Semi-flexible solar panel install

Don't be surprised if they failed due to the heat buildup.

mbevins said:

Don't be surprised if they failed due to the heat buildup.

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My first thought too. I searched, plenty about severe output reduction, but nothing about permanent frying.

mbevins said:

Don't be surprised if they failed due to the heat buildup.

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But that's a design flaw if that's the case. It's sunny...it gets hot.


Jim
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JDCAVE said:

But that's a design flaw if that's the case. It's sunny...it gets hot. Jim

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Conventional wisdom for conventional panels is a 1" airspace underneath for cooling. With semi flex versions I`m not sure, mfr should know(? any install instructions with panels). These panels were ok on canvas but that caused other issues, fixing which maybe led to excess heat build up.

JDCAVE said:

But that's a design flaw if that's the case. It's sunny...it gets hot.
Jim
Sent from my iPad using Trawler Forum

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Yes, quite true. I have two Unisolar flexible solar panels on the aft (not walked upon) part of my flybridge. i removed them from my canopy top because I could not prevent chafing. Anyway, all they have for ventilation underneath is a section of rubber rubbing strip about 2cm thick and 3cm wide longitudinally under the centre of each panel, and they are still poking out plenty 10 years down the track. Sounds like faulty panels to me.

They advertise these things as being able to glue them to almost any surface. No mention of air gaps or ventilation. Even a normal house panel has to be cooking on a roof in the hot Phoenix AZ sun.

Are your eBay panels Chinese? Just about any product I've bought from eBay to do with solar, garden lights, deck lights etc have not even lasted a season. The Chinese will feed melamine to their children and their pets for a buck. They will happily sell us crap and then buy our land with the profits.

We are so stupid in the west, we have layers of product laws.

Sorry about the rant, I feel your pain over your dead panels.

fryedaze said:

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.

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My guess is that its not heat. The manufacturer engineer requested that I take resistance readings at night to test the diodes. It looks like diode failure. I am hoping they can ship me two new panels. They requested I take pictures of the ohm meter readings. What BS, and boy that was fun at night on top of the bimini with ten thousand NY mosquitoes eating me alive!

Panel 1 Starboard + to - OPEN -to+ OPEN
Panel 2 Center +to- .945 K ohm -to+ 68.7K ohm

Panel 3 Port +to- .490k ohm -to+ 2.18k ohm

I'm afraid it's probably still a failure due to heat. Diodes typically fail when over heated. But if they warrant them that's all that matters.
However if they do replace them please take steps to ensure ventilation.

The diodes are sealed in the junction box on top of the panel where the leads exit.

mbevins said:

I'm afraid it's probably still a failure due to heat. Diodes typically fail when over heated. But if they warrant them that's all that matters.
However if they do replace them please take steps to ensure ventilation.

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That may be, but a solar panel's purpose is to sit in the hot sun, and needs to be designed accordingly. Every panel I have seen in the past 10 years has blocking diodes, and they work just fine in the harshest conditions.

And that is the point.
Unless I misunderstand the OP he's got a failure on all three units. So is it a quality issue or an install problem.

Dave,

Now that you're underway again, any solar updates/observations? Have you received your replacement panels?

Still waiting

FlyWright said:

Dave,

Now that you're underway again, any solar updates/observations? Have you received your replacement panels?

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Al, I am still hopeful that the eBay seller that I bought the panels from will replace the two bad panels. Apparently there is some trade war issue going on with China and the panels cant get through customs. I hope this isn't all a bunch of bull he's feeding me.
I still believe the setup I installed is a good one. I average 60-80 amp-hrs a day from the one good panel. If I can get three up and running I should get 180-240 a day in the summer months.

If the seller bails on me I will open the diode connection up(its filled with a rubber sealant) and see if it is the diodes and then replace them myself. If that doesn't work plan 'B' is to find another supplier with the exact same size and replace. I need the same size to fit the modification we did to the canvas.

As to all the comments on heat, I aint buyin it! Solar panels are cooked on hot roofs. Yes the panel output drops with heat, the panels don't fail because of heat. Mine just don't get that hot.
Dave

Dont know if they will work for you, but its a start on how to find some replacement diodes.

http://www.ebay.com/itm/15amp-Bypass-Blocking-Diode-for-DIY-Solar-Cells-Panel-/130488969237

as for heat, yes the bypass diodes can short out when over heated, thus giving you zero output. If you end up replacing the diodes, use thermal epoxy to pot them. That will conduct their heat to the case much better than a rubber potting.

good stuff in here if you wanna learn some about them.
http://www.vishay.com/docs/89398/solarcell.pdf

I have recently installed 820 watts of rigid Panels. so far I have seen a Peak of 747 watts. I have been averaging 3 kilowatts a day. On a full sunny day with low batteries I'm sure it will produce more

motion30 said:

I have recently installed 820 watts of rigid panels. so far I have seen a peak of 747 watts. I have been averaging 3 kilowatts a day. On a full sunny day with low batteries I'm sure it will produce more

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Wow, that's very good. I figured my semi flexible would put out half of its rating, but panels seem to do much better than that. Yep, the technology is coming along.

what_barnacles said:

Dont know if they will work for you, but its a start on how to find some replacement diodes.

