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Old 27-08-2017, 11:11   #61
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Re: Mounting solar panels on bimini

Yes, even if mounted properly, i.e. on a slightly curved but perfectly rigid/fixed surface, say poured concrete, the semi-flex panels are good for maybe 3-5 years, average.

If on a flexing surface, you're lucky to get that as a max.

The other big issue is the cells getting hot, another reason for metal backing with air flowing above and below.

You do **not** want them mounted on anything that insulates.

That temperature factor greatly affects both longevity and ongoing performance.

If I **needed** to use semi-flex, I would get most efficient per square foot, not terrible reputation, under $2 per watt and assume replacing every two years.
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Old 27-08-2017, 11:33   #62
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Re: Mounting solar panels on bimini

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Originally Posted by john61ct View Post
Yes, even if mounted properly, i.e. on a slightly curved but perfectly rigid/fixed surface, say poured concrete, the semi-flex panels are good for maybe 3-5 years, average.

If on a flexing surface, you're lucky to get that as a max.

The other big issue is the cells getting hot, another reason for metal backing with air flowing above and below.

You do **not** want them mounted on anything that insulates.

That temperature factor greatly affects both longevity and ongoing performance.

If I **needed** to use semi-flex, I would get most efficient per square foot, not terrible reputation, under $2 per watt and assume replacing every two years.
So now approaching the finale of my first cruising season of six months using flex panels.... and apparently doing everything wrong, how are they able to power my entire boat?
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Old 27-08-2017, 11:39   #63
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Re: Mounting solar panels on bimini

I am purposefully setting the expectations bar low, and outlining **my** approach, in response to people trying to compare them to expectations for frame-mounted glass panels.

Obviously it is always nice when those expectations are exceeded.

But I think spending say $7+ per watt on semi-flex, thinking you'll get decades of use out of them, is setting yourself up for anger and disappointment.
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Old 27-08-2017, 11:46   #64
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Re: Mounting solar panels on bimini

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Originally Posted by john61ct View Post
Yes, even if mounted properly, i.e. on a slightly curved but perfectly rigid/fixed surface, say poured concrete, the semi-flex panels are good for maybe 3-5 years, average.

If on a flexing surface, you're lucky to get that as a max.

The other big issue is the cells getting hot, another reason for metal backing with air flowing above and below.

You do **not** want them mounted on anything that insulates.

That temperature factor greatly affects both longevity and ongoing performance.

If I **needed** to use semi-flex, I would get most efficient per square foot, not terrible reputation, under $2 per watt and assume replacing every two years.
If you are correct with your longevity estimates, this doesn't sound acceptable to me. But I guess you'd have to assess at what point you consider them "done." Helpful points about temperature & air flow. Maybe Bruce will chime in with some real world experiences from the many boats I'm sure he's outfitted.

Your last comment brings up a source of confusion re: pricing, rep & quality. Even as I read this thread I'm getting pop-up ads from Amazon for cheapo panels made in China that advertise using well-reputed Sunpower cells. From what I can see, there seems to be a huge gap in cost bwtn. the cheapos from China and what is undoubtedly the top of the heap quality-wise, namely Solbian, Solara, Aurinco. Not much in between which I find rather odd. Renogy seemed to be a reasonable looking compromise at one point, but I see they are apparently no longer making flexible panels.

If your longevity estimates are correct, then your suggestion about just replacing cheaper panels every couple of years makes sense. But it also undercuts one of the primary attractions of installing solar over wind or hydro, namely the no-maintenance factor.
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Old 27-08-2017, 11:53   #65
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Re: Mounting solar panels on bimini

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Originally Posted by john61ct View Post
I am purposefully setting the expectations bar low, and outlining **my** approach, in response to people trying to compare them to expectations for frame-mounted glass panels.

Obviously it is always nice when those expectations are exceeded.

But I think spending say $7+ per watt on semi-flex, thinking you'll get decades of use out of them, is setting yourself up for anger and disappointment.
Decades from now I'll be 80 years old, replacing my flex panels probably won't be a priority at that time. Also consider the cost of the Solbian panels only represents less than the cost of two full tanks of diesel here in the Med and cost 40% less over here in Italy than in the USA.
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Old 27-08-2017, 11:55   #66
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Re: Mounting solar panels on bimini

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So now approaching the finale of my first cruising season of six months using flex panels.... and apparently doing everything wrong, how are they able to power my entire boat?
Hopefully the performance you're getting now will continue to meet or exceed expectations, but right now you're likely working with best case scenarios, i.e. new panels, long daylight hours, at anchor (with boom out) vs. underway . . . .

Then again, installing fixed panels on your boat may not be viable or desirable.
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Old 27-08-2017, 12:05   #67
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Re: Mounting solar panels on bimini

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Then again, installing fixed panels on your boat may not be viable or desirable, and downright UGLY.
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Old 27-08-2017, 12:19   #68
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Re: Mounting solar panels on bimini

Agreed. But for some function IS beautiful. Personally, I have a "thing" for clean decks, no arches, minimal clutter, but that's just me (and maybe my vanity ). My thinking could change, of course, once I'm cruising full-time.
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Old 27-08-2017, 12:21   #69
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Re: Mounting solar panels on bimini

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Renogy seemed to be a reasonable looking compromise at one point, but I see they are apparently no longer making flexible panels.
They got out, sold the whole production facility, because high failure rates led to unsustainable warranty claims. Likely due to the confusion caused by industry using the word "flexible" to mean "curved surface" but customers imagining "attach to cloth".


