All Stop!
Looks like I’ll be starting over on solar!
I was preparing to order semi-flexible 100W solar panels from Windy Nation early this morning, the same panels that Renogy offers. Six of ’em weigh about 25 pounds, versus three of the 195W panels from the Defiant that weigh 129 pounds to get the same wattage total. The Intrepid’s roof lift struts help a lot, but not that much!
Then I came across a post about how the cells on semi-flexible panels tend to cup (distort) on exposure to solar heat (pooling dirt), and that this deterioration is evident after just one year. That made me think about the usual warranty on these, which is just 5 or 10 years, and that’s a lot less than the 25 or 30-year warranty on rigid panels. Instead of glass, the protective coating is transparent plastic. When I then stumbled over a blog post detailing heat-failed Renogy panels and found that Renogy has pulled them from their product listing, that kinda caused a mental Chinese fire drill around here. The same panel technology is shared across the market, and other major sources for this type of panel have submerged as well.
Considering that I didn’t even order the Four Wheel Grandby pop-up until I could first be assured of a workable and fairly painless solar system – one which avoids an elaborate or laborious setup – such a revelation was unwelcome. The 12′-long Grandby roof is supported only at its front and rear ends, and the whole thing is something like 1-1/2″ thick, based upon a lightweight aluminum tube frame. That’s one reason why the factory limits its roof-mounted solar option to a single 160W solar panel, probably weighing about 30 pounds. Additional wattage is only available as a ground panel.
So conventional glass-faced solar panels pose no durability problems, but pose practical limits as to how much wattage can be installed on the largest Four Wheel’s roof. A warped roof can rarely be made straight again. An inspection of my Grandby’s roof shows it to be more or less flat on top, until it tapers thinner about 6″ from the edge. That affects the mounting area available. If panel weights go up, some care needs to be given to distributing weight along the roof surface instead of relying on a few common point mounts. With the roof being interrupted by two big vents and a solar panel SAE outlet, space for maximum wattage is at a premium. Heavily loading the roof asymmetrically side-to-side would be hard on the main supports.
On the face of it, it will be a significant challenge to place just 400 watts of solar on the Grandby’s roof such that I’ll be able to lift it, and that it will not pose a risk to the roof in some way. I’m still unwilling to perforate the roof for fasteners at this point. The remainder of wattage would have to be made up with ground panels, or at least panels located off-roof. That, or of course chop battery capacity to more conventional levels.
One thing caught my eye, however. The fried Renogy panel was fastened down much as I planned to do mine, with 3M mushroom-head tape in small pieces at the borders. That spaces the panel up nearly 1/4″. I was going to add more along the centerline to help keep the panel center up. Looking at the fry marks on the roof in the blog photos, that makes me suspect that the roof surface may have contributed to the panel’s overheat by direct contact, instead of wicking heat away. The value of adding a few support ribs under the panel might help with isolating it, but the value of a mere 1/4″ air gap is probably debatable in terms of cooling air flow. The value of backing the panel with a sheet of Reflectix comes to mind to do the spacing, since it has air gaps and can reflect heat both ways, but I’m well out of my element here as far as figuring out all that would be going on. Study time. A thin layer of insulation may be more appropriate.
Bottom line – the solar aspect of the Intrepid is on hold until I can work something up. Just to complicate matters, the claim is out that a better panel design is being worked on, but when, how much improved, and cost make it difficult to decide whether to work up a stopgap and gimp it, or fake up a final system and just live with it.
Strolling Amok 
As I recall the failed flexible panels had been glued down on the roof, no air gap.
I have been taking my one wipe panel outside & using an extension cord to bring the panel volts to the cotroller. It’s what I had but it’s been working well
100w not wipe!
Hi Doug,
Please forgive me if I sound “environmentally incorrect” here, but if a main reason to “boondock” is to distance one’s self far away from crowds, why not install a good diesel generator and eliminate all the problems that solar panels seem to present? Who is the noise going to bother? The bears? Just sayin’!
Paul K
The sun broke the mountains here about 0730, my panel light was on before that happened. That means I was getting electricity put back in my battery (for tonight) before the sun was up.
I have a little over $400 in the ‘system’ (100w panel, (2) 122amp hr marine batts, an MPPT controller) and could have done better on the batteries (225ah 6v deep cell golf cart batts here for $115ea)…
No noise, no fuel to store…it just works.
I’m not going to run a microwave or AC off this but the computer, phone & TV do just great.
