My production is way down from Juneish. Smoke, hot, angle of sun. No way one can compare this time of the years production to peak time. And it will continue to get worse
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16kw system only produces maximum of 11 -12kw (phoenix, AZ)
- Thread starter Squeezit
- Start date
charlesj
Active Member
One reason may be is that the sun is not at 90 degrees to the panels in late June, 20th but is further north of most of our locations in CA, AZ. Alaska may have it at 90 degrees. So, May may be the month or part of it anyhow as we don't stop nature, when it is just right and about August the same as the sun or the appearance of it is moving further south, less than 90 degrees and stops the cycle Dec 20/21.
As to daily production, Monterey's daylight changes 5 hours between Dec 20th and June 20, lots of solar radiation difference.
Then for the OP @Squeezit I don't think we know his installed inverter sizes, originally and with the replacement. Perhaps he got a smaller replacement inverter?
charlesj
Active Member
Yes, if that was originally and, if the replacement inverter is the same size. Without actual visual inspection perhaps he didn't get the right inverter replacement.
And, now in later September, sun is further south, down on the horizon than when it was producing the higher amount even if he has the proper inverter.
Hey thanks a ton for the responses guys. I was sure something was wrong with my system because when it was 120 outside, I was definitely getting higher numbers.
Anyways, the front of my inverters say this:
Inverter 1
Max power - point current (Imp) 11.48 A
Max Power - Point Voltage (Vmp) 380 v
Max system voltage (voc) 480 v
Short-circuit current (isc) 15 A
Inverter 2
Max power - point current (Imp) 20.14 A
Max Power - Point Voltage (Vmp) 400 v
Max system voltage (voc) 480 v
Short-circuit current (isc) 30 A
Inverter 1 is SE10000H-US
Inverter 2 is SE3800H-US
Sorry for being so late on adding this info
Anyways, the front of my inverters say this:
Inverter 1
Max power - point current (Imp) 11.48 A
Max Power - Point Voltage (Vmp) 380 v
Max system voltage (voc) 480 v
Short-circuit current (isc) 15 A
Inverter 2
Max power - point current (Imp) 20.14 A
Max Power - Point Voltage (Vmp) 400 v
Max system voltage (voc) 480 v
Short-circuit current (isc) 30 A
Inverter 1 is SE10000H-US
Inverter 2 is SE3800H-US
Sorry for being so late on adding this info
Yep, that implies max if both inverters are clipping would be 13.8kwh. But, basically no one ever gets the panel ratings since nothing is "perfect"
charlesj
Active Member
Panel rating uses flash testing for max output with more energy than what the sun will deliver, as best I know.
Realistically about 5%- about 8% less in reality.
charlesj
Active Member
Thanks for the info. When, month and day, did you produce that 13.6.
I did some cursory checks on line astronomy databases and such. You are 3 degrees south of me and your daylight length is a bit shorter than mine. I have 5 hours difference, you have 4:25 difference.
Solar noon comes at different time each day of the year from clock 12 noon.
The sun arc , sun's travel at about solar noon each day throughout the year (an interesting website Calculation of sun’s position in the sky for each location on the earth at any time of day)
from south to north also comes into the calculation of production. Because you are further south, the sun being perpendicular at solar noon for you comes earlier in the year that 20 June so by this date it is behind the panels a bit, so to speak. Also, your panel angle from horizontal.
Mine is a 4 in 12 pitched roof and is 19 degrees. 5 in 12 would be about 22.6 degrees.
If I used that link correctly for Mesa, then on 21 June the sun is 80 degrees up or 10 degrees shy or perpendicular to horizontal then if you roof is 4;12, the sun is about 10 degrees behind perpendicular, less generation. The sun would be perpendicular to that panel around late April.
Lots of variables affecting production.
Hey Charles,Thanks for the info. When, month and day, did you produce that 13.6.
Last time I did was in June just before my system broke. On June 7th I hit 14.3 kW,
The following 3 days I hit 13.8 - 14.0.
The week leading up to that I was also between 13.5 - 13.9.
My system broke for about 5 weeks, and since then I never hit 13 kw again, though I have hit 12.5 kw a couple times, I almost never go above 11.6.
I tried to figure out what I'm looking at but I can only barely get a clue:
I'm not sure what the individual panels are producing or which inverter is producing what- I tried to get an SE account from Tesla but gave up. There's really no way for me to hit my total system output since I have 33 panels facing south with a 20 degree east offset and 15 panels facing due west.
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charlesj
Active Member
That should have been Mesa.
If you can go back to it and scroll down from it you should see something like this image. Shows the sun arc at different times of year.
I found it, this is that sun travel.
Also, now it is late Sep, half way down for the sun's travel to the lowest point around Dec 20.
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CrazyRabbit
Active Member
giving OP a data point to compare to...
heat degrades about 10% in the south.
my best day was april 18 at 109.6kwh and in August and September I've been maxing at about 96kwh
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ZBB
Emperor
thanks. I’m in Houston and had our 16.2kW system installed in late June, with one of the inverters replaced in late July. We received PTO on Sept 1 - since then, max production was 94 and an average of 64 so far this mont (Hurricane Nicholas impacted production for about 4 days — with a low of 13 the day the storm hit. Sounds like April-May will be better before it heats up…
I’m also an AZ native, so would expect significantly less cloud shading impact for the OP. But the roof/panel Orientation may also very impacting OP’s production — looks like his roof peak is N-S, with panels facing E-W…
17 panels facing north and 2 facing east is not "nearly all are facing south", that's 40% of you production facing north away from the sun.
Sorry when I wrote that I was distracted at work.
I thought I only had like 3 panels facing north and I kinda screenshotted in a hurry without looking.
Looks like I have 17 facing north and 29 facing south with 2 facing east.
I feel like someone should have discussed this with me prior to me getting my system, I probably would have gotten a smaller system with less panels on the north side since those aren't nearly as useful...
I thought I only had like 3 panels facing north and I kinda screenshotted in a hurry without looking.
Looks like I have 17 facing north and 29 facing south with 2 facing east.
I feel like someone should have discussed this with me prior to me getting my system, I probably would have gotten a smaller system with less panels on the north side since those aren't nearly as useful...
Definitely not as much production as all pointing south, but still a lot of production around the summer solstice assuming the roof pitch on the North plane is not too bad.
We have 4 kW of our 12 kW on North facing surfaces roof and they kick in strongly from late April through August. And also start producing earlier because the south side has some shading until 8:30.
