Solar Panel Rails

 

The solar panels at our current house will be secured to the rafters via a rail mounting system.  There are commercially available rail systems, but those are very expensive.  I decided to make my own.  This is an ongoing project, so check back for updated pictures and details.

 

I'm using a heavy 3"x3" aluminum angle purchased from Amazon.  These are 4' sections.  Under $40 per section, free shipping, no tax.

Change of plans, got some scrap aluminum from a local salvage yard.  One piece is 2" box channel, the other a large piece of angle.  Couldn't find two pieces alike.  Doesn't matter though.

I made mounting brackets for the rails from another piece of 3" angle.  I used a Harbor Freight portable band saw (aka: portaband).  The brackets are 2" wide.

Rather than just drilling holes in the brackets, I decided to make slots.  This will allow some adjustment during installation.  I'm using a Grizzly combination mill/lathe.

Using a 1/2" end mill, a hole was bored into the bracket, then a slot was made.  Quick and easy.

A dozen brackets ready to go.

I have big paws, but these are big brackets.  Since I live in hurricane prone FL, I don't want my solar panels blowing away during a storm.

The rails were positioned on the garage floor, and the panels set in place.  The panels were spaced 1" apart, as recommended by Kyocera to allow proper cooling.

The piece of angle will be used as the lower rail.

The box channel will be used as the upper rail.

To prevent critters from building nests inside the box channel, it was sealed with plastic end caps.  The used aluminum was sanded to remove old stencils and adhesive.  They were then wiped down with Sharkhide, a metal protectant.

This is the recommended method for mounting the panels, per Kyocera.

 

Aligning the holes in the bottom of the panels, with holes in the rails, while hanging on a steep roof... nah, never mind.  I put feet on the panels, now I'll be able to see the holes, making alignment easy.

Using the rafter drilling guide I made, the first pilot hole was drilled from inside the attic.  My rafters are exactly on 24" centers, so the subsequent holes can be measured and drilled from topside.

A little hard to see, but there's now a hole through the rafter, plywood, and shingles.

The L-bracket I made earlier, was attached to the roof with a 3 1/2" x 3/8" stainless lag bolt.  A stainless fender washer was also used.  Because the brackets have a slot, there is some adjustment possible.  Roofing tar (in a caulk tube) was used in the drilled holes, and on the bolt threads, to prevent any water leaks.

By measuring the 24" spacing between rafters, each hole drilled all hit the intended rafters.  All the brackets for the lower rail have been installed in this picture.  The rail is leaning against the rail gutter, ready to install.

The lower rail was secured to the brackets with stainless hardware.  Because the rail was near the drip edge, all this work was done from the safety of the ladder.

The upper rail was more of a challenge.  Couldn't reach it from the ladder.  A rope was thrown over the peak of the roof, and tied to a tree on the far side.  This way I could climb on the steep roof, while holding onto the rope.  Once I was up there, I could stand on the lower rail while installing the upper.

To route the wires from the panels through the roof, I bought a product called Soladeck (that's the correct spelling).

To more closely match the color of the shingles, I decided to paint mine.  Home Power Magazine did the same in their article.  A heatgun was used to remove the decal.

I had a can of paint leftover from another job, and decided to use it.  Got this at Home Depot in the patio screen section.

First coat of paint drying.  I'll use a few coats before installing it.  Already drilled the holes for the 3/4" conduit bulkhead fittings.

The weather wasn't cooperative again this evening.  So rather than doing nothing, I decided to get the Soladeck ready to install.  Put on a few final coats of paint yesterday, and punched out the knock-out on the back of the box.  There are three different sizes to choose from, I selected the largest.  Room for future panels (hopefully).

The plastic grommet simply snaps in place.  It wasn't included, but is available in the electrical section of big box stores.  Prevents the wires from chaffing on the sharp edge.

The Soladeck fixture was installed.  Very simple using the supplied template and instructions.  Each panel has it's own separate cable.  This was the first of four being installed.

It was placed near the upper rail.

The lid is held in place with four screws.

I used PVC conduit to route the wiring from the solar panels, into the Soladeck.  UV rays are tough on wires here in FL.

The 130W Kyocera panel was hand carried up a ladder, and set in place.

Kyocera recommends a 5" gap between the roof and the panel to provide proper cooling.  A hot panel is less efficient.

The second panel going up.  While on the ladder, the panel is set on top of the upper rail, and in front of the lower rail.  This way it stays in place until I can get up on the roof to secure it.

Once on the roof, I use a couple of screwdrivers through the mounting feet, and into the pre-drilled rail.  A 1" gap was left between the panels to aid in cooling.  Eight 1/4-20 stainless fasteners were used to attach the mounting feet to the upper and lower rails.

All four panels are up.  More panels will go up when I get more material to fabricate more rails.  Notice the panels are in the shade?

It was easier to install the panels in the shade, but the old (dying) cedar trees have to go.  They are very messy trees, and shade the South side of the roof.

We used my wife's Jeep, and its winch, to pull the tree over after I notched it with a chainsaw.  Spent the last two days slicing up two trees, and hauling it to the curb.

 

More trees to go, but we now have a nice view of the lake next door.

 

On the right side, the wiring from the solar panels are protruding through the roof via the Soladeck fixture.  I'm also using a Greelee Fishstik to retrieve a 6 gauge cable.  This cable will route the power from the solar panels, to the charge controller in the garage below.

I made a 4 conductor terminal post from scrap hardware in the shop.  Each cable from the solar panels has a ring terminal that is connected to a terminal post (stainless steel bolt).  The 6 gauge feed cable is also connected.  This setup makes it easy to periodically test each solar panel, and disconnect one if needed.  The terminals on the right are reserved for the next solar panel array.

 

 

 

 

-Update-

With the trees gone, the South side of the roof gets full sun all day.  The battery box can be seen on the left.

The 4 Kyocera 130W panels are rated to produce 7.39 Amps at peak power.  4 panels should produce 29.56 Amps total.  Even though these panels are 5 years old, they still exceed the manufacturer's rating.  I plugged a heatgun into the inverter to put a heavy load on the battery bank, making the charge controller supply all available power. 

It wouldn't be healthy to run this much current through the 30A charge controller often, but I had to wait for the sun to peek out from behind a cloud, and run a heavy load during the peak part of the day.  Under normal conditions, this controller wouldn't see this much current.

As time permits, I'll continue adding the rest of the solar panels to the roof.  But for now, the system is operational at the new house.

 

 

 

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Last updated 11/10/13    All rights reserved.