Mounting panels with unistrut

[Hedges]

The threading let me extend a little more than 10ft upward in a few cases using a coupler + additional 2" pipe and let me use 2" galvanized flanges to hold the base within the concrete footers - https://www.lowes.com/pd/Mueller-Proline-2-in-dia-Galvanized-Floor-Flange-Fittings/4330338 - so the pole wouldn't slip downward.

I considered those, but they need multiple anchor bolts, and small ones.
Instead, I put a coupling on the bottom and screwed one of these in.

https://www.supplyhouse.com/Everflow-GMBU2002-2-x-1-2-Galvanized-Malleable-Hex-Bushing

Or rather, I used a large anchor bolt to secure the bushing to concrete. Then use a coupling to connect 2" conduit to it.

 

[Robkh]

I used IronRidge Top Caps - https://realgoods.com/ironridge-ground-mount-system-top-cap - which are made for this purpose.
They have options for 2" and 3" vertical pipe. Not pushing the specific link/company above - just the 1st one that popped up for google search.
View attachment 176630

I used the 2" version because my verticals are 2" x 10ft (threaded) galvanized pipe from Home Depot - https://www.homedepot.com/p/Southland-2-in-x-10-ft-Galvanized-Steel-Pipe-568-1200HC/100565809

The threading let me extend a little more than 10ft upward in a few cases using a coupler + additional 2" pipe and let me use 2" galvanized flanges to hold the base within the concrete footers - https://www.lowes.com/pd/Mueller-Proline-2-in-dia-Galvanized-Floor-Flange-Fittings/4330338 - so the pole wouldn't slip downward.

Thank you…you did a great build

 

[OffGridInTheCity]

I considered those, but they need multiple anchor bolts, and small ones.
Instead, I put a coupling on the bottom and screwed one of these in.

https://www.supplyhouse.com/Everflow-GMBU2002-2-x-1-2-Galvanized-Malleable-Hex-Bushing

View attachment 176637

Or rather, I used a large anchor bolt to secure the bushing to concrete. Then use a coupling to connect 2" conduit to it.

I didn't bolt the flange to the concrete but embedded it in the concrete a couple of inches above the bottom of the pour - the flange ensures the pole won't move vertically within the concrete footer.

I could have drilled holes in the vertical pipe and used horizontal re-bar for a similar purpose but flanges seemed easier for me at the time

 

[Hedges]

You did say "within the concrete footers"
In that case it also provides torsional rigidity (within strength limits of the conduit.)
More convenient when erecting (not flopping around) so long as in the right position.
I suppose you installed top caps and cross pipes before pouring?

In concrete, anything including coupling or pipe cap should be sufficient to prevent pull-out.

I just slapped mine on the surface of existing patio.
One anchor bolt didn't bite, but the others did.
Was 18 Sharp 165W panels, I've extended the array wider (20') for 24, will make wider still (21') with diagonal supports when I replace them with SunPower 327W panels (like in background). Those are 50% more efficient, more power in the same area.

 

[42OhmsPA]

Looking for feedback on my latest idea. I want to expand the ground mount to hold 2 additional panels....
What are your thoughts on a 26" max open air cantilever on each side of the ground mount? 12 gauge superstrut.
I would add the 'extensions' to the center of the mount so the outer sections of strut were full 10' sticks.
I haven't came up with a way to add support gusset without interfering with the tilt angle... I suppose I could add angle brackets to reduce the cantilever to ~20".

Feedback please? Is it worth a potential 740w gain?

Here's what I used for my ground mount array. Worked great, my only complaint is the width of the mid clamps. I'd find narrower ones next time.

I picked up stainless 1/4-20 bolts from the local Amish supply store.

1/4"-20 Cone Nuts, Strut Channel Nuts with Zinc Electroplate Finish, Twirl Nuts for Use with Strut Channel (10 Pack) (1/4"-20) https://a.co/d/eHkgdPf

The included clamp nuts don't work with standard strut, that's why I bought the cone nuts above.
Solar Panel Mid Clamps 1.06 Inch Solar Panel Bracket Aluminum Solar Mid Clam with Solar Mounting Brackets 32-50 mm Panel Clamps Adjustable End Clamps Panel Clamps (56 Pieces) https://a.co/d/eK48elg

 

[Hedges]

Looking for feedback on my latest idea. I want to expand the ground mount to hold 2 additional panels....
What are your thoughts on a 26" max open air cantilever on each side of the ground mount? 12 gauge superstrut.
I would add the 'extensions' to the center of the mount so the outer sections of strut were full 10' sticks.
I haven't came up with a way to add support gusset without interfering with the tilt angle... I suppose I could add angle brackets to reduce the cantilever to ~20".

Feedback please? Is it worth a potential 740w gain?
View attachment 180270

I think you could extend rails, add end piece, and add a truss to support end.

