TheSamba.com :: View topic - Flexible solar panels over the long term, any good?

Thu Jun 03, 2021 2:56 pm

I'm seeing some folks on Youtube saying that, over time, the flexible solar panels tend to overheat and aren't generally a good proposition. Any of you out there with experience on the subject?

If they don't hold up I'm thinking that maybe they could be mounted up top on an as-needed basis to help preserve them...

Thu Jun 03, 2021 3:30 pm

I would not recommend them. I have gone through two pairs and will not buy them again. I have mine permanently mounted and both times, a decent hail storm cut their output to about 10% of what they should be. Over time, the nice clear plastic coating turns dull and starts to peel. The only reason that I went for the second set is because I have them mounted on a curved surface and thought maybe the first hail storm was just unlucky.

Perhaps if you only pull them out when at camp they would be fine. Overheating not an issue for me as I installed with an air gap behind them.

Thu Jun 03, 2021 4:27 pm

The solar manufacturers had a heyday with these "flexible" panels at the consumer's expense. How would you react if the marketing copy read the truth about these products:

"Buy these new flexible panels that will fit in so many places! We can't guarantee them, but we promise that we used NO aluminum, NO glass, and because we saved so much money on those components, we are now ready to sell them to you at a higher price than those pesky "olde style" panels that last forever and use so much aluminum and glass. Order yours today!!"

Instead, the marketing cleverly side-stepped the longevity "feature" of the flexi-panel and displayed these panels cleverly cladding curved areas like the decks of sailboats.

Thu Jun 03, 2021 4:36 pm

I've had my two 120 watt flexible King Solar panels on my roof since summer 2016.

They've endured about 60,000 miles of travel and some bad hail storms.

I have them mounted on aluminum bar stock that is tensioned to keep the panels slightly bowed away from the roof surface. This also maintains a low profile, keeping the panels less conspicuous.

The aluminum bar stock frame has rubber bumpers mounted underneath it (they are actually sink drain stoppers) that keep the frame from flexing too much.

The laminate film on the surface of these panels peeled away long ago.

The efficacy of these panels has definitely declined since they are new. If I press on them, they sound a bit crispy/crunchy now, and because of that I have been giving thought to replacing them.

Ideally these are mounted directly on a fixed surface, where they will not flex and last longer. That has not happened with these panels. I still do not regret it.

As a side note, my home has 17 280 watt conventional glass/aluminum solar panels on the roof, for 15 years now. Good solar panels should last at least 25 years.

Despite their age, they still deliver sufficient energy to my Redarc DC/DC charger to keep my 200AH of LiFePO4 batteries charged up nicely. In fact, I used the van to run my house during the recent winter freeze, and an even more recent (last weekend) 26-hour power outage due to storms. In both cases, the panels were instrumental in recharging the house battery system that had been run down to 12.6 volts as it kept my home refrigerator running in the face of no grid power overnight.

They are definitely lighter and quieter than my original solid 100 watt panel.

I will most likely try flexible panels again, but I am looking at all options. I agree with Howesight above--the newness of the product allowed marketers and manufacturers to really sell something that wasn't totally developed.

I've been slowly looking for a good brand to buy. I have one spare 280 watt panel from my house installation and it's very tempting to put it on the van, as bulky as it would be.

The first photo below is mostly about kayaks, but you can barely see the panels on the top of the van.

The second photo was meant to show some antenna mounts, but you can also see how the panels are mounted in the background.

kourt

Thu Jun 03, 2021 5:26 pm

I have a panel I deploy remotely and after 10 years it is just fine.

Thu Jun 03, 2021 7:37 pm

dobryan wrote: I have a panel I deploy remotely and after 10 years it is just fine.

Same here. I have one to two 100 watts flex panels that i can deploy when and where needed that are about 8 years old now. I have a newish 150 watt flex panel permanently affixed to the roof. The newish one seems to be made cheaper but it charges fine so far.

Thu Jun 03, 2021 8:32 pm

I had a bad experience with flex panels. Had 4 100W panels on my roof from 2016-2021. All 4 were peeling after 2 years. I measured a significant decrease in charging current, so removed all 4 and tested. 1 was completely dead, 1 had 80% reduction in performance, and the other 2 had 50% reduction in performance.

Thu Jun 03, 2021 9:01 pm

Never mind the panels, Dave O. Where is that fabulous site 21 T? Need to go there.

Thu Jun 03, 2021 10:14 pm

I've discarded two HQST 50 watt flexible panels that lasted less than five years and am about to discard a six year old HQST 100 watt flexi panel. Each was producing about 25% or less of their rated capacity. I've replaced them with rigid panels.

GIGANTIC CAVEAT: 6-7 years ago I was buying off Amazon based on price alone. Cheap HQST brand solar panels = soon-to-be landfill. Likewise with a $25 solar controller.

There are plenty of flexible panels powering RTW sailboats, vans, etc. but my guess is few were $1 per watt Amazon cheapos, i.e. flexible isn't the key criterion, quality is. That said, stationary home installations use rigid panels for the reasons Kourt mentions.

Fri Jun 04, 2021 2:31 am

I have a 100 watt sunpower flex panel.

This one claims to be made better with materials which will not degrade so quickly.

Not that I trust that claim, but it is significantly more expensive per watt than what is/was available.

Mine's used as a portable, and not deployed often.

Such panels are slightly bendable, a limited number of times.

