Sun hours

[bcroe]

Well I made a little bit more progress today........this pic show the bracing/support bracket with a couple of bottom rails laid.....
Here's a pic with all of the bottom rails attached....
Finally this pic is a close up of another repurposing of the IronRidge 3" top cap assembly. I used the pipe clamp assy to hold in place the bracing/support bracket........

Looks good, do you have the panels to be put up? I wonder if it is better working in the recent heat
wave, compared to my erecting 24 panels in the middle of last winter?

No doubt some wires will be trenched in soon. I just got a very small trencher for that here, waiting
for cooler weather to use it. Bruce Roe

[DanS26]

Yes I sourced the panels late last year at a very good price......less than $0.40 per watt but I had to drive 100 miles to pick them up. They are Trina 245's a Tier I manufacturer.

With these 24 panels I will now combine 4 strings of 12 panels each for each inverter. Short Circuit Isc for each home run will be no more than 35.4 amps per inverter....the Fronius max allowed is 44 amps. Maximum Voc @ STC is 450 volts which should be no problem.

The Imp @ nominal temp is 20.7 amps for the Fronius 7.5.....I will probably exceed this by around 5 to 6 amps. Here is where the robustness and active cooling will play a role. I have six good operating years on these inverters and have them located on a north wall in very shady cool conditions.

[DanS26]

Bad way for me to formulate the question.

One more try:

What's the design wind speed in your area ?
Any calculations for wind forces and loads required ?
Is AHJ check/approval of the calcs/design required ?

Just curious.

No one required me to do perform or submit wind calcs. But as you can see from the pics the arrays are over built from a purely structural point of view. The only approvals I received was to comply with the POCO interconnection agreement. They were really only concerned about nameplate capacity and anti-islanding. The engineer did take a look at the array and his only comment was "sweet".

I live in a small valley surrounded by a hardwood forest. High speed winds usually pass overhead. A few years ago a tornado passed right over my house.....I could tell from satellite views of the tornado destruction path. Sitting in the valley allowed the winds to jump over my structures. But tornadoes still are a concern in this part of the country anywhere including low lying areas.

[J.P.M.]

No one required me to do perform or submit wind calcs. But as you can see from the pics the arrays are over built from a purely structural point of view. The only approvals I received was to comply with the POCO interconnection agreement. They were really only concerned about nameplate capacity and anti-islanding. The engineer did take a look at the array and his only comment was "sweet".

I live in a small valley surrounded by a hardwood forest. High speed winds usually pass overhead. A few years ago a tornado passed right over my house.....I could tell from satellite views of the tornado destruction path. Sitting in the valley allowed the winds to jump over my structures. But tornadoes still are a concern in this part of the country anywhere including low lying areas.

Thank you. Since no approving authority asked for such information, no harm, no foul. I'm on that page for sure. Often, municipal codes require design considers for what are called "external loads", and perform calculations per recognized design standards such as ASCE-7, etc. That such requirements were not addressed may mean they are not part of your AJH's requirements. Or, that any such requirements were simply ignored. I'd could spend a lot of time describing how much the AHJ inspectors miss or ignore code requirements and clear violations of code in my area. I suspect things may be similar in other areas.

I'm not trying to be more Catholic than the pope here, but requirements for such things as external loadings exist for a reason. I mean no offense in writing this, and I'm certain you did the construction in good faith, and with what you believe is due diligence with a sore back and muscles to show for it, but good faith and a lot of sweat doesn't guarantee good design. From what you write and how you write it, and IMO only, it seems you may have been a bit less than the necessarily knowledge/experience to determine robustness of a design.

But, as I wrote, maybe external loading are not a required consideration, and for sure, your constructions are absolutely NOMB.

Respectfully,

[littleharbor]

This thread has to be the longest one on Solar panel talk, 365 posts and counting. Is there any kind of award for that?

[bcroe]

With these 24 panels I will now combine 4 strings of 12 panels each for each inverter. Short
Circuit Isc for each home run will be no more than 35.4 amps per inverter....the Fronius max allowed is 44 amps.
Maximum Voc @ STC is 450 volts which should be no problem.

If I read this correctly, you will have a string of 12 E facing panels feeding one inverter. And a string of 12 W
facing panels feeding other other inverter. So the outputs will be unbalanced much of the day?

This problem resulting from using 2 inverters, has required me to use 2 of everything to stay balanced.
Bruce Roe

[J.P.M.]

This thread has to be the longest one on Solar panel talk, 365 posts and counting. Is there any kind of award for that?

Not sure, but maybe HXguy had a longer one a few years back when the greybeards here were giving him a DIY PV installation education that was probably the source of most of the knowledge to allow him to become an installer.

[littleharbor]

Not sure, but maybe HXguy had a longer one a few years back when the greybeards here were giving him a DIY PV installation education that was probably the source of most of the knowledge to allow him to become an installer.

You're right. 817 posts on 55 pages. I do remember it now that I looked it up. Good memory J. P. M.

