Our Do It Yourself Solar Array
Jump to Decisions, Opinions, and Stories
A word about my sponsor: For those of you that came in through a search engine. If you have any interest in real estate in North West Wisconsin please visit my sponsor at www.crexrealty.com. Located in Grantsburg Wisconsin. If you are not interested in real estate we also have regional information on the Grantsburg and Burnett county areas. Some of the highlights include: Crex Meadows wild life area, a growing list of Burnett county lakes information, links to the web pages of businesses in the Grantsburg area, and lastly, regional events and tourist attractions. |
Disclaimer: This information has been put here in the hope that someone finds it useful, We do not claim to be experts at installing a solar array, nor do we claim that the information you find here is the “best way”. The information that follows is simply how we installed a functioning 10.8 kilowatt array, that is tied to the electric grid and Co-Generates electricity with Polk Burnett Electric Cooperative. I also want to point out that working with various power tools, and working with electricity is hazardous. You need to decide for yourself if you want to do these things. Also here in Wisconsin we can still legally do our own construction and wiring. In your location that might not be true, so please check with your local building codes, if you are considering a project like this.
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Data from past months,
March, 2024 solar performance (PDF) March, 2024 Impact on our Electric purchase (PDF) Solstice and Summer vs Winter Chart (PDF)
4.03 Peak KW hrs per day
Spreadsheet in Open Office format.
solar_array_bom.xls
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First and foremost, I want to make clear that with this solar array, we are just as dependent on the power grid as we ever were. Meaning that if our power is interrupted for some reason, perhaps a storm, or a downed power line, our electricity will shut off just the same as anyone else, even if the sun is shining on a crystal clear day. I will explain this further later on, but I want to mention it right away, so that if you are only interested in “off grid” solar, or some other means of emergency power you may not want to continue reading this page. Also, I would like to quickly mention that this is a 10.8 kilowatt array, which means, the maximum power that it can generate is 10.8 kilowatts, it will normally output much less wattage, and I will explain that further as well. |
To back up just a little, questions #2 and #3 need to be answered in order to really have an answer for question #1. You need to have some idea of what size system, you want to install in order to be able to estimate the cost. You also need to make some kind of educated guess as to what the system will produce when it is running. This really comes down to the size of the system, times, the average daily sunlight that will fall on it.
There are many more questions to answer, and decisions to make, but I will try to explain some of the options, and why we chose one over another as we get on with building the system. So let’s get started!
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A short version of the story goes a little like this. I was looking for a small inexpensive generator on line to be able to have around for short term emergencies, like running my basement sump pump during a power outage, or warming my diesel tractor enough to start it on some cold winter morning, again, during a power outage. Now this is not to say that we have a big problem with power outages, but I really like knowing that I do have some means of generating some power if I need it. As I was searching for generators, I came across an advertisement that claimed solar generating systems with as little as a 2 to 4 year payback. I thought to myself, “yeah right”, the last time I checked the system would have to run for about 45 years to pay for itself. Anyway, I have always wanted to come up with some way to be independent from the power company, it is just really hard to compete with the cost of electricity from the grid. The above advertisement captured my interest enough to go check it out. We even went so far as to go visit this solar power outfit, and talked with the owner. At that point all I was really looking for is some basis to answer question #1. The person we talked to was kind of pushing a 5.4 kilowatt system, that he ball park quoted at a cost of $5,000 to $6,000. When I asked what about doubling the system to a 10.8 kilowatt system, he said going larger is a little less than double, because you still only need one inverter to make the system work, so he roughly quoted us about $19,000. Now I need to point out that the system we were talking about would primarily a (DIY) do it yourself system however they would take the time to show us step by step, how to do it right. This was all very appealing to me because I not only wanted to save money, but gaining the knowledge of how everything works as we put it together was also very important to me. To sum up our very brief initial conversation, he gave us information