Ground Mounted Solar Panels With Adjustable Angles

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I've wanted to experiment with solar panels for some time but I wasn't too enthusiastic about mounting panels on my roof. So my aha moment was realizing that I have a concrete walkway that was seldom used and the walkway runs from east to west. So mounting the panels along the walkway was just about perfect in terms of having the panels facing south; the walkway also makes a stable ground anchor.

Here's the main points I considered before starting the project:

  • I wanted a ground mounted system as I wasn't comfortable working on the roof and I also wanted to have the panel angles adjustable. Also, ground mounted panels are easy to access for repair and replacement.
  • Solar panels typically have a 25 year plus life span so it made sense to make the mounting system out of materials that would last that long. So I went with pressure treated wood, plated hinges, galvanized lag screws and SS screws. (The panels are further secured with aluminum flooring strips and PVC angle.)
  • I wanted to have a system that didn't require any heavy metal work or welding so the frames that hold the panels are made mostly with 2x4's and plywood.
  • I wanted a system capable of withstanding high winds and snow loads. The unused walkway works perfectly in providing a secure mounting method. Of course if I didn't have the walkway to work with I would have had to look at alternative ground mounting methods such as concrete piers, heavy blocks, screw anchors, etc.

I had enough space on the walkway to comfortably install two sets of five 100 watt panels. Each of the two "arrays" are therefore rated at 500 watts maximum total output.

Supplies:

Step 1: Designing and Ground Preparation

Design

I've been picking up the 100 watt Coleman brand solar panels from our local Canadian Tire store whenever they were on sale. Each panel measures approximately 26-1/4 x 39-3/4 inches. Those were the first dimensions that I started with to determine the lengths of the 2x4's that would form the main part of the panel support system. I kept in mind that there will be some thermal expansion of the panels so a space is required for this variation in size.

Also, each array must be sized so that adjusting the panel tilt angle can be done comfortably by one or two people. I selected 2x4x12's for the long dimension of the panel frame structure. This size holds 5 of my panels with a good space between panels. The overall height of the panel frame structure is approximately 48 inches.

(My original thoughts included a remote control angle adjustment. I have two 12 volt electric car jacks on hand and figured that they would be just "perfect" for this application. But after some sizing and wind load considerations I dropped this idea and went with the manually adjustable system that is described in this instructable.)

Ground preparation

I decided to anchor the panel system to the concrete walkway with pressure treated 4x4's that are seated in galvanized saddle brackets. (Saddle brackets are more commonly used in deck construction where the deck post ends fit in the saddle brackets. In deck construction the saddle bracket shafts are normally secured to the ground by embedding them in concrete piers.)

The most difficult part of this project was drilling the holes in the concrete walkway. I started with my consumer grade hammer drill with a 7/8 inch masonry bit. I ended up renting an industrial grade hammer drill that made the job much easier.

(I realize that most readers of this instructable will not have an unused concrete walkway available for solar panels so my main objective here is to show how the 2x4 panel support system was made and how I incorporated the adjustable angle feature.)

Once the holes were drilled I anchored the saddle bracket in the walkway with 2-part epoxy.

Note 1: To make handling easier I used 2x4x12's (rather than the heavier 4x4x12's) to get the saddle brackets positioned and glued in place. Once the epoxy cured I removed the 2x4's, painted the 4x4x12's, and installed them in the saddle brackets.

Note 2: I live in a high wind area so having the solar system firmly grounded was of primary importance. In this regard I anchored the 4x4x12's as well as the angle adjustment arms. An alternative to this design is to leave out the 4x4 component altogether and go with anchoring the angle adjustment arms only. The panel frames would then be hinged directly to the angle adjustment arms.


Step 2: Building the 2x4 Frames

This is perhaps the most significant part of the project as the primary goal was to have a way to mount the solar panels in a secure way and to have the tilt angle adjustable - all to be accomplished with readily available 2x4's, 4x4's and plywood.

The 2x4 frames hold the solar panels, and in turn, the frames are mounted to the 4x4 bases that are firmly anchored in the concrete walkway.

I built the fames on my back deck.

Referring to my rough sketched plans I cut the ends pieces of 2x4's to 40 inches. (The solar panels measure approximately 26-1/4 x 39-3/4). The 2x4x12's didn't need cutting.

To get a feel for the overall structure I test fitted the five panels in the clamped-up frame. Seeing that the sizes and spaces were good I then proceeded to nail the frame together. Before driving the first nails I made sure the structure was square by checking the diagonals. I double checked for square as I went along.