What, no blow dryer? You’re a good example that if one’s demands are modest, a workable system can be put into service very affordably. I’d be curious to find out how long your marine batteries last before they don’t do the job for you any more. I have not done well with the ones I had. Having owned a lot of lawn care equipment over the years, I vowed I’d have no more gas-powered engines or fuel storage once I hit the road.
Generators have 3 problems. Noise, long run times and vibration. Long run time is not the generators fault but it’s needed to fully charge a battery. The good part about generators is that in the early stage of the charge cycle the generator and an effective charger can provide the high amperage that the battery wants. In the later stages of charging, the amps go down and the remaining amps going in can take a long time. That’s very inefficient for all the fuel that is being burned. Early stages=High fuel use, high amps in. Late stage=Relatively high fuel use, low amps going in. A generator without an effective link between it and the battery is useless. A GOOD 3 or 4 stage battery charger is a must.
A generator can be part of an energy management program because it’s strong point is the ability to convert the gasoline or diesel into high amps. Some people will run their generator in the morning while needing to run other heavy loads such as toasters or coffee pots. They will then let the solar take over and do the lower amp, long time frame finish charging. Later in the evening they may run the generator again to do the heavy lifting and top off the batteries for the evening quiet time. Solars strong point is lower amps but many hours of at least some power coming in. It takes a large system to match the high amps of a generator.
When I decided on my energy management program I answered my number one question first. That question is do I want to run my air conditioner. My answer was yes I do at times so I had to have a large enough generator. Along with now having that big of a generator I decided that rather than buying a large inverter to power my heavy loads I would just do it with the convenient remote start generator. I seldom charge the batteries with the generator as I have 520 watts of solar. I also took extra measures to make the quiet Honda generator even more quiet. To me it’s a must do if you live this lifestyle.
If you invert to all your heavy loads (except ac) you will need a large inverter and battery bank. You also get into inverter quality issues and I felt it would cost me $1,500 to $2,000 for a high quality inverter so I only use a small inverter for tv’s etc.
It’s not cheap to be your own energy company. I spent over $5,000 and figure that most anyone trying to start out with basic boondocking is going to spend at least $1,500 to $2,000. There are many variables and it’s certainly not one size fits all. Generators are good and bad at times. Solar is good and bad at times. In an rv, in the end with only one choice, it’s solar.
Thou art forgiven, blasphemer! Seriously, my goal is to get away from the crowds…with their generators. If I didn’t mind finding space for a generator, lifting it to store and siphoning fuel out of the Ford’s tank to run it, I could chop off the cost of batteries, panels, and controller to a bare minimum. But I enjoy the utter silence of solar, and its passive performance. In this case, the “problems of solar” are entirely at my own insistence. Most folks are happy with a couple hundred watts of panel and a couple of small deep-cycles, and those pose no issues. I’m asking a lightweight pop-up to do what it’s not designed to do, and with little effort use it, so I can expect a balancing act with plenty of challenges. This week’s problem is to recover from what appeared to be a slam-dunk when planned, but is not so now. The semi-flexible panels are not “bad” per se, but have been found to be even less tolerant than expected for general use.
Oh dear! Sheesh. Not sure but I think you said you’d planned it having more than enough solar power. How about starting by cutting it closer, so you have just enough? If you run low you can park it in the sun and go for a bike ride or whatever…
What comes to mind after that is something you may have already mentioned, not sure: design a lightweight aluminum rack, which will of course have to be attached to the roof. A welder can put it together for you. Allow for airflow of an inch or so, so that problem’s taken care of. Rack might be able to hold enough conventional panels to keep you going.
Don’t know if any of this is helpful, just thinking out loud…
Sorry folks, posted that one in my sleep, please disregard.
We would never disregard your comments, Dawn! 😉
In a way, you’re spot-on, Dawn. Some manufacturers are now jumping through hoops to stop flex panels from being such a big warranty loss, and if I were to go minimal for now and wait it out, more tolerant panels may become available in time. Smart! I’m not known for doing the smart thing, though.
I’d considered the two types of factory racks early on, and there were space issues besides the weight and expense ones. The weight alone was such that I had to develop additional lifts to keep same from bending the roof. It got nuts. The roof can only take so much conventional panel wattage, and I was spending enough on racks to cancel out panel savings. If the space doesn’t get you, the weight will. Slapping some aluminum tubing up there to mount panels is entirely possible, but merely adds to the framed panel weight. They could work with flex panels as well, though it would be a pretty elaborate system, given enough wattage.