on how the grid tie inverter works, and talked a little about the government incentives that were currently going on. He also mentioned that they take care of dealing with the power company on the customers behalf, so we would be able to focus on installing the system, they would teach us how, and they would deal with the engineering and legal details. Now all of this was starting to sound pretty good to me, however we still needed to take a step back and look at really, how can this provide payback in 2 to 4 years? Since I had been tracking our electric bill for quite a few years, it was relatively easy for me to get an idea of our average power usage, and total cost of electric. I used this information and the rough cost quotes along with some of the information about government incentives that I acquired. No matter how I calculated it, I kept coming up with a payback on the system that ended up much closer to 10 years payback instead of 2 to 4 years. Even so a 10 year payback is not so unreasonable to quit looking at doing this project. In an email to the company I let them know what I was calculating for a payback time and asked if I was missing anything. I also requested a better quote on 5.4, and a 10.8 kilowatt system, so that I could run the numbers some more. In the meantime even though we really don’t have much for bills, we were not able to write a check for say $10,000 to $20,000 so we began the process of setting up a home equity line of credit, (HELOC) loan. While waiting for approval of a loan, I had not received the information I requested from the solar power outfit. If requested I can go into more details about that, but it is really water under the bridge now. In order to proceed, I really needed to come up with some way to reasonably answer question #1. I started to search the Internet primarily searching for what do we need, to make it work, and how much will it cost. Obviously the more I searched the more questions it produced. I tried to stay focused on what we need, and cost. I figured If I answer question #1, then I would worry about the “how” part of the equation later. By the time we were approved for the loan, I had come up with a total cost figure of around $18,000 for a system, knowing that we would change our mind on a few things, and the final cost would ultimately depend on exactly what we use for a ground mount, and if I forgot anything important. With this cost figure, I came up with an optimistic payback of maybe 6 to 7 years, including government incentives, and so forth, and a pessimistic payback, as much as about 13 years, including interest on the load, no government incentives, system producing less than expected, etc. So, with cost and payback all figured out to the best of my ability, it's now time to think about the “how”. |
We have some technical stuff to still work out. Because nothing that I researched would include batteries, or even bring me close to going off-grid, the fanciest solar generator I could build would not do much good without getting approval from our power company to do the interconnection. I decided to see what I could learn from www.polkburnett.com. Their website turned out to be quite informative, but like everything else, it did leave me with a few questions and points that I didn’t confidently understand. So, I used their web form mail to email Polk Burnett and ask them some of these questions. I was somewhat disappointed by their response, because instead of a reply to my email with the answers, I received a phone call from a person at Polk Burnett Electric Cooperative, while I was at work, in which they left a message stating for me to call them, and left a phone number. The problem was that I don’t have a convenient time to call them during their business hours. Now this really didn’t surprise me, because I had already decided that Polk Burnett would probably be less then helpful when it came to telling me how to generate power for myself. I would like to take this opportunity to clearly point out that through a somewhat humbling experience in working on this project, and out of all the dealings with on-line orders, shopping for parts etc. I am happy to report that it turned out that Polk Burnett Electric Cooperative was the EASIEST TO DEAL WITH. Back to the story. Because of the hours I work, it isn’t terribly convenient to talk with people on the phone, I stewed on this lack of email reply for a few weeks and then decided to write a somewhat polite new form mail explaining that talking to someone on the phone during their working hours was not exactly easy for me and then I laid all my questions out as best as possible in an answer, “Yes” or “No” format. I then got a prompt reply to my email in which they did answer the questions that I asked with “Yes” and “No” answers as well as some explanation to the points that I was little fuzzy on, and they pointed me to other documents to read for more information. Polk Burnett also has a flow chart that sort of graphically explains the process of being approved for co-generation system. Here is a PDF version of the Question/Answer email that I sent. The questions with the answers are toward the bottom.
