The walls are supposed to be filled with rigid foam. Take a look at the construction video:

https://www.youtube.com/watch?v=vMXneKc_fDo - https://www.youtube.com/watch?v=vMXneKc_fDo

Getting new Endurance tires put on today, solar panel and marine grade tinned copper 10 ga wire arrive tomorrow, so I will update soon on the chase situation. I will use a mirror an light to see down into that wall to make absolutely sure I can go from floor to ceiling without any obstruction. Kinda makes me want one of those HF inspection cameras now......sure would come in handy. 

I did think about pulling the factory solar wiring out and re-routing it, but decided just to stretch new better quality wire from battery's to panel. The stuff the factory uses is not sheathed or tinned and is pretty stiff stuff. 25' of Anchor marine grade duplex was only $36 shipped. 

I plan on mounting the surface mount Renogy 20 amp charge controller high up on that entry wall if all goes according to plan.  

You didn't mention it but if you haven't already planned for it, please do add an appropriately sized fuse at the + battery connection to your solar system. FR's unfused conductors leading to the Zamp outlet on my 179 were a hazard, any + conductors originating at the battery should be fused for safety. For 10awg wire you can use up to 30A. 

All I'll suggest here is that if there is any other place where you can mount the module that is on a flat roof surface you'll be better off as that will keep the cells from being under continuous bending stress. Just a friendly suggestion, not trying to start an argument 

 Leaving for Manitoba next week and the 'pod will be in a field at a classic rock fest for over a week with no hookups. I just want to keep my 2 6v's topped off and run a 12v fan on me at night. When I get back I will find a spot on the backside of the roof for a smaller panel, maybe a 100 watt. 

Also, my pod lives in an enclosed shed when not on the road, so the panel(s) will not be getting beat up by the weather/sun 365. 

The 179 has a big space behind the a/c, I plan on using that for a 350-ish watt module. 

Also, I found that on my r-pod, the trim strips that run from side to side on the ceiling, inside the trailer, are also 'covers' for the open C-channel aluminum frame. Double check yours of course, but that will give you an idea about where you can drill. On mine, there is 12v wiring inside those channels.

By the way, the rock festival sounds cool....gotta link for that?

That will help reduce the temperature of the fiberglass roof by adding insulation between the heat source (the sunlight on the solar module) and the roof. Under full sun on a windless day a direct mount solar module can run around 70-80 degrees above ambient temp, that's pretty darn hot.  

But it won't help the module itself run any cooler, the airflow through the tiny little holes in the coro-plast is pretty minimal. Now, if you worked up a way to flow water through the holes in the coro-plast (or used say EPDM rubber solar pool heater tubing under the module) that would cool the module effectively and provide hot water as well. Roughly speaking the 6 gal water tank would pick up about 20-25 degrees an hour under full sun conditions from a 160 watt size module. An RV mounted PV/Thermal solar system, sounds like a fun project 

https://rockinthefields.ca/ - https://rockinthefields.ca/

Here is the long explanation:

My wife is from Minnedosa & we have a house there. The first festival there was something like 25 years ago and called RockFest. They had some heavy hitters on stage, Billy Idol, Alice Cooper, Boston, Def Leppard, Jerry Lee Lewis, Pat Benitar, Joan Jet, Sammy Hagar, and many more. The site on Lake Minnedosa grew to a crowd of 20,000 over the years, and things kinda got out of control. Then the management got greedy, bands didn't get paid and the whole thing collapsed. 

Around 10 years ago a committee of volunteers re-organized the defunct festival and named it "Rock In The Fields" and it's all non-profit. It has slowly grown to a crowd of around 5,000 which is as big as they want it to get. My wife and I volunteer at the site along with friends and family. In return we get free entrance passes and a place to camp. I help with the set up and break down of the site, so we arrive almost a week ahead the kick-off. We have three stages up and running each day, so it's never a dull moment. 

Yes, the main benefit is for reduced heat transmission into the roof. That's the reason for doing it. 

But, expansion and contraction of the panel itself is also mitigated somewhat with the coroplast, and there should be less stress on the adhesives (or fasteners) and the underlying roof structure.

All you have to do it lay a flat palm on a flexible panel in full sun on a hot day...trust me on this...it wont take you very long to pull your hand away!

Too bad they didn't have their people contact my people...it's in early August, and in conflict with Sturgis! 

https://www.sturgismotorcyclerally.com/concerts/ - https://www.sturgismotorcyclerally.com/concerts/

Oh well... maybe next year!

