Opinions on a solar array

rgranger · Mar 6, 2017

That boat is loaded down....

Re: the frame! You might want aluminum for both the weight and for the fact that the frame on the solar panel will be aluminum. Dissimilar metals and all of that. SS might cause electrolysis ... weigh more .... and cost more

I know a guy who does custom racks for pick up truck beds... that might be a good way to go .... see if you can find a local shop that does that kind of work. ....or maybe one of those adjustable ones from Lowes will do the trick?????

walt · Mar 6, 2017

Estimate of the watts.. Some panels I just randomly looked at were in the range of 12.5 to 13.5 watts per square foot.

So if you can estimate the dimensions of that panel for length (feet) and width (feet), find the area L*W and multiply by 13 watts per square ft. Ie, panel power is approximately L*W*13 (L and W in ft)

sailnoproblem · Mar 6, 2017

I agree with the use of aluminum. Any Marine welding shop could do the job. They would use sch. 40 anodized aluminum pipe. You would have all the strength you need for the panel.
I'm sure you will have no problem finding a shop in Florida.

rgranger · Mar 6, 2017

Gene Neill said:
Really, aluminum? .

For sure..... they make entire hulls out of aluminum.... and the pipe for catamarans is usually aluminum... and airplanes. Pound for pound it is tough stufff... but it's density is 1/3 that is ss. So make it twice as thick and you will still be 1/3 less mass

CloudDiver · Mar 6, 2017

Gene... don't use Aluminum. Sch 40 anodized aluminum is probably more expensive than 1 inch polished stainless, and the anodize will be destroyed at every weld anyway. I pay about $40 for a 12 foot piece of polished 1 inch stainless, the welds are easy to re-polish with a hand-held sisal wheel. If you went with aluminum, you'd have bi-metal corrosion issues where stainless bolts would go through the aluminum flange into your deck. Don't worry about the aluminum frames of the panels, there are 100 ways to Sunday to mount the panels to the tubes so they don't touch the SS tubing. You remember the plastic clamps that @CaptDon01 used to mount his solar panels? Go with 1 inch stainless, tons of accessories (like fishing rod holders) are made to mount to 1 inch tube, and it will match everything else, plus no corrosion issues at the foot flange.
I could make this thing for you in one weekend if I just had a tube bender and a fish-mouth tube cutter. Unfortunately, a pro welding shop (that usually has 'marine' in the name) will charge $80 to $120 per hour and I think you'd be in this for at least $750.

CloudDiver · Mar 6, 2017

P.S., looking closer at the picture, you do not need a tube bender, so I could make this with the tools I have on hand (although a tube notcher would be handy, I don't absolutely need it). Problem is, you have to do the work ON the boat... No such thing as right angles, lots of measuring to get it right but all the cuts can be done with a mitre saw (I have a special DeWalt metal dry-cutting saw that uses 14 inch blades, carbide for stainless). The welds are simple, no crazy curves or anything to deal with. Probably get away with 40 lineal feet of 1 inch tube stock and the just 1 foot of flat stock to make the feet. With some insulators it could be done on deck, welded in place, without burning the gelcoat.

CloudDiver · Mar 6, 2017

These clamps;
https://www.westmarine.com/buy/west-marine--plastic-rail-clamps--5142070?recordNum=5

Or these (only difference is the thumb screw);
http://www.downwindmarine.com/Rail-Clamps-Universal-p-91002072.html

CloudDiver · Mar 6, 2017

When I was welding my new legs and cross member for my main sheet traveler, I wish I had gotten this;
https://www.amazon.com/SOLDERING-BOARD-TRANSITE-JEWELRY-WELDING/dp/B00YSYWMY6
A piece of hard fiberboard like this will prevent burning the gelcoat as the main legs are tack welded to the flanges. You would cut the pieces to match the flanges and drill holes in them so you sandwhich bolt the flange and insulator to the deck. Tack the legs in place just one or two tack welds, build up the rest of the structure components with tack welds, then finsh weld everything above the feet where the heat wont hurt anything. Then go back to the feet and tack as much as the torch can reach. Finish welding can be done off the boat, but if the insulator can handle a lot of heat you could almost finsh weld them in place (but I wouldn't risk it). My gelcoat was trashed on my boat and I was planning to paint anyway, but I still should have done this (the fire I started smelled really bad). I wish this board was only 1/4" thick and rated higher than 600 degrees, but I'm sure if I searched the interwebs hard enough I could find it.