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Time to do the paper work! |
You fill out an application form in which you detail specifics of your proposed generating system. In our case I filled out the application as detailed as I could, however I was still undecided about which inverter I was going to use, so I attached data sheets of two different grid tie inverters, and I highlighted the specs. I also put a note in the comment section that purchasing the equipment was pending the approval of co-generation. They also require a single line drawing (SLD) with the proper ANSI (American National Standards Institute) symbols that depicts your electric service and how the co-generation system interconnects to it. They also request some kind of layout drawing so that they can tell where the generating facility is, and where they can switch it off, etc. ALSO NOTE: That filling out the application is not any kind of binding contract. During the approval process if you change your mind and decide not to continue, that’s okay. Also depending on your current power entrance, the cost of upgrading it to co-generate might make you decide it is not worth it.
Once Polk Burnett receives your application, they look it over and also check what they have on file for your current electrical service to see if anything needs to be upgraded in order for your electrical service to properly handle the generation system that you are proposing to install. If something does need to be upgraded, or they need more information from you, they will let you know. Otherwise if everything checks out okay, they will then send you an approval letter, basically saying go ahead and build your system, and then contact Polk Burnett when your system is installed and ready to be tested. In our case we filled out the application form as well as we could, we created a single line drawing that showed all the major components of our current electrical service entrance, and the proposed solar generator, which shows a disconnect switch and how it is back-fed through a circuit breaker on our main distribution panel. We enclosed an overhead picture of our property, and I used a computer paint program to draw lines in for our existing service, as well as the proposed solar panel system. Within about a week we received an application approval letter from Polk Burnett Electric, briefly stating to go ahead and build the system.
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NOTE: These are links to the documents that were current at the time of this writing. They aren't necessarily current at the time that you are reading this, so please use these as examples only.
TIMEOUT! I don’t want to deal with all this mumbo jumbo…
We chose to do it all because we figured, why not try? What do we have to lose? |
Approved! |
So, at this point, we have a rough idea of the cost, we have an official “okay” from our power company, so now it is just to make the final decisions on what we want to buy and how we are going to install it. In a nutshell, for us making these decisions and getting to this point, probably represents about ½ of the time spent on the total installation. |
What we are going to put them on?
SnapNrack System Got Auger? Got Wood? |
We have a good idea of where we want to put our solar array, but what do we put it on? A quick list of options includes, wood, and variations of steel pipe, or any other way you can think of to prop up your panels. Keeping in mind of course that it would be very unpleasant to watch your investment blown away in the first thunderstorm that comes along. For me this decision was very difficult for mostly two reasons. One there isn’t really an abundance of detailed pictures on the Internet of ground mounted solar arrays. They are out there, you just have to look at a lot of roof mount installations in the process. Two, in the beginning of my research I was really only interested in some means of the array being adjustable, to get the best performance of the system as the seasons change. I do not regret doing the research at all, however every adjustable system I found either weighed heavily in the cost department, seemed complicated, or I was worried about the blown away in the first thunderstorm factor. Ultimately, I came across one website that completely changed my mind on the whole adjustable array concept. I don’t remember the words exactly, but it basically said, that an adjustable array will potentially yield about 30% more production, so rather that add the cost of a more expensive and more complicated mounting system, just add 30% more panels, mount it, and leave it alone. I don’t want to say that an adjustable system is by any means wrong, but right now we are interested in a fairly large, sturdy, long lasting trouble free mounting system as we can get. In my research that led me down two paths. It was more or less a toss-up between IronRidge, and SnapNrack. Both systems have a very effective on-line design tool, where you basically plug in information about the panels you want to use, how many, what wind conditions it will be exposed too, and so on. Ultimately for us SnapNrack won out, due to the fact that it is constructed with smaller more manageable pipe. Since a lot of the time, it was just my wife and I working on the installation, not needing special equipment to deal with very heavy pipe was very appealing to us. Now I should note that light pipe does not make it weaker, in fact with the bracing and so forth it might actually be a little stronger, but I don’t care to make that claim. It really comes down to the fact that since the SnapNrack system uses pipe that is half the size of IronRidge, you end up putting twice as many anchors in the ground, and with bracing you probably end up using about twice as much pipe. For this reason, the cost of either system is very comparable to the other, so it really was a choice of which size pipe do I want to try to lug around the yard. |
I started by making some crude CAD drawings, to get some idea of how the system would be laid out, and what the angle measurements should be.
