Solar Panel Mounting Using a Strut Channel Base

[TucsonJim]

As I'm recuperating from a medical procedure, I'm gathering components and ideas to build the solar array on the roof of the Solitude. I've mapped the roof and I'll be installing ten 200 watt panels for a total of 2000 watts. This will be two series strings of 1000 watts. The RV has two solar glands on the roof which connect to the front utility bay. I've already installed two 150/60 Victron MPPT controllers and panel shut off switch/breakers.

When I mount the panels, I plan on installing a strut channel base. Then I'll mount tiltable mounts and the panels on the strut channel. Here's a photo that I snapped from a video on YouTube * that demonstrates the concept There are a few benefits to doing this. There will be fewer screw penetrations into the roof. The panels will sit higher off the roof and allow better airflow. And it's easier to replace the system or components if needed in the future.



I will make some modifications to the design you see in the photo. I plan on placing small pads between the strut channel and the roof to allow for water run off under the channel.

Question #1: There are a variety of different strut channel materials available. Our local Lowes has galvanized steel channel for a great price at very reasonable prices. I'm hoping a materials person like Country Campers or Cate&Rob can weigh in. How will galvanized strut channel hold up to rusting? The channel will not be in direct contact with the roof, and living in Arizona, rain is rather infrequent. Should I consider priming and painting the channel with a rust inhibiting paint?

Question #2: The bottom of the panels will be high enough that I can place a panel over the plumbing and attic vents. This will allow for more continuous runs, and may have an added benefit of keeping those plastic parts out of direct sunlight. The parts can be accessed by simply tilting the panels. Does anyone see any drawbacks to this plan?



* Photo courtesy of Travel New Trails YouTube channel. Here's a link to his video:
https://youtu.be/aO3SSkT4CwU?si=Ffa6x9_zuvFrdSGW

Thanks,

Jim

[Country Campers]

Jim,

I have seen those struts used on other set ups but have not heard any "bad" reports. There are other options but a little more money, strut channel | McMaster-Carr, they have steel galvanized as well. Painting would be an option for the steel but if the galvanized job is not good the paint will do nothing. I would not go thru the effort of painting, keep an eye on it and if needs attention then paint it, or go with the aluminum and not worry about it, plus save some weight.

What kind of pad will you put under the strut? This will be important, I would suggest a Delrin or UHMW type material, this would have to be compatible with any sealant used.

Brian

PS: I have been dreaming of a motorized tilting assembly for these strut applications but have not made any head way yet.

[Scott'n'Wendy]

RE, galvanized strut. It will only rust where you cut it.
They have aluminium strut.....but pricey.

[Country Campers]

RE, galvanized strut. It will only rust where you cut it.
They have aluminium strut.....but pricey.

That is a good point. Jim if you go with the galvanized strut do a layout so you do not have to cut it to length. Scratches and such will lead to rust as well. They do make galvanized spray paint, well they use to.

Brian

[TucsonJim]

Jim,

I would suggest a Delrin or UHMW type material, this would have to be compatible with any sealant used.

That's a great suggestion. I think UHMW would be a better choice due to it's high UV tolerance. It's also pretty easy to cut on a table saw. One of Delrin's drawbacks is UV degradation.

UHMW also appears to be very resistive to acids (except oxidizing acids), alkalis, and many organic solvents. So I believe it would do well with lap sealant.

Thanks for the suggestions. You saved me some research time.

Jim

[TucsonJim]

While planning this build, I realized that I neglected to consider corrosion between dissimilar metals. If my channels are galvanized, and the solar mounts are aluminum, I'm setting myself up for galvanic corrosion. So I need to plan to eliminate it by insulating the materials, using a sacrificial anode, or selecting similar metals such as aluminum channel and aluminum mounts. Of course, for galvanic corrosion to occur, the metals need to be in solution (rain). So maybe I'm over-thinking it.

Jim

[Cate&Rob]

Galvanic corrosion occurs when two dissimilar metals are immersed in a conductive solution and are electrically connected. One metal (the cathode) is protected, whilst the other (the anode) is corroded. I don’t think this would be a problem on an RV roof.

Rob

[Cate&Rob]

TucsonJimCountry Campers

Jim: With all you are putting into this entire system . . . go with aluminum channels and stainless fasteners. You will not regret this.

Jim & Brian: Between the two of you, I am sure you can come up with a powered tilting system. 12V linear actuators are becoming quite affordable. Something like https://www.amazon.com/ECO-WORTHY-33...XEALw_wcB&th=1

Rob

[TedS]

Use sealants to prevent water intrusion where dissimilar metals meet to eliminate one necessary element of for galvanic corrosion. And/or insulation like nonmetallic washers.

[Yoda]

TucsonJimCountry Campers

Jim: With all you are putting into this entire system . . . go with aluminum channels and stainless fasteners. You will not regret this.

Jim & Brian: Between the two of you, I am sure you can come up with a powered tilting system. 12V linear actuators are becoming quite affordable. Something like https://www.amazon.com/ECO-WORTHY-33...w_wcB&th=1

Rob

TucsonJim At least it is Rob trying to spend your money this time. You have numerous metal fabricators there. Maybe call around on the aluminum channel pricing - you might get lucky. Otherwise with the galvanized check on powder coating pricing after you have everything cut. Naz shows a track system on thier site too. https://www.solar-electric.com/tamar...l?gad_source=1
I am surprised at all of the tilting mounts out there- pricey especially for 10 of them. . I am sure with your skill set you can make something. I like Robs idea - would save climbing on the roof.

[Country Campers]

Another track option UTOOL 48 Inch Double Cut Profile Universal T Track with Predrilled Mounting Holes and Screws for wood, Sandblast Anodized Aluminum Extrusion T Rail Track for Woodworking, 4Pack (Sapphire Blue) - Amazon.com

Brian

[Scott'n'Wendy]

Jim & Brian: Between the two of you, I am sure you can come up with a powered tilting system.

Rob

I was thinking this as well. Because..how often are you going to want to go up on the roof to manually tilt them?
I'd mount solid flat rather than manual tilting. Unless you can do it from the ground?

[TucsonJim]

I was thinking this as well. Because..how often are you going to want to go up on the roof to manually tilt them?
I'd mount solid flat rather than manual tilting. Unless you can do it from the ground?

I already have the panels and manual tilting mounts purchased. Since we camp at lower latitudes than the folks up north, we don't tilt the panels and usually generate a pretty good solar yield. If I can yield 1500 watts out of the 2000 watt bank, I will be very satisfied.

The reason I use tilt mounts is to allow for roof cleaning and maintenance. I had flat Z mounted panels several years ago. When I removed them to upgrade, the roof was badly stained from dirt and debris that became trapped under them.

This time I'm using tilt mounts from Rich Solar. They are $40 per set. So ten of them were $400. I've already attached one set to the panels and they fit great:
https://a.co/d/3W9IHSb

The panels I'm using are also from Rich Solar. 200 watts each. $200 each. Ten for $2000.
https://a.co/d/8XPqEmT

Jim

[Jlawles2]

I'd love to design a system with 2 layers of panels. Bottom layer is on full extension slides with actuators to extend them. Double the solar capacity with the flip of a switch.

[TucsonJim]

I'd love to design a system with 2 layers of panels. Bottom layer is on full extension slides with actuators to extend them. Double the solar capacity with the flip of a switch.

That is exactly what my friends Joshua and Elizabeth have done with their Solitude.
Jim