{edit: Woodstock 50 appears to be circling the drain....a lousy lineup of bands, conflicting schedules with Sturgis, and legal and financial issues means it may not happen}

Have you heard of MusicFest at Steamboat Springs, Colorado? The bands aren't posted yet but it always a great lineup of Texas country, rock and roll, etc.

http://themusicfest.com/home/ - http://themusicfest.com/home/

This one is on my bucket list also....but I'm NOT a snow-skier so I will just have to sit in the lodge, drink hot toddies and watch the cute snow bunnies...

Which would not be all bad.

I did some of my early work on solar module performance in Phoenix, where I regularly saw module temps approaching 100C/212F. At that point not only do you really want to avoid touching them but you'll be significantly degrading the lifetime of the plastics in the solar module and, worse, in your rPod roof. The electrical performance will drop by about 30% as well. 

I have one that failed a couple of years ago, after less than 2 years of intermittent use, and I have begun to slice it up to see if I can use a few of the individual cells in a small project un-related to camping or RVing. The thin conductors between cells are a bit of a puzzle...but I'll figure it out. 

At any rate, the life and health of the flexible panel is quite secondary, in my opinion, to the life and integrity of the r-pod roof and the foam underneath the outer skin...so I would gladly let the panel destroy itself in thermal run-away to save the r-pod roof, if it came to that.  

The only panel I have secured to my r-pod roof is a small 50w rigid glass panel with an air-gap under it. Otherwise I have portable and truck-mounted rigid glass panels that should last for many years, without damaging anything or self-destructing.

Oh yeah, that's one of the biggest issues with them: cell breakage, overheating,  cupping, scratching, dirt adhesion. Those are the main issues in what I think are probably the order of importance. Add hail damage toward the top of the list if you live or camp in a place that gets serious hail. I did a post on this back around the beginning of the year, and there's lots of comments on it on the internet. 

To see what you have temp wise, measure with the suns rays falling perpendicular to the solar module surface, cloudless sky, no or slight wind at most, wait for at least 60 minutes of sun exposure to get things stabilized. You don't really need to do the measurement on a hot day, just measure the difference between the module and ambient temp. You should see something like 100F plus above ambient temp. That will track whatever ambient temp you see later.  In the east you're not likely going to see 200F module temps, you have to go to the western deserts to get that. 

Assuming you're charging, check out several solar cells, the temp will probably vary slightly from one to the next due to electrical variations, and if you find one that's broken the unbroken part will be hotter than the rest. 

If you're careful measuring you can even see the temp difference when the module is charging compared to when its not. If you connect the module the temp goes down around 10F because some of the solar energy is being converted to electricity so doesn't show up as heat. There is no other electrical device that when you turn it on the temp drops (a fridge doesn't count because the condenser coil heats up when you turn it on). 

The cell interconnect tabs run from the front of one cell to the back of the next, which is what creates the series string of cells. Depending on what you have they are usually solder coated copper ribbon. Google "solar cell tabbing ribbon", it is available on ebay if you want more. 

The tabs can be a real PITA to work with especially on the cell fronts because they are machine soldered to the cell metallization layer, which is very thin. Try removing the tabs from the backs of the cells rather than the fronts, there is more metallization on the cell backs to re-solder to.  There should be visible spots where the tabbing machine attached the ribbons to the cells, if you place your soldering iron on those spots while gently pulling the tabs they should come off, one spot at a time. 

The cells are imbedded in the PET or ETFE or XYZ or whatever the plastic polymer is.

Do you remember when we were kids and you would see those clear acrylic paper weights with a scorpion embedded inside?

 

Imagine trying to extract that scorpion without damaging it. Chisels, dremels, utility knives, micro torches, scrapers, nippers, cutters, surgical tweezers, files etc.......I have all kinds of tools available but my eyes and hands just dont work like they did when I was 25 years old. I managed to uncover some of the copper and do some voltage tests in full sunlight but the results are inconclusive...so far.

And, there seems to be a parallel pair and a series pair of ribbon conductors sandwiched on each edge of each cell. A total of 8 connections PER CELL. Who knew? Or possibly some of those ribbons are embedded between the cell and the polymer with no electrical connection....its really hard to tell, and you cant see it without an x-ray machine....and mine is, wouldn't you know, at the repair shop. 

The conductors are so thin they get mangled when I get close to them with any of the tools I've tried...maybe some kind of solvent that would dissolve the plastic but leave the copper, silver, and silicon un touched...of course, whatever that gallon of miracle chemical costs I could simply buy whatever small cells I want from the ebay store.

No, these were designed to stay put. But....the panel is junk anyway, so I'm having fun with it. Learning is a lifelong passion for me. 