Anyone with some basic knowledge of geometry could probably whip these numbers out with a calculator. Anyway, armed with some layout measurements, and a tape measure, my wife and I went out and put some stakes in the ground just as soon as the ground was soft enough to drive a stake into.
We used one of the 21ft pipes for the Horizontal run to suspend the vertical piers with the SnapNrack "tee" fittings, and the "X" support frame. |
As I previously mentioned, the SnapNRack system has an on-line design tool, so all you need to do is input the specifications of the system you want to build. It then creates an Excel file that lists all the materials you need, approximate dimensions of the lengths of pipe, and even an estimate of how much concrete that you will need. Originally, I wanted to build a 10 kilowatt system, and I was looking at doing it with 250 watt panels. So, in the design tool I specified mounting 40 panels in a landscape configuration that would be arranged in 10 columns each being 4 panels high. (40 panels X 250 watts each, equals 10,000 watts).
In our system there are 16 piers, 8-front, and 8-back. The design tool shows different depths for the front and back piers, but we augered 12 inch holes, 48 inches deep for all the piers. We suspended the vertical pipes in the hole surrounded by a premade re-rod made up of 3, 6 inch circles welded to 3 vertical rods. Most people would probably say the re-rod was not necessary, but I figure if I’m going to pour cement, it will have some kind of re-rod in it as well. We also mixed in the nylon concrete fibers with each batch of concrete simply to help strengthen the mix. For us the whole idea of going with a ground mount system is that hopefully the ground mount will far out last the solar generating components, so eventually when it is time to replace the array, then new panels, and probably electronics can be put right back on this long lasting mount. We’ll see how it works out. To go into a little more detail about the SnapNrack system, as well as the IronRidge system. The Idea is that you buy all the connecting components, and panel mounting rails etc. in kind of a kit. Then the structural pipe that you will use can be purchased through a local supplier. In our case we ended up getting all our 1-1/2 inch schedule 40 galvanized pipe from a local Menards store.
The ground was not exactly level so the wood bracing is bolted together to allow it to pivot. This way the support height can be easily adjusted by the distance that the legs of brace are spread. Once we had the support bracing up and located where we wanted it, we measured across to horizontal pipe to mark the locations of the vertical pier. We then dropped a plumb bob to give us the location to auger the hole. We placed the re-rod assembly in the hole, and then a custom cut vertical pier with a piece of re-rod welded to it as sort of an anti-rotation 'key'. All the vertical piers were suspended approximately 1 foot above the bottom of the hole. Since we were mixing our own cement, we did 2 to 3 piers at a time. Once everything was setup, we mixed the concrete and poured it in via a wheel barrow. The square form is made of 2x6 boards and is 18" X 18" (inside), and it is mostly for looks. Its functional purpose is to allow me to weed whip around the vertical pipe, without actually whipping the pipe, thus helping to preserve the galvanized plating and prevent premature rust. |
Installing the ground mount system.
Since the desired face angle was 45 degrees and we couldn’t really depend on measuring from the ground, we set the two front pier outer corners, one at a time. We drove stakes in the ground, approximately 3 ft square around where the pier was to be placed. Sorry I never took a picture of this, but the idea here was to clamp boards to the stakes at the right height. Then we could place a horizontal pipe across the boards to suspend the front pier at the right height and location to produce the 45 degree angle. At this point we simply temporarily mounted one of the solar panel racking rails with a 45 degree level on it to adjust the suspended pier, and hold it in place until the poured concrete set up. Once we had both the outside corners of the front piers placed and the concrete was hard, we then placed a string line from one to the other so that we could mark and stake drill holes for the remaining front piers. When we were ready to set the piers, we did 3 at a time using supports that we made up from the existing square cement forms that were used on the rest of the piers. We suspended the pipes with the forms using the string line to guide the height and location. |
Suspended vertical piers ready for cement. | Vertical pier with re-rod suspended in drilled hole. |
Ground mount piers with bracing. |
Time to rough in the electrical.
