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Fastening PVs


Chris Hobson
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I have welded 2 steel frames (6 panels each) of 38 mm sq tubing and 76x38 mm rectagular tubing on which I plan to mount my PVs using Tek screws. I am copying the idea from a set of PVs installed near me. Any major concerns (except using tek screws that are too long)? This is a ground installation so I have access to the back of each panel.

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  • 2 weeks later...

We have spent today mounting PVs

 

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6 panels up and steel frame ready to take next 6. The frame is hinged on the bottom edge and this is the pitch for winter . It could go upright a bit more but I did not want a structure that would catch the wind. (Winter is definitely our windiest time).

 

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Attached panels with Tek screws R80 for 100 screws - 8 screws per panel.

 

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Earthing with Earthing clips.

 

Panels face due North and in the background you can see one of my problems. I live in a narrow valley and so the sun only gets to the panels at about 8:20 am and sets 3:30 pm in winter. Fortunately there is nothing to shade them 9am to 3 pm.

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Looking good! My panels don't produce anything to mention before 8.00 currently, although they are in the sun producing some few watts until 5:30. Bulk of power produced is between 10 and 3. I wouldn't worry too much about that last dregs of sunlight producing anything much.

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That will unfortunately will have to wait. I have been on a fairly steep learning curve and will want to sit and admire my installation for a while. How easy is it to build a tracker? My design is very simple and could be mounted on a turn table fairly easily. 

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That will unfortunately will have to wait. I have been on a fairly steep learning curve and will want to sit and admire my installation for a while. How easy is it to build a tracker? My design is very simple and could be mounted on a turn table fairly easily. 

 

The electronics in a tracker is very simple. There are hundreds of circuits available on the net. The simple circuits use a pair of LDRs and an op-amp per axis with a suitable H-bridge to drive the motor. If you can do the motors and gears you are 80% there. Keep in mind that you usually do tracking on 2 axis. I noticed that the tilt of your panels are quite steep. In SA the steepest most effective tilt angle is about 30

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Hi SuperDIY

 

I used solartilt.com to look at various options. The panels can pivot to various tilt angles as the frames are hinged in front. They are at 45for winter. The correct tilt should be 56but I was concerned that one is going to catch the wind. There is a small increase in efficiency due to a winter tilt, but any improvement in winter is welcome. It will be 29o for autumn and spring and 100 for summer (supposed to be 6o but the panels only self-clean at 10o or more tilt).

 

OK, great.  :)  

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  • 1 month later...

Hi SuperDIY

 

I used solartilt.com to look at various options. The panels can pivot to various tilt angles as the frames are hinged in front. They are at 45for winter. The correct tilt should be 56but I was concerned that one is going to catch the wind. There is a small increase in efficiency due to a winter tilt, but any improvement in winter is welcome. It will be 29o for autumn and spring and 100 for summer (supposed to be 6o but the panels only self-clean at 10o or more tilt).

Wish I could find an efficient way to tils 12x 255W panels on a normal pitched tile roof. 

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From what I understand from various sites that there is not a huge gain from (+-5%) from a tilt set of panels over a fixed tilt. It was so easy for me to implement that I made the system a 4 season tilt system.

My neighbor says the same. He build a stand to mount 9 panels on, with solar tracker, but ended up not using it cause he's too afraid the panels might fly off during the windy months. He recons the gain wasn't enough to justify the cost. 

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It has been mentioned to me by a solar tracking supplier that it is cheaper to add a panel or two than to get the same value spent on a tracking setup.

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