Panel mount options on side of barn

[cdsolar]

I am building a Solar system for a barn to provide power for network
gear: camera to watch animals, lights, and occasional small AC tool
use with an inverter.

Previously, I had set up a single 30W panel on a chicken coop with a small
battery and PWM SCC to run LED lights to keep the chickens laying
further into the fall.

To mount this 30W solar panel, I used a tilt mount with the base of the
tilt mount vertically mounted on the side of the chicken coop and the panel
tilted upwards on the arm with optimal angle set for the sun (the wall of the
coop is on the south side (and I am in the Northern hemisphere).

This mount worked well.

I am now buildng a more complete system for the barn proper, as stated above.
The barn also has a south wall where I want to mount the panels.
I will have 4 400W panels.

I investigated doing the same thing, with tilt mounts vertically mounted to
the side of the barn and the panels tilted upwards from vertical to the proper
angle.

But 400W solar panels are 50lbs or there about. What I can find is something like this

Amazon.com

But any of these I find seem to be rated by the wattage of the panel they recommend,
(including this one) and I cannot find something that explicitly says it supports 400W panels.

I suspect that the size and weight of the panel correlates directly for the purpose of what these
mounts can handle.

So given the weight of a 400W panel and the fact that I am mounting the base vertically
and tilting the panel upwards, what are my options if not a tilt mount?

I have reasons not to mount them on the roof, hence I want to mount to the side of the barn
that faces directly south.

Any info would be appreciated, thank you.

 

[MichaelK]

I've made all my mounts out of unistrut members. Easy material to work with, and it can be bolted together if you don't do welding. I made a triangular shaped roof mount that holds four large residential grid-tie style panels on a flat shed roof. I suppose exactly the same mount could be rotated 90 degrees and mounted sideways on a wall.

I would make certain that all the bolts holding the frame up on the wall are mounted into the studs of the wall, and that the roof overhang does not partially shade the panels. How high off the ground is this going to be?

Before getting to that stage though, I'd suggest taking a step back, and first come up with a complete system plan first before starting construction. Make an itemized list of what you want to power, power tools, milking station, lights, ect. Once you have numbers, then begins component selection. What charge controller you need, how big and inverter, how big batteries, ect. Get this done first before you start mounting stuff up on the walls.

People here will be happy to help you with the planning and avoiding pitfalls. Lots of times here we spend time helping people overcoming the problems caused by buying the wrong stuff, bought for the wrong reasons, that they paid good money for.

 

[cdsolar]

Michael,

I have already designed my system and am choosing product at this time. At the moment I am trying to figure out how I will mount my panels. Hence my question.

 

[timselectric]

I don't see a problem with what you want to do. As long as you connect to the structural members of the barn. And try to spread the weight across several.

 

[cdsolar]

I don't see a problem with what you want to do. As long as you connect to the structural members of the barn. And try to spread the weight across several.

Tim,

Thanks. What I will probably end up doing is mounting a wood panel to several struts of the barn, and then build triangular supports for the panels from there, angled appropriately for my latitude.

-Chris

 

[KITROBASKIN]

Going triangular is what I would do, as opposed to relying on connectors to keep the panels rigid.
Hopefully you have lived there long enough to see what and how the weather might throw at your system, plus potential threats from living beings including fecal deposits and cattle curiosity.

Sounds like a fun project!

 

[schmism]

Some 8" gate T hinges with the leg of the T welded to some uni strut. the top of the T bolted to the barn and a return bottom piece of strut to set the angle. 2 of these per pannel (8 total)

 

[cdsolar]

Going triangular is what I would do, as opposed to relying on connectors to keep the panels rigid.
Hopefully you have lived there long enough to see what and how the weather might throw at your system, plus potential threats from living beings including fecal deposits and cattle curiosity.

Sounds like a fun project!

Thanks. I found this, which my idea matches. Of course I would have to size appropriately.

https://footprinthero.com/diy-solar-panel-wall-mount

 

[740GLE]

Does the barn not have a roof?

Seems like making the mounting more complicated, costly and possible less output by not using the roof.

 

[rhino]

Does the barn not have a roof?

Seems like making the mounting more complicated, costly and possible less output by not using the roof.

Unless you get snow in winter.

 

[zanydroid]

I investigated this a while back. Make sure PVWatts and your local snow conditions / latitude merits this.

The blocker for me was terrible PVwatts performance (before even factoring in the cost of my time to resolve permitting blockers) and a lot of difficulty in getting the engineering approval needed from my AHJ. Very few people seem to know how to get drawings / calculations done for wall mounts because they are not standard.

 

[Ampster]

Does the barn not have a roof?

I had the same question, until I reread the thread. Earlier in the thread, the OP mentioned he had reasons to not want to mount them on the roof, hence the thread title.

 

[cdsolar]

I have no permit requirements for my barn, and this particular project is for my barn proper. I may later use the roof of the barn for panels for my house itself, but I cannot do that now. ($$)

 

[zanydroid]

OK without permit requirements it’s not that hard to find mounting ideas / come up with something with unistrut as people recommend. (a host of problems come when you need to prove that it’s strong enough to other people)

 

[JAS]

I used aluminum unistrut from Grainger. It's lighter than steel and less chance of galvanic corrosion with the panels. I could actually get it cheaper shipped from Grainger than I could get steel from my local Lowe's. (That was about a year ago. don't know the pricing now)

 

[zanydroid]

BTW it's hard to beat the cost of flat roof mounts if you want something that started with properly vetted engineering (Unistrut falls into that category, they have listed products for roof mounts). If you load up the Unistrut etc's free design tools for roof mounts you'll see that it's concerned about a lot of stuff and takes into account framing size/spacing, wind load for your location, soil properties, pitch, ... Solar panels are heavy and can generate a lot of "lift"

I wouldn't really trust mounts on Amazon TBH, no AHJ will accept a random one, and I don't think you should be willing to compromise over standard practice unless you have a great reason for (avoiding custom engineering fees is one, maybe).

 

[Ampster]

Solar panels are heavy and can generate a lot of "lift"

It is their surface area that causes the lift when the wind blows. The weight is static and per square foot is much less than a roof load, which is why they can usually be installed without having to increase framing members.

 

[zanydroid]

It is their surface area that causes the lift when the wind blows. The weight is static and per square foot is much less than a roof load, which is why they can usually be installed without having to increase framing members.

Yes. For my AHJ if the pitch, framing spacing, and framing lumber dimensions are within pretty normal numbers they just accept a UL listing / basic stats.

I think there is some higher torque though from the fact that the mass is higher up from the framing members than the roof deck and shingles, which probably needs to be double checked for seismic goodness.

Unfortunately a wall mount is NOT a standard roof pitch ?, so you cannot do that. Nor should you expect a roof mount to work at 90 degree vertical.

 

[Ampster]

Yes, weight would side load the racking and connections of the panels to the racking. I am not an engineer but the Unirac and Ironridge design tools might give an approximation. I would enter the steepest pitch the tool will take and add some more connections. That might be the simplest since the OP does not have to submit stamped engineering drawings.

 

[zanydroid]

When I was considering the wall mounts, I worried that the clamps would not be able to hold the shear loads from the weight of the panels. On normal roof pitches they hold a fraction of the weight, vs 100% of the weight. So I would have supplemented it with some "redneck engineering", like add some horizontal channel to carry the vertical weight of the panels.

(I'm not a mechanical engineer)