Semi-flexible solar panel install

I nominate this one for project thread of the year! Great job, Dave! It looks like you planned very well for this upgrade and executed it beautifully. For under $2000, you have greatly enhanced your boat's electrical capability and flexibility. This is something I have been thinking about for quite some time and would definitely incorporate into my boat in a similar fashion if I ever take to longer trips counted in weeks rather than days.

I suspect the marine semi-flexible panels that come with Velcro are intended for installation directly onto the FB canvas. Was there any guidance from the mfr about heat buildup or mounting requirements? Being semi-flexible, they probably required some sort of support from below and the bimini fabric seems like a natural support structure.

I like the FB bimini location as one which has nearly full exposure (I just have a radar Mast and a couple antennas) as opposed to a cockpit cover location. On my boat, the FB rail canvas plus the radar mast would provide considerable shading of the panels and reduce their effectiveness. I've learned from from others that it doesn't take much shade to cut the panel output considerably.

Thanks for the detailed thread, Dave! Very nice work!

FlyWright said:

I suspect the marine semi-flexible panels that come with Velcro are intended for installation directly onto the FB canvas. Was there any guidance from the mfr about heat buildup or mounting requirements? Being semi-flexible, they probably required some sort of support from below and the bimini fabric seems like a natural support structure.
Thanks for the detailed thread, Dave! Very nice work!

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Thanks for the kind words. I really can't answer your questions because "as usual" I did some research and then searched for the cheapest product I could find. My panels are $299 each vs $900 each from one of the name brand suppliers. The supplier doesn't really have any support for the product that I can tell. They were purchase on eBay from Discountpv.com. I just checked the web site and they may be going out of business. The panels did not have velcro, the canvas guy sewed it on.

Here is a quote from another site that look like they sell the same ones I have. "These panels are not designed to be walked on. if mounting on a flexible canvas type surface, such as a Bimini top, tent or canopy, caution should be used to be sure no hard braces are located behind the panel and that the canvas type surface be extremely tight and rigid. Strong flexing over years may cause failure and care should be taken when selecting a installation location. Please call should you have any questions or concerns about the installation site you are considering. These panels are very flexible and therefore not recommended for portable use unless they are attached to a backing to minimize excessive bending and flexing."
https://www.emarineinc.com/100W-Semi-Flexible-Solar-Panel

subscribed

I bought my rigid panels and controllers on Ebay, after 4 years no probs. I thought panels were panels, but recently there was discussion here regarding house roof installations, about panels rated tier 1, 2, and 3 (higher no.= lesser quality).
Seeing the install rules for flexibles, for now think I`d stay conservative with rigid if adding panel. Maybe Dave can report performance a few years down the track.

I have been helping a friend with a 600 watt solar install on a 55' Tayana sailboat that he intends to sail around the world. We did a lot of research on the different solid panels. There are different levels of quality. The one thing that stood out for me was the Salt Mist corrosion testing that the better panel were certified for. If you look up the standards for the testing they really put the panels through a lot.

TÜV Rheinland’s Salt Mist Corrosion Test
IEC61701:2011 Edition 2, Severity Level 6 is highest testing level in the industry.

Big thumbs up for Morningstar tech support

We have had the panels up and running for almost four weeks now. I have seen 350 watts output so far. For the last two weeks I have noticed that the TS MPPT 45 charge controller, absorption stage voltage was 15.1 vdc. I have been concerned because the manual says the absorption set point is 14.6vdc. I finally sent an email to Morningstar tech support with my question. To my surprise they called me the next day to resolve my question. It turns out that 15.1 vdc is correct for batteries that are a 45F. The temperature compensation raises voltage as the temps drop. The tech even knew what temp my batts were based on the charge 15.1 vdc. It was a big relief for me because all I could see was cooked batteries in my future. The fine print in the manual indicated 14.6 vdc absorption voltage is at 77F/25C. It was great to get that kind of service

Sagging solar panels

So I have been pleased so far with the solar panel performance. The battery charger hasn't been on for over a month and the batteries are always topped off. I climbed up to ensure there was no bird crap on the panels and discovered that the panels were no longer in a nice slow even arc. The canvas and the solar panels had relaxed and had the shape of a stretched out 'M'. I got a sick feeling in my stomach thinking that they wouldn't last long with those conditions. I obtained (3) 24"X48"X 1/4" sheets of plexi glass, rounded and smoothed all the edges and slid them under each of the solar panels. The panels went back to the previous smooth arc and the canvas went the same due to the Velcro on the panel bottoms. I will keep an eye on it and provide an update on future changes if the occur.
I didn't get pictures, so here is one of the initial arc and a drawing of what happened.