Sumner · Mar 6, 2017

If you aren't going to have the self steering wind vane I'd move them back and lower if possible. That might get them past the backstay. Any shading at all, even the backstay is going to hurt performance.

I'd guess they have somewhere between 180 and 250 watts. The real key is what you are going to have. Take some measurements of where yours will be and look for panels that will fit that space and you will know the wattage.

I think most people are overly optimistic on how much amperage they are going to get from panels. They probably won't ever be at max due to the fact they won't ever be 90 degrees to the sun and a good part of the day the sun is even lower at a worst angle. If you are looking at longer trips I'd also go with an MPPT controller to maximize whatever solar you have.

Here is a little formula that I use to try and give a realistic guess as too how many amp/hrs I'd average given that some days might be cloudy.

Average daily amp/hr = (((watts)/12) * 6)/2

It has seemed to be close from my experience.

I have a lot of Aluminum on both boats....

... held together with SS fasteners and so far no problems and it sounds like from this...

http://www.practicalmachinist.com/vb/general-archive/will-s-s-bolts-work-aluminum-88508/

... that others have had similar results, but one needs to do what one feels comfortable with. I do use anti-seize on the nuts and bolts,

Sumner
===========================================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Wyoming, Canada, Florida, Bahamas

centerline · Mar 6, 2017

6061 aluminum is a structural grade with a higher degree of corrosion resistance (as compared to a non structural grade) and nearly equal to the structural properties of steel for the same thickness, although the aluminum is much more flexible.
it is not anodized unless you order it that way, but it is not something that is much concern because raw aluminum exposed to the open air does not corrode like aluminum in closed in areas does... the stainless fasteners can speed the onset of corrosion, but its slower to develop in the 6061, it can be slowed more by using lanacote on the hardware when its installed.... there are many many UN-anodized aluminum masts and booms on boats that have withstood the elements for several years... and still going strong.
It wouldnt be a concern to me to go either way... stainless or aluminum for that application.

sailnoproblem · Mar 7, 2017

If you want to buy the anodized aluminum pipe or SS tube contact TACO marine. They are in Miami. I fabricated Towers, bow rails and pulpits for years and bought a lot of material from them..
They also carry mounting pads. As for the stainless and aluminum contacting, I have never had a problem with stainless bolts and aluminum pads.
If you are not a experienced welder don't try it yourself, as you will not be happy with the results.

sailnoproblem · Mar 7, 2017

Just thought I would add my two cents again. Stainless tube is going to flex a lot, as compared to Aluminum pipe. The Stainless tube wall thickness is 1/16", and unless you can angle the structure inboard it's going to flex a lot. I don't know the weight of the panel, and the height of the frame you want to fabricate. Again just my opinion.

Maine Sail · Mar 7, 2017

Gene Neill said:
I'm thinking about copying this Albin Vega's solar arrangement (minus the loose panel bungeed to the cabin roof). There is precious little room on a Vega for panels, and this is the best looking setup I have found so far. Without knowing any particulars on these panels, including their measurements, can anyone take a stab at what wattage/amperage we might be looking at here? Just roughly, of course. For perspective, the boat is identical to mine, 27' LOA with 8' beam.

I'm also curious about what one might have to pay to have a stainless rack like the one pictured, and any other thoughts or comments anyone might have.

Thanks in advance!