We laid two conduits underground from the main power panel to the inverter power panel out at the solar array. The bigger 2” conduit has the #4 awg wire for the 240 VAC circuit running in it. The smaller 1” conduit has the CAT5 ethernet communication wire running in it. For the ground wire it simply worked out really nice to lay it in between the two conduits, in which it was connected to two ground rods, in the conduit trench. We put one ground rod basically right under the power panel, and then another one ten feet out from the panel but still in the trench. The conduit was buried a minimum of 24 inches deep. To make sure we stayed on track with the depth we made a simple wooden gauge that we dropped in the trench and slid it along as we dug. |
2 poles for the future power panel to hold the solar inverter. We augered 6” diameter holes 48” deep. We suspended the poles about 1 foot off bottom in the same manner as the piers. | |
Main power panel. On the reverse side is the meter box, and the main distribution breaker panel. On this side the upper left box is the future Solar Interconnection Disconnect Switch. The Wisconsin rules of co-generation requires this switch to be lockable (Meaning it can be switched off, and a padlock can be put on it to “lock” it in the off position.) for safety reasons, so that the power company can lock out the system while performing repair or maintenance to the local power grid.
NOTE: Part of the co-generation agreement with Polk Burnett Electric, is that they can come on the property and lock out this switch, any time it is necessary to perform work on the grid. The box on the lower left is a junction box that is serving more or less as an adapter, sizing down the 2” conduit to 1” which fits the switch box without modification. There are many ways we could have downsized the conduit. I chose the junction box so that I could leave a loop of extra wire in there just in case I need it in the future. The Box mounted lower on the right side is a disconnect switch that completely shuts off the power coming from the grid. I installed that more for personal preference, and protection then necessity. |
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The Future solar power panel. We originally intended the panel to stay very much like this, with the inverter and junction boxes mounted to them and just leave it that way. The Inverter is designed to be indoor/outdoor, they just don’t want it placed in direct sunlight, or other extreme environmental conditions. Otherwise it is designed and supposed to handle being outdoors just fine. | |
Trench leading to the main power panel. The trench is a minimum of 24 inches deep.
NOTE: Please don’t throw caution to the wind here. Call to have any underground systems located before you dig. |
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To make sure we stayed at the proper depth we made kind of a depth gauge. ( The ‘T’ shaped 2x4 thing laying on the left.) As we went along, we dropped that in the trench to see actually how deep we were. It was quick and easy, and seemed to work quite well. | |
As previously mentioned, the larger conduit contains the power wires and the smaller conduit contains the network communication cable. Since at peak power the solar inverter could be outputting as much as 45 to 50 amps we wanted a little bit of space between the two conduits to help prevent the electromagnetic fields of the heavy current from effecting the communication wire. They could have been spaced apart with anything, but I printed spacers which made it very easy to provide a place to clip the ground wire into as well. Here is the STL file for anyone interested in using it, or getting a better look at it. | |
Grounding the System. Here we have two 8 ft. ground rods placed 10 feet apart from each other. We figure more grounding is better, so even though the electrical system was grounded with two 8 ft rods on the other side of the power panel at the time of the service entrance upgrade, we added two more ground rods shown in this picture. The Ground wire shown here is leaving the main power panel and going out to the inverter panel where it loops into the solar inverter, and then back out to two more 8 ft. ground rods that were placed on the south side of the array.
