Fitting a semi-flexible solar panel to a sprayhood

[Dazedkipper]

I have a couple of 30w panels which I'm thinking of fitting to the top/sides of my sprayhood so that one will always be in full sun irrespective of which way the boat is laying when on the mooring. The panels have 4off 8mm id eyelets and I was thinking in terms of some sort of quick fix/release system a bit like a drop nose pin but the sail maker tells me there isn't anything like that available. He's talking about sewing material to the hood to make a pocket that the panel will slide into and be secured on one edge with Velcro. He hasn't seen a panel yet but I don't think it's going to work because the panels nearly fill the available flat section of the hood.
So my question is simple, can anyone suggest other methods of fitting panels? They do need to be easily removed if I need to fold the hood down.

 

[Mistroma]

Sagging in the middle is one thing to watch with at least some, in not all, semi-flexible panels. I had panels that did not like taking a concave shape. The manufacturers said my bimini mounting was fine but changed their minds when they failed in 6-8 weeks. The explanation was micro-fractures caused by compression of the upper layer.

Probably something to keep in mind when designing the attachment system. I tried angled aluminium brackets to stop sagging. Unfortunately, they still sagged in the middle. More supports would have worked but I'd just be making semi-flexible panels into rigid ones.

 

[gregcope]

I attached a 110W with simple bungee through the eyelets.

Worked well. Even at F7 and above.

However after a couple of seasons the panel failed - i assume due to micro cracks.

I would do it again, if I was I would try to make a backer out of GF to add to the panel to avoid flexing and make it rigid to the shape of the sprayhood.

I still have the sprayhood and can either find or take pictures

 

[gregcope]

Photos

 

[William_H]

Not withstanding concerns re concave bend on panels etc. gregscope system of having tags sewn on to top of hood witha small lashing from eyelet in tag to eylet in panel. If you have room for that method. If not perhaps tag with eyelet under the hood with lashing around the edge. You could attach tags in situ using a piece of cloth and thin whipping twine and needle to sew it on. ol'will

 

[Mistroma]

I meant to say earlier that it wasn't just the concave bend. I think it's a combination of flexing and the concave bend. I think the manufacturers eventually decided that some flexing would be OK as long as the panel went from flat to slightly convex. Flexing would eventually cause damage but the concave shape accelerates failure.

 

[Dazedkipper]

I attached a 110W with simple bungee through the eyelets.

Worked well. Even at F7 and above.

However after a couple of seasons the panel failed - i assume due to micro cracks.

I would do it again, if I was I would try to make a backer out of GF to add to the panel to avoid flexing and make it rigid to the shape of the sprayhood.

I still have the sprayhood and can either find or take pictures

That's a neat solution, I'll see it will work for me.

 

[alahol2]

Toggles, a la duffel coat, on bungee cord.

 

[Dazedkipper]

Before posting my question I searched the forum and found some posts talking about using industrial/HD Velcro. If anyone has experience of that I'd be interested to learn more.

 

[LittleSister]

Sagging in the middle is one thing to watch with at least some, in not all, semi-flexible panels. I had panels that did not like taking a concave shape.

I meant to say earlier that it wasn't just the concave bend. I think it's a combination of flexing and the concave bend. I think the manufacturers eventually decided that some flexing would be OK as long as the panel went from flat to slightly convex. Flexing would eventually cause damage but the concave shape accelerates failure.

When I was researching potential semi-flexible panels some time ago, more than one manufacturer/supplier was at pains to stress that -
a) curving of the panel could only be tolerated length-wise, not width-wise;
b) the maximum degree of flexure allowable was specified (e.g. in mm per metre) - and in all cases was quite modest;
c) one should be very careful to avoid flexing the panel during unpacking and manhandling before installation; and
d) clearly the panel had to be supported by some other surface - it wasn't designed and built to be self-supporting.

I found such information helpful, and steered away from suppliers who were selling panels without specifying their installation requirements.

I think such limitations mean that for mounting on e.g. a sprayhood a flexible panel (or perhaps even a rigid panel) would be more appropriate than a semi-flexible panel.

 

[dankilb]

Heard recently of people having success first mounting panels on to the thin honeycomb plastic sheet that lorry sides are made of (if I understood correctly). These can then take fasteners and hold the curve of canvaswork.

 

[Trident]

Neodymium magnets - fix one to each corner of the panel and one underneath the canvas - you will not get them apart again unless you slide the underneath magnet off sideways - these have been tested with 200w panels in up to 40 knots (by me on several boats I've fitted these to) and come in packs of 10 with a handy hole in the magnet for bolting it to the panel for about £12 from Amazon

 

[William_H]

Before posting my question I searched the forum and found some posts talking about using industrial/HD Velcro. If anyone has experience of that I'd be interested to learn more.

Velcro has very good hold capabilities in tension mode. ie straight pull apart. However of course it is also the way the velcro attach is released. The area of velcrro attach dictates the strength of the attach. (ability to resit being pulled off) However velcro can have a much higher strength in the sheer mode.ie the pull sideways. ie sliding apart. This can be exploited by having the velcro pass though a loop and back onto itself. Giving a 2 part purchase (double strength) but also having the load in a sheer or pull sideways. You have to lift the velcro apart to disconnect. Often found in battery hold down straps or straps to hold gear. The problem is that you need a hook on one side pile on the other to get the velcro to return back onto itself. You can sometimes find double sided velcro sold as cable ties or you can sew a piece of pile onto the back of hook section where it will attach. (or vise versa) (look for 40mm wide velcro for real strength) (Yes I love it) ol'will

 

[gregcope]

I like @Trident solution. Cheap and reversable.

Here is a close up of mine. Notice that there is a mark around the outline of the panel. I assume this is from some gentle rubbing. For longevity i would have added another reinforcement strips.

 

[dunedin]

Before posting my question I searched the forum and found some posts talking about using industrial/HD Velcro. If anyone has experience of that I'd be interested to learn more.

Us - see the other thread posts #2 and I think #16 - Protecting sprayhood from flexible solar panel sharp edges

About 8 years now, kept in place all year round, without any issues at all

 

[samfieldhouse]

My 100w flexoble re ivy panel has been on my spray hood for 4 years. No issues thus far.
Was cranking out 4a charge all day today.