'Flexible' might imply it can flap in the breeze like a flag without issue, which they most certainly cannot.

To keep mine from bending excessively deploying it, I made a lightweight 1/2 inch thick vertical grain doug fir frame and extra attachment points around the perimeter, and if laid flat keep it slightly elevated for some ventilation underneath.

Still delivers expected wattage when aimed at the sun, but I do not deploy it often.

I'm Saving it for when/If I really need it, as I have 200 watts of hard mounted panels already, the extra hundred just helps make for happier batteries.

Fri Jun 04, 2021 5:07 am

DuncanS wrote: Never mind the panels, Dave O. Where is that fabulous site 21 T? Need to go there.

Looks like Boyd's Key West Campground.

kourt

22 December 2016:

Fri Jun 04, 2021 5:30 am

DuncanS wrote: Never mind the panels, Dave O. Where is that fabulous site 21 T? Need to go there.

Boyds Campground, Key West, FL 8)

Fri Jun 04, 2021 5:32 am

kourt wrote: DuncanS wrote: Never mind the panels, Dave O. Where is that fabulous site 21 T? Need to go there.

Looks like Boyd's Key West Campground.

kourt

22 December 2016:

Very nice! Yes!

Fri Jun 04, 2021 6:32 am

Fiberglass-backed ETFE panels (whatever that means.)

They've been on the van with 3M UHB tape for a couple of years and have been through blizzards, hailstorms, high wind, heat, whatever, and still work perfectly.

https://www.lensunsolar.com/Lensun-80W-12V-Fibergl...an,rv,boat

55 on the front, 65 on the back (not pictured.)

They're stiffer and heavier than the standard flexible panels.

Fri Jun 04, 2021 6:52 am

We recently bought the Jackery 100w panel. I guess it's more of a flexible panel than a rigid, traditional panel, yes? no?
It's the 3rd gen version.
Time will tell how it performs and holds up, but since it won't be mounted to our Vanagon permanently, it should see longer service life, I'm guessing.

https://www.jackery.com/products/solarsaga-100w-solar-panel

Paired it with the Jackery 500 solar gen unit, and a longer cable to chase the Sun if needed.

Was on the fence about mounting 2nd battery in the Vanagon along with the charging system set-up for that, then decided to go with the portable Solar system since we could always use the unit indoors if we lost power[ luckily, rare for us here in Chicago, but it does happen]

Fri Jun 04, 2021 7:07 am

dobryan wrote: I have a panel I deploy remotely and after 10 years it is just fine.

I have that same set up as an additional aux panel when I'm at a site where the van is in the shade. Weird seeing, as I have that exact panel AND ladder that I use to prop up the panel. Works really well and gives me access to the roof box.

Per answering OP. My flexible panel doesn't live outside all the time, so I'm sure it will last longer. However, it does already have a lot of scratches on the plastic surface above the cells. I'm sure this does not improve the situation.

Also, FWIW, I've read lots about all panels needing to be mounted off the surface to allow air to travel under them to keep them from overheating. Being laminated to a hot surface will compromise even a new panel's performance.

Fri Jun 04, 2021 7:19 am

Crooked Designer wrote:

Also, FWIW, I've read lots about all panels needing to be mounted off the surface to allow air to travel under them to keep them from overheating. Being laminated to a hot surface will compromise even a new panel's performance.

Here is how I did the flexible panel on the euroBus. Time will tell how long it will last.

dobryan wrote: I finally installed the solar panel on the NAHT.

170W flex panel.

https://www.emarineinc.com/sunpower-170w-solar-panel

The NAHT has some bumps and such on the center portion for a vent and likely for structural reasons. I needed to bridge those to create a reasonably 'flat' surface for the solar panel.

I chose to use 10mm coroplast as the material since it would allow good air separation to help keep the panel cooler.

To adhere the coroplast to the panel and then to the NAHT I used VHB tape. And then I used roofing tape to finish off the edges of the panel to NAHT.

Panel VHB'd to the NAHT.

Note that the solar panel wiring is tucked under the panel. I had prewired the NAHT for solar anticipating panels on the rear deck area and so I used a utility box especially design for solar wiring. Unfortunately that box was too tall for the panel to fit on top of it so I had to cut it apart to get it off of the solar wiring that went thru it. I used the 3M marine adhesive from the NAHT install to seal up the area where the wiring came thru the NAHT. The nice thing is that the connections are not visible and out of the weather. The bad thing is I may have to destroy the solar panel if I ever need access to them.

And the roof tape is applied.

Everything works well. The panel and the Victron solar controller are happy with each other.

Mon Aug 01, 2022 8:58 am

I bought a couple flex panels years ago. They were a great price.

I used to take them out and lean them against the vehicle to adjust their angle. One day, I forgot they were there, and ran over them. They still produced about 80% after being run over!

But they did decline steadily over some ten years or so. I gave them to a local student to use in a high school science fair project.

So, there were pros and cons. A non-flex panel would have been useless after running it over! But I don't think I'd buy flex again, unless I had a very specific use case that demanded it.

Thu Aug 04, 2022 7:12 pm

I installed LENSUN panels on a few vans now, and on many boats, I bond them on poly carbonate sheets so they can vent, this is the first gen of my concept, currently ready to launch the second gen version with even more ventilation- panels need to breath to dissipate

heat or they will have a short life!

full story here-

https://www.thesamba.com/vw/forum/viewtopic.php?t=731545