My Solar Arrays
 

Several years back, I went on the National Solar Tour. I decided then that I had to have a solar array so I could have some control over my utility bills as I get nearer to retirement. So, this is what we built in hopes of making a difference. My wife and I are very pleased with the results.

Daryl was our Tour Guide and a solar installer. He was just the guy I needed to have help me. He showed a tilting rack that he'd designed to hold six panels, so I asked him to design a system for me with a rack similar to the one he had already made, and try and buy everything American made. I only started with 4 175w panels and the new to the market Enphase micro inverters. {The Sharp 175’s were $898.00/each in January 2009!}

I hired out having the rack footers installed so they would be what I needed and that ability was not in my skill set. I've included a couple of pictures as we populated the first array.

http://ecorenovator.org/forum/attach...ittle-rack-jpg

http://ecorenovator.org/forum/attach...dules-tilt-jpg

I started this array after the local utility told me they would NOT allow me to tie onto the grid. We had a bit of false hope in August of 2009 and I celebrated by buying two more Sharp 175’s at $498.00/each to finish populating the first rack.

On the down side, those American made Enphase inverters were now Chinese made. There's a noticable difference between the American and Chinese made inverters, some changes for the better, some for taking the expense out of manufacturinig them.

Are you Huntsville Utilities or something else?

I am on Arab Electric Cooperative, Huntsville has been on the TVA program quite some time before Arab came on board. Last time I asked, there were still only 4 or 5 solar arrays on the program through AEC.

In August 2011 the membership voted 81% to go onto the TVA program, so the Board of Directors grudgingly set the program up. I say grudgingly because the Board spokesman commented in the newspaper that they were going on the program because the membership voted for it, but he was against it.

Since the utility was going to charge me a fee to apply to tie on, I decided to go all the way and build an array that could meet my anticipated future needs. Plan A had been to build 4 little racks like shown on my first post. {You'll note the extra piers for another rack in that post.} But when I got in touch with Daryl with my new Plan B, I asked him to design a big array and stay with Sharp solar panels. I like that they are made in Memphis, TN and they seem to do what they are supposed to. I also asked him to use an American made inverter, I didn't want to buy any more Chinese inverters. We designed it with 24 240w Sharp Panels and an SMA Sunny Boy 5000 inverter. I know, 24 * 240 = 5760 rated watts. I was confused at the choice of a smaller capacity inverter too. He explained that in poorer conditions, like most of the winter, we could have a problem with the system dropping off line from under voltage if we didn't do it this way. On the brighter side, I've seen the output peak a 5.11 kW on the inverter display. :D

After the schematic that I submitted with my grid tie application was approved, we started ordering parts again. This time, even with bigger panels, the price had dropped to $337.00 each. To recap, I'll put it in dollars per rated watt. First purchase $5.13/watt, second purchase at $2.85/watt and last purchase at $1.40/watt. I'm sure the last also benefitted from being two dozen instead of 4 and 2 respectively.

My boss has been VERY good to me over the years, and this was no exception. We build large price signs on site where I work. Engineers, fabricators, welders, painters, etc. are all right here. DPW designed the rack system, but you buy the big steel pieces that make up the columns and the horizontal beam locally. So, going through our regular supplier, I ordered the pipe to make the 4 10'6" columns and the square tubing to span the 43' I needed. When it came in, the materials went directly into the fab shop to be cut to length, brackets fabricated and welded in place, etc. When they finished it, they took them across the yard and dropped them off in the paint shop. They were put at the front of the line in each case. From the time the raw materials were delivered until I loaded the painted and ready to go in the ground columns and the beam on my lawnmower trailer was 2 and a half days. :thumbup:

Here's a few pictures to show the DPW designed rack system being installed.

http://ecorenovator.org/forum/attach...-big-array-jpg

http://ecorenovator.org/forum/attach...-big-array-jpg

After the four columns were installed, I took over on the assembly. I added the DPW pipe column top pieces, the 43' cross beam {3 sections}, the bracketry for the rails the solar panels mount on, the rails and then the panels themselves. Spacing the rails in a reasonably even manner across the beam was more difficult than I thought it would be. I did a lot of readjusting to make them fit around the obstructions and make them look right to the eye. Another issue I ran across was that the stainless steel fasteners would gall if I tried to take them apart after tightening them down. I destroyed several fasteners before asking someone how to get around the problem. The solution was to apply some Loctite Anti-Sieze Compound liberally to the threads of every fastener before I put the nuts on and tightened them.

I had a lot of practice installing the 24 solar panels. I put them all on in exactly the same manner the first time. Three panels fit onto one pair of rails, and there are eight pairs of rails. {Going forward, I'm calling those three panels on a pair of rails a column of panels.} When I was finished, I looked back at the wiring diagram and saw that every other column of panels were to be installed opposite the column next to it. That way, every two side by side columns of panels would have their junction boxes facing one another.:eek: After removing and reinstalling half of them, I called Daryl and told him he needed to check my work so we could wire it up and finish it. He came out and quickly pointed out that I had not installed the grounding clips that go under the corner of EVERY panel. I didn't have to take them off, just loosen one corner of each panel to install the clips. There's also the time involved in making sure all the spacing is the same on all the panels so that when you step back a bit and look at your work, it looks like you put them on with care, not haphazardly. I wanted it to look neat and orderly, so ....

I 'm adding the pictures of the finished arrays and a closeup of the decal we printed to show the tilt angles. I also put a small label at the top to show the summer and winter combinations so that the two racks will be tilted to as close an angle as possible. As close as they are together, if they aren't tilted to almost the same angle, they will cast a shadow on one another during the course of the day. I also want to show you the folks from commissioning the array. From left to right, my electrician {licensed electrician is required by TVA to sign off on the install}, then me, the 2 TVA inspectors, our local utility supervisor / inspecter {this is the very first PV system commissioned in AEC service area}, and Daryl. A final picture showing the Sunny Boy in my garage, and if you look close enough you can see the Enphase Envoy propped up one the lower right side of the picture.

http://ecorenovator.org/forum/attach...ilt-decals-jpg

http://ecorenovator.org/forum/attach...oth-arrays-jpg

http://ecorenovator.org/forum/attach...day-people-jpg

http://ecorenovator.org/forum/attach...-boy-envoy-jpg

I need to add some explanations why we built it the way we did. In most cases, this heavy structure isn't really needed. Matter of fact, one of the solar arrays in my area that was installed after mine uses far lighter materials making a fixed, non-tilting, non-tracking array. I wanted to be able to tilt the array to try to squeeze out some extra kWh's compared to a fixed mount system. Since I made that choice, I had to put in a much heavier structure to resist the wind loading at every possible tilt angle. I did not want a tracking array, because trackers can malfunction and I don't know how to fix them.

The system was not mounted on the roof of our home for two reasons. The most important reason is, my wife said no. She didn't want me climbing on the roof to clean them periodically {and possibly falling off}, and didn't want the potential leaks in the roof.

The other reason was that our roof is not facing close enough to true South to get the best results.

Performance has been what I hoped it to be. In the first year, we made a bit over 9,900 kWh's, year two we made a bit more than 10,200 kWh's. Dividing the total to date by the 882 days since it went live, it's averaged just slightly under 27 kWh's per day. I have been truly blessed to be able to afford to build this and I smile every time I look out back and think about generating our own electricity. To date, we are just over 46% paid back in tax credit {30%} and power generated {> 16%}. Thanks for letting me share. :)

When did you complete the installation?

It was commissioned on 12/17/12.