Introduction: 6.3 KiloWatt Ground Mount Home Solar Array

Picture of 6.3 KiloWatt Ground Mount Home Solar Array

For several years, I have toyed with the idea of installing my own solar array. In that time, I have done a lot of reading and research. I have eyed systems on Amazon, Wholesalesolar, and Ecodirect. I finally purchased 4 panels after getting bids from several places and installed them on my roof. This was my "pilot" project. A proof-of-concept to show my wife that it wasn't that difficult, I could do it, and it would save money.

I finally convinced her it would be a worthwhile project to add 24 ground-mount panels in late fall of 2016 because 1) The $2000 state tax credit has a high likelihood of getting phased out in 2017, 2) I found a very reasonably priced source for panels and inverter, and 3) February is close, so the tax credits would be received with the tax return in just a few months.

I outline the steps I followed here in case others can benefit from lessons learned.

This kind of project is not for everyone. You are dealing with high voltages and/or currents. Things have to be designed and installed correctly as there is a risk of damage to property and lives. I am an electrical engineer and I have a brother-in-law, co-workers, and a beekeeper friend who are electricians. This is not a requirement, but was very helpful. The equipment used must be UL-listed and meet building code requirements. The power company requires a building permit to ensure everything is done correctly. For example, a back-feeding inverter could electrocute a power company employee working to repair downed power lines. If you are a DIYer, have your plans reviewed by someone who knows what they are doing!

Another excellent Instructable on the basics (a little more generic than mine) is located at

If you like my project, please Vote for it!

If you are interested in pursuing a project and would like to speak to my "solar guy", send me a private message through Instructables and I will pass on his contact info.

Step 1: Planning

Picture of Planning

I had considered adding more panels to my roof. I even laid out how many and where my panels would go. But there are disadvantages to filling up your roof with panels (replacing shingles). There are advantages to a ground-mount system -- snow removal is easy and by utilizing a manual tilting system, my "solar guy" says I can produce 1 MegaWatt more per year than a similar roof-mounted system. This would require manually changing the angle several times a year - 0 degrees in summer, ~30 degrees in spring and fall, and 60 degrees in the winter (for Utah).

The disadvantages to a ground mount system as I saw at the time were the distance involved, which increased the voltage drop and required larger wires and additional cost. I would also need to trench ~400 feet.

Step 2: Sizing

Picture of Sizing

You can find a lot of information about sizing solar array's online. I just need to say that for me, there is no incentive to size it larger than my average yearly usage. My solar guy provided a report that based on my location, I can expect about 11 MWh per year (11,000 kWh) of electricity from 24 255 Watt panels and a 6000 Watt inverter. I figure the 4 panels on my roof will make about 15% more. My power company provided a 2-year history of my usage when I created an online account. In 2014 I used 12.5 MWh, in 2015, it was 11.5 MWh. So I'm in the ballpark.

You can visit PVWatts, which is a database of locations and will estimate what your output would be based on the number and output of your panels.

Step 3: Net Metering Application

The regional power company, which owns the grid and supplies power to my home, does have a net meter program. They require a building permit to ensure everything is completed according to the building code. They require an application to participate in net metering. The information required is very basic, including the model of the inverter and the expected output of the system. They accepted the PDF application via email and acknowledged that they had received it. They also emailed when it was approved and gave me 9 months to complete the project. Net meter application attached.

Step 4: Panel Orientation

Picture of Panel Orientation

You can find a lot about this on the Internet. But the solar guy convinced me with his demonstration that in areas that receive a lot of snowfall, the landscape orientation works best. He had a small fan connected to a panel. When he placed cardboard over the panel while it was in portrait orientation, the fan shut off with only about an inch of the panel covered. When he covered the panel in landscape, the fan continued to run until it was 2/3 covered. This has to do with the way the panels are wired internally. To make a long story short, all 3 internal circuits open when the bottom of the portrait-installed panel is covered. But 1 of the 3 internal circuits are still closed when the bottom 2/3 of the cells are covered on a landscape-installed panel. Yes, it only produces 1/3 or 2/3 of its potential, but it is still producing something.

I would guess 95%+ of array installations I have seen in Utah are done in portrait. It is much easier and faster to do a portrait-mode installation. But it will produce less electricity than a landscape installation. At some point, I plan on re-orienting my existing 4 panels on the roof.

Step 5: Obtaining the Building Permit

Picture of Obtaining the Building Permit

Step 2: Obtaining the building permit from the city.

