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Old 11-07-2018, 06:41   #16
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Re: Recommened Flexible Solar panels.

Good imput about other cruisers experience's with panel's, thanks, found a company that have various size's 100w plus with Sunpower cells around the $300AUD mark with a five year warranty which doesn't sound too bad, if fitted well with plenty of air circulation under them (rigidly mounted to avoid too much wobble) then I guess they should be fine, just see how they go. What do you do, suck it and see.

Cheers Rod.
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Old 11-07-2018, 07:30   #17
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Re: Recommened Flexible Solar panels.

I think you guys need to understand how flexible panels are able to flex before making decisions on what is good and what is crap.

They use really thin silicon wafers just like framed rigid panels, and bond them to several layers of materials. To a degree, the wafers will bend without cracking, just like you might see a large glass window flex when the wind blows against it really hard (we had one in the dining room in our old house which would flex so much I always cringed).

I think the failure is likely coming from fatigue on the constant vibration, which is causing stress fractures in the cells (or maybe in the solder connections). Mounting on a fabric Bimini or similar and the fluttering from the wind is going to cause a lot of vibration over time. This is probably why some people get 5+ years from their panels and others only get a few months before a cell in one of the strings has cracked and the panel acts like it is partially shaded, giving just 20% of full output.

I am going to experiment with Renogy 100 watt and 160 watt flexible panels when they get back in stock. They are about $199 and $299 respectively and claim to be able to curve something like 243 degrees. I want to see if mounting them to a slightly more rigid backing like 1/16" aluminum sheet will dampen the vibration, improve life/heat sinking, and still allow the panel to be light and thin.
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Old 11-07-2018, 07:49   #18
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Re: Recommened Flexible Solar panels.

The flex is only to allow mounting on a slightly curved, but 100% rigid surface, like concrete or a water tank.

Any actual flexing while in use will lead to a very short lifespan.

And heat must not be allowed to build up, if the mounting platform is not an effective heat sink itself then there must be a free flow of air underneath, but that air must not cause any movement of the mounting platform.
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Old 11-07-2018, 07:58   #19
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Re: Recommened Flexible Solar panels.

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Originally Posted by john61ct View Post
The flex is only to allow mounting on a slightly curved, but 100% rigid surface, like concrete or a water tank.

Any actual flexing while in use will lead to a very short lifespan.

And heat must not be allowed to build up, if the mounting platform is not an effective heat sink itself then there must be a free flow of air underneath, but that air must not cause any movement of the mounting platform.
This is why I am thinking a fairly rigid aluminum sheet backing would greatly extend the life and possibly improve the power output of a flexible panel. It would take some experimenting to figure out the best thickness and trade-off for rigidity vs weight but I think you could still end up with a panel that is half the weight of a framed panel and much much thinner. For me the thinness is key, as I want to be able to easily stow eight to twelve 160 watt panels stacked together in the cockpit lazarette. Having the stack be 80 pounds and 2 inches thick is better than having a 160 pound stack of rigid panels that is 10 inches thick.
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Old 11-07-2018, 08:43   #20
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Re: Recommened Flexible Solar panels.

if you glue them to a aluminium surface, they will die, there are thermal extensions and contractions of both material like a bi-metal piece and the weaker will bend and break. It creates a lot of stress to the cells. Glas modules are different, because glas contains a lot of silitium too and has similar thermal expansions.
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Old 11-07-2018, 09:14   #21
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Re: Recommened Flexible Solar panels.

What if you bonded them to the aluminum with Sikaflex, such that the 600% expansion or whatever that it has would allow for the thermal differences? I had thought about this already and was trying to figure out a material that would not expand differently than the panel but be rigid and rugged. Some sort of UHMW plastic or something? But then you lose the heat sinking.

I guess the obvious thing would be to attach them to fiberglass panels...can you buy thin fiberglass panels?
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Old 11-07-2018, 09:18   #22
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Re: Recommened Flexible Solar panels.

Deploying then stowing that many big panels does not seem practical to me.
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Old 11-07-2018, 09:24   #23
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Re: Recommened Flexible Solar panels.

Many flex panel suppliers offer aluminum backing,

https://www.leadingedgepower.com/fle...l-1261969.html
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Old 11-07-2018, 09:43   #24
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Re: Recommened Flexible Solar panels.

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Deploying then stowing that many big panels does not seem practical to me.
Why? I bet it would be faster and take up less room than deploying and stowing a spinnaker.
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Old 11-07-2018, 09:46   #25
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Re: Recommened Flexible Solar panels.

But that thickness does not in itself provide enough rigidity.

Great heat sink though.

If it is securely mounted on a frame that does so, and allows air circulation below, then IMO you'd likely be able to average a 3-year lifespan, barring damage from high winds etc.
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Old 11-07-2018, 10:11   #26
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Re: Recommened Flexible Solar panels.

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Originally Posted by john61ct View Post
But that thickness does not in itself provide enough rigidity.

Great heat sink though.

If it is securely mounted on a frame that does so, and allows air circulation below, then IMO you'd likely be able to average a 3-year lifespan, barring damage from high winds etc.
I recently saw a video about a new superyacht, with solar panels printed on in the carbon fibre / dacron sails. Totally new concept
I guess it was the Black Pearl...

https://youtu.be/9qipWHayS-c
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Old 11-07-2018, 14:14   #27
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Re: Recommened Flexible Solar panels.

FWIW: the flex panel that I reported upon upthread was one that came mounted on a thinish aluminium plate... perhaps one mm thick. This allows overall flexing, but should help with the local flexing of individual cells.

Damn thing still failed, as reported.

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Old 11-07-2018, 18:17   #28
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Re: Recommened Flexible Solar panels.

I really want to try the Renogy 100W and 160W flexible panels but they seem to be constantly out of stock (that popular or problems manufacturing?)

"Meet the Renogy 160W Flexible Solar Panel, the culmination of cutting-edge technology and precision. This ultra-lightweight panel can achieve up to an incredible 248-degree arc of flexibility thanks to advanced solar cell technology and lamination techniques. "

$299 for the 160W and sometimes I see the 100W for $179
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Old 11-07-2018, 19:33   #29
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Re: Recommened Flexible Solar panels.

On my second set of two 100w semi-flex. First were coated with the shiny PET coating, they fogged up after three years. New set is covered with EFTE, really impressed with them. Getting 10% more power and they stay clean. Both made with SunPower cells. Also thinner and lighter. Backed with fiberglass, but they make a less flexible one backed with aluminum.
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Old 11-07-2018, 23:17   #30
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Re: Recommened Flexible Solar panels.

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On my second set of two 100w semi-flex. First were coated with the shiny PET coating, they fogged up after three years. New set is covered with EFTE, really impressed with them. Getting 10% more power and they stay clean. Both made with SunPower cells. Also thinner and lighter. Backed with fiberglass, but they make a less flexible one backed with aluminum.
Puffcard, name of or brand of these?

Regards Rod.
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