Mounting 5 large panels on Jayco Greyhawk - Questions

[Captain Morgan]

Hello,

After playing solar tetris for a year, I think the best I can do is 5 longer panels around 39.5" - 40" width, this is all I have between the AC and air vent, and the edge of the roof.

I can get qty 5 of the 445w panels by running lengthwise down the edges of the roof on both sides, 3 on one side and 2 on the other. Even this requires I remove the two skylights which I'm 100% OK with.

The ask here is about mounting. I have some roof schematics from Jayco and there doesn't appear to be much in the way of rafters per say. I don't even know for a fact if there is any wood anywhere.

Would it be better to run aluminum strut down the roof with lots of SS screws and dicor, then mount the panels to that?

I wanted a motorized tilt option but for 5 panels I just can't spent the money.

Do you folks have any installation pics or knowledge about the roof materials and structure of a Greyhawk?

Thanks in advance!


Trina Solar TSM-410-DE15H > 410 Watt Mono Solar Panel = 79.69" x 39.53" x 1.38" / 5*410 = 2,050w

LONGi LR4-72HBD-440M Hi-MO4 BiFacial 440 Watt Mono PERC Module = 82.44" x 40.8" x 1.37" / 5*440 = 2,200

LONGi LR4-72HPH-445M > 445 Watt Mono Solar Panel = 82.44" x 40.71" x 1.38" / 5*445 = 2,225w

[pconroy]

If you're considering bifacials, I think you will need some elevation between the roof and the back of the panel. I watched Will Prowse's videos on bifacial and I think he notes the manufacturers recommendations.


I'm probably not going to exceed 400 watts on ours, so I'm happy with the aluminum railing approach. But if I was going to toss a ton of solar on top, I think I'd keep the railing approach too.


It seems like it gives you more flexibility.

[Captain Morgan]

Thanks for that!


I'm really leaning toward the largest panels if I can get them mounted. The bifacials are just another example of what could fit.


LONGi LR4-72HPH-445M > 445 Watt Mono Solar Panel


I still have questions about the roof construction and materials, types of rail / strut to use, clips and so on.

[kyuan]

This is how my installation looks like.

the roof materials and structure of a Greyhawk --> I do not know much but the installation kit ( bracket, nail ) works fine.

btw I have 6 Renogy 100W solar panels. 2 in serial then 3 pairs in parallel, since the solar prep can run max @30A.

Originally Posted by Captain Morgan

Hello,

After playing solar tetris for a year, I think the best I can do is 5 longer panels around 39.5" - 40" width, this is all I have between the AC and air vent, and the edge of the roof.

I can get qty 5 of the 445w panels by running lengthwise down the edges of the roof on both sides, 3 on one side and 2 on the other. Even this requires I remove the two skylights which I'm 100% OK with.

The ask here is about mounting. I have some roof schematics from Jayco and there doesn't appear to be much in the way of rafters per say. I don't even know for a fact if there is any wood anywhere.

Would it be better to run aluminum strut down the roof with lots of SS screws and dicor, then mount the panels to that?

I wanted a motorized tilt option but for 5 panels I just can't spent the money.

Do you folks have any installation pics or knowledge about the roof materials and structure of a Greyhawk?

Thanks in advance!


Trina Solar TSM-410-DE15H > 410 Watt Mono Solar Panel = 79.69" x 39.53" x 1.38" / 5*410 = 2,050w

LONGi LR4-72HBD-440M Hi-MO4 BiFacial 440 Watt Mono PERC Module = 82.44" x 40.8" x 1.37" / 5*440 = 2,200

LONGi LR4-72HPH-445M > 445 Watt Mono Solar Panel = 82.44" x 40.71" x 1.38" / 5*445 = 2,225w

[Jagiven]

What roof structure is our Greyhawk. Is it wood beamed or is it the vacuum bonded structure? This will tell you exactly what structure you have to work with. If vacuum bonded, there is virtually no solid sub structure. There are fasteners you can use.

As for mounting. I like the idea of an aluminum rails, and determine how best to minimize roof penetration's. Dry fit everything first. Mark it, drill it out. Apply a little dicor to the screw hole, and just a tad bit around it. Screw in the fixture, and then seal around the unit. I would also look at how to apply Eternabond cap to ensure you do not have any small cracks in the future to deal with.

I like your design concept. Please post details once you have it completed.

[Captain Morgan]

I bought 5 of the Trina 410w panels.

