UniStrut panel clamps?

chrisstratton

New Member
Joined
May 24, 2021
Messages
72
Looking for recommendations for clamps to fasten PV panels to a bus roof mounted piece of uni-strut. I REALLY like IronRidge's UFO, or the Tamarack Solar 50/50, but can't see spending $250 JUST FOR SHIPPING to get one of their systems. So - guess I'm doomed to UniStrut, a product I love to hate as you can't get the socket heads down into the bolt head when surface mounting the unistrut. Help??
 

chrisstratton

New Member
Joined
May 24, 2021
Messages
72
I have a bunch of these They are just sitting in a box on a shelf now
I could use 4 of the mid clamps and 8 of the end clamps (maybe 5 and 9 each in case I lose parts?) in case you'd like to fit some in a flat rate small box or envelope? PayPal or Venmo/CashApp? BTW - you wouldn't have any extra unistrut spring nuts? My plan is to mount 2 sets of 2 panels on the bus roof (the ceiling fan prevents my combining them all). So I figure each set would need 2 mid and 4 end clamp thingies). Or am I missing something??
 

Lt.Dan

Photon Sorcerer
Joined
Dec 25, 2020
Messages
1,199
Location
Visalia, Ca
I could use 4 of the mid clamps and 8 of the end clamps (maybe 5 and 9 each in case I lose parts?) in case you'd like to fit some in a flat rate small box or envelope? PayPal or Venmo/CashApp? BTW - you wouldn't have any extra unistrut spring nuts? My plan is to mount 2 sets of 2 panels on the bus roof (the ceiling fan prevents my combining them all). So I figure each set would need 2 mid and 4 end clamp thingies). Or am I missing something??
Send me a message. We'll work it out.
 

DIDDLYV

Solar Enthusiast
Joined
Mar 1, 2021
Messages
91
Do really need to surface mount the panels. One can buy 6 ft lengths of 1 x 3 aluminum angle and make a bracket that mounts to the unistrut and another that mounts to the panel and hook the two together like a tilt bracket. The advantage is you have room to get hands and tools under the panels to tighten bolts etc. If you need surface mount the clamps shown above will do the trick.
 

chrisstratton

New Member
Joined
May 24, 2021
Messages
72
Do really need to surface mount the panels. One can buy 6 ft lengths of 1 x 3 aluminum angle and make a bracket that mounts to the unistrut and another that mounts to the panel and hook the two together like a tilt bracket. The advantage is you have room to get hands and tools under the panels to tighten bolts etc. If you need surface mount the clamps shown above will do the trick.
The current idea is to place 4ft unistrut panels perpendicular to the bus's length, bolted to the ribs/roof. On top of that 10ft unistrut segments will be placed parallel to the length of the bus. Panels placed across those 10ft unistruts and secured to the struts with the clips Lt. Dan mentioned.
 

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
1,679
Location
USA
Instead of 10' long Unistrut, which is really heavy, use some 1.5" 80/20 aluminum extrusion. Those can be mounted to the 4' Unistrut crossbeams. Then the panels can be bolted to the aluminum extrusion and/or the IronRidge panel mounts work well with the 80/20 extrusions.

I did this for my setup. To save on shipping of the 80/20 rails, buy them in shorter lengths. You can also buy flat plates and fasteners to join two ends of the extrusion together. I just posted my design for this (see post #14):

 

chrisstratton

New Member
Joined
May 24, 2021
Messages
72
Instead of 10' long Unistrut, which is really heavy, use some 1.5" 80/20 aluminum extrusion. Those can be mounted to the 4' Unistrut crossbeams. Then the panels can be bolted to the aluminum extrusion and/or the IronRidge panel mounts work well with the 80/20 extrusions.

I did this for my setup. To save on shipping of the 80/20 rails, buy them in shorter lengths. You can also buy flat plates and fasteners to join two ends of the extrusion together. I just posted my design for this (see post #14):

What are the "U" shaped parts which attach the upper 80/20 to the uni-strut called? EDITED - never mind, found them. Silly money for the unistrut attachments and parts. Does the weight of the unistrut really matter that much?
 
