A25 - solar on the coach roof

[Sunsetrider]

Technically I suppose this topic belong in my 6-page fridge thread. But it is also quite independent of the issues there.

I have taken delivery of my solar panel and batteries (and SOC meter and MPPT Controller) and I need to decide on the installation method on the coach rooftop. I am not sure of the construction of the coach roof. My 260W panel will pretty much fill the space between the rails, and top to bottom. I need to figure out where to bring the cables through, but more importantly:

Shall I thru-bolt? Or simply use screws. If screws, my plan is to use epoxy down the drilled hole and Life-stuff for caulking under the z-bracket. My concern - if the roof is a foam-centred sandwich, the epoxy down the hole won't do much good. I think a lot depends on the coach roof construction profile.

I used thru-bolt (obvi) for the windlass and relocate of the bow cleat, but the solar panel will not be subject to those kinds of stresses. But I'd like to know what's under the skin before I start drilling.

[dkirsop]

The trunk cabin roof is of sandwich construction with foam core between the two fibreglass layers. Marine plywood is used as a filler under the hand rails in order to take up the load on the screws which attach it to the roof. There is also a duct that extends from the starboard ventilator back to the head. Oh yes, there are also conduits moulded into the roof that contain the wiring to the overhead lights.

Before drilling, bolting or other means of permanent attachment, why don't you first try to temporarily secure the panel and see how you like it. The trunk cabin roof is prime real-estate on my boat and often serves as an outdoor lounge platform (with the windshield as back rest) from which to observe sunsets, surroundings and other boaters. If the panel has grommets lash it to the handrail for a season and see how it works with your use of the boat before committing to a permanent installation.

[Sunsetrider]

Well, this panel isn't going to fit anywhere else on the boat. I chose that location because although certainly over the past 3 years some folks have enjoyed lounging there, the very forward location is much more frequently used. And I am mainly a solo sailor. Choosing this location is a compromise and a sacrifice, no doubt. But the alternatives are just not workable on this relatively small boat.

I see from the manual now that the foam core is Divinycell. The total thickness of the skin is just a titch under a half inch. And I have only a single overhead light, so I imagine I can stay away from the location.

I might very well look into your suggestion of lashing to the handrails in any event, for the time being. I think that method will hold it in place, especially with my excellent CPS-induced marlinspike skills! Thank you for the suggestion. There are no grommets as such, so chafe is a big issue to be addressed, maybe with teensy shackles/carabinieri?

[Jay Knoll]

I don't know what type of panel(s) you're planning on installing on the boat, but I do think that there is an advantage to having some air space behind the panel. -- I'm sure that there are other more learned members here who can confirm that fact.

Anyway here are the brackets I used on my A27FC, I did screw them down to the roof, I used 3/4" screws and boat life caulk underneath each bracket.

https://www.amazon.com/dp/B00ZAW18AY/re ... 8232544066

[Jay Knoll]

Slightly cheaper here but shipping might even out the cost (assuming you don't have Amazon Prime)
http://www.unlimited-solar.com/solar-pa ... ing-white/

[DesertAlbin736]

I like Jay's idea about the corner pieces. But don't forget, the coach roof is "crowned", that is curved athwartships. So corners on a rigid flat panel may have to be raised enough to clear that curvature, unless you had flexible panels.

Here's another crazy idea: If you had lift davits for a dinghy on the stern, you could mount the solar panel across the top of davits. What are the dimensions of the panel?

Solar panel atop davits like this off the stern? Just sayin'.

davits installed.JPG

[Jay Knoll]

Here's how my installation turned out, I had to cut off one leg of some of the brackets to accommodate the width I had to work with but they are still plenty strong.

There is a slight curvature to the roof don't know if the 25 has a more extreme curve the panels that run fore and aft went down without any problem, the athwartship panel was a bit fussier, I positioned the brackets screwed them down put the panel in place and then drilled the holes for the screws

[Beta Don]

I thru bolted mine. The bolts come up thru from below, a washer on the inside, a fender washer and a nut on the top side and then a short piece of 1/2" PVC pipe as a spacer between the deck and the panel, then a nut holding the panel down. I used both sealant and a rubber 'O' ring between the fender washer and the top of the deck to ensure no leaks. I think I used 2" bolts, 1/4 diameter, everything stainless of course. I used spacers about 1" long so I was able to get my fingers under the panel to put the nuts on. 4 bolts, each one about 6" from the corners

P1000160.jpg

Don

[Sunsetrider]

I have been posting here like a crazed person but for some reason (exhaustion?) I keep pushing the "post reply" button instead of "Submit". Now I am too exhausted to re-type it all.

Suffice to say:
1. I asked Jay why he chose to use screws instead of glue as recommended by the mfgr. Ease of repair when removed in future? Lack of confidence in the use of an adhesive? I really like that solution and I think I will order the 3-pack tomorrow from the Manufacturer
[urlhttp://www.unlimited-solar.com/solar-panel-uni ... ing-white/][/url]

the brackets, the Sikaflex 252 and the thing that brings the cables inside.

2. Don - Very tidy installation, but after all the exhausting work done and to do on this project (all of which is beyond my ability) I am now looking for simpler solutions, and glopping glue fits that criterion nicely!

[Beta Don]

I have been posting here like a crazed person but for some reason (exhaustion?) I keep pushing the "post reply" button instead of "Submit". Now I am too exhausted to re-type it all.

I too do this all the doggone time!! - It would be GREAT if they could modify the format so there's only one way to post

Fortunately, when you push 'Post Reply' and get a blank screen, all is not lost - If you hit your back arrow in the upper left corner of the screen, it will take you back one page and everything you wrote will still be there and THEN you can hit 'Submit" and make your post . . . . all without having to re-type anything

Don

[Jay Knoll]

I just thought screws would be more secure, I did put caulk underneath each bracket so I guess it is kind of a belt and suspenders approach

[Sunsetrider]

As I thought. I think I will trust the glue.

[DesertAlbin736]

I through bolted our much smaller solar panel to the hard top roof & used washers as spacers to clear the roof curvature.

DSCN2054.JPG

From underneath you can see where the bolts come through. When I made the hard top I made sure to include plywood backers where the bolts would come through & caulked the holes. The slight indentations on the underside of the hard top show where the plywood backing blocks are. In this photo you can see the output cable routed through the roof, back to the aft edge, over to the starboard side, along the top of the side window, and down the corner post of the windshield.

DSCN2019 (1280x960).jpg

This shows the plywood backers that were included in the layup for the solar panel attachment points and for the hinges for the hatch covers. The letters, F, G, etc were my code for placing the pieces of foam coring, like a jigsaw puzzle, with layers numbered, of which there we three, alternating with chopped strand mat & resin.

DSCN1919R.jpg

[Sunsetrider]

Good advance planning, DA. Nice job.

[Sunsetrider]

Well - I bought the brackets that Jay Knoll referenced, but the crowning on my coach roof was too extreme to accommodate a flat surface the size of those corner brackets. So I was stumped. The Z clips I had originally were too small to work. In desperation, I googled a metal fabricator in my nearby city and got a positive response. I am very pleased with the result!Costly though - $90 CAD. But I need to get that panel mounted. Now I have to decide whether to screw or thru-bolt. Just squirt epoxy down the pre-drilled screw hole and caulking under the foot of the clips?