My Broken (Repaired) Solar Panel
In the previous post I made repairs to the broken panel making it safe[r] to handle. No, it's not completely safe with the exposed shattered pane of glass covering the front. It can still cut skin and clothing very easily if you brush up against it. The repair work keeps the panel from flexing when lifted and moving about.
Test Output Power before doing more work on the panel
Now that the solar panel can be moved around without pieces of glass falling off with every bump, we can move it into direct sunlight to test the Power Output. I verified the panel does put out 60 volts DC when sunlight shines on the solar cells. This confirms the rewiring job was done correctly because it used to measure 30 volts DC. Before I invest any more time and money into this broken 200 watt panel we need to find out if it is still capable of putting out some Real Power.
I attached some 12 gauge wires to the output terminals of the panel and connected the other ends to a DC motor I have. Purchased from a surplus sales company, it's a Lawn Boy lawn mower motor, rated at 36 volts operation. This will give me an indication if I can pull some amps out of the panel. So here goes, out into the sunlight. The motor spins! As I expose more of the panel to direct sunlight the motor spins faster and faster. Good!
A voltmeter is attached to the motor terminals and amp meter in series with one lead to monitor what is going on. So I move the panel further into the sun and the voltage goes to about 40 volts, pulling about 1.5 amps, that's 60 watts! Nice. OK, the test is done and was successful. Now it's time to get on with building a frame that can be attached to the ground outside.
A voltmeter is attached to the motor terminals and amp meter in series with one lead to monitor what is going on. So I move the panel further into the sun and the voltage goes to about 40 volts, pulling about 1.5 amps, that's 60 watts! Nice. OK, the test is done and was successful. Now it's time to get on with building a frame that can be attached to the ground outside.
Ground mounting design
My thoughts are to mount this panel to the ground using concrete poured into round holes dug into the ground, just like I did with the big system that powers my home. This will make the design of the metal frame fairly simple and it only needs to support one panel.
The base of the frame will be rectangular in shape to match the outline of the panel in landscape, long side parallel with the ground. Landscape mounting will give the concrete posts good spacing to attach the four legs of the frame to the ground. At my location on Planet Earth, the declination is about 39 degrees above the equator. So the panel will attach to the base frame and be secured at that angle.
Let's keep this simple to figure out how to build the frame and get the angle right. The work bench on which the solar panel is clamped is level, so that will be my reference. I used some B-Line metal bolted together at 90 degrees to be my "square". I'll hold it up to the back of the panel with the angle measuring tool held against one leg of the "square". When the angle tool points to 39 degrees I'll count the holes in the B-Line from the 90 degree corner to the edge of the panel. That will be the length for the Base leg. Then count the holes on the other leg of my "square" to find the length of the Back leg.
The tool is an Empire Polycast Magnetic Protractor. Its pointer uses gravity making it always point down to the calibrated scale marked in degrees. A Google search for empire magnetic polycast protractor will bring up lots of results so you can see what this tool is that I am using.
[ photo of basic framework sitting on solar panel ]
Here the Base leg is on the right side in the photo which is one end of the rectangular base of the frame. The width of the Base will be long enough to attach at about 6 inches in from each end on the solar panel.
To attach the mounting frame to the solar panel frame, I'll cut some short pieces of B-Line to make little 90 degree brackets. These will attach the frame to the solar panel at four points. You can see the short brackets resting against the back of the solar panel frame. Once everything was in place and squared up I marked the panel through the little brackets where I need to drill holes for mounting.
[ photo of long leg diagonal braces ]
The bottom of the frame is on the left in this photo. The two back legs are supported with diagonal brackets for stability. They held the frame rigid and square while I was positioning it for marking the drilling locations.
I may have gone overboard with the diagonal braces as the following photos show, but I don't want the wind to damage the panel or blow it away. That probably won't happen...
[ photo of diagonal brace view from outside frame ]
[ photo of diagonal brace view from inside frame ]
[ photo of diagonal brace view from rear attached to back leg ]
[ photo of diagonal brace view from rear attached to base ]
Yeah, that ought to hold...