Although I am an electrical engineer, I do not know the building code. With some help from the "solar guy", who is selling me the panels and inverter, I was able to get the building permit through the AHJ (Authority Having Jurisdiction). This is the guy who is the code expert and is contracted by my city to ensure my project will be done properly (at least according to him). Because permits are very specific to the local jurisdiction, I am not making my building permit available. I am sharing the single-line drawings. This step took hours and hours. It required my submitting it twice to the city, having two reviews, several conversations with the AHJ, and finally receiving back the permit with "redlines", or changes that the AHJ required. My permit required:

Panel specs (JA Solar JAP60-255/3BB)
Inverter specs (Sunny Boy 6000-tl-us)

A photo of my main supply panel and meter
A single-line drawing
A site-map with the layout of my panels and location of inverter
Engineering for the ground-mount system
A list of required labels (yes, there were tons of labels required)

One quick story - I had intended to mount the inverter in the garage. The AHJ told me I would need a rapid shutdown system. This is a button placed in a convenient spot for the firefighters to press if they are fighting a fire at your home. Once the button is pressed, there is no voltage on the PV wires so they can safely cut into the roof or walls. This was an added cost I had hoped to avoid. And everything I read about says it was intended for roof-mount systems, not ground-mount. The AHJ told me if I installed the inverter "in or on the house", it needed a rapid shutdown button. The solar guy told me I should mount the inverter on a couple of poles set next to my house. The AHJ agreed this would work. He was gone for a week, and when he returned, I received a phone call from him. I had included a drawing with the inverter mounting shown. He indicated he wasn't sure about the way I was mounting the inverter on the two poles. He told me he thought the best way would be to mount it to the house. This sure seemed like a contradiction to me. He is OK with the inverter mounted on the outside of the house but not inside the garage. At this point, I let the AHJ have the reins and told him that sounded like a great idea!

Step 6: Selecting a Ground-mount System

There are a couple of caveats I want to mention. I had planned on using a ground mount system that my solar guy had designed. It uses Unistrut for the structure and IronRidge racking for the panels. I knew I would need engineering completed. The AHJ stated in no uncertain terms that I could not use Unistrut. This material does not meet the UL2703 grounding standard for solar. Rather than arguing with him and getting on his bad side, I elected to go with a pre-engineered system. I ended up buying a system from Snap-n-rack. This cost ~$2400, where the Unistrut system would have been around $1000. Disappointing, but ultimately, the engineering for the Unirac system would have cost around $800. And the additional $600 only increases the payback by a few months. It came with documentation proving the engineering specs. The city requirements were to withstand 150 mph winds and a 43 psf snow load.

Most of the ground-mount systems out there had ridiculous requirements for the holes. One of them needed 10 holes, 7.5' deep and 24" in diameter. That would have required 5 yards of concrete! Some of them weren't designed for a 2 x 12 array. I liked the Snapnrack because the 12" diameter hole was much more reasonable. The back holes were 5.5' deep with the front holes only 3.5'. It also looked fairly simple to assemble. The online design tool shows the basic design (PDF attachment). It consists of vertical pipes set in concrete in 12" diameter holes. Pipe fittings are used to connect these to horizontal pipes that make up the beams. The rails are connected to the beams using straps. The panels then connect to the rails with clamps.

Step 7: Trenching and Drilling Holes

Picture of Trenching and Drilling Holes

I rented a trencher and an auger on a Saturday, thinking I could get both items completed. The auger was a one-man machine on wheels that was hydraulically powered. It was also a big pain. I would have been better off with a skid-mounted auger. What I thought was going to take an hour or two ended up being more than 5. And I was exhausted. But I plowed ahead and rented the trencher. That was a beast. It was very difficult to control. It had rained recently, and all of the shaded areas were wet which made the wheels slip. My trenches are not very straight as a result. I learned to trench halfway to 18 inches, then trench again the rest of the way. I finished after dark. I don't know if I have ever been more tired.

The city required an inspection of the trench and footings, which I passed with flying colors. It helped that they didn't look at the holes. It was rainy, making everything a mud mess. The building inspector checked my trench in several places to make sure it was over 18 inches deep and then went on his way.

Step 8: Concrete and Vertical Pipes

Picture of Concrete and Vertical Pipes

I purchased concrete from the local hardware stores and mixed by hand. It would have been nice to have a cement mixer and in hindsight, I should have bought one from Harbor Freight. It took more than a week to get all 12 pipes cut and set in hand-mixed concrete. Snapnrack design requires you to purchase 23' lengths of 1.5" galvanized pipe. I had to source that locally. I used a freeware program I found online to optimize the use of the pipe. Snapnrack overestimated the lengths, but I supposed that is better than under-estimating. I ended up with 2 extra lengths.

As you can see in the picture, the rear pipe is longer than the front pipe, and this determines the angle of the solar panels. I had planned to be able to manually tilt my array, but I lost this capability because I could not use the Unistrut design. I do hope to go back at some point and add the ability to tilt. But that is a project for another day.

Step 9: Conduit and Cable Sizing and Pulling

Picture of Conduit and Cable Sizing and Pulling

My next step was to run the wiring from the inverter mounting location to the array location. My inverter is a Sunny Boy, and they have a great online design tool. To limit my voltage loss and cost, it calculated that I needed to use 4 gauge aluminum wire. I bought 1800 feet of it but was given 2000 feet. I wish they had told me that. I pulled the wire from the house to the array one at a time. I was worried I wouldn't have enough and the first couple of wires were cutting it close. When I realized I had more, I left the last 3 much longer.