[DanS26]

If I read this correctly, you will have a string of 12 E facing panels feeding one inverter. And a string of 12 W
facing panels feeding other other inverter. So the outputs will be unbalanced much of the day?

This problem resulting from using 2 inverters, has required me to use 2 of everything to stay balanced.
Bruce Roe

Let me clarify.....12 E facing panels paralleled with 36 S facing panels for inverter A.....then 12 W facing panels also paralleled with 36 S facing panels for inverter B. So both inverters will be balanced for much of the day.

I get a small amount of morning shade so the Trina 245's E facing will be matched with the Kyocera 245's S facing in the morning and the Trina 245's W facing will be matched with the Kyocera 235's in the afternoon. Just to make the entire system balanced.

I use a TED Pro system to monitor each inverter production so I will know immediately if this balancing act will pay off.

[bcroe]

A proposal for a 20MW solar installation was not well received, in this rural,
zoned AG area. My schedule shows 10 meetings to attend, I am part of the opposition.
Bruce Roe

Last night I and 100 of my neighbors attended another county meeting on zoning a 20MW solar
plant, right in the middle of AG and residential, in direct conflict with the COMPREHENSIVE PLAN
of every governing body in the area, based on a loophole in the regulations and the presence of a
major substation to the nearby Byron Nuke. The solar co brought 5 representatives for a
presentation, which I thought was vague and glanced over most details. All pictures were of
a different type system than proposed, and incomplete.

The meeting lasted 6 hours 40 minutes. There was a petition against it signed by literally half
the residents of the village and nearby area. At the end it took about 8 minutes for the 20MW
proposal to be voted down unanimously.

There are a number of smaller 4MW proposals going, it remains to be seen if this is a trend.
Bruce Roe

[bcroe]

Solved another reoccurring problem on the back solar acre. Getting wiring trenched in has meant
renting/transporting a machine, or hiring someone. Both of those have been a hassle, and digging
by hand is less acceptable every year. I finally bought this absolute bottom price unit, which does
not even include self propulsion. The hand cranked winch I added here probably works even
better. It seems pretty rugged, and that little Honda engine works just fine. Bruce Roe

Trench2.JPG

[bcroe]

Last night I and 100 of my neighbors attended another county meeting on zoning a 20MW solar
plant, right in the middle of AG and residential, in direct conflict with the COMPREHENSIVE PLAN
of every governing body in the area, based on a loophole in the regulations and the presence of a
major substation to the nearby Byron Nuke. The solar co brought 5 representatives for a
presentation, which I thought was vague and glanced over most details. All pictures were of
a different type system than proposed, and incomplete.

The meeting lasted 6 hours 40 minutes. There was a petition against it signed by literally half
the residents of the village and nearby area. At the end it took about 8 minutes for the 20MW
proposal to be voted down unanimously.

There are a number of smaller 4MW proposals going, it remains to be seen if this is a trend.
Bruce Roe

Update a month later. A member of the county board (who I also have worked with in LIONS)
proposed a 6 month MORATORIUM on any industrial scale solar in our rural AG setting. The
county is to prepare a whole set of guidelines (like other counties) to deal with zoning requests,
instead of the questionable arrangement that had been passed a year or so ago (proposed by
WHO?) to grease the skids. Obviously there has been a lot of behind the scenes stuff, the
moratorium passed 21 to 1. This does not mean no industrial solar ever, but it sure puts the
brakes on what was happening before.

I got to know a lot of neighbors better. Bruce Roe

[bcroe]

Just like April 2018, the 15KW inverter plant today managed 151 KWH in best sun. That would be
10.07 GHI/day I believe. A clamp on meter check noted, the 2 newest strings with identical sun
differed in output by nearly 10%. That is enough for me to wonder if there is a panel section being
bypassed. I may add some taps and check it out later. If 1/3 and 2/3 tap connections are brought
over to the combiner box, I can check the voltage of each group of 4 panels in the string of 12.
Finding something, taps are moved to increase resolution of the suspect section. Later.
Bruce Roe

[bcroe]

Managed 155 KWH even with some rather minor clouding, I think a record here for May. Cutting some
trees added a bit, but there is still room to move some panels for a better combination of orientations.
Took half a year to get 2 strings exactly right, guess it could be done by 2024.

In any case 10.33 GHI/day is pretty good, is there any other arrangement (not in orbit) that can do that
at 42 deg lat? Still waiting for warmer nights to attach test points to string 12. Bruce Roe

[J.P.M.]

Managed 155 KWH even with some rather minor clouding, I think a record here for May. Cutting some
trees added a bit, but there is still room to move some panels for a better combination of orientations.
Took half a year to get 2 strings exactly right, guess it could be done by 2024.

In any case 10.33 GHI/day is pretty good, is there any other arrangement (not in orbit) that can do that
at 42 deg lat? Still waiting for warmer nights to attach test points to string 12. Bruce Roe

Bruce:

I forgot and I'm too lazy to root around for an answer: How many STC kW of PV do you currently have installed ?

Thanx,

J.P.M.