Flexible Solar Panels

[Rberriz]

Cost Aside
Is there any reason not to use flexible solar?
I am installing these all on a crown. Which has a lot of curves and I think the flat panels are an eyesore. The way I figure, given the shapes, I could fit ~4000w of solar covering most of the roof. Is the only thing preventing people from using them the price?

[Whatthefak]

I've been thinking of the same, but I only see them installed with that super tape. I wouldn't want to lose my panels to the highway.

Also on a crown more curves = more shade on your panels

[Rberriz]

Originally Posted by Whatthefak

I've been thinking of the same, but I only see them installed with that super tape. I wouldn't want to lose my panels to the highway.

Also on a crown more curves = more shade on your panels

True
But if I can load up with 4000+ Watts,
Who cares right?

[Whatthefak]

A little shade on each panel along one side can stop each shaded (even a little) from producing any power. Place correctly I think it'd be fine. I'm more worried about the mounting

[Rberriz]

Well I was thinking using some type of super adhesive and glue them to a 1/8” pvc sheet. Then fastening this to the roof.
This could also act as a thermal barrier between the hot roof and the panel.

[Whatthefak]

Doesn't sound like a bad plan, I'm very interested in seeing how it goes.

I'm not to that point yet but I'll get there and I like your idea so please keep me posted

[joeblack5]

I can agree on the great curves . I would not want to dress that up to much .
May you can find a way to follow the curves but leave an inch or 1.5 " to ventilate the panels. Looks hotter . Better for the panels and better for the temperature in the bus. The use of multiple small mppt controllers can reduce the shadow effect.

Good luck
Later J

[Tango]

No evidence but "heard" that applying flex panels directly to a metal body was a bad idea. Supposedly the heat from the steel impairs the panels ability to produce juice. Anyone???

[Iceni John]

Originally Posted by Tango

No evidence but "heard" that applying flex panels directly to a metal body was a bad idea. Supposedly the heat from the steel impairs the panels ability to produce juice. Anyone???

Absolutely correct. All PV panels, including the flexible ones, are derated according to temperature - when they get hotter they produce less power. That's why I have a healthy air gap under my panels, plus they shade my roof very well to lower the interior ceiling temperature.

What should be of more concern to you is the long-term durability of flexible panels. There's good reason that they don't have a 25-year power warranty, like all good-quality rigid panels have. Some folk on the NAWS forum have reported problems with their flexible panels after only a few years, including total premature failure in some cases. Not good. I suggest you rethink the whole flex thing and consider using "proper" panels instead. (What sort of panels do the large commercial installations and solar farms use? If flex were better, they would use them.)

The very curved roof of Crowns is actually a benefit if you want to do what I did with my eight Sharp 255W poly panels. I first made a walkway between my two roof hatches that's about 5 inches above the roof, and from this walkway I've hinged each of my panels - when stowed down against the roof for travel they are at 21 degrees below horizontal, and I can raise them to horizontal or to 21, 33 or 45 degrees up. If parked with the sun to the left I keep the left four panels down and raise the right four panels to whichever angle produces the best harvest depending on the season; if the sun's on the right side I just do the opposite. This way I have half my panels at 21 degrees (guess what the year-round optimum angle is for fixed panels in Southern California? Yup, 21 degrees!), and the other half at what works best for the sun's angle above the horizon. It's only slightly less efficient than having all the panels fully tiltable, but that's almost impossible on a bus, and a whole load more efficient than the usual flat setup on most RVs. Angled panels also keep themselves cleaner than flat ones because rain will wash dirt off them; I do however have a pair of quick-connect water outlets on my walkway so I can easily and safely wash down all my panels without needing to lug heavy buckets of water or hoses up to the roof. Yeah!

If you watch the YouTube video of Buses Gone Wild VII you can see my bus with the panels' hinged support frames in place but before I put the panels themselves into the frames.

John

[ComfortEagle]

Originally Posted by Iceni John

Absolutely correct. All PV panels, including the flexible ones, are derated according to temperature - when they get hotter they produce less power. That's why I have a healthy air gap under my panels, plus they shade my roof very well to lower the interior ceiling temperature.

What should be of more concern to you is the long-term durability of flexible panels. There's good reason that they don't have a 25-year power warranty, like all good-quality rigid panels have. Some folk on the NAWS forum have reported problems with their flexible panels after only a few years, including total premature failure in some cases. Not good. I suggest you rethink the whole flex thing and consider using "proper" panels instead. (What sort of panels do the large commercial installations and solar farms use? If flex were better, they would use them.)