Thanks for noting that, Rob. That seems to be the commonality. Even those mounted with reclosable tape were left to droop to full contact. I’m not discovering any failures at all for unmounted or ground panels. That’s inspired me to research further, to try to get a grip on the failure dynamics.
Dang! I hate it when a plan falls apart! Hope you can find another solution.
Heck fire, Linda, I hope so too! I gotta find something, by jimini! 😉
Humm, dont ya just hate it when a plan crashes. But then maybe it hasn’t. I cant remember every word of your previous posts about this but obviously you have few choices.
Frame work on roof to hold conventional panels: void warr, too heavy, punch roof full of holes, roof damage/bending. It’s possible but is it practical?
Brackets under cab over to hold removable panels: pain in the fanny to deal with all the time, need to shim camper up for added room, theft
Shim camper up and slide panels under: does floor framing allow for this, same other issues as cab under storage just easier on your back.
Store in backseat area: same pain in rear and theft issue, also easier on your back, if rear seat is removed it could create more storage room in general.
I have considered portable panels but just knew that I would end up hating it. In and out, in and out. No way, I cant do it. I’m too busy doing nothing to commit to that and having them in the way all the time.
So it does come down to using flexible panels. I researched it some and do see that AM solar has used them on one of their rigs and experienced the same issues. The winns panels look like they used a shovel to clean them off. I do understand that the little spot of dirt that forms creates the main problem. If you add up the bad characteristic of the flexible and come up with a way to deal with them, they may still be the best choice.
Problems with them: heat build up and dirt. How hot will they be in the areas that you travel vs the areas that the winns and AM solar travel? I cant imagine the dirt being a daily or even weekly problem. I guess it ends up being a maintenance issue of going to a car wash and spraying them off at some interval.
So it’s a heat vs life span divided by cost issue. 400 watts seems to be about $1,000. Will they last for 5 years and cost $200 per year? Can you live with reduced output if 400 watts turns into 300 watts? What is the worse case scenario you can live with? Maybe 3 years of life for $350 per year?
I ran my first TT on a generator for a year. I went through all the normal upgrades, better converter that could do 14.4 volts, a real battery charger ($$400) that would do a full charge in 4 hours. Heavy cables etc. People told me that the batteries would only last 6 months and said theirs are 8 or 9 or 10 years old. Well, the batteries are going on 2 years and still perform well. My whole goal was to charge the batteries and get the generator shut off as quickly as possible. When thinking about it more and knowing how little generator time I had to do I could have lived with the batteries lasting one year. Yes it would have cost me $350 for one year but it’s only 4 tanks of diesel fuel.
If I had gotten home from all those miles of driving and said oh I bought 4 more tanks of fuel than I wanted to , would I cancel my next trip or regret the trip I just took. NO, it’s just the cost of doing business. I’m now on solar.
So, in rigging this thing out and putting a thousand dollars worth of panels up there and say they last for 4 years, can you stomach $250 more in your budget per year? What price will you pay to not have to lug stuff out all the time and then worry about it walking away?
Maybe the flex panels aren’t really that bad? Maybe you can adopt a program of dealing with their issues. I’m not trying to talk you into them or anything else, just trying to throw all ideas out there.
You may be better off with an pwm controller this time if running panels that are not exactly the same over time. (having to replace a panel ??) Easy to parallel when needed.
Can you run one conventional up there and maybe 2 flex or flex on the roof and one stored under the bed or something that can be pulled out when you have poor sun or longer stays in more remote areas. It’s just so nice to NOT be messing with them all the time. Oh, that’s right I don’t need to keep telling you that! 🙂
I spent many years relying on only a 1000 watt portable Honda generator and stopping in an electrical site once a week or so. A couple or four 6V golf cart batteries did well under that regime.
But finally I settled on a couple of Renogy 100W suitcase solar panels. They come complete with controllers and a fold out stand, take only a minute or so to set up (I permanently attached one end of the snap together cables so I don’t have to uncover the batteries to use them). These easily keep up with a couple of 6 V batteries. And they have enough line to move them around quite a bit to catch the full sun.