I then laid out the conduit. Conduit sizing rules stated that I needed 2" PVC conduit to fit my 5 wires - 1 ground and 4 conductors. I thought I might be able to slide the conduit down the wire and then glue the conduit together. But code requires the conduit to be glued together and then pull the cable. I have a beekeeping friend who is also an electrician. He supplied me with pull string, twine, and oxtail rope along with a "mouse" I sucked through with a shop vac. I used the mouse to pull the string to pull the twine to pull the rope to pull the cable. I divided my pull at roughly halfway, then had to glue one joint in the middle. I do think dividing the pull made it easier, but it took more time. I was fortunate (I guess) to have my two boys help me, as you can see in the picture.

Step 10: The Inverter

Picture of The Inverter

The inverter is where half the magic happens. The other half of the magic is the solar panel itself. The inverter takes the variable 300-600 V DC (depending on brightness of the sun) from the panels and converts it to 240 V AC. You can find many discussions about whether to use a string inverter or micro-inverters. My opinion is that micro-inverters are a superior technology, but they are also more expensive. With string inverters, the panels are connected in series, with each panel adding it's own voltage onto the total. This feeds into a single large inverter. With micro-inverters, one small inverter is connected to each panel, and these are connected in parallel. Rather than the voltage adding up, the current is added together, with each micro-inverter producing around 1A of current (depending on panel output).

For me, it made more sense to do a string inverter because:

1) The system losses are less with a higher voltage over the distances I am facing.
2) I was given a discount because the solar guy was closing out the older inverters right before the newer inverters were being released. There was no way I would have ever produced enough electricity to justify the higher cost of the micro-inverters.

The design of the system required two "strings" of 12 panels each. This means I have 2 separate circuits feeding into the inverter. That is why I needed 5 wires between the inverter and the array. 2 positive, 2 negative, and one ground. The above pictures show the color coded wires connected to the inverter.

The inverter also has a disconnect so I can turn the switch and disconnect the panels if maintenance is required on the inverter. This does leave a high voltage on the wires, so care must be taken to disconnect the circuit at the panels if maintenance is required on them or the 4 gauge aluminum wiring.

Code also required the use of a gel to prevent the oxidation of the aluminum. Copper wiring oxidizes, but oxidized copper still conducts electricity. Oxidized aluminum does not conduct electricity. Since this system will be in use for 30 or 40 years, it's best to prevent oxidation right from the start.

Step 11: Building the Snap-n-rack

Picture of Building the Snap-n-rack

Vertical pipes were cemented in the holes. Horizontal pipes were connected to vertical pipes with very slick pipe fittings. Support beams also connected with pipe fittings in enough places to meet the engineering requirements. Finished results are shown in the photos.

Step 12: A/C Circuit and Grid Tie-in

Picture of A/C Circuit and Grid Tie-in

The AHJ required me to install a new sub-panel that is used as a solar combiner. It has 2 circuit breakers - a 20 A for the 4 roof panels and a 40 A for the ground-based panels. This then feeds to a new 50A breaker that was installed in my main service panel. I had a licensed electrician do this work. Because he was my brother-in-law, he didn't charge me anything. It took about 2 hours.

My main panel had multiple spaces, but the AHJ made sure I understood that the 50A breaker had to be installed in the top space, opposite the existing 200A breaker that feeds the panel in my house. The breaker spaces by the 200A breaker are rated for 200A total. The top space is on a separate bus and is rated for 50A. There is potential for damage and fire if the 50A breaker were not installed in the top space. Many homes would need an upgrade of the main service panel to support a solar installation.

I also needed to run conduit from the inverter to the new sub-panel, as shown in the picture. I installed all the conduit, then used a piece of tissue tied to a string as a "mouse" to pull the string, then the twine, and then the
THHN-2 cable. I pulled all 4 8 AWG conductors - 2 x hot, neutral, and ground - at the same time. The Sunny Boy design app specified 8 AWG conductors to keep total system voltage losses to less than 1%.

Step 13: Mounting Rails and Panels

Picture of Mounting Rails and Panels

The rails connected to the horizontal pipe beams with a pre-manufactured strap and rail nuts. The nuts snap into the bottom of the rail and a bolt goes through the strap into the nut. The nut actually bites into the rail, forming a grounding metal-to-metal bond. The rail has 2 straps - one on the high pipe, one on the low pipe.

At this point, I was ready to start mounting panels. The panels mount with the use of a C-clamp that slides into the top of the rail and once again bites into the rail to create a grounding bond. It tightens with a bolt. They also come with a nifty pre-fastened strap that is used to hold the clamp in place while tightening.

