DIY Solar

[HobieFan]

Has anyone gone off the deep end and built your own solar panels?

I worked on a design team a few years ago building a solar car and we built our own arrays. They were much more efficient and we were able to tailor the voltage for our power trackers, lay them flush on angular surfaces without mounting hardware, include gaps for access ports and repair individual cells if they were damaged, etc.

Any thoughts?

Imagine a boat where the decking above the hatch was laid flush with individual cells. I think it would be beautiful! Would have to coat it with a sealant. When I was working on the car, we had a materials engineer and donated equipment, so we had some expensive Elastomer, which worked great.

Anyway, I don't know how it reacts to salt water, ect, so I haven't seriously considered it over a commercial panel, but it's at least a little appealing.

[Islandmike]

I would love to see some info on that. I presently have 3 65watt panels on my boat and would love to have more. I am sold on the benifits of solar. Looking forward to more post on how to make your own.

[TritonSailor]

If you had the knowledge to do it, then go for it. I don't think I would go for it though because I would have a hard time avoiding putting my foot through it. You would need a good amount of room for it to work. Not only space for laying it out, but space to get around it when walking on the deck. I don't know how many people would be able to walk around and avoid stepping on them, especially in heavy seas. I couldn't, but I'm a big lummox!

Jeff

[idpnd]

A friend has got extremely flat solar panels that are glued onto the surface of the hatches and elsewhere. You only get a small bit sticking out where the controller is. These are perfectly walkable and efficient afaik

[Jetexas]

On the gadget blogs I keep hearing of breakthroughs in flexible arrays or photovoltaic paints, but I've yet to see a real-world application of any of those technologies.

The only two snags I see are:
a) as mentioned before, if your entire deck was covered in it, could you walk on it?
b) does the deck get enough sun or will it be too shaded by masts, sails, etc.?

I've noticed some panels on the market can be mounted flush, but others recommend mounting them with airflow underneath to increase efficiency.

At my marina, the majority of those I see mounted are on the handrails around the nose of the boat or along the edges of the foredeck mounted on waist-high metal stands.

I think if I was putting solar on my boat, I'd build a new companionway cover that had panels built into it as well as two more layers of panels that would slide out and lock in a cantelevered postion to the left and right - kind of satellite style, I guess. On one hand it's not the most efficient placement since I'll have payed for three arrays, but when it's collapsed, I'm only utilizing one. However, it gets them off the deck and completely out of the way when I need them stowed and locked down. Also, being on the companionway cover (I'm sure it has a name, I just haven't learned it yet), it's easy to run the electric lines inside to the battery without drilling new holes, worrying about sealing them, etc.

[HobieFan]

I like the idea of putting them on the companionway cover, but I have a pretty substantial dodger up there.

I need to go measure some areas and maybe pick up some foam core cutouts of the size of the panels I'm looking at to see about locating them.

I think I'm going to give up on the concept of mounting them flush on deck. I don't think they can be walked on anyway, so putting them flush just decreases the light and increases the headache and shadowing.

It could be quite inexpensive compared to the pre-built and sealed panels, but you have to make sure they're sealed yourself and do all of the soldering and wiring... mmm

[Tellie]

Bunch of Youtube examples of guys building their own solar panels. Ebay sells all kinds of solar panel parts to build your own.

[Rene]

I have installed 4, 85w kiocera panels ( not sure I've spelled it right) on my boat. The controller is located inside the salon and can be programed to charge both banks in the proportion of your choice. The panels can be articulated for efficiency and quickly disconnected and removed for severe weather protection. They are mounted high on a stern arch which also serves as a mount for dingy davits, sat phone antenna and tracking TV antenna. This mounting gives optimum exposure to the sun and protection from mechanical damage. The 20+ amps generated during peak hours is sufficient to run an 80 gpd watermaker and top up both battery banks. I think mounting flexible panels on cabin tops or hard dodgers is a great idea. Shading and mech. damage may become an issue. Mounting panels on life lines and rails can create several problems with sheets and other running rigging. Would like to hear more on home builts; cost, durability etc.

[seandepagnier]

If you have many cells in series then shade one cell, it knocks out the whole string. I think for this reason, strategic placement of strings of cells would be important.

