The best choice of substrate for my Solar arch roof

[ritchyp]

Hi,
I will be moving aboard in the Summer and heading to the Med. I am building a solar arch (and shaded area as my yacht's cockpit configuration is no good for a Bimni in any case)
It will be slightly curved and I will be using six 130 Watt flexible PV panels to save on weight. These ones have a better efficiency rating than most rigid 35mm panels weighing 10KGs. Inexpensive too.
Anyway that is not something I wish to debate

I have been looking at Subtrates or types of board to stick them on. I was hoping to find something thinner and lighter and stronger than marine ply. GRP sheeting was a thought but The want £500 a sheet!! the cheapest I found after hunting around online for an hour, was £360 for a sheet of GRP 2.4m x 1.2m x 13mm. I need 2 sheets with a bit of waste. The area is 2.2m wide and a similar length. MDF was suggested but that is not durable enough and doesn't do well in the wet or heat. It needs to be strong so that a 50 or 60 knot gust of wind would not rip it it off its brackets. Ideas...?

Cheers

 

[Minerva]

How about some Foam you can them
Laminate under a couple of Layers of glass cloth?

 

[jaminb]

The micro racers use foam to attach flexi solar to

 

[ritchyp]

Thanks but not what I had in mind. I don't have the facilities to do that

 

[ritchyp]

Hi,
I will be heading to the Med in the Summer. I am building a solar arch to charge a 300ah LifPO4 Battery (and as a shaded area as my yacht's cockpit configuration is no good for a Bimini in any case)
It will be slightly curved and I will be using six 130 Watt flexible PV panels to save on weight. These ones have a better efficiency rating than most rigid 35mm panels weighing 10KGs. Inexpensive too.
Anyway that is not something I wish to debate

I have been looking at Subtrates or types of board to stick them on. I was hoping to find something thinner and lighter and stronger than marine ply. GRP sheeting was a thought but The want £500 a sheet!! the cheapest I found after hunting around online for an hour, was £360 for a sheet of GRP 2.4m x 1.2m x 13mm. I would need 2 sheets with a bit of waste. The area is 2.2m wide and a similar length. MDF was suggested but that is not durable enough and doesn't do well in the wet or heat. It needs to be strong so that a 50 or 60 knot gust of wind would not rip it it off its brackets.

The area will be approximately 2..2m wide and a minimum of 2.1m long. The aft shroud is dominating the design. I will make a 25mm hole for the shroud to pass through and have 2 panels in front of it and 4 behind. The drawing is not accurate, just an rough diagram i did weeks ago but now I know have 700mm between the shroud and the end of the boom at a height of 2m above the deck.

 

[William_H]

I acknowledge that you do not wish to debate your choice of panel. However panel efficency declines with temperature. Domestic PV panels are always mounted well above the roof to allow for airflow to cool the under side of panel. So rigid panels open underneath would be better IMHO than flexible on a sunbstrate. Have a look at domestic PV panels for best efficiency and price. (price due to enormous numbers made) ol'will

 

[ritchyp]

I acknowledge that you do not wish to debate your choice of panel. However panel efficency declines with temperature. Domestic PV panels are always mounted well above the roof to allow for airflow to cool the under side of panel. So rigid panels open underneath would be better IMHO than flexible on a sunbstrate. Have a look at domestic PV panels for best efficiency and price. (price due to enormous numbers made) ol'will

I started with domestic panels and they would be the roof itself but I spent a whole day trying to find a minimum of 600 watts and in a configuration of 4 or 6 that would work around the shroud. 700 mm to clear the boom safely. Also adding 50 to 60 kg that high would mess up my centre of gravity and righting angle

The flexible panels are 130 watt so it gives me 780 watts and they are 23% efficient and weigh only 2kg. If curved slightly they will get more sunlight. they have built in diodes to stop back flow and I need them to generate 600w

 

[Neeves]

You say you don't have the facilities to build.