Those panels appear to be in the 85W to 100W size range. Without knowing the efficiency of the cells it is impossible to guestimate the actual output. Panels range froma low of about 14% to over 23% efficient these days. A higher efficiency panel packs more wattage into a smaller sq in foot print.

The easiest, and likely most cost efficient mounting solution, would be to order a two bow 1" SS .065 walled bimini frame and mount the panels to that. You don't need the Sunbrella if you don't want it.. To stiffen it, side to side & fore aft, you cross brace it to the push pit as shown in the image below. A rigid mount eliminates a "strapped" bimini. A fore/aft stretcher bar also serves to stiffen the bows. This was a large vessel and needed three bows. You would only need two.

Add some Gemini Mounts and away you go... DO NOT cheap out on the Gemini Mounts John has engineered these for the strength needed to hold actual glass/aluminum framed solar panels. I had a customer purchased some Gemini knock offs and two snapped 170nm off-shore en-route to Bermuda..

Gemini mounts are extremely strong. This customer, with a power boat, has done the great loop (outside route - St. Lawrence Seaway, Nova Scotia, Newfoundland etc.), including multiple storms with two 140W Kyocera panels held in place with 4 Gemini Mounts.

deltaten · Mar 7, 2017

I. Mounted my pair of 50 watters on the sternrail. Mebbe just me; but doesn't anyone else think some scaffold kluged on the back of a sailboat ruins it? I've always been a huge proponent of "form follows function"; but c'mon.....some of these plumber's nightmares are downright fugly. Similar (IMO) as shingles on the coach roof etc.
Does it work?
Yes!
Is it safe and sound?
Mebbe?
Does it " fit" the boat and look good?
Absotively not!

Jest sayin'

Sumner · Mar 7, 2017

deltaten said:
...
Does it " fit" the boat and look good?
Absotively not!
Jest sayin'

Does it let me cruise for months on end with refrigeration and not ever have to run the engine or a generator or tie up at a marina. Absolutely

. I'm a cruiser and don't want to listen to an engine running ever day.

I'm pretty much a person that doesn't give to much thought to how others think about my boat as long as what I have is working for me. I'm not saying what I do is for anyone else and I'll keep my thought of what I think of their boat to myself

,

Sumner
==========================================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...http://purplesagetradingpost.com/sumner/endeavour-main/endeavour-index.html
Mac Trips to Utah, Idaho, Wyoming, Canada, Florida, Bahamas

centerline · Mar 7, 2017

deltaten said:
Mebbe just me; but doesn't anyone else think some scaffold kluged on the back of a sailboat ruins it? I've always been a huge proponent of "form follows function"; but c'mon.....some of these plumber's nightmares are downright fugly. Similar (IMO) as shingles on the coach roof etc.
Does it work?
Yes!
Is it safe and sound?
Mebbe?
Does it " fit" the boat and look good?
Absotively not!

Jest sayin'

In some warped context, I kinda agree... in fact, a boat with a big ugly pole sticking uo out of the middle of it with all sorts of wires and ropes tied and hanging from it, with short metal posts around the parimeter with another wire connecting the short posts together and safety gear, fenders and other necessary and un-necessary equipment strapped to it, is a real eyesore...
And some of these ugly hulks even have another small boat strapped piggy back to it, with another motor that isnt even big enough to push the monstrosity thru the water.
Im not sure what they were thinking when they built a boat like this...
and then somone who was wanting a quiet renewable energy source attached more ugly equipment to the already UN-streamlined boat...
why cant we all just be happy floating around close to shore on a simple piece of wood or plastic... it would be so much cheaper and the ugly would be at its bare minimum...

But then, when talking about ugly, what is one comparing All the ugly to?...

rgranger · Mar 8, 2017

Gene Neill said:
In all fairness, @Maine Sail 's Bimini suggestion looks pretty good to me. More attractive, cheaper, throws more shade, what's not to love?

That does seem like the right answer. And if a bad storm is coming, you could easily detach and stow to prevent wind damage etc.