Semi-Flexible Solar Panel Usage

[Exile]

Originally Posted by 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.

One of the most informative posts I've read yet re: the potential pitfalls of semi-flexible panels. Thanks.

[Exile]

Originally Posted by john61ct

Example of the backpacker style

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

Originally Posted by john61ct

Example of the suitcase style

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

Get one of each, see how they go then expand

These have always looked intriguing for at anchor along with ease of storage. Once again, however, there are the relatively inexpensive ones you linked to & then a big jump up to the US-made ones ($1000+) which are claimed to be used by the military. In either case it sounds like you're best off securing them well so they move as little as possible in a breeze. I always envisioned having portable panels which I could drape over the boom (in-mast furling) at anchor or at the dock but that seems like a good way to shorten their life.

[Mike OReilly]

I fully agree with the more knowledgable posters here (Thin and John). Semi-flex should not be constantly flexed. Their main advantage is weight and the ability to bend slightly to fit lightly curved surfaces. I don’t think they should be constantly flexing, nor should then be constantly walked on (as some describe them). Mechanical fatigue is inevitable.

My experience is limited to my own system, which consists of two fixed panels and two semi-flex. The semi-flex are higher-end ones which came mounted on aluminum. I have these on my cabin top, hinged so I can angle them as needed. They are not walked on, and don’t flex. They are seven years old now, and still performing like new.

My two fixed panels are on my bimini — they are my bimini. They never move.

[Exile]

Originally Posted by Mike OReilly

I fully agree with the more knowledgable posters here (Thin and John). Semi-flex should not be constantly flexed. Their main advantage is weight and the ability to bend slightly to fit lightly curved surfaces. I don’t think they should be constantly flexing, nor should then be constantly walked on (as some describe them). Mechanical fatigue is inevitable.

My experience is limited to my own system, which consists of two fixed panels and two semi-flex. The semi-flex are higher-end ones which came mounted on aluminum. I have these on my cabin top, hinged so I can angle them as needed. They are not walked on, and don’t flex. They are seven years old now, and still performing like new.

My two fixed panels are on my bimini — they are my bimini. They never move.

I think you guys corrected what I think is a common misperception that "semi-flex" = "portable." That was my misperception at least.

[GTom]

Being skeptical so far I dismissed the idea of getting a flex panel but I see they have the same ~20% efficiency as the heavy rigid ones. Doing some research, one can find good deals too.

I like this one, a Freedom 30 covered with 400Wp worth of Elfeland semiflex modules, which are apparently not more expensive than most rigid panels!

Hopefully buying a boat within half a year, this is my top candidate however, I have to check if I can fit such a big panel somewhere... just as the OP, also thinking on adding more panels while at anchor maybe on some lightweight DIY carbon fiber "bridge" over the transom.

Originally Posted by Exile

I think you guys corrected what I think is a common misperception that "semi-flex" = "portable." That was my misperception at least.

Absolutely right! Semi flex adds some flexibility regarding mounting options (and of course weighs MUCH less). If you are after portability, folding is the buzzword.

[Exile]

Originally Posted by GTom

Absolutely right! Semi flex adds some flexibility regarding mounting options (and of course weighs MUCH less). If you are after portability, folding is the buzzword.

For portability, I've also looked at "rollable," but that could be even more subject to damage. Foldable looks promising but I wonder if could be damaged if stowed under bunks or settee cushions with people sleeping/sitting on top.

[Paul L]

Originally Posted by GTom

Being skeptical so far I dismissed the idea of getting a flex panel but I see they have the same ~20% efficiency as the heavy rigid ones. Doing some research, one can find good deals too.

I like this one, a Freedom 30 covered with 400Wp worth of Elfeland semiflex modules, which are apparently not more expensive than most rigid panels!

Hopefully buying a boat within half a year, this is my top candidate however, I have to check if I can fit such a big panel somewhere... just as the OP, also thinking on adding more panels while at anchor maybe on some lightweight DIY carbon fiber "bridge" over the transom.



Absolutely right! Semi flex adds some flexibility regarding mounting options (and of course weighs MUCH less). If you are after portability, folding is the buzzword.

Just be clear that the flex panels will have a significantly shorter lifespan. The coatings are getting better, but still not near the lifetime of hard panels. Say 4 years vs 8-10 years as an example.

[john61ct]

Originally Posted by Exile

For portability, I've also looked at "rollable," but that could be even more subject to damage. Foldable looks promising but I wonder if could be damaged if stowed under bunks or settee cushions with people sleeping/sitting on top.

Yes, easily damaged best stowed straight / flat and well protected, firmly sandwiched without any stresses at all.

If you had the room, folding "suitcase style made from framed panels would last longer, but they take up more space and are lots heavier.

On day, PV sailcloth will be affordable.

[GTom]

Originally Posted by Paul L

Just be clear that the flex panels will have a significantly shorter lifespan. The coatings are getting better, but still not near the lifetime of hard panels. Say 4 years vs 8-10 years as an example.

Rigid panels claim 20+years, not 8-10 AFAIK... I don't see why a well supported, not stressed flex panel should die before 10 years. I also hope that solar efficiency in the next 10 years will climb to 40+%, meaning I won't mind replacing 4 square meter panels with only 2.

[Paul L]

Originally Posted by GTom

Rigid panels claim 20+years, not 8-10 AFAIK... I don't see why a well supported, not stressed flex panel should die before 10 years. I also hope that solar efficiency in the next 10 years will climb to 40+%, meaning I won't mind replacing 4 square meter panels with only 2.

The 20 year claim is land based. The cells will last but the Kinect I n boxes tend to age, some way past 10 years.

Flex panels have been used on cruising boats for long enough to get a feel for their lifetime. I swapped out my flex panels after 4 years where they had fogged heavily and the junction boxes needed to be reattached. Even the high end marine flex panels start to haze in a few years in the tropics.

[GTom]

Originally Posted by Paul L

The 20 year claim is land based. The cells will last but the Kinect I n boxes tend to age, some way past 10 years.

Flex panels have been used on cruising boats for long enough to get a feel for their lifetime. I swapped out my flex panels after 4 years where they had fogged heavily and the junction boxes needed to be reattached. Even the high end marine flex panels start to haze in a few years in the tropics.

Were they PET or PTFE covered?

[Paul L]

Originally Posted by GTom

Were they PET or PTFE covered?

Not sure what the original panels were, but I 've seen many flex panels in the tropics that have hazed over. My current panels are ETFE panels. They are about 18 months and have a light haze.

[john61ct]

In the ideal world some flex panels may last more than 3-4 years.

The way most are installed I reckon that's an optimistic average.

But that's OK for many, long as you're aware, make your choices.

Over ten is a long time to keep old tech going even if you can.

[GTom]

Originally Posted by john61ct

In the ideal world some flex panels may last more than 3-4 years.

The way most are installed I reckon that's an optimistic average.

But that's OK for many, long as you're aware, make your choices.

Over ten is a long time to keep old tech going even if you can.

True, until 300€ buys me 300W worth of panels, I don't mind much if it lasts just 3 years...

[Mike OReilly]

Hmmm, seven years with my semi-flex from Aurinco. But not in the tropics, and only in use for about six months each year. No apparent sign of any deterioration, either in amp output or in hazing.