15Amp Bypass Blocking Diode for DIY Solar Cells Panel | eBay

as for heat, yes the bypass diodes can short out when over heated, thus giving you zero output. If you end up replacing the diodes, use thermal epoxy to pot them. That will conduct their heat to the case much better than a rubber potting.

good stuff in here if you wanna learn some about them.
http://www.vishay.com/docs/89398/solarcell.pdf

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Thanks WB, this why I love TF!!

Update

Well here we are at Joe Wheeler SP in Alabama. I purchased some new diodes for the panels so I could attempt a repair. I dug out the RTV encapsulation on the two failed panels and took readings. The STB panel had no output before I removed the RTV but after, it suddenly was working great. I checked the diodes and they were fine. Not sure what the issue was but I now have two working panels and we are hitting 170watts at midday. It was probably one of the MC4 connectors. The port panel has full 31vdc output at no load but goes to 19 volts and only 5-10 watts when loaded. The diodes are fine. Haven't come up with any possible cause when doing my internet research. I would appreciate any insights TF may have. Looks like I will replace the port panel.

The eBay seller, Discountsolar has stiffed me on replacements or a refund. He strung me along saying he was getting replacements and then he stopped responding to my communications. That's the down side of going cheap on eBay.

Dave I am glad that your panels are working again.

Retraction, I take it back

fryedaze said:

The eBay seller, Discountsolar has stiffed me on replacements or a refund. He strung me along saying he was getting replacements and then he stopped responding to my communications. That's the down side of going cheap on eBay.

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The ebay seller has come through!!!!!!!!!!!!!!! The two new replacement panels are on the way, free of charge!! Will have to wait until we hit the Gulf Coast of Florida to change the panels out. It will require sewing new Velcro to the new panels.

That's great to hear! Are the 2 modified panels still producing juice?

I never modified any of the panels. The diode type was different than what I ordered. The panels have flat square diodes set into a small circuit board and I ordered the round can type. To attempt a repair I would have to disassemble everything and rewire the connection box. I wish I would have taken pictures. One panel is dead and the other is intermittent. I essentially have one good panel. Its going to be a happy ending but I wont get it reconfigured until we are in Long Boat Key in January.

fryedaze said:

I never modified any of the panels.

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My bad....I recalled post 79 incorrectly.

Update

I finally got around to replacing one of the failed solar panels. The supplier said he was sending two panels but he only sent one. I will continue to bug the crap out of him hoping I get another panel. I have been running on 1 1/2 panels. One has always worked at 100%, one was <50% and the other was zero. I installed the new panel today, replacing the zero output panel. During the install I discovered that the panel was burnt. I had thought it was bird crap but the back of the panel was rippled and deformed. The other panel look like new. Once everything was hooked up I got 225-240 watts with clear skies. Its a little warm here in Marathon so I am loosing due to warm panels. With the degraded panel I got about 85 amp-hrs a day while cruising here, but that was a poor test due to cruising every day. I think I will be happy with 150 amp-hrs a day. That is 50% of our usage.


I did a destructive test on the failed panel. It was very brittle. A new one will bend end to end fairly easily. This one only got half way there and snapped. Not sure if its heat or just what the sun does to the plastic layer they put on the cells.
Still learnin and sharin

Dave, Your experience makes me think the design and development of this type of panel has further to go, I would be wary of fitting them.

You may be right, or it could just be that I bought cheap China eBay panels.

I appreciate the update, Dave...the good, the bad and the ugly. It's all part of the learning curve. You're helping many of us sideliners.

Hmmm. Sure wish I'd have taken a look at those when you were here, Dave. Sun exposure and plastics aren't exactly friends, but I sure figured the materials to be more tested-durable than that. You've been here in So. Florida for a while now. What are you getting out of them?

FlyWright said:

I appreciate the update, Dave...the good, the bad and the ugly. It's all part of the learning curve. You're helping many of us sideliners.

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I think it's still an option for solar. The wafers/cells in these panels are the same as they use in the rigid units. I am still skeptical of the heat argument. The conditions on a hot roof in Arizona have to be much worse. Unfortunately I can't take the panel apart to see what went wrong. I suspect bad tabbing between cells caused a hot shot. I wil keep the experiment going and continue to share what I learn.