An inverted triangle, with vertical in the middle resembling this roof framing.
The vertical ties to edge of existing panel and is under tension, two diagonals are under compression.
One of these in middle of upper row of panels, one in middle of lower row. That should allow tilt without hitting posts.

 

[chilly2]

Here's what I used for my ground mount array. Worked great, my only complaint is the width of the mid clamps. I'd find narrower ones next time.

I picked up stainless 1/4-20 bolts from the local Amish supply store.

1/4"-20 Cone Nuts, Strut Channel Nuts with Zinc Electroplate Finish, Twirl Nuts for Use with Strut Channel (10 Pack) (1/4"-20) https://a.co/d/eHkgdPf

The included clamp nuts don't work with standard strut, that's why I bought the cone nuts above.
Solar Panel Mid Clamps 1.06 Inch Solar Panel Bracket Aluminum Solar Mid Clam with Solar Mounting Brackets 32-50 mm Panel Clamps Adjustable End Clamps Panel Clamps (56 Pieces) https://a.co/d/eK48elg

Ah that wonderful open view for the panels in the first pic!

 

[LimitedPowers]

Since joining this thread I've been forced to redesign my panel mounts. Like many others I've found the top clamp type of mount to be inferior. Especially when run into channel strut using a sprng nut. The tolerance on most of the designs I see online for sale is poor and can't grip the edges of the panel firmly enough, even more so with my narrow frame edge. Panels using these rely on the integrity of the entire array of clamps working, a single panel falling loose or removed for service might slacken the whole row of panels enough for them to let go and take a slide.

Far better for my build is a design that uses aluminum L brackets and stainless bolts through the panel lower frame for a rock solid mount.

I use 316 stainless hardware whenever possible. Sourcing 316 stainless on ebay is actually much faster, cheaper and easier than anywhere I've found. You can find 316 stainless spring nuts on ebay as well for about $1 each , which are normally very expensive to buy at a supplier.

The L brackets were a bit tougher to source, but I found some on Amazon. They needed to be redrilled to 1/4" to match the spring nut, which is why aluminum was a great choice. I spun out 50 or so with a step bit and a drill press in about an hour. As you can see from the photo the most crucial part of this was to get a double mount between panels that would still fit within the 1" spacing I had already laid out in the rails . I had to find the narrow type of saddle washer normally used to mount allthread, and then hope the inner surfaces of the L brackets would be kind enough to mate without slopping up the alignment. One winds up a few mm higher than the other but it looks like a win. Very strong, I'd guess the pull out force on this design exceeds 300 lbs. I used 6.5 ft lbs. on the bolt running down into the spring nut. I'll also use blue loctite in the actual install.

For the panel bolts I used 316 SS M5 bolts just long enough to get through the panel frame with a matching 316 SS flange nut. This will let me torque the bolt down from the outside with a single tool as it bites into the aluminum. More pics to come in the next few weeks and I'll show the roof mounts and the adapters I made to mate Quickbolts / Microflashing to channel strut bases.

 

[ricardocello]

For the panel bolts I used 316 SS M5 bolts just long enough to get through the panel frame with a matching 316 SS flange nut.

Did you have problems with galling when tightening those stainless bolts?
I had a painful experience with that, and had to put some messy anti-galling stuff on the threads

 

[LimitedPowers]

Yes! I learned what galling was on this project! I only just now learned the proper torque for 1/4" x 20 type bolts in channel strut hardware like spring nuts is 6 ft. lbs. For this application I found 6.5 ft lbs to be perfect. No galling and no more broken bolts.

 

[ricardocello]

Yes! I learned what galling was on this project! I only just now learned the proper torque for 1/4" x 20 type bolts in channel strut hardware like spring nuts is 6 ft. lbs. For this application I found 6.5 ft lbs to be perfect. No galling and no more broken bolts.

I thought I was being smart getting all stainless hardware for my unistrut to panel connections.
I was cranking those bolts way too fast and with too much torque,and had to cut three of the bolts out when they seized.
I was blaming McMaster Carr for crappy hardware, until I found out I was the idiot. Lesson learned.

So whenever someone mentions stainless, I ask about galling. It’s a great word for that,

 

[HRTKD]

When working with different metals, I look at this chart to see what I'm up against.

 

[ricardocello]

When working with different metals, I look at this chart to see what I'm up against.

Based on that chart, do you consider galvanized steel to be steel or zinc?
Because I definitely mix stainless and galvanized all over the place.

Aluminum I know better, and put tape and nylon washers to prevent corrosion.

 

[HRTKD]

Based on that chart, do you consider galvanized steel to be steel or zinc?
Because I definitely mix stainless and galvanized all over the place.

Aluminum I know better, and put tape and nylon washers to prevent corrosion.

Galvanized steel is zinc coated steel. On that chart I treat it as zinc. But I'm no metallurgist.