I did have a bit of bad luck with my order. The web design function had a bug for my specific configuration - 2 x 12 panels. It sent me rails that were too short. I was supposed to cut a single rail in half to end up with 2 rails. But I ended up with 1 1/2 rails. I discovered this over the Thanksgiving weekend. So I was only able to mount half the panels (as shown in the picture). It took over 2 weeks to finally receive replacement rails due to a lost shipment and a misunderstanding causing them to send me roof rails instead of ground rails. The nice 60 degree weather turned to snow and sub-freezing temperatures. Not a pleasant time.

Step 14: Grounding the Array

Picture of Grounding the Array

Grounding the array is an important step. Lightning does not have to strike the array directly in order to cause damage. Lightning in the area can induce voltages that can cause panels to fail. I purchased an 8 foot copper grounding rod and drove that into the ground under my array. I used a lug to connect a 4 AWG bare copper wire to the ground rod. I connect the bare copper to each of my panels using a small ground lug that fastens to the frame of the panel with a screw. In my particular setup, this is only required once for each column of panels. The rails are electrically bond together to the frames of the panels. So running one bare copper wire along the length of the array grounds the 2 panels in the column.

Step 15: "The PV Wiring Must Be Inaccessible"

Picture of "The PV Wiring Must Be Inaccessible"

I still don't quite get this whole idea. One of the requirements for my building permit was to make the PV wiring inaccessible. It seems like since this a standard requirement, a company like Snapnrack would have a nifty solution like their nifty c-clamp straps. But they don't. What I came up with was to use a "hardware cloth" from the local hardware store. It is a stiff metal mesh. With my first 12 panels installed, I could more clearly see what I needed to do. But I had to go back and remove the clamps I had already installed. I cut holes through the mesh where I needed to put the bolts through to connect with the rail nuts. I then bent and wired the top of the mesh to the panels, making it very difficult for someone (a child) to put their hands in and touch the PV wiring. Not that it really matters, because the wiring is insulated and would not electrocute someone unless they cut through the insulation. The connectors themselves snap together and only come apart by using a screwdriver inserted into a slot. So someone would have to be pretty determined to touch somewhere they weren't supposed to. The AHJ really emphasized this step, so I was worried about whether the building inspector would approve it. He had no problem at all. I also made a "cage" out of the hardware cloth to enclose the wiring that went into the junction box and tied to the 4 gauge aluminum wires going to my house.

Step 16: Final Inspection

Picture of Final Inspection

I originally had my inspection schedule on the Monday after Thanksgiving weekend. The power company doesn't schedule the placement of their net meter until approval is received from the building inspector. I was hoping the inspector would give his approval to my roof panels and the 12 mounted panels. But my hopes were dashed. I was told he could only give final approval once the whole system was installed. On the morning of the day we were scheduled to fly to sunny Orlando on vacation, he inspected my system and gave me final approval! Once the power company was notified, it took about 2 1/2 weeks for them to install the net meter.

Step 17: Finished Product and Payback Time

Picture of Finished Product and Payback Time

These are a couple of pictures of the finished product from the front and back. The snow-covered mountains make a nice backdrop, eh? The neighbors who get the back view were pleasantly surprised and don't mind them. They were really OK with it when I told them some of the ground-mount systems would have been over 12 feet tall.

The project cost totaled $11,300. I will receive a $2000 tax credit from the state, and $3390 from the feds, making the final cost $5910. It is expected to produce about $1500 of electricity per year. Even at a conservative $1400, the simple payback is 4.2 years. If it does produce as expected, the payback will be 3.9 years.

My power company does a simple net meter. When my panels produce more than I use, the meter runs backwards. When I use more then my panels produce, it runs forward. My kwh production is subtracted from the khw used each month, and I pay for the difference. If I produce more than I use in a month, I bank the kwh's. In March, they reset the bank to zero. This makes it so there is no incentive to produce more than I use.

I know several people who have installed solar power systems. I question the economics some of them are getting. Paying $25k-$30k ($15-$18 after tax credits) for a system, without borrowing the money, will result in a ~12-15 year simple payback. If you borrow the money, it adds on another 3-5 years. I wonder how many of those people will still be in their home after 20 years. If you are considering such a system, dig into the numbers the salespeople are giving you and fight back with a healthy dose of skepticism. And a leased system makes no economic sense at all.

Not everyone is going to elect to install a system from the ground up like me. But you could act as your own general contractor and hire out the work to subs and save a lot of money. Then it might be worth it. Buying the panels and inverter from my solar guy helped out a lot too. His prices beat anything I could find online.

After more than 3 months of planning and hard work, I still think it was worth it to install my system.

Step 18: The Future of (my) Solar

I have the ability to add up to 10 or so more panels on my roof using the existing wiring. Why might I do this? My solar guy heats his house with electric space heaters in each room. He also drives a Chevy Volt. He heats his water with an electric heat pump water heater. Adding panels would enable me to do those things. But I can look at those kinds of things down the road. The first thing was to get the panels installed and working.

