Semi-Flexible Solar Panel Usage

[john61ct]

Example of the suitcase style

https://www.ebay.com/itm/Elfeland-12...-/372033708133

Get one of each, see how they go then expand

[Paul L]

Originally Posted by john61ct

Example of the backpacker style

https://m.ebay.com/itm/Lensun-100W-1...s/222594755454

Pretty giant when rolled out. 8ft to get 100watts.

[waterman46]

Originally Posted by john61ct

Example of the backpacker style

https://m.ebay.com/itm/Lensun-100W-1...s/222594755454

Thanks, that one is quite interesting for my application, especially the ease of storage compared to a non-folding type.

[thinwater]

Originally Posted by waterman46

I am considering getting two semi-flexible solar panels. I'd like to temporarily position them on the foredeck while at anchor, to take advantage of the best location for shadow-free coverage. With our ketch rig there doesn't seem to be many other locations with few shadows. I'd store the panels below when not at anchor.

I've read that it's necessary to put some kind of backing on these panels to prevent damage, if they are to be moved around in this way. Any ideas on what material, thickness and attachment method, should be used? I'm thinking of attaching each panel to a sheet of maybe 1/16" acrylic plastic using contact cement. Better ideas?

Find a place to mount them, even if there is some shade. The extra hours will easily make up for the shade. You will NOT be happy with panels you have to move or their life span.

[OceanPlanet]

We've made some custom foldable panels using small Solbian SP sub-panels. Rather pricey, however we were able to get 150W to fold into 18 x 12 x 2". I forget the exact folded out dimensions, but it's around 4ft x 2.5ft...

[waterman46]

Originally Posted by Paul L

Pretty giant when rolled out. 8ft to get 100watts.

They say length is 1300mm. I calculate that just a little over 4'3". Some deceptive headline in that ad though, it says 10A panel but further down in the specs they get it right at about 6A.

[Mike OReilly]

Originally Posted by thinwater

Find a place to mount them, even if there is some shade. The extra hours will easily make up for the shade. You will NOT be happy with panels you have to move or their life span.

I’ll second Thin’s comments here. My first move into solar was to carry two flexible panels that I’d pull out and move on deck whenever possible (anchorages, easy sailing). They had to be reconnected to the batteries each time, which made the task a bit of a PITA. My initial enthusiasm waned over time such that they got pulled out less and less.

My fixed panels start collecting long before I get up in the morning, and sometimes after I’ve gone to bed. They collect when it’s overcast or partly cloudy. They are always ready to go. Install and (mostly) forget. The only thing I do when at anchor is swing the boom out.

I can see something like what OceanPlanet offers for my motorcycling trips (might look into this!), but I can’t see it making sense for my floating home.

[Paul L]

Originally Posted by waterman46

They say length is 1300mm. I calculate that just a little over 4'3". Some deceptive headline in that ad though, it says 10A panel but further down in the specs they get it right at about 6A.

Must have missed the trigonometric to imperial calculation.

4 feet isn't too bad, but I sure wouldn't want to lug these out daily.

[waterman46]

Originally Posted by Mike OReilly

I’ll second Thin’s comments here. My first move into solar was to carry two flexible panels that I’d pull out and move on deck whenever possible (anchorages, easy sailing). They had to be reconnected to the batteries each time, which made the task a bit of a PITA. My initial enthusiasm waned over time such that they got pulled out less and less.

My fixed panels start collecting long before I get up in the morning, and sometimes after I’ve gone to bed. They collect when it’s overcast or partly cloudy. They are always ready to go. Install and (mostly) forget. The only thing I do when at anchor is swing the boom out.

I can see something like what OceanPlanet offers for my motorcycling trips (might look into this!), but I can’t see it making sense for my floating home.

I appreciate your inputs on this.

On the west coast of Mexico where we have spent most of our cruising time, the wind blows offshore in the morning and onshore in the afternoon. That means the bow is facing the sun in the morning, and when the sea breeze comes up in the afternoon the boat swings so the bow is again facing the sun. So for most of the day, the rigging shadows fall on the aft part of the boat. I know, sounds wierd, but its real.

I already have two large framed panels mounted on the port and starboard quarters. They are each on multiaxis mounts that I designed to allow nearly any angle and can be extended out from the boat to get as far away as possible from rigging shadows. I have a ketch rig, so it does add a few problems in avoiding shadows. I could add two more panels above my dighy davits, and may do that sometime as well.

At anchor I adjust these panels often during each day to get as much sun as possible. Lowering the mizzen boom to the deck helps. Still, there are shadows almost always, on one or both panels.

I just look at all the shadows aft, then I see the large sunny foredeck, and it seems such a waste! I don't think I want any permanently mounted panels forward of the mainmast, where they would be quite exposed to the elements while underway, add windage and interfere with foresails and dingy launching.