Why is grounding important? Properly grounding your system has much more to do with preventing the lightning strike instead of arresting the lightning after it hits. If an electrical system does get hit by lightning, there is very little that can be done to protect or arrest the electrical currents as the voltage generated by the strike drains off. A properly grounded system tends to drain the potential differential energy in a controlled manner, and thus hopefully prevent the lightning strike from ever happening. |
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The soil we have here is a heavy clay mixture that doesn’t drain real well. When it came time to fill in the trench, we covered the conduit and ground wire with a few inches of heavy soil. Then we partially filled the trench with rock to act as a drainage ditch out to the pasture area. Hopefully that will help drain off some of the snow melt, and extra water during the spring time. | |
Solar Inverter Power Panel. The more I thought about it, the more I couldn’t stomach the idea of the brand new solar inverter (Fronius) being directly exposed to the weather. We found what I like to refer to as an outdoor closet at Menards. it is basically a simple to put together small plastic shallow storage building that you might put some shovels, rakes, or garden supplies in. To prepare for mounting the ‘Fronius Closet’ we poured a slab of cement.
NOTE, the small wood box, around the conduit, and the short pieces of PVC around the two poles. The idea here is knowing that the cement slab is going to move around a little bit, due to the frost, we are hoping to isolate the slab from the poles and the conduit to allow the slab to move without putting pressure on the poles and conduit. We’ll see in a few years how that all works out. The PVC was a cut from an extra piece of conduit that I split in half with a hack saw. I then taped it back together around the poles with electrical tape. The re-rod has vertical threaded rods welded to it to eventually bolt down the ‘Fronious Closet’. |
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Here we have the cement finished, and the ‘Fronious Closet’ all mounted in place, ready to have a solar array built around it. This set us back a couple weeks, but for now I really like the way it turned out, and I think it will end up being well worth the small investment, and delay in completing the project. | |
This picture is a bit of a ‘fast-forward’ as you can see that most of the wiring is complete. We decided that since we now have this nice little enclosed power panel, that a couple outlets to plug into would be nice as well. More importantly though, since knowing that the solar inverter is going to generate some heat while it generates power, we needed a means of exhausting the heat out of the closet. The silver box above the panel is an inexpensive bathroom fan, which will eventually be controlled by a temperature controller to exhaust heat out as necessary.
The large box with the exposed wiring is the mount for the Fronius solar inverter. The D.C. voltage comes in from the solar panels on the left side. The RED wires are simply black wires covered with red heat shrink to differentiate the positive and negative leads. The A.C. voltage goes out the right side. The large WHITE wire again, is simply a black wire with white heat shrink, to show that it is the neutral wire. The large bare wire is of course the #6 awg ground wire that I mentioned a few pictures up. The smaller wires are the ‘Hot’ (L1) neutral and ground of the small branch circuit to supply power to the outlets and fan. |
Let’s Get’r Done!
So now we have a ground mounted rack for the solar panels, an electrical circuit to tie in to the main electrical service, and a place to mount the inverter in which we can tie in the electrical power coming from the solar panels. For us the next logical step is getting the panels mounted on the rack, and getting the system running! |
Let’s make these things useful!
String Theory isn't just to describe the Cosmos |
There are basically two major types of grid tie solar inverters. String Inverters convert the DC electricity from a group of solar panels wired in series into usable AC electricity used by your house and the electrical grid. Micro Inverters convert the DC electricity from a single panel, or in some cases a pair of panels into usable AC electricity used by your house or the power grid.
Since this system uses a String Inverter, that is what we will be explaining in detail, but I would like to point out the pros and cons of both.
String Inverters are basically one large inverter capable of handling the entire array of solar panels, so they are typically less expensive than a group of Micro Inverters that would handle the same size array with the same power output. However, a string of solar panels wired to a String Inverter depends on the exposure of sunlight to be the same across the entire string to work at its full potential. If something like a tree, or maybe a dormer shadows one of the panels in the string, then the entire string will be reduced in performance to the level of the shadowed panel. A system with Micro Inverters takes the power from each panel, so each panel is not affected by the exposure of sunlight to the panel next to it. So even though Micro Inverts may cost more to install, they may greatly offset the extra expense of installation by the better performance. This is completely dependent on your individual location and how your array will be exposed to the sun.