For the inner roof mounting of these 80" panels, I could use 4 Renogy Solar Panel Mounting Z Bracket Mounts per panel inside, set on top of flat aluminum strip drilled into my roof with the double sided Eterna-bond type materials the entire length.

On the outside of the panels I would use a set of 4 Heavy Duty Z-Style Mounting Brackets per panel outside, offsetting the distance from the outer flat aluminum strip as above. This might leave a slight lean of the panels towards the outer edge of the RV, which is a good thing to vacate water and dirt. This will be 8 mounts along the lengths of the panels and reinforced with short bars on the inside lip of the panels for extra strength.

This seems simple and inexpensive. I could use strut in place of the flat aluminum bar, but I don't think I need to.

Thoughts?

[pconroy]

Originally Posted by Captain Morgan

Thoughts?

Only thought I have is that with 2000 watts of power, you should offer to power nine other campers near by.

[Captain Morgan]

LOL well, if they're buying drinks they can BYOC - bring your own cord.


This Lifep04 battery bank weighs 370lb just for the batts, with hardware is around 400lb. This 48v system is something like 30,000A and 28.8kwh of juice being fed from the panels, 30A or 50A shore, the Onan 4000 Gen and the alternator. While driving around I could get charge from both the panels and the alternator.

[Captain Morgan]

Please re,mind me again what's the best eternabond like stuff I need to secure the aluminum strips and the brackets to the roof? I think it was a double sided tape? Is it Eterna?


I've used some Marine 5200 permanent on the roof. And man is it permanent.




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[Grumpy]

Eternabond is only a sealing tape. I'd look at the 3M auto trim tape.

[pconroy]

Originally Posted by Grumpy

Eternabond is only a sealing tape. I'd look at the 3M auto trim tape.

Agreed - I'm using 3M VHB tape on my panels. If you check the 3M Catalog, there are literally dozens of different types of VHB tape.


I went with what had good reviews on Amazon. And went for 1" wide.

[Jagiven]

Originally Posted by Captain Morgan

Please re,mind me again what's the best eternabond like stuff I need to secure the aluminum strips and the brackets to the roof? I think it was a double sided tape? Is it Eterna?


I've used some Marine 5200 permanent on the roof. And man is it permanent.

.

Link to eternabond's double sided tape
https://www.eternabond.com/DoubleStick-p/cr-ds.htm

I have used 3M VHB. As others have said there are dozens of different VHBs 3M makes, and the application is not the same for each. Some do require a primer.

[Captain Morgan]

THX

The big fat role I have already for a repair is about 4" wide and thick heavy duty stuff.

What I'm looking to do is lay down a thin stretch of the double sided stuff @ 2" wide and then lay the aluminum on top of it, then use galvanized self tapping screws (I'll drill smaller pilot holes) that come with a rubber gasket every so often to secure into the roof. Then use something like dicor or eterna to cover those screw heads.

I can use those same screws on the mounting brackets attached to the aluminum and those too will go through the aluminum and into the roof for even more anchor points.

The HW for the solar panel will be SS and not related to this ask.

Since I only need to run enough of the aluminum strip for 3 panels (2 runs per side), I think this should suffice for my "aluminum to roof seal and stick" purposes?

EternaBond® DoubleStick
[Size:2" x 50' (DS-2-50)]
$112.14

And then what of the screw head sealer? Are you still suggesting a 3M VHB etc? Or just a dab of the self leveling dicor stuff? Or small bits of the eterna bond I already have?

I need 66.6' + of aluminum strip to make the 2 runs on ea side. If I can find anything solid to drill into like a rafter that would be great. Otherwise maybe another screw in between them, plus the bracket mount screws should be enough?

(that's 4 brackets per each side of each panel = 8 screws per panel side, 16 per panel total = a lot of screws through the aluminum strips)

I bought these brackets to use all around = https://www.amazon.com/gp/product/B08PP9YRZK/



Thx again!




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[pconroy]

Originally Posted by Captain Morgan

And then what of the screw head sealer? Are you still suggesting a 3M VHB etc? Or just a dab of the self leveling dicor stuff? Or small bits of the eterna bond I already have?

Me? I'd dicor over the screws. That's what Jayco does.

[Captain Morgan]

I have two tubes of the Dicor self leveling that should be enough for 80 - 100 screw heads. My concern is if it ever really hardens and cures and stays in place. I don't want it running and looking all willy-nilly hobo style.


And the Eterna-Bond strip, for under the aluminum . . . everyone OK with that idea?


Thanks again.


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