[Mike OReilly]

Originally Posted by waterman46

...I already have two large framed panels mounted on the port and starboard quarters. They are each on multiaxis mounts that I designed to allow nearly any angle and can be extended out from the boat to get as far away as possible from rigging shadows. I have a ketch rig, so it does add a few problems in avoiding shadows. I could add two more panels above my dighy davits, and may do that sometime as well.

At anchor I adjust these panels often during each day to get as much sun as possible. Lowering the mizzen boom to the deck helps. Still, there are shadows almost always, on one or both panels.

I hear ya. Sailboats are not very good platforms for solar panels. It’s virtually impossible to avoid some shading much of the time. My older-style cutter has a very long boom which overlaps all my panels. A ketch would be even more challenging (my previous boat was a ketch).

In designing my setup I assume 1/2 my panels will be at least partly shaded almost all the time. This is why I ran all my panels in parallel. Two seasons ago I installed a new MPPT controller (Victron 100/30). It made a huge difference to my system. I’m amazed at how many amps it can draw from my 400 watts, even when shaded, and/or in heavy overcast skies.

Techie whizzes can probably explain what’s going on, but this controller seems to manage the shading way better than my previous one.

[u4ea32]

I have NOT YET done this, but I intend to. I’d love to hear comments.

I intend to buy some semi-flexble or flexible solar panels, that can be easily stowed under pilot berths.

I intend to deploy them at anchor or slip on a full length deck cover. This canvas deck cover will hang over a taught centerline rope that runs from backstay to mast, and mast to forestay, say 8 feet above the deck, and also over lines running above the life lines, maybe 5or 6 feet above the deck: backstay to running backstay to shrouds to forestay. So a mostly complete tent.

I do not intend to have any structure to hold the panels while sailing. Only that the panels will be draped over this boat tent.

What do you think about that plan?

[zboss]

Originally Posted by waterman46

I just look at all the shadows aft, then I see the large sunny foredeck, and it seems such a waste! I don't think I want any permanently mounted panels forward of the mainmast, where they would be quite exposed to the elements while underway, add windage and interfere with foresails and dingy launching.

Coastal Climate is having a big sale on small Solara walk ons.

Solara | Solar | Marine | Boat | Coastal Climate Control

[Mike OReilly]

u4ea32, it’s hard to fully envision your plans, but in general it seems problematic to me. First off, too much assembly/disassembly. Unless you rarely move the boat, or only occasionally use it beyond the marina, this sounds like it will be a major PITA to put up and take down.

Can you store that much material and panels down below? Sounds like a lot…

And you mention the use of fully flexible panels, as opposed to semi-flex. As far as I know, all fully flexible panels are made with amorphous crystals. These are cheap, flexible but not very efficient and don’t put out many amps. They might be OK for trickle charge applications, but not as primary battery chargers.

Your boat has plenty of potential for mounting fixed panels. I’d do that … This is the approach that has worked well for me.

[thinwater]

The thing that many do no understand is that semi-flexible panels are NOT flexible. Yes, you can flex them, but not very many times.

The problem is that they use the same fragile cells rigid panels use, but with out the protection of glass and frame. If you mount them to a rigid surface (curved deck) and don't wank on them, they do fine. If you flex them moving them, sleeping on them, cleaning them, or on a loose bimini, they sprout micro cracks you can't even see and loose most of their capacity. So the rule is semi-flexible panels require even more mounting care than rigid panels. Moving them is a big no-no. Just read the instructions.

The actual flexible panels are expensive inefficient, and don't last very long.

Sorry, but no free lunch. This is why you mount them and simply put up with the shading. Try saving power instead. Ditch the frig, limit the use of fans, use LED lights, get up with the sun, and go to bed when it is dark.

[john61ct]

I think it's safe to assume, unless a member explicitly states otherwise when they write "flexible" they mean the semi-flex type.

Many people don't understand their disadvantages.

Yes, they only last say 3-5 year average when well mounted to a fixed rigid surface. That surface can have a slight curve to it, but as stated, if the cells themselves get flexed after initial install, or if they aren't given good airflow below the cells for cooling, they won't last long at all.

As opposed to the much less expensive framed glass panels, which are much cheaper and routinely last ten years or more.

Now there are also portable folding panels made from semi-flex, designed for camping use. They are expensive and may not last very long, but may be "easier" to stow below and deploy.

That strategy would be reasonable IMO where an efficient gennie provides the bulk of AH charged each cycle, and a bank of PSOC-resistant chemistry is used, like Firefly Oasis or LFP.

Thus the solar need only be deployed **when convenient** when a 'long tail' top up to 100% full is desired with Firefly's, or with LFP when you want to reduce gennie runtimes.

If solar is to provide most charging AH most of the time, relying on portable panels would be a major PITA, although I suppose could be used to supplement once the space for fixed ones has been max'd out.