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Power Production Drop Off

I have a 12kw system which was starting to produce up to 65kwh a day with a max of 10kw about three weeks ago. However the next day it only hit 44kwh or so. I assumed it was just clouds or something. However, fast forward a few weeks and even on a cloudy day I would get much above the 44kwh, and my max output is under 7. I thought it might have been dirt, dust, and pollen as we are not too far from a freeways and home construction. However I washed them with a hose and a soft brush with only minimal improvement.

Any ideas on what could cause such a drop off? Anyway to look into this on my own?
 

MorrisonHiker

Well-Known Member
Moderator
Mar 8, 2015
10,546
10,569
Colorado
Can you provide additional details, such as what inverters you have?

You might want to check these existing threads as well:
 
I have a solar edge hd wave inverter. Do t have the model number handy bu I think it was the 11400 one. I’m not sure what details would be helpful to run the gremlin down? It has the green and blue light on. The system size is ~12kw. I have panels on the west east and south of my home. At noonish on April 6 my panels produced around 10kw. Today at noon they produced 6.6 kw. They have been cleaned. They are all in full light of the sun.
 

nwdiver

Well-Known Member
Feb 17, 2013
8,855
12,936
United States
I have a solar edge hd wave inverter. Do t have the model number handy bu I think it was the 11400 one. I’m not sure what details would be helpful to run the gremlin down? It has the green and blue light on. The system size is ~12kw. I have panels on the west east and south of my home. At noonish on April 6 my panels produced around 10kw. Today at noon they produced 6.6 kw. They have been cleaned. They are all in full light of the sun.

Do you have access to the layout? Sounds like you might have lost a string.

Screen Shot 2021-04-26 at 2.12.43 PM.png
 
Maybe. Or through solar edge. Annoying that Tesla doesn't give access to the SE app...
Okay I am working with them through Chat and they are giving me access through the SE portal. however when I ask them to explain how I could the drop off from 10kw to 7k and 65 to 45 kwh they say they don't see any "issues" but do see the drop off. They will have the "tier 2" team review it. I will follow up with any updates.

Should I expect a lightning fast response from the tier 2 team? ;)
 

nwdiver

Well-Known Member
Feb 17, 2013
8,855
12,936
United States
So I was able to get the them to recognize the problem and send someone out. Here is better view of the bottom 12 panels. After a full day the produced next to nothing whereas the others were 1.2 to 1.5 kWh. Any ideas what could cause 1/3 of my panels to produce next to nothing?View attachment 657870

Most likely those 12 panels were all on one string and there's a connection in that string that came loose somewhere. It happens.
 

nwdiver

Well-Known Member
Feb 17, 2013
8,855
12,936
United States
Makes sense. Thanks for the help! Does the layout on solar edge app saying it’s all one string mean anything? Tesla said the layout wasn’t entered so I would assume it doesn’t.

No. The SE layout doesn't necessarily tell you much about the electrical arrangement. The SE system I installed is 3 strings but the layout lists all panels as being on one.
 
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sorka

Well-Known Member
Feb 28, 2015
9,457
7,766
Merced, CA
Makes sense.

Awesome. Thanks for that heads up. They should be at my place in a couple weeks and I will provide an update then.

It's unfortunate that it takes even that long for outright failures. I've seen customers here reporting up to 3 months to get an inverter replaced. If that goes out at the start of summer, you could lose half years NEM credit in those 3 months with peak production x higher peak summer rates.
 
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It's unfortunate that it takes even that long for outright failures. I've seen customers here reporting up to 3 months to get an inverter replaced. If that goes out at the start of summer, you could lose half years NEM credit in those 3 months with peak production x higher peak summer rates.
Yikes. I went with Tesla as their price was thousands lower than competitors though they had support “issues”. Hopefully I don’t have a 3 month issue though!
 
So I had Tesla out yesterday and they allegedly "connected" all the strings. However I wasn't there as all my equipment is outside and I received no call or text. I I also didn't notice any difference in power production and when I looked in the solar edge monitoring the same 12 panels showed they were not producing. So I am doubtful that they did anything.

I called tesla and they tried to say everything was mechanically fine and everything was okay. I assured them it was not, and even mentioned the solar edge info which elicited the "WE DON"T SUPPORT IT" response. Sigh. They also said that my panels were in the shade, but I informed them not at NOON. They said wait a full 24 hours and see if everything is okay.

I will call back tomorrow and see what I can do.
 
Oh boy so I had a number of chats with tesla support. Turns on the first guy that came out didn't do anything like I thought. He told home base that he couldn't fix the problem so it was elevated to Level 2 support to review further. The people I chatted with didn't tell me this until the next week after I had spent hours chatting and filing a service a request. Sigh.

Anyway they finally sent out a very nice tech who was there on Friday June 11. I showed him the solar edge info and power drop off and he agreed it was odd. He checked out the panels and connections, but ultimately said it was the connections to the inverter.

Apparently the original installers had placed all the panels on one connection in the inverter. He said there were two lines coming from the roof panels and he just connected them separately in the inverter. Net result is my power generation is back up to over 9kw at peek which is what I was getting back in April.

I am not sure why this changes the things, but i'll take it for now. Obviously at 9kw peek is still less than 12.24 kwp, but the panels are quite dirty now so I am going to clean them this weekend and see if I improves the performance. Also my inverter is only rated to 10 or 11kw anyway apparently. Shrug.

Thanks for the help!
 

h2ofun

Active Member
Aug 11, 2020
3,605
867
auburn, ca
Oh boy so I had a number of chats with tesla support. Turns on the first guy that came out didn't do anything like I thought. He told home base that he couldn't fix the problem so it was elevated to Level 2 support to review further. The people I chatted with didn't tell me this until the next week after I had spent hours chatting and filing a service a request. Sigh.

Anyway they finally sent out a very nice tech who was there on Friday June 11. I showed him the solar edge info and power drop off and he agreed it was odd. He checked out the panels and connections, but ultimately said it was the connections to the inverter.

Apparently the original installers had placed all the panels on one connection in the inverter. He said there were two lines coming from the roof panels and he just connected them separately in the inverter. Net result is my power generation is back up to over 9kw at peek which is what I was getting back in April.

I am not sure why this changes the things, but i'll take it for now. Obviously at 9kw peek is still less than 12.24 kwp, but the panels are quite dirty now so I am going to clean them this weekend and see if I improves the performance. Also my inverter is only rated to 10 or 11kw anyway apparently. Shrug.

Thanks for the help!
You will never get more than the max inverter output
 

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