Another next step is a battery backup system. The Powerwall 2 looks promising, and there are a number of competitors to it that are potentially cheaper. I really like the idea of using less grid power and being more self-reliant. But one thing I have realized is that due to temperature inversions and extended stormy weather, I will never be able to go off-grid unless I install a generator. And with a generator, you are dealing with cost, fuel, and noise. On my worst day so far, I only produced 2 kWh. At a daily average usage of ~25 kWh, I would need over a hundred panels to be completely self-reliant.

In my state, there has been a lot of discussion as the power company has proposed additional fees for solar customers. The state legislature will most likely phase out the state tax credit. While this will hurt the solar industry, I question some of the tactics that are used to sell systems that have extended payback times. And I have a vested interest in a healthy grid, as I want the juice to flow when I flip the switch. But there must be balance, with new fees being fair and not excessive. I buy some philosophical arguments that the solar industry is propped up artificially by the government and that it wouldn't be viable without favorable government policy. But not enough that I didn't take advantage of the tax credits.

The other issue is that the power grid is designed to deliver electricity, not absorb it. In Hawaii, so many people did rooftop solar, that demand in the daytime went negative. And there are issues with base usage vs peak usage that are outlined really well in this article.


ve6cmm (author)2017-12-26

Great Article! I was recently involved in installing 1066 panels in Northern Manitoba, providing almost 300KWh. It is the largest Micro-grid array in Canada. Power for the community is provided by diesel generators which is very expensive so the solar system was installed to cut the cost of diesel during daylight hours.

I have installed a PRE-solar system in my house. I do not have panels installed yet, but as we have several different power rates during the day, I thought that I would install the batteries, inverter, disconnects, etc, and charge the batteries from the grid when the rates are lowest. With the system as it stands, I can run the entire time that the rates are the highest at $0.15/KWh, and consume power only when the rate is the lowest at $0.06/KWh.

I am hoping to install panels in 2018 so that I can go off grid. I have a natural gas generator that will provide power when the solar system is running low.

As it stands right now, I am always running off the inverter. The battery charger, when it is on during the low cost period, has enough power to charge the batteries and run the inverter. Of course, during the night when the rates are lowest, my power consumption is low as well.

This is not as good as a true solar system, but if your power system charges different rates, this is one way to cut your costs without having to put in solar panels.

rramesh68 (author)2017-10-02

Let me start by saying this is a great write up.

I have just invested in my first 100w 12v panel two days ago after having decided to try my hand at converting some of the lighting at my house to LED solar based.That is when I came across this article.

My constraints (though I am an electrical engineer) include solar powered projects being an uncharted territory, lack of much open space in my 80 year old house and excessive tree cover where I have some space for experimenting.

Notwithstanding I am so encouraged to go ahead and thank you for that. I will start small and scale things up.

NoyaFieldsOrg (author)2017-05-26

Great article, awesome explanation and photos. Happy to hear about the timely payback and hope it works out for you.

backinthelab (author)2017-03-05

Excellent instructable, one of the best I've read. I have 60 230w panels sitting in my garage and was trying to figure out if they should go on the roof or ground and I think you've just helped make that decision for me! How is the voltage drop effecting your system? I would also have about a 400' run and that was a big concern for me. Thanks for this great write-up!

kwinana (author)backinthelab2017-03-05

My 24 255W panels have a combined output of 6120 watts. I regularly reach 6100 watts on a sunny but cold day. The voltage drop so far has been minimal. The larger the cable, the lower the drop. My 4 gauge aluminum wire is working great. I was worried once that I would break the cable when I was pulling it. But I got through that and have had no problems. If you use aluminum cable, just be careful working with it and be sure to use the antioxidant paste on it.

jimvandamme (author)2017-01-26

I was confused that Unistrut wouldn't meet the "grounding" requirement, being steel and all; but I suspect it's more complicated than that. I see a copy of the UL code would cost $502 in PDF format, so I wasn't interested enough to find out.

In Germany all this red tape has been standardized, and it costs much less to put in systems there.

kwinana (author)jimvandamme2017-01-26

Unistrut is UL467 certified. But the 2014 electrical code requires solar power systems to meet UL2703. But someone's roof isn't UL2703 certified. Someone's garage or barn surely isn't. What is the difference between that and a Unistrut structure? I was going to use UL2703 certified Iron Ridge racking. Still, it would have required additional cost for the engineering. The cost difference wasn't going to be that much. Rather than argue about it, I just moved on.