The Plexi reinforcement is a great solution. You are doing a project that I plan to do at a later date.

Resourceful thinking, Dave. A lot of us are watching and hoping to copy your successful install. I had my doubts about semi-flexible panels, but you're the 2nd user I know now, both of which seem to be working well. Time, sun, weather and temperature will tell.

Thanks, I had to get the info out on the panels sagging. I didn't want others to go down the same road. I am pretty sure the panels would have failed in time because of the cyclic stress from the wind moving the canvas with that sag in there, not to mention the tighter arc it had.
Its all a bit of and experiment for me. If the panels fail I am out $900, not that bad really in the trawler world.

I'll be interested in heat buildup at the solar panels with the plexiglass panels in place.

FlyWright said:

I'll be interested in heat buildup at the solar panels with the plexiglass panels in place.

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Me too, I checked today with the gun and the surface was 122F in direct full sunlight. The back side was 108F. Its 85F here in Maryland. The panels only had 130watts of demand due to fully charge batteries. When I get out on the hook the next few weeks I will pull temps when they are pumping out 300+ watts.
We start the loop Monday. Should have lots of good test data to look at

fryedaze said:

We start the loop Monday. Should have lots of good test data to look at

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Well, that's exciting! Hope you have the time of your lives! Keep us posted on your travels!!

Cheers!

Congrats Dave! I'm thinking of a similar setup on my PH roof but would go with the rigid panels in my situation. About 450-500 watts of panels would be about right for my situation. I'd like to limit the runtime on my genny to <1 hr per day and also bring the batteries up to a full SOC on a more regular basis when off the grid.


Jim
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Great thread, thanks for sharing all the details!

Performance info

Well, its day 5 of the Fryedaze great loop adventure. We have had the opportunity to anchor out and see what the solar panels will do. The key test was two days in Swan Creek Rock Hall Md. The power pigs on Fryedaze eat 300-330 amp-hrs a day. On a pretty good day the panels gave back 195 amp-hrs of that. That's not the 80% I was looking for but then I wrongly assumed we only used 250 amp-hrs a day. I did get to see a crappy performance day when it rained all day and was overcast. The panels never went over 60watts. Our 940 amp-hrs bank will hold us for a few days.
Once I figure out how to connect the data logger to the laptop I will overload all the engineering geeks with DATA.

Dave
Fryedaze in Utschs marina Cape May

Dave, is that the new curvature with the lexan panels in place? Looks perfect to me.

FlyWright said:

Dave, is that the new curvature with the lexan panels in place? Looks perfect to me.

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Yes, it worked out really well.

Hi Dave: perhaps you mentioned this already. Does the SOC of your batteries reach 100% at some time in the day when you are off grid? How does your genset use tie in to the equation?

Jim


Jim
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JDCAVE said:

Hi Dave: perhaps you mentioned this already. Does the SOC of your batteries reach 100% at some time in the day when you are off grid? How does your genset use tie in to the equation?

Jim


Jim
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No the Victron SOC doesn't go back to 100%. Big round numbers we use about 300 amp-hrs a day and the panels give back 190-200 amp-hrs. We haven't used the genset as our battery charging source because we haven't stayed in any place more than two days. I could probably stay out 4-5 days before I would need a charge. Unfortunately if I had to put back 500 amp-hrs with the charger and the genset alternator it would take a while, each is only 40 amps. My engine alts are 150 amp-hrs each controlled by Sterling regulators. They recover the batteries pretty quickly.