To make all of those diagonal brackets fit as nicely as they do, I cut a notch out of each end just the right length. And on the correct side too! Here is how I made them start to finish:
[ photo of bracket before any cuts were made ]
[ photo of bracket with starting long notch ]
[ photo of bracket with finished long notch ]
[ photo of bracket with starting short notch ]
[ photo of bracket with finished short notch ]
[ photo of finished bracket with both ends filed smooth ]
In the above photo is one of the finished brackets, filed smooth where the cuts were made. You can see the pieces removed from it sitting on the back of the vice. This pretty much finishes up the frame to mount the solar panel.
The next step is to make the parts that will attach the frame to the concrete posts. To do that I'll use the same technique I used for the big system, long threaded rods buried inside the poured concrete posts. A threaded rod sticking out of concrete makes a very strong attachment point, and it's adjustable too. The threaded rod gives you plenty of room to make adjustments in height to level up the base of the frame.
Gregg Scholfield 2-7-2013
The base of the frame will be rectangular in shape to match the outline of the panel in landscape, long side parallel with the ground. Landscape mounting will give the concrete posts good spacing to attach the four legs of the frame to the ground. At my location on Planet Earth, the declination is about 39 degrees above the equator. So the panel will attach to the base frame and be secured at that angle.
Let's keep this simple to figure out how to build the frame and get the angle right. The work bench on which the solar panel is clamped is level, so that will be my reference. I used some B-Line metal bolted together at 90 degrees to be my "square". I'll hold it up to the back of the panel with the angle measuring tool held against one leg of the "square". When the angle tool points to 39 degrees I'll count the holes in the B-Line from the 90 degree corner to the edge of the panel. That will be the length for the Base leg. Then count the holes on the other leg of my "square" to find the length of the Back leg.
The tool is an Empire Polycast Magnetic Protractor. Its pointer uses gravity making it always point down to the calibrated scale marked in degrees. A Google search for empire magnetic polycast protractor will bring up lots of results so you can see what this tool is that I am using.
[ photo of basic framework sitting on solar panel ]
Here the Base leg is on the right side in the photo which is one end of the rectangular base of the frame. The width of the Base will be long enough to attach at about 6 inches in from each end on the solar panel.
To attach the mounting frame to the solar panel frame, I'll cut some short pieces of B-Line to make little 90 degree brackets. These will attach the frame to the solar panel at four points. You can see the short brackets resting against the back of the solar panel frame. Once everything was in place and squared up I marked the panel through the little brackets where I need to drill holes for mounting.
[ photo of long leg diagonal braces ]
The bottom of the frame is on the left in this photo. The two back legs are supported with diagonal brackets for stability. They held the frame rigid and square while I was positioning it for marking the drilling locations.
I may have gone overboard with the diagonal braces as the following photos show, but I don't want the wind to damage the panel or blow it away. That probably won't happen...
[ photo of diagonal brace view from outside frame ]
[ photo of diagonal brace view from inside frame ]
[ photo of diagonal brace view from rear attached to back leg ]
[ photo of diagonal brace view from rear attached to base ]
Yeah, that ought to hold...
To make all of those diagonal brackets fit as nicely as they do, I cut a notch out of each end just the right length. And on the correct side too! Here is how I made them start to finish:
[ photo of bracket before any cuts were made ]
[ photo of bracket with starting long notch ]
[ photo of bracket with finished long notch ]
[ photo of bracket with starting short notch ]
[ photo of bracket with finished short notch ]
[ photo of finished bracket with both ends filed smooth ]
In the above photo is one of the finished brackets, filed smooth where the cuts were made. You can see the pieces removed from it sitting on the back of the vice. This pretty much finishes up the frame to mount the solar panel.
The next step is to make the parts that will attach the frame to the concrete posts. To do that I'll use the same technique I used for the big system, long threaded rods buried inside the poured concrete posts. A threaded rod sticking out of concrete makes a very strong attachment point, and it's adjustable too. The threaded rod gives you plenty of room to make adjustments in height to level up the base of the frame.
Gregg Scholfield 2-7-2013
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