JoshB260 (author)kwinana2017-03-02

What you have is simply an AHJ who doesn't really fully understand the meaning of the code requirement. He is simply covering his rear end. This is common, because most AHJ's are just former electricians. They know how to be an electrician and wire a house or a motor, but they don't know the basics of how electricity really works, and so are unwilling to allow anything outside of code even when the code is irrelevant. Frankly, the grounding requirement was probably inserted into the code by a company representative working for a company that provides racking as a way to ensure people had to buy their racking to meet code rather than just cobble together their own rack however they saw fit. About 3/4 (and this is probably low) of the people who get together to write the code are either academics who have never wired anything, or special interests of some sort with something to sell. This is why we have the arc fault requirement on new wiring, even though if it is really useful anywhere it is on really old wiring where the insulation is degrading over time, and a ground is not even present as a safety measure. At any rate, it is best to never argue with the AHJ, just nod politely and say "yes sir" and do what he wants. I've been told by more than one contractor to do something bone headed to get it past the inspector, and the "go back and make it right later".

ai4px (author)2017-01-27

Very nice article. Thanks so much for the behind the scenes details. Also the article about solar making the grid go negative was very insightful. Can you imagine making 99% solar power and only 1% from a generation plant. If a surge on the grid were to cause a frequency shift by 0.5hz, all the solar inverters would go off line all at once. Loads would be shed, cities cut off... and once the grid was stable again, bam all the solar inverters come back on line 5 minutes later all at the exactly same time, exactly the same cycle and the grid trips out. From there it's a nasty repeating event. It would seem prudent for the manufacturers of the grid tie inverters to randomize the time they wait for a grid OK signal.

JoshB260 (author)ai4px2017-03-02

You are not wrong. Currently those big fossil plants have a ton of what is called "spinning reserve" which can resist frequency fluctuations. Without significant storage penetration the practical limit of solar that can be absorbed is maybe 20-25% before thing start to go haywire really quickly.

sunil vijaya (author)2017-02-22

Absolutely great article did business with solar, found hybrid inverters most economical, power suppliers will go bankrupt once every home begins stotage, companies biggest worry is that

sidcypher (author)2017-02-06

I install Solar for a living, and this is a damn good write up.. I personally would have gone with a 4x4 instead of a 2x6 layout as the SnR ground mount rails are made for 4 panels and that would have resulted with less holes. I also would have gone with a SolarEdge inverter over SMA (or enphase as 240v x 450' = huge wire), as the code requirement for rapid shutdown is built in (thought not required on ground mounts), not an extra piece of equipment.

SnapNRack is some good stuff, we use it on every ground mount.

I do not see a knifeblade (firesafety) disconnect, does your AHJ not require that?Our AHJ's don't allow for breakered disconnects.

Please forgive the shading, as this picture was taken about 5:30pm long after the solar window..

kwinana (author)sidcypher2017-02-06

Thanks for the positive comments. Micro-inverters are a great product. But the string inverter was a better choice in my case because of the distance involved and I got a great deal.

It was pretty frustrating trying to deal with the AHJ on the rapid shutdown, because I did a ground-mount and I don't think it should have been required for my ground-mount system. But mounting it on the outside of the house was an OK compromise.

The circuit breakers do count as the disconnect. No knifeblade required from my AHJ. I did have to label the breaker as a rapid shutdown disconnect.

The neighbors behind me wouldn't have appreciated the height of the structure if I had done a 4x4. And I like my neighbors. I want them to like me. So 2x12 worked fine, even if more holes was a pain. The SnR is a nifty design. It went together easy. I just wish I wouldn't have had the ordering issues with them. A lot of that wouldn't have been an issue if I built these things regularly and knew what I was dealing with.

sidcypher (author)kwinana2017-02-06

Solar Edge with DC Optimizers is what I meant, keep that high voltage DC. Instead of optimizing the 2 strings you have, it optimizes at the module level with still (in your case) 2 strings running back to the inverter.

Yeah the Rapid shutdown isn't required at the array for ground mounts by my AHJ, only if high voltage DC goes INTO the house, needless to say we mount outside with ground mounts. The Rapid Shutdown is for DC wires only, your breaker box is acting as the Fire Safety Disconnect. If they flip the breaker you still have high voltage (+50VDC) DC to the inverter (of course that DC disconnect is right there as well), only leaving high voltage DC underground to the array, which is no big deal..

Ya know, I didn't think about that. Where I am is most likely much further south, as we aim for 22 degree's tilt. You seem to be closer to maybe 30 degrees?

Again, awesome job, certainly not for most DIY'ers. We spend a lot of time going behind DIY'er arrays to bring up to code since AHJ's fail it, and lock out/tag out it.

sidcypher (author)sidcypher2017-02-06

Also, as a side note.. Do you have any kind of monitoring system with that? Like an eguage, SMA still hasn't built one into the inverters. Or are you just looking at the screen everyday to see production?

And for anyone else interested in Solar please use dsire to make sure you take advantage of all incentives you can.

kwinana (author)sidcypher2017-02-06

I did buy the data logger card for the inverter. It is installed, but I have yet to run an ethernet cable to it. It hasn't been a priority. I've been too busy at home and at work. One method of monitoring is the monthly electric bill. I'm still waiting for January's. I can also look at the net meter each day.

