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Tesla Inverter Issues

Just got my site survey done here in Northern Ca. Spoke with the tech who did the survey from my local installation hub and he said they've been taking out a lot of Tesla Inverters and replacing them with Deltas as there has been some massive issue with the Tesla Inverter and the rollout. He didn't know too much detail on specifics but I'm wondering if anyone else has heard of this? I'm a little concerned because my design calls for 4 separate strings and I'm not sure there is another string inverter that has this capability with 4 separate inputs. Wondering how it would affect my install.
 

MCNE

Member
Mar 12, 2021
183
38
Texas
Just got my site survey done here in Northern Ca. Spoke with the tech who did the survey from my local installation hub and he said they've been taking out a lot of Tesla Inverters and replacing them with Deltas as there has been some massive issue with the Tesla Inverter and the rollout. He didn't know too much detail on specifics but I'm wondering if anyone else has heard of this? I'm a little concerned because my design calls for 4 separate strings and I'm not sure there is another string inverter that has this capability with 4 separate inputs. Wondering how it would affect my install.
I haven’t started using mine other than the two day test I performed so I’m hoping this isn’t going to be an issue. I take everything I hear now from those guys with a grain of salt. Maybe someone who’s had them running for a few weeks can provide their experience as well. The thanks for sharing this.
 
I don't think we've heard much about issues here on the forum. Maybe a couple posts, one I recall of a mis-wired string not producing and I thought there was one other with Tesla Inverter issues.

Any chance there was confusion about it being SolarEdge inverters coming out? As per this thread:

This post in particular: Solar inverter changed prior to install
 
He also noted that he didn't know if it was just on some batches of them or all of them, but that it was chaos over at Tesla right now and I would most likely not get a Tesla Inverter until a fix is in place but said that could come at any point. I'm thinking of having them install whatever they have and get them to replace it when the Tesla Inverter issues are sorted out in the future. He mentioned speaking to the install guys about that and have them put it in writing.
 
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His words about this problem were a bit harsher and said they've been "ripping them out" on several installs, and that this is a widespread problem going on all over the country. He also noted that he didn't know if it was just on some batches of them or all of them, but that it was chaos over at Tesla right now and I would most likely not get a Tesla Inverter until a fix is in place but said that could come at any point. He didn't mention that communication at Tesla, even to employees is not that great. I'm thinking of having them install whatever they have and get them to replace it when the Tesla Inverter issues are sorted out in the future. He mentioned speaking to the install guys about that and have them put it in writing.
I think your approach sounds reasonable from a customer perspective, but I am not sure Tesla will go along, and definitely get it in writing. Tesla will likely not want to replace a functional Delta inverter with theirs once the Delta is installed. I do not know if the installers will have the authority to make such a commitment, so you may need to discuss with your advisor, and I expect the advisor will offer the options to proceed with a Delta (not to be replaced by a Tesla) or delay the project until the Tesla inverter is ready (assuming it is the case that there are issues with them.)

As to your original question, it looks like the larger Delta M-Series inverters support 6 strings, but only have three independent MPPT channels (2 strings per MPPT.) How that potentially affects the design of your specific install I do not know.
 
I just had a 21.5kW solar roof system installed that uses two 7.6 and one 3.8 Tesla inverters. These are not Solar Edge. They are the new Tesla units.

All of the strings and inverters have been online for about two hours when Tesla was here testing so far in the first week without something going wrong.

Probably number one is that Inverter #1 is stuck in a self test boot loop. It cycles through 1 of 6 up to just past 3 of 6 and then when it goes to step 4 of 6 it hangs and eventually reboots. This happens over and over again. Turning the 40 amp breaker on and off several times does not help. I finally figured out that it will come up if the other two inverters are shut off. So I throw the breakers for inverters 2 and 3 off, then power on inverter 1. When it comes up and starts producing power I turn on inverters 2 and 3 and everything is OK. Go figure..

Problem number two is that string 2 on inverter number 2 does not show up. It worked last week so I am not sure what happened. String 1 and 3 work fine.

I opened a ticket with Tesla last week and have yet to hear back from them.
 
I just had a 21.5kW solar roof system installed that uses two 7.6 and one 3.8 Tesla inverters. These are not Solar Edge. They are the new Tesla units.

All of the strings and inverters have been online for about two hours when Tesla was here testing so far in the first week without something going wrong.

Probably number one is that Inverter #1 is stuck in a self test boot loop. It cycles through 1 of 6 up to just past 3 of 6 and then when it goes to step 4 of 6 it hangs and eventually reboots. This happens over and over again. Turning the 40 amp breaker on and off several times does not help. I finally figured out that it will come up if the other two inverters are shut off. So I throw the breakers for inverters 2 and 3 off, then power on inverter 1. When it comes up and starts producing power I turn on inverters 2 and 3 and everything is OK. Go figure..

