6th inverter (hopefully not just looking at it so they have to come back again to replace it)...

Very frustrating but still worth the 35% I saved over the next least expensive installer.

 

[BGbreeder]

I have a 34KW, 5PW, 3PW+ system (so 3 PW+ inverters) that was installed in July '22. They have replaced 5 inverters so far and are coming out on Monday to replace a 6th inverter (hopefully not just looking at it so they have to come back again to replace it)...

Very frustrating but still worth the 35% I saved over the next least expensive installer.

Do you have any whole house surge protectors?

 

[CrazyRabbit]

They are failing do to heat. I suspect the 3.8kw inverters don’t fail since they have the same cooling system with half the load.
My inverter is “c00l”! In air conditioned garage!

 

[Wahiawahi]

I came here to see if anyone else had a broken inverter a couple of months after installation.
My 9.6kw system with 2 powerwalls was installed October 2022. They only gave us a 7.6kw inverter. We were in self consumption mode until we received permission to turn on June 26, 2023.
July 14, 2023 we had a fire a couple of inches from the powerwalls and inverter. Tesla came out a week later and said our system was fine and the diagnostic test was good. Fast forward to August 14, 2023 and we went from 7.7kw to zero. Our inverter stopped working. We contacted Tesla and did the troubleshooting. I’ve put in numerous work orders, and no one has contacted me. At this point I’m livid. Their customer service is horrendous. My blood pressure is rising just thinking about this.

I knew something was wrong when I found out they were only giving us a 7.6kw inverter for a 9.6kw system. Every single day before the inverter broke we had production of 7.7kw. We even got 7.8kw which shouldn’t be possible with a 7.6kw inverter.
Tesla went cheap.
Apparently others have had the same problem with Tesla inverters and we are all paying for Tesla’s mistake.

 

[charlesj]

I came here to see if anyone else had a broken inverter a couple of months after installation.
My 9.6kw system with 2 powerwalls was installed October 2022. They only gave us a 7.6kw inverter. We were in self consumption mode until we received permission to turn on June 26, 2023.
July 14, 2023 we had a fire a couple of inches from the powerwalls and inverter. Tesla came out a week later and said our system was fine and the diagnostic test was good. Fast forward to August 14, 2023 and we went from 7.7kw to zero. Our inverter stopped working. We contacted Tesla and did the troubleshooting. I’ve put in numerous work orders, and no one has contacted me. At this point I’m livid. Their customer service is horrendous. My blood pressure is rising just thinking about this.

I knew something was wrong when I found out they were only giving us a 7.6kw inverter for a 9.6kw system. Every single day before the inverter broke we had production of 7.7kw. We even got 7.8kw which shouldn’t be possible with a 7.6kw inverter.
Tesla went cheap.
Apparently others have had the same problem with Tesla inverters and we are all paying for Tesla’s mistake.

No, nothing really wrong with that setup as that represents a 1.26 DC to AC ratio. It may be on the low side as some go 1.5 ratio.
Also depends on inverter specs, if given, what is the max ratio it can handle.

 

[DrSmile]

What exactly happens to the excess power when solar production exceeds the inverter maximum? I know it clips, but it seems like the energy hast to go somewhere? Is it converted to heat? Given that there seem to be so many string inverter failures it seems fair to ask whether a high DC/AC ratio results in more failures.

 

[yblaser]

What exactly happens to the excess power when solar production exceeds the inverter maximum? I know it clips, but it seems like the energy hast to go somewhere? Is it converted to heat? Given that there seem to be so many string inverter failures it seems fair to ask whether a high DC/AC ratio results in more failures.

Semantics, but the solar production will never exceed the inverter maximum. The inverter regulates the solar production by choosing where it operates on the V-I curve of the panels. Normally the inverter tries to optimize the V-I to reach the maximum power point (MPP) for a particular string. If operating off the MPP the panels will get a little bit warmer. No excess energy is dissipated in the inverter.

That said, with a >1 DC:AC the inverter will be operating at its full output power for more hours per day. I would think that inverters are rated and tested to operate at their full power output continuously and DC:AC >1 is ubiquitous in solar installs. Certainly though this will put a higher average thermal load on the inverter.

 

[DrSmile]

Thanks Yblaser. What happens when the grid voltage drops as it does around here on hot days? I notice the inverter will still output the same wattage, is it doing that by raising the amps? I would think this is also not good for the inverter.

 

[smjacobs]

They are failing do to heat. I suspect the 3.8kw inverters don’t fail since they have the same cooling system with half the load.
My inverter is “c00l”! In air conditioned garage!

I totally agree. My 7.8 inverter blew on it's first July ever. System installed in Dec 2022 and July 1 the inverter blew. My 10.4 Kw system was getting clipped daily by the one inverter and finally that one inverter blew. It took Tesla from 7/1 - 12/13 before they finally replaced it. I made them install a 2nd smaller inverter as well to prevent that from happening again. I now plan to take them to small claims court for the cost of that 2nd inverter and believe my system should have been designed this way from the start. The lack of producing energy and consuming it instead from July - Dec was the best thing that could have happened to my power company. At my True-up I OWED