Last edited:

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
1,679
Location
USA
Does the weight of the unistrut really matter that much?
That's up to you and your build but it's not a good idea to have lots of weight up high. It will already be heavy with the panels and Unistrut crossbeams. You can save 40lbs using the 80/20 rails instead of more Unistrut.

One other big benefit of the 80/20 rails is that they give you better mounting options. The feet on the end of the IronRidge UFO mounts fit just fine in the 80/20 rail slot. I don't know how you would use them with a Unistrut rail.
 

Lt.Dan

Photon Sorcerer
Joined
Dec 25, 2020
Messages
1,199
Location
Visalia, Ca
That's up to you and your build but it's not a good idea to have lots of weight up high. It will already be heavy with the panels and Unistrut crossbeams. You can save 40lbs using the 80/20 rails instead of more Unistrut.

One other big benefit of the 80/20 rails is that they give you better mounting options. The feet on the end of the IronRidge UFO mounts fit just fine in the 80/20 rail slot. I don't know how you would use them with a Unistrut rail.
I put over 160' of standard galvanized unistrut and 12x 240w panels on top of my 13'-5" tall 5th wheel and didnt notice a difference at all.

But I'm cheap and didnt want to spend 3-4 times as much for the mounting system than I did the actual solar panels lol.
 

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
1,679
Location
USA
Your 5th wheel is already a massive beast. :) I'm working with a little 7x14 trailer.

And of course there's a big cost difference between 20' of rail and 160' of rail. I wouldn't want to use 160' of 80/20 either.
 

Lt.Dan

Photon Sorcerer
Joined
Dec 25, 2020
Messages
1,199
Location
Visalia, Ca
Your 5th wheel is already a massive beast. :) I'm working with a little 7x14 trailer.

And of course there's a big cost difference between 20' of rail and 160' of rail. I wouldn't want to use 160' of 80/20 either.
You got me there lol. I was just trying to make a comparison that I dont think the galv unistrut will be that much of a weight difference, especially if its not very tall to begin with.

One thing to note though, is to ensure the roof of the trailer will support the weight. That would be my determining factor to if I went aluminum or not.
 

Supervstech

Administrator
Staff member
Moderator
Joined
Sep 21, 2019
Messages
6,536
Location
Belmont, NC
For unistrut, I like cone nuts.. the spring nuts are a pain to use.

cone nuts slide into the strut, and the plastic cone holds the nut tight to the strut. Just slide them in the end, and rotate to lock.
 

Poverty Pony

Solar Enthusiast
Joined
Feb 19, 2021
Messages
24
If you have enough $$$ there is aluminum unistrut available. also fiberglass and even stainless. look at mcmaster-carr for examples.

I will have to try the cone nuts, the springs sometimes try my patience.
 

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
1,679
Location
USA
I will have to try the cone nuts
I used the cone nuts. They are super simple and easy.

I picked up some aluminum unistrut for my van build.
When you say "picked up" do you mean you found a store you could go buy them from (if so, where?) or do you simply mean you purchased them online and paid a lot for shipping?
 

Poverty Pony

Solar Enthusiast
Joined
Feb 19, 2021
Messages
24
Well shut my mouth... it seems that aluminum unistrut is actually cheaper than steel these days! Stainless is about double vs zinc plated steel, aluminum and fiberglass are about 80% of steel. At least at McMaster-carr. if you need large quantities it's probably not the cheapest supplier. Yet another reason to make friends with an electrician ;)
 

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
1,679
Location
USA
How is the strength between the steel and aluminum? Thinking about the crossbeams only being supported at the ends. My crossbeams are 85" so I had to make sure they were strong enough with the weight of the panels and other parts.
 

Poverty Pony

Solar Enthusiast
Joined
Feb 19, 2021
Messages
24
depends on the alloy, but generally aluminum is stronger than a similar weight of steel... but since the aluminum unistrut is much lighter (steel is denser than aluminum and the cross sectional area of the strut channels is the same, ergo the aluminum is lighter), it's not as strong.

designing things like this makes me wish I took some mechanical engineering classes. as an EE I feel like i'm winging it most of the time.

I know from experience that unistrut is pretty strong stuff, but it can twist and bend vs square, non-perforated metal tubing of a similar size. one has to take some care in how it's used in a design.
 
Last edited:
Top