Yes, I was just wondering if you gave your genny a kick in the morning to get the SOC to 80%, if the solar would get you to 100% sometime later in the day. It would be nice to get to 100% sometime once every few days. Just thinking about my own situation...next year when I get onto this project.

Jim
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JDCAVE said:

Yes, I was just wondering if you gave your genny a kick in the morning to get the SOC to 80%, if the solar would get you to 100% sometime later in the day. It would be nice to get to 100% sometime once every few days. Just thinking about my own situation...next year when I get onto this project.

Jim
Sent from my iPad using Trawler Forum

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My panels are 450 watts. They will never put 450 out. I think if I had 50% more output I could be self sufficient. So my assumption is if I had about 700 watts of panels It would handle the 300 amp-hrs (3800 watts-hrs) I burn a day. The panels are giving me about 2500 watt-hrs a day now.
If I had that big Krogen I would mount 3- 300 watt house panels up on the roof.

Great write up Dave and thank you for taking us along. On our new to us 41 footer, I was really contemplating a solar system very similar to yours but I'm afraid with the twin Cummins 5.9's down in the cave, I do not have the space for more batteries. I'm curious how many you added (and where) and what kind of space they took up. I wonder if the Lithium-ion batteries would work?

When I finally decide to head home to Texas I'm thinking of going on the route (I think) you are taking instead of traveling down the east coast and over. I will be following your journey, safe travels and much joy!
Rob

What kind of adhesive did you use on the velco that's attached to the solar panel? My luck has been the adhesive that comes on self adhering velco becomes soft under the sun and then comes unglued. But that my luck....lol

roguewave said:

Great write up Dave and thank you for taking us along. On our new to us 41 footer, I was really contemplating a solar system very similar to yours but I'm afraid with the twin Cummins 5.9's down in the cave, I do not have the space for more batteries. I'm curious how many you added (and where) and what kind of space they took up. I wonder if the Lithium-ion batteries would work?

When I finally decide to head home to Texas I'm thinking of going on the route (I think) you are taking instead of traveling down the east coast and over. I will be following your journey, safe travels and much joy!
Rob

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I don't have the measurements but between my mains its packed with the batteries. No extra room at all. I had an 8D for each engine, but have changed one out for a 4D and will do the same with the other when it croaks. The 8Ds are over kill as engine batteries (IMHO) and weigh to much. I had a Group 31 batt for the genset and got rid of it for space considerations. The genset is setup on the engine batteries. The rest of the space is covered with 8- 235 amp-hr Crown 6vot batteries. If I had more room I would add a few more.
Dave

bankerboy1 said:

What kind of adhesive did you use on the velco that's attached to the solar panel? My luck has been the adhesive that comes on self adhering velco becomes soft under the sun and then comes unglued. But that my luck....lol

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The canvas guys stitched them on.

Panel performance update

I think I have a heat issue. Now that the outside temps are in the mid 80s I am not getting the output I got in March. In March I saw 350 watts on a cold clear day, without the plexiglass backing. I have only observed highs of 150 watts at mid day now. Today at noon I pulled up a panel and felt the back side. It was hot to the touch. The back was hotter than the front in direct sunlight. Not sure how to resolve this one. I need the plexiglass to keep them flat and I cant let the wind get under it or they will tear off on a high wind day. I will cogitate on it for a while and maybe come up with a solution. If anyone has an idea I would appreciate it.
Dave

Perhaps drilling holes in the plexiglass. Which could be problematic if you're not actually using Lexan . If using Lexan a series of 1" holes equally spaced should allow some heat dissipation through the back.

Dave, looks like the panels need some air flow underneath to properly cool. If you could run some slats from the forward edge to the aft edge between the lexan and the panels, you should get some air flow. Maybe a 1-1.5 inch standoff?

This way the lexan holds the shape and the slats allow air flow.

Failed Panels

Maybe its not heat. I disconnected panels one at a time and the port panel output was zero. The middle was 85 watts( normal for 0930 in the morning) and the starboard panel was 5 watts. I think I have two failed panels. I have a message into the vendor. I will let you know what happens. These panels were hitting 320-350 watts three weeks ago.