They come with a nice cover, and when folded together both travel easily behind the seat in a standard pickup. A little less than $500 for 200 Watts, no heavy lifting, and no installation worries!
http://www.amazon.com/Renogy-Watts-Monocrystalline-Foldable-Suitcase/dp/B00HR8YNK6/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1450105934&sr=1-1-catcorr&keywords=renogy+suitcase+100w
Bob G
Very well described, Bob! You certainly made a “case” for these panel sets, since there is no technical challenge but to open it up and attach its alligator clips to your battery. You pay dearly for that convenience, but if your needs are modest and you have a safe place to tuck the panel set(s) away, it’s a very effective way to go.
One thing you might not have considered is that your energy use may be considerably less in a smaller camper. That’s the way it turned out for me. I started out in a 27 foot fifth wheel and 4 6V batteries (nominally 400 Ah) lasted me about 3 days, maybe 4, when they were half discharged and I had to do something. In my present 17 foot pull behind I find that 2 such batteries last just as long as 4 did before. I just gradually used less over time. The only thing I have now that runs on AC is the coffee grinder.
I now use about 35 Ah per day. Lights, water pump, charging the laptops and phone, and a little music in the evenings. The two 100W panels create together about 14A in full sun, so they can easily keep up with my usage in only about 3 – 5 hours a day, weather permitting.
More batteries, or more panels, would be redundant. When you’ve got what you need, quit digging.
Good point, Bob. I’ll be cutting down from a 27″ iMac rolling all day and a 28″ TV all evening to a laptop for both. Still got the e-bike, and the camper has an e-fridge that the Defiant lacks. Should still be less juice overall. However, since I’m sitting on a pile of AGMs and would like to discharge them as little as possible in order to extend their service life, that means keeping as many as reasonably possible. Plus, I prefer not to change activities because weather is not permitting. Most days, I’ve got a computer or TV rolling up to 16 hours a day, no joke. Not your typical outdoorsy camper, and the computer may well be grinding away on something while I’m biking to town. Between that and the e-bike and fridge, I’d be replacing pounded batteries pretty frequently. I will be using less power since the Intrepid’s hardware will draw less, but I’d prefer to use that difference to preserve the battery pack. I’ve been burning through 20-25% of my 400Ah pack, 40% now and then, and I’d like to get that to 10%, if possible. Oddball? Yup.
Ha. If you’re not already an “outdoorsy type”, you soon will be after a few months in that cramped little cabin.
Structurally speaking, you are asking for trouble if you put any more weight on that crank-up roof than you have now. I doubt the lift system is engineered for it, and how the weight is spread may be as important as the amount.
From what I have read, the extremely light and flexible roll-out panels do not last out in the weather, and are inefficient while they do.
The question then becomes “where else are you going to put your panels?”. In your case, the only place handy is “on the ground”. The fold out suitcase panels are the cleanest, easiest, and most efficient solution for anything that goes on the ground.
I had a truck camper once, and the most persistent problem I had was not with power, but with excessive weight, to the extent that it was unsafe to drive in the mountains. Which is why I got rid of it. Cutting back the number of batteries to just what you need is a good way to save substantial weight. The magic number may be a while in making itself known, but you can try to calculate it if you are pretty good at factoring with fudge.
Habitually drawing down the batteries a little more than you are used to may just be the price you have to pay for doing business. Which is why I use golf cart batteries. They can take the abuse, and they are cheap to replace. Two of them lasted 7 years.
The elephant in the room is water. How on earth are you going to carry enough water to keep you out in the boonies more than a weekend? That is, without scaring the bears? I’ll have to look back in your blog to see if you have addressed this.
Good luck.
Biting insects aside, I’ve found that I enjoy the outdoors much more when there is no feeling of being in a camping neighborhood. However, the front dinette FWC is surprisingly non-claustrophobic, which I might be able to show with my iPhone before long. I believe that I have more problems dealing with a lack of storage for needed equipment than I do with small spaces for myself.
The crank-up lifting mechanism on the FWC consists of myself, and my arms and back. Torsion springs in the F&R support panels help with the initial shove up, and a set of four automotive lift struts take over for the weight once the roof is up a bit. Mine is optioned with higher lift ratings, in the expectation of adding substantial solar. With this type of system, whatever weight you add to the roof (watercraft being the most popular), is weight that you yourself bench press upward. Some folks use special assist jacks from inside to aid the lift when they don’t want to go through a roof unload/load routine each time they want to raise the roof. The roof support system at the front and rear edges is decidedly hardy so that there are no unpleasant surprises during an overnight of heavy, wet snow, but the roof platform itself is thin in section and made from thinwall aluminum tube. Any weight added up top needs to have the actual load points be located as close to the front and rear edges as possible, particularly in longer FWC models like mine. The standard setup places two lift struts near center, which is better at dealing with roof loading in general.