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Home Runs aren’t just for Baseball anymore! |
These are the Home Run conduits leading to the junction box that transition to the flexible conduits that go to the Fronius inverter. These conduits are anchored to the back side of the panel mount rails using the snap in bolt mounts, and the conduit clamps that we 3D printed. |
If you look closely at the picture to the left you can see the conduit ends at a TEE fitting. We used the TEE fitting to extend to end fittings where we brought the Home Run lines into the conduit. We printed the plug below to serve as kind of a grommet. We simply ‘glued’ them in with silicone sealer. |
snap-n-rack_conduit_pad_01.stl This printed spacer was used with the snap in rail anchor below, to mount all of the conduit fittings, in order to stand them off of the rails the same distance that the conduit clamps hold the conduit off of the rails. |
Here we have the conduit clamp assembled with 1/4” bolts held by the SnapNrack mount, which you can see up inside the rail. We used nyloc nuts, but that probably wouldn’t really matter. |
conduit_j_box_lid_01.stl The Junction box is actually a switch, or outlet box. I was not able to find blank covers for them, so I printed covers to fit. |
conduit_wire_plug_01.stl A 3D printed plug that we pushed into the conduit fitting, to protect the wire and keep stuff out of the conduit. |
snap-n-rack_mnt_base_01.stl This is the printed snap in anchor that was used for mounting all the Home Run components to the rails. We simply inserted the right length 1/4” bolt so that the head was captured in the hex pocket. |
snap-n-rack_conduit_clamp_01.stl |
All the AC wiring is done. All of the DC wiring that deals with any exposed wires, or tightening terminals is done. Now all that we have left are unconnected solar panel DC wires that all have connectors on them. The only thing left then is to start hooking the panels together one by one, in a string fashion. I started at the bottom panels and with the Negative side, I attached the Negative panel wire to the mating Negative connector of the first Home Run line. I then proceeded across the array hooking the Positive wire of the previous panel to the Negative wire of the next panel. When I got to the end I connected the remaining Positive panel wire to the mating Positive Home Run line which completed the circuit for that string. I repeated this with all four strings to complete all the DC wiring. |
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Connecting the panels into strings |
The SnapNrack system bill of material called out some wire management clips that snap into the rail and are designed to hold wires in, so that you can kind of use the rail as a wire trough. The clips certainly pop in tight and would do their job nicely, and if I were stringing the panels together in a vertical fashion this probably would have worked just fine. However, we had set everything up to connect the panels together horizontally across the array. In this case we really didn’t have any way to support the individual panel wires that made up the strings. Our solution was to go buy the cheapest 1/2” pvc pipe that we could get. We originally used zip ties to strap the pvc pipe to the underside of the panel mounting rails. We did four horizontal pipes across the array, which provided a convenient support structure to tie the panel wires to. I later made some clamps and anchors, again using the 3D printer, to make solid permanent mounts for the pvc pipe. It all came together quite nicely and added very little expense to the system. Wire management is critical in building a long lasting system. Any wires allowed to flap around in the wind, or have the weight of snow or ice build up on them are going to seriously reduce the life of the system. |
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s-n-r_pvc_mnt_base_02.stl s-n-r_pvc_wire_support_clamp_01.stl |
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Turn on the Sun! Let's generate some power!
NOT QUITE YET, but almost! |
So, we have the system completely built, wired, and ready to turn on to see whether it all works or not. THE MOST IMPORTANT REASON WE ARE STILL NOT READY TO TURN THE SYSTEM ON AT THIS POINT, IS BECAUSE THE POWER COMPANY STILL DOESN’T KNOW THAT THE SYSTEM IS READY. The following is a “check list” of sorts to make sure everything is done prior to having the power company visit and if all goes well, they will install the new smart meter that will interconnect the system to the power grid. You will sign an Interconnection agreement, and then you are approved to run your co-generation facility. |
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All comments are welcome!
Positive or Negative. If you would like to make a comment,
please E-mail me at dean@crexrealty.com.
