New PV System, Production Issues??

[owensct]

Hi All,

New solar owner and newbie here and I am seeing some issues with my production and I’m trying to figure out as I don’t think it’s working correctly and I wanted to post some information on the forum here to see if what I’m seeing would be considered normal or if there is possibly an issue that my installer should have to address before AI pay him the balance due for my installation.

I have attached a PDF that will hopefully provide some clarity on my issue/questions.

My system consists of the following:
2 Solar Edge Se3800AUS inverters
22 Solar Edge op 300 W Power Optimizers
22 Helios Works with Mono modules, (12 panels on inverter 1, 10 panels on inverter 2).

I have a two story home in Ewa Beach Hawaii. The projected sun zone is 500 out 450 average out to 5.5 hours, (not sure what this means but it was on my quote). The system was installed at the end of November and the issue detailed below has been occurring since day one. Being in Hawaii we don’t have a winter to speak of and I live on a part of the island of Oahu that gets more sun than other parts of the island. Although in the winter months we do get a lot more clouds and rain than in summer.

Twelve panels are located on the North facing part of the roof and ten are located on the south facing part of the roof. There is nothing that can shade the panels like trees etc, (other than clouds of course).

On a good day the total production I see is typically 20 to 22+ Kwh. However, the issue I’m seeing is in regards to the output I am getting from the panels on each of the inverters. For example the individual panels on inverter 1 tend to produce 295 to 350 Wh in general, while at the same time the panels on inverter 2 are producing in the neighborhood of between 40-49 Wh, which is a substantial difference in performance. The difference in production between the two sets of panels is fairly consistent throughout the day. I could understand it if the panels on inverter 1 produced good at a certain time of the day, and then started to decline while the panels on inverter 2 started to produce better at another time of the day, but that is not the case. The panels on Inverter 2 produce 60%+ less than the panels on Inverter 1 regardless of the time of day.

My installer told me that the panels on the South side of the roof are going to produce less than those on the North side of the roof, but a 60% or more difference in production seems pretty extreme to me. I have days where individual panels on inverter 1 have all produced above 1kwh for a total days production of almost 13 kwh and then on inverter 2 none of the panels make it to 500 wh for the entire day with the total production of 4 kwh for the day.

So my questions for the forum members are:
1. In your opinion is this normal or is something not right?

2. Other than the location/amount of sunlight does anyone have any thoughts/ideas or suggestions as to what might be causing the issue? ie panels connected/configured wrong, problem with the power optimizers, inverter etc.

3. Is it reasonable for me to expect my installer to try to do things to resolve this before paying him the balance of what I owe him?

I really really appreciate any thoughts, suggestions and feedback as I am a total newbie when it comes to solar and I want to be reasonable in my expectations, but I also want to get the full value out of what is a considerable investment.

Aloha,

Gordon

[bonaire]

Did your installer give you explicit production number expectations for each independent array *before* they started the work? That's what good installers do. Whether it is a PVWatts output or some other calculation.

Sounds like the poor performing roof is very steep. Do you have roof angles and other engineering papers from the install? Any "photos from the ground" to show here?

I am not an installer - but I would have put the panels on R-1 on the "big side" of the roof facing SSE. The picture you gave of the top of house schematic indicate the roof is probably steep and west-facing (not a good choice for HI solar). This is a series string and even though you have power optimizers, you have shade issues and that kills it. You actually should have some shade issues on the E side too later in the day. Can you do a graph of the "good" inverter output? I think it must be dropping off after 2-3 pm. Your 1/09 3-4pm picture shows very little generated on the "good side". So, it's having the same issue, just later in the day.

Updated:
In your overhead picture, the North is actually West, so that's wrong there. Your cul-de-sac circle is actually North.

I found your house on google earth. The peak of the roof there may be shading the panels since the sun passes over the house from E to W (backyard to frontyard). I think this was a bad job and the south roof should have been used, not the E/W roofs. The S roof at your North 21* lattitude should be fine. It's pitched a little steep for 21* N but better than what they did. Click on the picture below.

HI_photo.jpg

Lastly, if you get others' agreement here, talk to a lawyer about it as it may get tricky if they didn't do a good job and you hold back final payment until it is done to your satisfaction. At a minimum, their limited skills influenced the productivity of the job - and isn't HI paying a 35% rebate on this? They need to represent you and the state against your installer.

[bonaire]

owensct - anyfeedback on my feedback?
Also, Rick(Naptown) - did you see the same thing I did here?

I guess things could be left as is and the problem broken down into an "expectations" issue. But I would think putting modules on the E/W sides of the house versus the big SSE roof was part of the design problem.

[Naptown]

I did not dig deep enough to verify what you stated