If you can source a part panel of foam, slightly over size then that is all the space you need to build the panel I understand you need. 10mm foam curved to what ever curve you want, a layer of glass on top and the following day one underneath. Curve the foam, lay up the glass on top, one evening. The following morning it will have set, remove (hide under bed) that night reverse the structure and add another layer of glass - the following morning you have a crude roof. Fill and fair outdoors.

In Oz we can buy foam panels already glassed - but they are flat - used to build catamarans Composite Panels - ATL Composites . You would need to induce a curve which in your case might be pre-bent stainless tube (and you simply attach the panel to the tubes (bolt through) or 'U' clips (as used to secure ducting or pipes).

Jonathan

 

[rogerthebodger]

This is the setup I made for goal posts to support some solar panels and the cover over the cockpit to protect from the African sun

The first cover was made from sunbrella but it allowed rain to pass through.

I then replaced it with 10 mm thick PVC foam center sheets with solar panels mounted on top.

I also fitted small gutters along the side to catch rain water for water collection if needed be.

https://flic.kr/p/VKo3Yn

https://flic.kr/p/WM5REc

https://flic.kr/p/WYNTMn

 

[ritchyp]

What if I drill cooling holes in the board to let air in under the panels. Still need to find a the perfect boards or sheets of polymer or some composite type

 

[rogerthebodger]

What if I drill cooling holes in the board to let air in under the panels. Still need to find a the perfect boards or sheets of polymer or some composite type

My panels are mounted about 40 - 50 mm above the PVC so has plenty of ait flow

 

[Sea Change]

If weight and cost are your main concern, twin wall polycarbonate could work. It's quite brittle though, might need some reinforcement at the attachment points.

I, like most people, just went for rigid panels. Cheaper and much easier to work with. The earlier designs of flexi panel tended to delaminate after a few years, especially if allowed to flex back and forth.

I have one flexi panel on the boat and it's just falling apart now. Corrosion getting in and its turning green inside.

If I was buying again, for a bimini or arch I would consider bifacial panels.

 

[PaulRainbow]

Hi,
I will be heading to the Med in the Summer. I am building a solar arch to charge a 300ah LifPO4 Battery (and as a shaded area as my yacht's cockpit configuration is no good for a Bimini in any case)
It will be slightly curved and I will be using six 130 Watt flexible PV panels to save on weight. These ones have a better efficiency rating than most rigid 35mm panels weighing 10KGs. Inexpensive too.
Anyway that is not something I wish to debate

I have been looking at Subtrates or types of board to stick them on. I was hoping to find something thinner and lighter and stronger than marine ply. GRP sheeting was a thought but The want £500 a sheet!! the cheapest I found after hunting around online for an hour, was £360 for a sheet of GRP 2.4m x 1.2m x 13mm. I would need 2 sheets with a bit of waste. The area is 2.2m wide and a similar length. MDF was suggested but that is not durable enough and doesn't do well in the wet or heat. It needs to be strong so that a 50 or 60 knot gust of wind would not rip it it off its brackets.

The area will be approximately 2..2m wide and a minimum of 2.1m long. The aft shroud is dominating the design. I will make a 25mm hole for the shroud to pass through and have 2 panels in front of it and 4 behind. The drawing is not accurate, just an rough diagram i did weeks ago but now I know have 700mm between the shroud and the end of the boom at a height of 2m above the deck.

Foamex ; Full sheet, 5mm thick £33.79 plus VAT

5mm White Matt Foam PVC - Buy Online Now - We Cut To Size!

Edges not terribly smooth when cut, might want to smooth them with some epoxy on exposed edges. Faces have a pretty smooth, matt finish, typically used outdoors for signs.

 

[Scarboroughsloop]

You could have a look at Polywood

Poly-wood sheet white 1220 x 2440 mm x 6 mm thickness (Vetus SH06WH)

 

[rogerthebodger]

Polywood is simply high density polyethene which chopping boards are generally made from.

Cannot be glued but can be heat welded