Advice on latest semi flex small solar panels please

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pcatterall

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The 2 little panels either side of our dog house roof are showing signs of failure after 10 plus years. They have multiple cracks across where the base material that holds the elements appears to have melted and leaked out onto the surface. One shows no charge and I guess the other will follow! Boat is in the Med.

These are only small panels but every little helps! They are 25cm wide and 35cm long but they could just as well be up to 75 long and 25 wide.
Is it ok to glue semi flex panels to the roof? If so then I guess that the terminal block should be on top rather than underneath.
Lots of panels on ebay but a big variation in price.

Any recommendations please.
 
pcatterall said:
The 2 little panels either side of our dog house roof are showing signs of failure after 10 plus years. They have multiple cracks across where the base material that holds the elements appears to have melted and leaked out onto the surface. One shows no charge and I guess the other will follow! Boat is in the Med.

These are only small panels but every little helps! They are 25cm wide and 35cm long but they could just as well be up to 75 long and 25 wide.
Is it ok to glue semi flex panels to the roof? If so then I guess that the terminal block should be on top rather than underneath.
Lots of panels on ebay but a big variation in price.

Any recommendations please.
Click to expand...

Yes, don't buy cheap rubbish panels Peter. We're already seeing failures of cheap Ebay panels, after very, very short times.
 
I was looking today for panels small enough for me to take out to Turkey, and found that 50 watt panels vary enormously in price. The cheapest ones are less than £50 delivered, but probably not going to last long. The best ones are ETFE coated like this 60 watt one. https://www.ebay.co.uk/itm/60W-Rein...-ETFE-coating-German-solar-cells/142978345086. Whether the good panels will last more than twice as long as cheap ones, so as to justify the more than double price is hard to know.
 
pcatterall said:
The 2 little panels either side of our dog house roof are showing signs of failure after 10 plus years. They have multiple cracks across where the base material that holds the elements appears to have melted and leaked out onto the surface. One shows no charge and I guess the other will follow! Boat is in the Med.

These are only small panels but every little helps! They are 25cm wide and 35cm long but they could just as well be up to 75 long and 25 wide.
Is it ok to glue semi flex panels to the roof? If so then I guess that the terminal block should be on top rather than underneath.
Lots of panels on ebay but a big variation in price.

Any recommendations please.
Click to expand...

I have a Spectralite semiflexible panel. The instructions say that it can be "attached with adhesive". Sikaflex is suggested. The terminal block is on the top surface

Check with the documentation for any panel you may be considering.

Remember though that a panel Sikaflexed down may be difficult to remove if/when the time comes
 
My understanding is that a panel performs better if there is some ventilation underneath due to cooling. Having said that, the last three installations were held by bolts through the coach roofs. I used Lensum panels on both but have no info on how long they lasted except that it is > 5 years. I would avoid unbranded panels from eBay.
 
I would sugggest;

- go a bit bigger to maximise charge
- go for more than one location to avoid shading issues
- ETFE are stronger, however many panels fail by delamination
- i would bolt and glue for strength
- Panels dont like bending much, which will also impact delaminatation
- my next ones are going to be cheap, i will get spares, the might break
- fixing time/cost is an issue. Either go high quality and hope they last, or cheap and get spares to make it easy to replace.
 
After a long time searching I found a 30w lensun on ebay semi flexible etfe type which fits on the hatch garage for £69.
Used butyl tape to fix it to the hatch just around the outside so that it can be removed by cutting through the butyl with a blade.
 
I wouldn't trust butyl tape alone as it's a sealant rather than an adhesive.At least the stuff I've used is.
peteK said:
After a long time searching I found a 30w lensun on ebay semi flexible etfe type which fits on the hatch garage for £69.
Used butyl tape to fix it to the hatch just around the outside so that it can be removed by cutting through the butyl with a blade.
Click to expand...
 
NASA Marine suggest fixing their panels by either screwing to the surface using the 4 pre-drilled holes and grommets or sticking them down with mastic.
 
I have two Photonic universe 50w panels attached to the coachroof by small squares of self adhesive Velcro. The Velcro on the coachroof should peel off/scrape off when the time comes to replace.

Donald
 
I've used 3M Dual Lock. It's like Velcro, but MUCH stronger, plus the adhesive comes off cleanly.

My read is that premature semi-flex panel failures are mostly the result of continued or overly severe flexing. They use the SAME cells as glass panels, but without the structure. The better ones are reinforced. The cheaper ones must be mounted more carefully. I've had good experiences (>5 years) with cheap panels, but they are mounted to the deck. I doubt they would do well on canvas. They are secured by screws; less chance of flex than Velcro, since there is no gap. Not much heating, because they are mounted to a thin turtle.
 
Thanks guys. The panels are going on the rigid dog house roof. Sometimes sat on but not stood on! I think I will go for the cheapo end of the market and accept ( potentially ) shorter life.
Probably glue down with strips of glue. Most Velcro adhesive lasts about 4 weeks in the med, I usually have to glue it down with epoxy! Finding long thin ones is a bit of an issue as ideally they should not be above 25cm wide but up to 70cm long.
 
thinwater said:
I've used 3M Dual Lock. It's like Velcro, but MUCH stronger, plus the adhesive comes off cleanly.

My read is that premature semi-flex panel failures are mostly the result of continued or overly severe flexing. They use the SAME cells as glass panels, but without the structure. The better ones are reinforced. The cheaper ones must be mounted more carefully. I've had good experiences (>5 years) with cheap panels, but they are mounted to the deck. I doubt they would do well on canvas. They are secured by screws; less chance of flex than Velcro, since there is no gap. Not much heating, because they are mounted to a thin turtle.
Click to expand...

Are you not worried that the thin turtle will swim off with solar panel
 
I've had 3 Sunware panels, 2 of which have delaminated and leaked at the integral junction box. The other (32W) still looks OK after 7 years. One of the failed 48W panels was replaced under warranty but the replacement is now also delaminating.
5 years ago I fitted two ebay Biard rigid 100W panels for about £90 each. These still look fine and work perfectly.
The deck mounted Sunware panels are less efficient in tropical conditions, probably due to the high temperatures that they reach, whereas the Biard rigid panels are mounted so that air circulates freely around them.
Sunware panels are prone to failure if allowed to flex.
 
pcatterall said:
Thanks guys. The panels are going on the rigid dog house roof. Sometimes sat on but not stood on! I think I will go for the cheapo end of the market and accept ( potentially ) shorter life.
Probably glue down with strips of glue. Most Velcro adhesive lasts about 4 weeks in the med, I usually have to glue it down with epoxy! Finding long thin ones is a bit of an issue as ideally they should not be above 25cm wide but up to 70cm long.
Click to expand...
I tracked down some narrow ones at Lensun they fitted between main hatch and grab rails - only 20w though. Their website invites you to ask a question so you could try that rather than wading through the entire range.
 
ghostlymoron said:
I tracked down some narrow ones at Lensun they fitted between main hatch and grab rails - only 20w though. Their website invites you to ask a question so you could try that rather than wading through the entire range.
Click to expand...

Yes that's where I need to fit mine. I could always use 2 shorter ones to utilise the extra available length.
 
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