The very curved roof of Crowns is actually a benefit if you want to do what I did with my eight Sharp 255W poly panels. I first made a walkway between my two roof hatches that's about 5 inches above the roof, and from this walkway I've hinged each of my panels - when stowed down against the roof for travel they are at 21 degrees below horizontal, and I can raise them to horizontal or to 21, 33 or 45 degrees up. If parked with the sun to the left I keep the left four panels down and raise the right four panels to whichever angle produces the best harvest depending on the season; if the sun's on the right side I just do the opposite. This way I have half my panels at 21 degrees (guess what the year-round optimum angle is for fixed panels in Southern California? Yup, 21 degrees!), and the other half at what works best for the sun's angle above the horizon. It's only slightly less efficient than having all the panels fully tiltable, but that's almost impossible on a bus, and a whole load more efficient than the usual flat setup on most RVs. Angled panels also keep themselves cleaner than flat ones because rain will wash dirt off them; I do however have a pair of quick-connect water outlets on my walkway so I can easily and safely wash down all my panels without needing to lug heavy buckets of water or hoses up to the roof. Yeah!

If you watch the YouTube video of Buses Gone Wild VII you can see my bus with the panels' hinged support frames in place but before I put the panels themselves into the frames.

John

Buses Gone Wild VII...? No other pics to share?

[Rberriz]

The only issue I’m still having is aesthetics. In a lot of way this bus is taking a form over function approach. Not in all ways, but taking solar panels and putting them up on top doesn’t sit well with my, albeit jaded, eye.
The panels I’m looking at have a 10 year warranty and can be custom manufactured to fit the roof perfectly.
I can put 3780 in flex panels.
In the top of the line LG (60 cell) I can only put 2640.
I’m not an expert but a 43% increase in overall power should mitigate the fact that I won’t be able to angle them? Maybe?

Now I see I need to do something to act as a barrier between the panels and the metal.
Does anyone have any ideas on a good, thin, heat barrier? A think piece of PVC (1/8”)?

[ComfortEagle]

Originally Posted by Rberriz

The only issue I’m still having is aesthetics. In a lot of way this bus is taking a form over function approach. Not in all ways, but taking solar panels and putting them up on top doesn’t sit well with my, albeit jaded, eye...

Aren't you planning to do a roof raise on the Crown?

[Rberriz]

Originally Posted by ComfortEagle

Aren't you planning to do a roof raise on the Crown?

Yes we are.
We also have a couple other major designs changes we’ve decided on.
I just ordered a 7’ x 7’ window/door that is hinged along the top. We have two heavy duty actuators that will open the side of the bus and this window will become an awning outside. In raising our roof we will artificially raise our floor 3 inches. This will allow us to put a floor under the floor, that will extend out from the bus giving us a 7x7 covered deck on the side.

[Iceni John]

Originally Posted by ComfortEagle

Buses Gone Wild VII...? No other pics to share?

Nope. Sorry!

[Dave in Tucson]

The flexible panels are not as efficient as flat panels besides not being anywhere near as durable. And consider that almost no panel, flat or flexible, will produce as much as they are rated for. Those posted ratings are for laboratory conditions, not real world conditions. I'm planning hinged flat panels for angle adjustment.

[sandbagger2u]

If I had my druthers, I would not put any holes in my roof nor worsen the airflow over the roof reducing gas mileage. But if mounting flexible directly to roof is a bad idea, then what's a newbie to do? I have a short 6 window bus and I want to install a 5000 btu air conditioner, a frig and a tv and some other do-dads.

[sportyrick]

we were wondering if you put corrugated plastic under the flexible solar panel would that be sufficient to dissipate the heat?

[flattracker]

As I had previously posted, I am installing flexible solar panels on the roof of my Crown. I am using insulation between the panels and the roof of the bus. They will be along the centerline of the bus where the curves are not as significant. I will be using 1/4" rivnuts to secure the panels. The rivnuts and screws will be stainless with stainless washers that have rubber on one side. I am installing 1 kw of capacity. Maybe I won't get a full Kw, but appearance and aerodynamics are also important to me. Each of the rivnuts will also be sealed with silicone to assure waterproofing. Once a couple panels are installed I will collect some temperature and power output data to see the result of the insulation.

[sandbagger2u]

Originally Posted by flattracker

As I had previously posted, I am installing flexible solar panels on the roof of my Crown. I am using insulation between the panels and the roof of the bus. They will be along the centerline of the bus where the curves are not as significant. I will be using 1/4" rivnuts to secure the panels. The rivnuts and screws will be stainless with stainless washers that have rubber on one side. I am installing 1 kw of capacity. Maybe I won't get a full Kw, but appearance and aerodynamics are also important to me. Each of the rivnuts will also be sealed with silicone to assure waterproofing. Once a couple panels are installed I will collect some temperature and power output data to see the result of the insulation.

Interested to see how this works out for you. What kind of insulation will you use? Adhesive? I'm not doing this for a few months. Thinking about radioactivity mitigation.

[flattracker]

I will be using US Energy 5mm Reflective foam insulation. It has an aluminized surface on both sides. When the panels are installed they won't be noticeable on the roof of the bus. Given that the panel thickness of about 1/8" and 5mm thickness of the insulation, they won't have much effect on airflow over the bus. They also don't weigh as much as conventional solar panels.