ELISOL (author)2017-02-04


This is the most detailed and informative treatment for installing solar panels. I was in the process of getting bids for an installation but the article convinced me that it would not be appropriate.


kwinana (author)ELISOL2017-02-06

What is appropriate for one person would not for another. For me, it wasn't worth going through the process unless the system paid for itself. But if you believe in human-caused global warming, then you might be able to argue that the cost is a secondary factor in deciding to install solar.

Daniel434 (author)2017-02-04

Very good article ! Actually we can recondition batteris at home

Thank you Kyle and Jennifer ! :)

gdrozd (author)2017-01-31

I can sell you a 26kWh battery pack

Its from a crashed 2015 Fiat 500e

Battery pack is made by Bosch

gdrozd@gmail dot com

kwinana (author)gdrozd2017-02-01

The timing isn't right for me. I'll look at doing something in a year or so. Thanks for the offer.

gdrozd (author)kwinana2017-02-01

No problem. Ill probably still have it :)

I can be reached at

How much are you asking for those batteries?

kwinana (author)gdrozd2017-02-01

Do they need to be "excercised" regularly?

gdrozd (author)kwinana2017-02-01

They are happily charged at 65%
Thats what they like

JamesM743 (author)2017-02-03

I will definitely do it here in Zimbabwe where we sometimes have electricity.

Mickleblade (author)2017-01-25

wow, what a project for a DIYer. However, would it have been affordable without the tax breaks? My sister makes a load of money from a roofload of panels, great, but in reality everybody elses taxes are paying her that money so it's not fair.

kwinana (author)Mickleblade2017-01-25

With an $11,300 cost, if it saves me $1500/year in electricity, that is a 7.5 year payback without the tax credits. I think that is still reasonable. I would still have ~20 years of free power. Your sister probably pays interest on the loan she took out to pay for the panels and had an expensive install because she didn't install the panels herself. Certainly without the tax credits, her project wouldn't be economically viable (and may not be with the tax credits). I have gone back and forth personally about whether or not I should take the tax credits. Personally, I don't think the government should subsidize solar. But then again, I pay a lot of taxes myself. And I will still pay a lot of taxes even with the tax credits. The Cabela's up the road from me received a very generous tax incentive to build. Is that fair? No. Many internet-based vendors don't require the payment of state sales tax. Very unfair to brick-and-mortar stores. There are many more examples of unfair tax policy. I think the government subsidies should probably go away for solar and a whole host of other things. But while they are there, I do plan to take them.

gravityisweak (author)kwinana2017-01-25

Good points. I like to think that the government propping up solar, at least for a while will be helpful in the long run. It pumped a lot of money into the solar industry to allow for more efficient/cheaper panels to be developed. This moves the solar industry closer to being self sufficient when the government finally does decide to stop helping. It also has the effect of getting many more people to reduce their demand for oil and allows us to buy less oil from other countries, and/or save our own oil resources for a longer period of time. I also like the fact that it allows people like you, to have more control over certain aspects of their lives if they choose to. It feels good to know you don't need the utility company to survive. You may need them for extra comfort and security, but that's about it. Nice instructable!

carbonates (author)gravityisweak2017-01-26

I am all for solar, but this misconception that solar somehow replaces oil needs to stop. Unless you live on a small island in the Caribbean, the South Pacific, in a remote cabin somewhere with a generator, or somewhere in Southeast Asia, electricity is not generated with oil. Solar does nearly nothing to reduce the demand for oil, which is a necessary raw material used to make components of a solar system and is not used to generate electricity. The idea that solar will allow us to import less oil is pure fallacy until the day that electric cars, electric trains, electric airplanes, electric ships, and electric trucks exist and are a significant portion of the transportation fleet (where these do exist they depend on fossil fuels or nuclear power to generate electricity today).

kwinana (author)carbonates2017-01-26

The primary motivation for my project was not environmental, but economic and self-sufficiency. The particular model of Sunny Boy I have has "backup" power capability. It has a separate outlet (not connected to my home) that will produce up to 1500 Watts of electricity I can use to power things during the day. But what you say is quite true. Here we get most of our electricity from coal and natural gas, so rooftop solar does reduce some CO2 production.

mickeytwotimes (author)kwinana2017-02-01

lets get back on subject...what should a person pay forpanelor flexible panels and where to buy How about buying from china?

kwinana (author)mickeytwotimes2017-02-01

The guy I bought from was pretty reasonable cost-wise. The price trend seems to be on the decline. Many of the panels on the market are made in Asian countries. Where are you located? Are you thinking about installing a solar system?

gravityisweak (author)carbonates2017-01-26

I don't remember reading anything here about anyone thinking solar is the end-all be-all. But I'm not sure how you can argue that the author of this post isn't personally going to be reducing his own demand for oil for about the next 20 or so years. Heck, just look at his story about his "solar guy" using it for just about everything, including his car. Solar is currently only a tiny fraction of our energy generation. But the longer it continues to improve, the better chance it has of becoming a bigger piece of the energy market.