Problem number two is that string 2 on inverter number 2 does not show up. It worked last week so I am not sure what happened. String 1 and 3 work fine.

I opened a ticket with Tesla last week and have yet to hear back from them.
This seems to be exactly why they might be in a panic to have them removed and replaced for the time being. Good info. Thanks for sharing.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,305
18,115
Riverside Co. CA
(moderator note: I am not moving this post into the large "tesla inverter" thread that currently exists ( Tesla Unveils New Tesla Brand Solar Inverter ). My reasoning is, the information from this OP regarding someone from a Tesla install team stating there might be widespread problems is new news.

This could be a local installers opinion, or something more widespread, but it is news that many would be interested in so I chose to not move it to the large existing discussion)
 
This is interesting news. Before PTO, I had the inverter on a day here and a day there just to make sure there’s no significant issue, it appears to be working fine. I left home on the day of PTO and inverter was turned off, I guess I’ll keep an eye on it when I get home in another week or so. One thing I noticed though it appears most Tesla tech has no working knowledge of it, for that matter that goes for the TEG2 as well. It’s like everyone just stared at them and on the phone with someone trying to get it right. They did not jumper CT1 in the TEG2 on output from the Tesla inverter so I was only seeing output directly from the inverter but not as an integrated Power Flow from the TEG2. When they came back again and finally got all the connections right they spent 2 hours then realized that everything has to do a hard reset, then poof, I can see everything working. One caution on switching inverter, they would need to change the engineering diagram before they can send it to your utility for PTO application, it may introduce delay.
 
Interesting. I’m in Massachusetts and recently got 3 inverters (7.6) installed. Two of them are having issues with specific strings. The crew were quick to blame the MCI-1 and are coming back on Wednesday. The symptoms being (1) strings not appearing, (2) low volt / high amp.

does anyone know how you can login without doing a power cycle? Hard to see what it’s doing without that.
 

MCNE

Member
Mar 12, 2021
183
38
Texas
Interesting. I’m in Massachusetts and recently got 3 inverters (7.6) installed. Two of them are having issues with specific strings. The crew were quick to blame the MCI-1 and are coming back on Wednesday. The symptoms being (1) strings not appearing, (2) low volt / high amp.

does anyone know how you can login without doing a power cycle? Hard to see what it’s doing without that.
I tried but couldn’t find a way to access them without a reboot. Mine aren’t in production yet but I’m wondering if Tesla pushed a recent update to those in production.
 

miimura

Well-Known Member
Aug 21, 2013
7,203
7,156
Los Altos, CA
There are reports of problems with the new Tesla inverter in one of the Tesla Energy Facebook groups.

One person posted a picture of string input terminals melted. These terminals are push-in type that I'm not a fan of. You have to strip the wire to the proper length and firmly and completely insert the wire. I suspect that quality of termination would be improved by using ferrules when the wire is stranded as opposed to solid core.

Another person posted that their problems were resolved by replacing two of the 3 MCIs (mid-circuit interrupter) on one string. The MCI used with the Tesla inverter is a new Tesla branded unit that allows the system to comply with rapid shutdown requirements.
 
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There are reports of problems with the new Tesla inverter in one of the Tesla Energy Facebook groups.

One person posted a picture of string input terminals melted. These terminals are push-in type that I'm not a fan of. You have to strip the wire to the proper length and firmly and completely insert the wire. I suspect that quality of termination would be improved by using ferrules when the wire is stranded as opposed to solid core.

Another person posted that their problems were resolved by replacing two of the 3 MCIs (mid-circuit interrupter) on one string. The MCI used with the Tesla inverter is a new Tesla branded unit that allows the system to comply with rapid shutdown requirements.
I have had them for a month now since PTO with no issues. The 7.6 Inverter's water pump gurgles like it may be low on coolant, but other than that all has been good.
 
My 6kw system is only giving half the normal output today (sunny without clouds). It is a new system with new inverter (without PTO). Maybe it is the inverter? Right now at 1:06pm it only gives 2.5kw, vs 5kw normally (for the last couple of days).

Also I do hear water flow inside the inverter. Not sure if it is the coolant.
 

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jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
6,550
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Northern California
My 6kw system is only giving half the normal output today (sunny without clouds). It is a new system with new inverter (without PTO). Maybe it is the inverter? Right now at 1:06pm it only gives 2.5kw, vs 5kw normally (for the last couple of days).

Also I do hear water flow inside the inverter. Not sure if it is the coolant.
The water sound is likely the coolant moving around between the heat sinks and radiator. You can hear water flowing through Powerwalls doing the same thing.
 

MCNE

Member
Mar 12, 2021
183
38
Texas
We had Tesla come out again today to commission the system. Everything works fine, no issues with the inverters. The reason they were having issues before today was human error - didn’t plug in one of the connections. Will see how it performs and report back.

I asked whether they had heard of any issues, the short answer was no.
That's good news, thanks for sharing!
 
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