Can you mount a solar panel landscape with horizontal rails and clamp it longways?

To fit one more panel on my shed, I could go landscape, 2 rows of 3 instead of 5 in a row, portrait.

I saw that to do this I am supposed to mount rails horizontally and then put another set of rail on top going vertically and then mount the panels with clamps on the long edges.

What happens if I just clamp the panels on the short edges? Does the extra 600mm of panel width between clamps really cause issues with expansion etc?

I don't like the idea of two sets of rails, horizontal and vertical, as I think it will look a mess from the side, which will be visible due to the panels being on a shed/workshop and in plain view from our living room! I want to get them as close to the roof tiles as possible really.

The roof is constructed from wood. horizontal rafters with vertical boarding, then insulation, then roofing felt tiles running horizontal rows.

Just using vertical rails is an option, if I could find a roof hook that is supposed to mount that way.

Depends on the panel and allowed mounting guidelines. Larger panels may not allow it.

Iron ridge rack design tool allows each way but it’s up to you verify your panels can do it.

Is this for a grid-tie application where all the panels are wired in one series run? If off-grid, that's a big complication going from 6 to 5. Six can be wired as 6S1P, 3S2P, 2S3P, or 1S6P. Five would only be wireable as 5S1P or 1S5P.

In any case, leave an 1/8" gap between panels, and there will not be any problems. I would not physically press panels together in either orientation.

740GLE said:

Depends on the panel and allowed mounting guidelines. Larger panels may not allow it.

Iron ridge rack design tool allows each way but it’s up to you verify your panels can do it.

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I'll see if I can get a datasheet on the panels. The are LG and are used so that may not be too easy.

What is the exact model? You are looking for installation manual and not the spec sheet. Spec sheets don't show how to mount. All the ones I've looked at allow mounting how you want but they have significantly less structural strength. i.e. Instead of 5400Pa on front of panel it may only handle 1800Pa in that configuration. But it does depend on the panel (especially frame thickness). I have older 315W Kyocera panel which was "large" for the time and it actually has aluminum framing going across the back center of the panel as well. You don't see that in any panels today even ones that are much larger than that one.

rhino said:

What is the exact model? You are looking for installation manual and not the spec sheet. Spec sheets don't show how to mount. All the ones I've looked at allow mounting how you want but they have significantly less structural strength. i.e. Instead of 5400Pa on front of panel it may only handle 1800Pa in that configuration. But it does depend on the panel (especially frame thickness). I have older 315W Kyocera panel which was "large" for the time and it actually has aluminum framing going across the back center of the panel as well. You don't see that in any panels today even ones that are much larger than that one.

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Its an LG315N1C-G4. Max load 6000Pa.

Found the installation manual. It states that when mounting with clamps, "the module may be fastened to a support using clamps on both the long edge and the short edge"

However none of the drawings in the appendix show landscape mounting.

Like this?

Horizontal Iron Ridge rails, landscape panels, except 2 on the right.

In a mobile environment I would never clamp large panels on the short sides. In your static environment my preference would still be to clamp on the long sides, but it will work to clamp on the short sides. Your wind load rating is pretty good, so if you need to clamp on the short sides it should work OK.

jfpetesn said:

Like this?

View attachment 142295

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Yes, but can't see how the clamps are fitted in this pic?

Sean Very North said:

View attachment 142381

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Interesting! These pics are not in the install manual I downloaded. BT00002151_3530.pdf

rich4 said:

Interesting! These pics are not in the install manual I downloaded. BT00002151_3530.pdf

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I've just googled and downloaded that document, clamp positions are included, just in a slightly different format to the document I posted a screenshot from.

Sean Very North said:

I've just googled and downloaded that document, clamp positions are included, just in a slightly different format to the document I posted a screenshot from.

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These are the only clamp drawings I found in there.

Just noticed a house in our village has landscape mounted panels with the clamps on the shorter edges. Been there for years.

If you don't have snow load or hurricanes then short side should be fine.