16x panels rail mounted vs. 15x panels direct mounted on metal roof

[ho1]

I'm planning an install of solar panels on my off-grid cabin, which has metal roofing (26 gauge PBR-profile). I have been looking at S-5 that have several options with brackets that fit right over the profile on my metal roof. These brackets can then attach to either their PV-Kit which mounts directly to solar panels, or I can mount a rail to these brackets and then mount the solar panels to the rails in a more traditional fashion. Because I'm getting snow and occasionally strong winds, I'd like to mount the panels at two place along the long sides (as opposed to attaching along the short sides).

The options I would like some input on are shown below (disregard the left/right positioning of the arrays on the roof)

S-5 RibBracket: https://buys-5.com/product/s-5-ribbracket-iii/
S-5 PV-Kit: https://buys-5.com/product/pvkit-2-0-midgrab-with-black-anodized-top-grab/

Option 1:
16x 390W panels mounted in portrait orientation to 4 rails (each rail ~30 ft long)
Rails attached to roof using S-5 bracket.
Pros:
I can fit 16 panels on there
The rails will make cable management easier
The rails will make the install easier as I can use it for support when moving on the (7:12) roof
Rails can be reused in the (distant) future if I decide to re-do the array

Cons:
More expensive because I'll need 120 ft of railing
Possibly a bit higher profile (more distance between roof and panel)
More work?



Option 2:
15x 390W panels mounted in landscape orientation to directly to metal roof
S-5 RibBracket and PV-Kit
Pros:
Lower cost (thanks to no railing)
Possibly easier/faster install
Low profile installation (still with sufficient airgap between panels and roof)

Cons:
I can fit one less panel
More difficult to service if I need to get to a central panel (unlikely?)

 

[dopeassjackson]

I plan on useing the S5 brackets to attach unistrut to then the pannels to the strut is prety easy with amazon brackets. Your rails would then cost about $300.

I plan on setting my s5 brackets in a pattern that each is as close to the edge of a pannel as possible. Solar pannels dont transfer the weight of snow/wind in the middle, only the edges.

 

[1201]

I'm planning an install of solar panels on my off-grid cabin, which has metal roofing (26 gauge PBR-profile). I have been looking at S-5 that have several options with brackets that fit right over the profile on my metal roof. These brackets can then attach to either their PV-Kit which mounts directly to solar panels, or I can mount a rail to these brackets and then mount the solar panels to the rails in a more traditional fashion. Because I'm getting snow and occasionally strong winds, I'd like to mount the panels at two place along the long sides (as opposed to attaching along the short sides).

The options I would like some input on are shown below (disregard the left/right positioning of the arrays on the roof)

S-5 RibBracket: https://buys-5.com/product/s-5-ribbracket-iii/
S-5 PV-Kit: https://buys-5.com/product/pvkit-2-0-midgrab-with-black-anodized-top-grab/

Option 1:
16x 390W panels mounted in portrait orientation to 4 rails (each rail ~30 ft long)
Rails attached to roof using S-5 bracket.
Pros:
I can fit 16 panels on there
The rails will make cable management easier
The rails will make the install easier as I can use it for support when moving on the (7:12) roof
Rails can be reused in the (distant) future if I decide to re-do the array

Cons:
More expensive because I'll need 120 ft of railing
Possibly a bit higher profile (more distance between roof and panel)
More work?

View attachment 198171

Option 2:
15x 390W panels mounted in landscape orientation to directly to metal roof
S-5 RibBracket and PV-Kit
Pros:
Lower cost (thanks to no railing)
Possibly easier/faster install
Low profile installation (still with sufficient airgap between panels and roof)

Cons:
I can fit one less panel
More difficult to service if I need to get to a central panel (unlikely?)

View attachment 198172

I think you'll find the direct method is higher cost and harder to install.

Also if your ribs are 12 o.c will the attachments land where you need them?

Iron ridge xr10 is cheap!

 

[pollenface]

Go with the option that gives you an air gap.

I make my own rails and mounts because all the rail options confuse me.

 

[Rocketman]

One question- what charge controller specs do you need?

With 16 panels - you get 2x8 or 4x4
With 15 panels - you get 3x5

Will all options work for your planned controller?

I would go rail and 16 - but I always like more panels

 

[ho1]

Thanks all - I'll go with rails and 16 then!

Probably IronRidge XR-100 because the XR-10 doesn't support the snow load I have to design for.