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Decisions, Opinions, and Stories…
The number one reason for keeping our solar array ‘On-Grid’ is because we were already on the grid. We wanted to generate our own electricity, but it is a really big step to become your own power plant. I will be the first to admit that I have complained about paying my way too expensive electric bill ever since I had to start paying it. However, if you think about it for a little while, you will realize how inconvenient it is when the power goes out. We have become so dependent on electricity, that it really upsets our lives when we don’t have it. Now, right here would be a good argument for being Off-Grid so that you never have to depend on the big bad power company again. Right? I am not trying to be a commercial for your local power company in any way, but from our experience the power that we buy from the power grid is pretty darn reliable. When the power does go out for some reason, we can be very confident that some one is out on the job trying to fix the problem. So, to put this in perspective, it seems like we can never walk into a Walmart without spending a hundred dollars or more, but yet we sorely disapprove of paying for our monthly electric bill. I personally believe the only real phone is one that still has a cord attached to it, and yet I know many people who pay as much or more for their cell phone plan as they do for electricity.
During my research on Grid-Tie compared to Off-Grid, I found out that there really is no middle ground. The components that make up a system are either designed to use storage batteries, or they are designed to not have any storage and be connected to the grid. You certainly could design a system capable of doing both, however, I believe the cost would quickly out weigh the benefit of designing such a system.
It is my opinion that at this point, battery technology simply is not good enough to compete with being on the grid. Batteries wear out, lose energy due to heating while they are being charged, lose energy due to heating while they are being discharged, and also lose energy just sitting there. At the beginning of this whole project, the 1st objective was to build a power generation system that will pay for itself in as little time as possible. At the time that we made the decision to install solar panels, a grid tie system seemed to be the best way to do this. Please don’t get me wrong, I am still looking for the perfect energy storage solution. I just don’t believe that right now, batteries would be a good investment. A couple things that I would also like to point out. Hypothetically speaking, let’s say that you have a solar array with a battery bank that is capable of storing 3 days worth of power. Obviously you can manage your power usage, for example, save bread baking or cloths washing for the sunny days, and try to minimally use appliances at night, or on cloudy days. Now let’s say you have two weeks of beautiful sunny weather, and after one week all your clothes are washed, bread is baked, and life is good. When the batteries have reached full charge, they can’t take any more. To do so, will damage the batteries. This means that at the end of all your sunny days you still only have 3 days of reserve power. Now, compare this to a Grid-Tie system where every day that is sunny will put power into the grid, of course, this is any power above what you are currently using. So, going back to our hypothetical situation, when the bread is baked and the clothes are washed, your solar array continues to put power into the grid, which will never become fully charged. As long as the sun is shinning the system keeps outputting, and the Net Meter keeps track of power going out compared to power coming in. This very reason is why it is such a big step to go from being on the grid, where you simply plug in your appliance and let it run, compared to being off the grid, and constantly managing how much reserve power you have left.
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I didn’t even know the name, Fronius, until we had spoke with with the owner of the solar power outfit that I mentioned above. He had talked up Fronius by explaining that Fronius is world wide, but they have USA head quarters right down in Portage, Indiana and if you have any questions or trouble, that Fronius has great support. When I checked into Fronius myself, I found out that they have been making welding equipment for a very long time, and have been using inverter technology in that equipment as well. Now, this all sounded good, but when you get right down to it, Americans can make some pretty good stuff too. I started searching for solar grid tie inverters to see what was available, especially made in America. If you look, you will find some American made inverters that are supposedly actually made in America. However, the ones that I found have not been in business long enough to prove themselves. We simply were not prepared to take the risk of a large investment on an inverter that is made in USA with out some substantial history of performance. I came across the “Sunny Boy” made by SMA who proudly promotes that they are USA based. It might be stupid, but I really liked the name, and that kept me interested enough to really look into what they have to offer. The Sunny Boy has a unique feature that apparently no one else had thought of, but I thought was really great! This feature is a separate “emergency” outlet that is isolated from the grid tie circuit. So if your power is out, meaning your solar array is shutdown for safety reasons, but the sun is still shining, it can output up to 2000 watts of power directly from the solar panels. Here is a link to a website that explains it in more detail.
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