The 1/2x6x48 inch pressure treated plywood boards have two main functions: they serve as gussets between the 2x4's (thereby joining the corners and keeping the corners square), and they support the solar panels. I cut the boards on my portable table saw from a sheet of 1/2 inch 4x8 ft. pressure treated plywood.

In addition to the plywood supports I decided to use Simpson galvanized corner brackets on the other side of the 2x4 frame. This might be a bit of overkill but I went with it anyway.

At this stage I already had the saddle brackets epoxied in the concrete so I went ahead with painting the 4x4x12's. After that I removed the temporary 2x4x12's and permanently mounted the 4x4x12's in the saddle brackets.

I also painted the panel frames to get them ready for mounting to the 4x4's with hinges.

Step 3: Mounting the Panel Frames to the 4x4x12's With Hinges

This was a satisfying part of the project as two major sections of the system were completed and now I just had to join them together with hinges.

As the 5/16 x 2 inch galvanized lag screws were driven into the wood along its length (rather than near the ends) there was no need to drill pilot holes before driving the screws home.

Hinges are forgiving when it comes to connecting large wooden project sections where there might be some warping, twisting, cupping or other kinds of distortion due to wood movement. And in this project the concrete walkway sections no doubt shift up and down with the seasons. So even if the solar panels were not intended to have adjustable tilt angles, the hinges would still be a good choice to make the connection between the ground anchors and the panel frames.

(5-1/4 inch "gate" hinges were chosen for this part of the project.)

Step 4: More Ground Anchoring for the Angle Adjustment Feature

As with the rest of the project I didn't skimp on parts and materials for the panel angle adjusting feature of the project. I went with Simpson stainless steel concrete anchors and galvanized angle brackets.

In this step the photos show me removing some sod to make good clearance for the 2x6, ground anchored, angle adjustment bar. This step was necessary as the turf was somewhat higher than the concrete walkway. I found that a long blade in my reciprocating saw worked good to cut the sods before tearing them out with the pickaxe.

I first secured the bars to the already anchored 4x4's with Simpson angle brackets. This helped keep the bars in place while I drilled the 1/2 inch holes in the concrete for the Simpson concrete anchors. The video in Step 1 provides more info on this procedure.

Step 5: Lots of Holes in the Angle Adjustment Bar

Before I got serious about cutting 2x4's for the solar panel adjusting system I whipped-up a rough mockup of the angle adjustment components. A length of 2x4x48 represented the panel frame section of the triangle.

The final selected length of both the ground anchor bar (48 inches) and the adjustable angle bar (60 inches) gave me a solar panel tilt angle range from about 20 degrees to the horizontal to about 76 degrees to the horizontal.

I made up a drill press jig to keep the holes evenly spaced in the adjustable angle bar. The hole spacing is equal to the distance between the two in-line holes in the T-hinge. With this spacing, and after selecting the tilt angle for the panels, I could use either one or two bolts to secure the panel/frame assembly in place. As the tilt angle would be adjusted seasonally I used stainless steel bolts, flat washers, lock washers and wing nuts to make the join reliable and convenient over the years. (After completing the project I found that just one bolt was sufficient to secure the panel assembly firmly in place.)

The video in Step 1 further describes the jig and the drilling process.

Step 6: Time to Get the Solar Panels Installed in the Frames and Secured in Place

When installed, the panels rest on one leg of a length of PVC plastic angle. The other leg of the 90 degree angle angle keeps the bottoms of the panels in place. The tops of the panels are secured in place with a strip of aluminum flooring trim.

Before installing the panels I adjusted the frame to the maximum tilt angle (about 76 degrees) as this was found to be the most convenient angle to aid with installing the plastic angle and the flooring strips.

I cut both the PVC angle and the aluminum trim on my miter saw. I secured both in place with stainless steel wood screws. The screws self-countersink in the plastic angle.

Temporary wooden spacer blocks make the spacing between panels equal.

The video gives a good idea of the procedure that I used.

To remove a panel for repair or replacement you only have to remove the top strip of flooring trim. The panel can then be tipped out, lifted, and removed. The reverse procedure is followed to install a panel.

So a big question is how long will this solar system last... to get some idea please see the next Step.

Step 7: Fast Forward Through Two Winters to Present Day

I finished installing the system in November (about 18 months ago) so the system has endured two winters, and of course spring, summer, fall, and spring again.