carbonates (author)gravityisweak2017-01-27

You said this, which is what I replied to: "getting many more people to reduce their demand for oil and allows us to buy less oil from other countries"

You do not seem to get that oil is not used to generate electricity except in minor and exceptional situations. Solar should be a bigger piece of the energy market, but its presence is irrelevant to the need for oil. I did not argue that the author was not making a valuable contribution, but did argue with your mischaracterization and misunderstanding of the energy market.

gravityisweak (author)carbonates2017-01-27

Not sure where you live, but where I'm from we use giant tanks of oil to heat our homes. I literally burn oil for heat and hot water every day. So whether or not the oil is used to generate electricity, I can stop using oil if I heat with solar instead. So my "misconception that solar somehow replaces oil" is not as much of a misconception as you'd like to think.

jatkins729 (author)carbonates2017-01-26

carbonates, You are right, little baseload electricity is generated using oil. Thus most solar comparisons cite # of homes powered, not oil offset. But since solar is the cheapest source of energy in a growing number of US locations, you might like more up to date info. A reliable site for all things solar worldwide is Also, since we are now hearing a lot about cars, buses, trucks, cities, and even countries power by renewable electricity. A great and reliable site about all that is, including cars, HVAC and others.

tmalovich (author)carbonates2017-01-26

electric cars, electric trains, electric airplanes, electric ships, and electric trucks DO exist and hydroelectric and solar power are significant sources of energy.

kwinana (author)gravityisweak2017-01-26

My primary motivation was economic. As you say, I love having a little bit of extra comfort and security.

KarenJ2 (author)kwinana2017-01-26

The government also gives the oil industry huge tax subsidies. I really don't like my tax dollars going to prop up companies like Exxon Mobil etc. The vast majority of US tax subsidies go to very large corporations. I find it only fair that the government should offer subsidies to average citizens like us. This is especially true when reducing our use of fossil fuels is vital to our very survival. I realize that locally produced, point of use solar is only a partial solution, but it is still a valuable one. Particularly in area's like the northeast. We live in NH and with the high electric rates that we have here, our 8.2 KW solar system that we installed in 2015 generates closer to $3,000 per year. This includes our ability to sell renewable energy credits (REC's) through a regional broker who "collects" the combined total of power generated from individual solar producers, like us, and sells the REC's quarterly in a regional market. We then receive a check from the broker for our share based on our total, not net, production. We have a separate REC meter that keeps a running total of our solar production prior to going into the net meter from the power company. I don't know if they have programs like this in the west but it might be worth looking into.

awisner1 (author)KarenJ22017-01-26

You are so right about subsidies --

kwinana (author)KarenJ22017-01-26

Very interesting. Nothing like that here.

FrankP102 (author)kwinana2017-01-26

It would be nice if you posted specifics of panels and components used in the project. Thank you.

kwinana (author)FrankP1022017-01-26

I added the models of the panels and inverter in the building permit step.

betorobotics (author)Mickleblade2017-01-26

Getting a tax incentive for having a PV array is not unfair to others. If anything there should be more incentives for people who spare others having to breathe in the CO2 that it takes to create the energy they spend. While you may think its not fair for those who pay taxes, its not fair that those who strive to save the air still have to breathe other's pollution.

kwinana (author)betorobotics2017-01-26

I figure everyone has the same opportunity to take the tax credit. They could all install a system just like me. It is fair in that sense. I don't really want to get into a political discussion, and Instructables has a nice comment policy, so I want to be positive and constructive. I don't personally feel like CO2 is a pollutant. If you could ask the plants, they would argue it is an essential nutrient.

Anyway, thanks for the comments and discussion.

cupofsoup (author)2017-01-28

what is the batteries up keep like ,how long do they last , how much do they cost. ive been trying to get solar for ever something always gets in the way , im disabled from a motor cycle crash and can seem to hold a job im slower then other people and depressed most of the time needless to say its hard to get moneys saved up to get solar.i need to find the best way to do this myself ,people just dont gave a dam about sucking the planet dry it seems to me .solar energy ..i feel.. should be at the top of the list and truning salt water into freash water lol another story.the govt should have kicking free solar stuff ,now and a long time ago!geuss what im asking is whats the best way to get hooked up for a guy like me.YOU AND YOUR WIFE ARE GREAT PEOPLE...gary thornton

kwinana (author)cupofsoup2017-02-01

I haven't researched batteries much. If you want to get hooked up with solar, do the research and move ahead if it is worth it to you.

hermanwahsletn (author)2017-01-29

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I live in the Canaria Islands where the sun always shine. As an engineer I might copy this project. However I have enemies, politicians. The bureaucracy level is high and we have to pay a ”solar tax”. If we don´t do the things according to the book, there is a fine up to 60 million Euros.

About This Instructable




Bio: We have 3 boys and homestead a whole acre. We grow a big garden each year and have ~3 dozen fruit trees.
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