Typical solar cells are very brittle. I have gotten 80 watts of cell wafers (for $60) then mounted them between glass, it was lots more work, but also a cheaper panel.

The individual cells are not designed to be stepped on, or they can crack. The flexible cells are different and probably work better for mounting on a deck, but the cost is very high ($20 per watt or more)

[HobieFan]

Recognizing that shading one of the elements in a series kills the voltage of the whole series, it would be beneficial to design them after studying the shading patterns of your deck both when at anchor and when sailing, so you could cluster the cells to shaded/sunny spots at different angles and times of day.

I think with the right setup, you could improve shade-resultant voltage issues by 50% or more...

Hmmm.. I might take a day and study the shading patterns of my boat and see if I can't figure out a good way to mount them efficiently.

It's great if you can spend $5000 for 6 panels, but if 3 are constantly shaded, what's the point? :-)

Typical solar cells are very brittle. I have gotten 80 watts of cell wafers (for $60) then mounted them between glass, it was lots more work, but also a cheaper panel.

I've also thought of building my own panels instead of flush-mounting the individual cells.

What kind of glass did you use for this mounting? Lexan? Automotive tempered? What did you back the cells with? Fiberglass? Wood? How do you mount them?

I can handle the cells easy and cheap, and don't mind soldering and wiring, but mounting issues is one big reason I consider commercial panels...

[ColdFusion]

Originally Posted by HobieFan

What kind of glass did you use for this mounting? Lexan? Automotive tempered? What did you back the cells with? Fiberglass? Wood? How do you mount them?

I purchased a number of individual solar cells a while ago but haven't got round to building a panel out of them yet, as was the original intention. I'm also not sure what to back the cells with, although I had considered some kind of alloy for strength/low weight. As for the glass, I had planned on using polycarbonate (cheap/low weight/good impact resistance). Should the glass/poly rest on the surface of the cells or should there be an air gap? I'd be very interested to hear what others have done.

[HobieFan]

I'm pretty sure you want to air and water seal the glass. I would press it tight against the cells and seal around the perimeter with a good silicone sealant.

In the past, I've bare-coated the cells with elastomer coating, which is the most efficient way, short of leaving the cells bare to the elements, but you lose the strength and crack and chip-resistance of the glass plating.

For the cost vs effort tradeoff, I'm looking into these panels:

Off grid solar panels for battery charging using Evergreen solar cells

They're decent (not stellar) quality and efficiency and are already backed with aluminum. If they don't have glass coating, I can fix that easily enough and I'd probably add an extra layer of sealant, just to make sure they're marine capable, but at less than 1/4 the price of "marine grade" cells of comparable cost, they seem like a good compromise for the DIY budget without spending weeks tabbing, soldering and backing individual cells.

[Microship]

The work-around for uneven shading (pretty hard to avoid on a sailboat, though a big array on the arch gets close) is to dedicate a peak-power tracker to each sub-array. Then they contribute as they can, as efficiently as possible, and the lit ones don't dump power into the dark ones.

Steve

[forsailbyowner]

I have 10 smaller panels mounted on top of my dodger and bimini. Four of them are 30 watt" go solar"
Extreme duty thin panels. They have a stainless backing and a tedlar coating. They are warranteed for twenty years output capacity, I have my doubts. They have turned from extremely clear to having a white semi opaque appearance in four years. Since purchasing I've seen some similiar looking panels that had the coating peeling up like potato chips. I got the other 6 panels from a gent in tampa. That was in on the development of a brand of panels. He said they had been testing the. Tedlar coating but had problems with adhesion to the cells. I have a diode on each panel. This way if one panel has some part shaded it doesn't affect the output of the others. I use no regulation but keep a good eye on the voltage. If it climbs in the 15 volt range I turn down the fridge temp and turn the tunes up. I have a large 8 battery bank so even peak output is a trickle charge. Checked gravity yesterday and was
%100 without running engine for two weeks. I run 400 watt sewing machine, fans, tv,radio and fridge daily.

[seandepagnier]

I was going to mount my solar panel on a 2 axis fixture on the stern so you can manually aim the panel at the sun, and all angles are possible (work at early morning or sunset even) This should also help avoid shade most of the time because of location and height, but it is impossible to completely avoid shade all of the time.