ETFE (Tefzel) is the front superstrate material in most "flexible" modules.  The encapsulant is usually EVA (ethylene vinyl acetate) in any module. In the layup there is the superstrate, an EVA sheet, the cell circuit, another EVA sheet, then the backsheet, usually PVF (Tedlar). The layup is placed in a laminator which de-airs the assembly, then cures the EVA under heat and pressure. Once heated properly long enough the EVA becomes highly cross linked so a really tough material. IOW, you're not getting that module apart without destroying the cells. If you want to try anything at all try a heat gun. If the module wasn't properly laminated and the EVA cross linked to begin with it remains soft and flexible and will peel off.  It will drip and burn though if you get it hot enough.

There won't be both series and parallel connections between the same cells, that would just short them out, so I'm curious what module you're working on.  Some module designs use separate conductors concealed behind the cells to return the cell row output back to one end of the module, but usually there is a bus bar that connects one row to the next which is reversed so the series string can just continue on back and forth along the module. They're not Sunpower cells with all the contracts on the back are they? 

If you want to make your own custom modules buy a stack of cells and some interconnect ribbon and bus bar material. Its really pretty cheap nowadays. That part is pretty straightforward DIY, fun to come up with a design that fits where you want it to go. and has the voltage you want.  You just need a good soldering station and some jigs and fixtures.   Its the encapsulation that's hard to do in your garage, unless you want to build a laminator, you'd need a vacuum pump and bag and silicone heating blanket. Or you could go for poured urethane. 

None of this will save any money over just buying off the shelf of course. 

I will figure this out, make a video of it, upload it to youtube and make MILLIONS of dollars in micro-payments.

THEN I can buy that fifth wheel r-pod in the year 3535....

Ambient air temps, about 96. Panels exposed for about an hour.

The flexible panel was directly on a surface, the glass panel has some limited airflow under it, but that airflow is also quite warm.

I think one or two seasons with a flexible panel is about all they can be expected to provide, and this is why they usually have just a one year warranty.

The 15 degree difference sounds about right if you weren't getting ambient air temp behind the glass module (IOW, it wasn't a fully open rack mount). The rule of thumb is with 4 inches or more air space you get about 25 degrees hotter for a surface mount than for an open rack mount at 1 full sun (1000w/m2) irradiance and still air. If there's any wind both the difference and the actual temps are of course lower. Less than 4 inches and the stand off module will heat up until the difference drops to zero when there is no airflow under the module. 

Even then though, the roof temp will be less with the glass module because there is an insulating air gap. That's important both to keep from damaging the roof and keeping it cooler inside the trailer. 

Tefzel "flexible" modules are generally considered to be a 5 year product tops. Glass modules are a 30 plus year product. Urethane potted modules around 10 years, but they're expensive. 

In solar reliability testing there are a standard set of accelerated life tests that are loosely correlated with years in the field. Those are done on any new design to certify it and also to establish an initial warranty period. The "flexible" modules would generally only last about 1/4 or 1/5 as long in these tests as glass modules.

But there are big variations in the real world environments that these products face. Hot sunny desert climates and warm humid coastal climates are the hardest, with different failure mechanisms for each.  And its certainly possible for them to last longer especially if you'e in a benign climate or in your case if your trailer is under cover most of the time. YMMV. 

OG, I was thinking of a similar setup for my 179. I was planning a first phase where I install a Victron MPPT controller and one portable panel that I would plug into the Zamp connector after i rewired it to the controller. Do you think the Zamp wire would be sufficient for a 100 watt panel?  I’m aware I have to reverse the polarity. 

I plan to install a second rigid panel on the roof at a later date. I was hopeful that I could run the wire down the rear wall of the head. I’ve removed the sink so I have good access. Have you considered how you would line up the mounting points with the frame?

My plan is to buy a 72 cell large format module the same length as the rPod is wide, there are many alternatives to choose from. Plus, they are the lowest cost modules you can get on a per watt basis, you can often get them on CL or Ebay really inexpensively left over from a large solar project.  Then I would mount it using vertical aluminum plates on each end to the upper trailer wall edges rather than to the roof. The upper walls are a continuous 1 inch aluminum square tube so the mounting plates can be attached anywhere. I would use self tapping screws into both the end frames of the module and the upper wall tubes. The screws can go all the way through both walls of the aluminum square tubes and the tips would be concealed within the roof. That should be a very strong connection as the screws would be in shear rather than tension, and there would be no holes in the roof itself. 

I'm planning to remove the TV antenna and use that hole as the wire chase, I don't use the antenna anyway. 

One thing though, MPPT controllers depend on the solar module voltage being above the battery charge voltage, they are actually a step down dc/dc converter. Also, you can't connect both a 100 watt 12V module and a 350-ish watt 35-ish volt module to the same MPPT input simultaneously. So, I'd suggest getting a separate small PWM charge controller for the 100W module. Or get two 350W-ish modules and keep one portable and put one on the roof, then run both modules into the MPPT controller in parallel.  They're big things to lug around though, about 39 inches wide and 77 inches long and weigh about 50 lbs.