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But it also undercuts one of the primary attractions of installing solar over wind or hydro, namely the no-maintenance factor.
Well a good permanent **mounting** setup should allow quick and easy swapping out of panels as they failed, assuming similar-sized replacements are available.

Zippers, or even making use of included grommets?

Obviously I wouldn't recommend directly gluing them to permanent surfaces.
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Old 27-08-2017, 13:23   #70
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Re: Mounting solar panels on bimini

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They got out, sold the whole production facility, because high failure rates led to unsustainable warranty claims. Likely due to the confusion caused by industry using the word "flexible" to mean "curved surface" but customers imagining "attach to cloth".

Interesting. Sounds like you are quite familiar with the industry. For a layman it's proven rather difficult to get through all the marketing & make informed decisions.

Well a good permanent **mounting** setup should allow quick and easy swapping out of panels as they failed, assuming similar-sized replacements are available.

Zippers, or even making use of included grommets?

Obviously I wouldn't recommend directly gluing them to permanent surfaces.
All good points. I've also looked at "foldable" & "roll-up" panels that have grommets, the idea being to deploy over the boom with lines at anchor and store below while underway. Same sorts of issues, i.e. either exorbitantly expensive for the wattage (e.g. Power Film) or cheapos from China of dubious quality. Solbian now makes a "flexible" panel with grommets and a controller built in to the panel itself, but I think having a "flexible" draped over the boom & secured with lines would likely destroy it. Maybe mounted on a rigid board which could be stowed under a mattress while underway. Or perhaps one of those "portable" arrays I've seen which have rigid panels, but I'd have to have a way of securing on deck.

Thus far I think the answer might be a Watt&Sea while underway and some sort of removable solar panel while at anchor. Would always have the genset for backup provided I don't run out of fuel.
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Old 27-08-2017, 15:27   #71
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Re: Mounting solar panels on bimini

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WOW! Six whole months! Now I understand the all encompassing authority on the subject....

Think I'll stick to those with the skills and talent to install their own systems and some useful time and experience to share. Plenty around here fortunately.

And to keep the rattle down:

This message is hidden because Kenomac is on your ignore list
As stated earlier in this thread, we've owned solar arrays to power our home and business for 12 years... and now solar is powering the boat. You must have missed it.

Still waiting for those pics of your expert installation..............

But thanks for putting me on your ignore list, much appreciated.
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Old 27-08-2017, 19:28   #72
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Re: Mounting solar panels on bimini

I'm glad that there are some people who are happy with their semi-flexible panels, just like the people who were in love with their AGM batteries. If you don't have to buy panels yet, give these early adopters a few years to get some real world experience.

My own experience--the semi flexible panel lost 80% of its output after 12 months in the tropics. The rigid panels lost 10% of their output after 15 years.
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Old 28-08-2017, 21:02   #73
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Re: Mounting solar panels on bimini

So....the marina called today and said my boat is still floating, so that's good news. I bought the nylon mounts for the panels, they are Renogy 100 watt panels and I got four. I also bought 1" stainless steel tubing and a bunch of different fittings to mount the panels above my existing bimini and to increase the support of the existing bimini.
The Admiral has purchased additional bimini material so we can add to our existing setup.
I have one MPPT controller for the four panels and all the fittings, fuses and wire i need to get it operational. It'll be a busy time for us but we have beer and wine.
We're driving all night Thursday to get to the boat and should arrive Friday late morning. Apparently there's still large areas without power including the Stripes gas station right around the corner but the marina got power back today and we have a generator just in case.
One of our goals is to video the marina and show the damage or lack thereof from Harvey. Since none of the news stations seem to think this is important, we figured we could do it.
I would definitly like to explore the flex panels as an addition to my hard panels and I'm looking forward to Kenomacs posts about his panels performance, I promise not to ignore him replacing them every "X" years would be a financial hardship for us, whatever I buy needs to last at least 10 years.
I'll post the marina videos to youtube and or theollengroup.com (my starter cruiser site) so you guys can see any damage.
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Old 28-08-2017, 23:26   #74
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Re: Mounting solar panels on bimini

Very glad to hear your boat weathered the storm.

The main point I'm been trying to make, is how much shading issues can diminish solar output when placed on a bimini. So many people persist in installing plenty of panels but only one controller.... then complain about poor production numbers. The shading issue needs to be addressed.

I'm now on day seven without having to run the generator only because shading is taken into consideration on a daily basis and numbers are still at 84-86% in the morning and 95-98% at sunset. Tomorrow I plan to hook up the waterheater full-time to the 230v inverter to see if I can get even more production/useage out of the panels. When my wife returns tomorrow, I fully expect our electrical usage will nearly double, but we'll also be on the move much more with the engine alternator providing the additional amps.

Good luck with your install and please post updates.
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Old 28-08-2017, 23:44   #75
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Re: Mounting solar panels on bimini

Quote:
Originally Posted by john61ct View Post
Yes, even if mounted properly, i.e. on a slightly curved but perfectly rigid/fixed surface, say poured concrete, the semi-flex panels are good for maybe 3-5 years, average.

If on a flexing surface, you're lucky to get that as a max.

The other big issue is the cells getting hot, another reason for metal backing with air flowing above and below.

You do **not** want them mounted on anything that insulates.

That temperature factor greatly affects both longevity and ongoing performance.

If I **needed** to use semi-flex, I would get most efficient per square foot, not terrible reputation, under $2 per watt and assume replacing every two years.
I think your 3-5 year life time for flex panels used on a full-time cruising boat is pretty spot on. I,'ve seen high end flex panels totally fogged up after 3 years in the tropics. Seen panel connectors falling off of cheap panels in 2.5 years. The low cost panels are far more cost effective.
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