All photos and the video in the preceding steps were taken about 18 months ago; I took the photos in this step over the past 2 weeks. (Yes, this is the kind of spring we get here.)

Observations after 18 months

  1. Some light surface corrosion on the gate hinges
  2. Paint will require some minor touching up this summer
  3. The exposed MC4 connectors now have a chalky like finish
  4. All panels are still giving electrical output

I am very pleased with the condition of the solar panel system after spending 18 months in our climate. Looks like the system will give many years of service without having to spend much time on maintenance or repairs.

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    18 Discussions

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    andymbush

    Question 24 days ago on Step 7

    What have you found about the output relative to angle and what is the optimum angle?

    5 answers
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    flame7andymbush

    Answer 1 day ago

    You must look that up for your own location. Most solar sites have charts on their sites plus there is one on wikipedia and there are also government sites.

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    rmoore03andymbush

    Answer 19 days ago

    Since several people have asked about this, maybe I can help. I design, install, and maintain PV systems(NABCEP assoiciate level certified). You can get an estimate of the power output based on different angles here: https://pvwatts.nrel.gov/

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    rmoore03rmoore03

    Reply 19 days ago

    We use this as an estimating tool when doing our initial system proposals to get an idea of how much power a system might generate given a specific location and system size, it will calculate the estimated system output for a given angle as well.

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    nlinventorandymbush

    Answer 23 days ago

    I don't have enough solid info yet to talk about pros and cons of angles etc. But I hope to get something out on that aspect of the project in the future.

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    KipA2

    19 days ago

    As much as I like this, people need to check local code on ground mounting solar panels. It's ridiculous, but I can cover an entire 200 square foot un-permitted shed with panels and only need an electrical permit if I connect it to the grid, but if I want to build a more simple attached ground mount exclusively for panels, regardless of on/off grid, my county requires a permit.

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    ludgidiya

    22 days ago

    Hello, perfect performance!
    What is the real power output playing with the angles of the panels?
    What is the efficiency of the system compare with the price of the panels in some time span? How much power do you produce per year?
    How many sunny days do you have per year?
    I would like some numbers to get the big picture of 1000W system please?
    I'm on my way to install 1000W wind power.
    Are hooked to the grid? Do you use the power for heating or lighting?
    Angel

    1 reply
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    nlinventorludgidiya

    Reply 22 days ago

    Sorry I just don't have any useful info at this time. I had a major delay since finishing the physical system; my intention is to set up a measuring method over the next while after which I should be able to present my findings.

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    nlinventornikonman461

    Reply 22 days ago

    I'm working (slowly) on setting up a measuring setup so that I can provide any useful info regarding output re angles and that kind of thing. Right now nothing really useful to show in that regard.

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    tytower

    24 days ago

    My first thought was the hinges . You can't buy decent galvanised hinges these days so I suggest you swap over to stainless or brass would do it well too . The gal hinges will rust up inside around the pin and break the screws out at some time so I would get them swapped now.

    Would like to hear what you run the output to and what systems you have set up . For cheap sources of Lithium Iron Phosphate see this facebook site and my instructible on here

    https://www.facebook.com/groups/271980786862023/?ref=bookmarks

    https://www.instructables.com/id/Working-System-LiFePo4-Battery-and-Spotlights-With/

    1 reply
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    nlinventortytower

    Reply 23 days ago

    Yes getting suitable galvanized or SS hinges can be a problem at least locally. But with the present setup it's not a big deal to change hinges over the years as the arrays are at ground level. I don't have enough solid info yet to talk about pros and cons of angles etc. But I hope to get something out on that aspect of the project in the future.

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    DaveP72

    24 days ago

    I to didn`t want to mount panels on my house roof. so I made an adjustable frame out of angle iron. maybe one day I will add a tilt motor.

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    malijai

    25 days ago

    Very very nice and usefull system. I would like to have something similar to our water heater which goes completely covered by snow in winter, but it is not possible because of the pipe system ;(
    How many batteries do you have inside? How do you use it ?
    Thanks

    1 reply
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    nlinventormalijai

    Reply 24 days ago

    Thanks. This is an experimental solar setup. For example I brought each panel output individually into my "power house". In this way I can interconnect the panels in any desired series or parallel way or in any series-parallel way. I hope to continue with the setup to a point where I can explain what I have learned about my experiments. But for now I just wanted to show how I made the frames for the panels and how I connected them to the ground.