The only roll-up panels I can recommend for durability are those offered by P3 Solar, and they are inefficient for their physical size as well as expensive, but are available in up to 200W capacities. For that reason, they are off my radar. Semi-flexible panels weigh about 4 pounds per 100 watts, which makes roof-mounting on FWC’s units practical. They may actually be too light for the lift struts that I selected. You rightly point out that for ground applications, suitcase panels are a great way to go as long as you’re willing to deploy, stake and strap them down against high winds. I see them as ideal for forest camping, where my roof mounted ones would struggle to find any direct sunlight.
Weight will not be a decisive issue with my particular camper, which weighs in at about 1,050 pounds dry with my options and 1,300 pounds with propane, one of my AGMs, and a filled 20-gallon water tank. Adding three more batteries pumps that to 1,480. Adding in solar, my personal effects and a few gallons of shower water may take that up several hundred pounds, but the result should still fall way short of the Mighty Furd’s 2,460-pound cargo limit, so I do not expect to share the unhappy experiences you had with your own truck camper, particularly due to the relatively low center of gravity of the FWC. Considering its auto-braking trans, sizable four-wheel discs and some 650 foot-pounds of torque, the Furd hasn’t posed many adventures in hauling the true 7,000-pound weight of the nose-heavy Defiant, the loaded 70-gallon Tankmin (680 pounds) and a bed fully loaded with equipment up and down steep mountain passes, so I’m not much concerned about carrying just the FWC onboard. Since I will be traveling solo in a purely-stock vehicle, I will be avoiding especially challenging off-road situations (officially known as chickening out).
The FWC has no provision for more than two small AGMs carried internally, since AGMs are the only safe way to go for living-area storage. I don’t see the weight penalty of packing in several more of them at bed-floor level as nearly as much of a concern as the loss of storage space they will cause. The fact that, unlike golf cart batteries, they are expensive to replace makes me want to add enough (which I already have) to decrease the draw-down each day to improve their service life. I’ve looked at mounting two batteries in special frame-mounted carriers below the truck bed, but these would need to be identical AGMs since all batteries need to match, and servicing flooded batteries in that location would be difficult.
Water for my planned 5-7 day escapades should work with the FWC’s 20-gallon tank, since I won’t be using any of it for showers. That water will be carried in a cab-stowed container. The Defiant has a tank of the same capacity (which is pretty pathetic for a 26′ TT), and that has been able to last me a week despite being shared for showers. So I’m optimistic that the FWC will do fine for its shorter times of camping duration, and that I may actually come out of it less odorous. I will be showering outside with solar-heated water, so I won’t mind traumatizing bears as much as I would their laughing and pointing. It really does a number on your self-image when you see a bear dragging a portable shower enclosure from another campsite to yours.
But plans are different than results from actual use, so this build-out could get interesting once the Intrepid launches in March. How exciting it will be to have lots of readers taking the time to write “I told ya so!”
Now that’s a comment! All good considerations, Ron. Your statement, “I’m too busy doing nothing to commit to that and having them in the way all the time” reminds me of a quote from one of my favorite movies that goes something like “I lived my dream of doing nothing, and it was everything I thought it could be!” It’s a lifestyle. You seem to have a two-handed grip on the realities of benefits and drawbacks in the larger view. I’ve gone through quite a few iterations, and am currently leaning toward staying the course, but altering the mounting in such a way as to (hopefully) raise the panel’s temperature tolerance in a roof mount situation. If I could bump the failure threshold from 90 closer to 100 degrees ambient in high-arc sun, I’d be thrilled. Affordably, of course. Kinda sounds like you need a project!
Panels mounted on a roof rack? http://www.prolineracks.com/thule-542-artificial-rain-gutters.html would help you out
Yep, I looked at that, and an integrated Thule rack system is available on all FWC models as an option, and can likely be added later as well. I found that I could even obtain an additional sliding crossmember if I needed the additional support under panels, though it’s best to keep the crossmembers as far forward and rearward as possible to keep the loads near the roof supports. If you’re willing to drill holes in your roof, the adapters you link to are a handy way to get a rack up there.
I should learn to be quiet. I’m over by Yuma. So it needs to be lightweight and strong and keep the panel from flapping in the wind? I was pondering that earlier after reading your comments. Huummm? Come on everyone, keep burning those brain cells and ideas flowing.
Liquid cooled? NO
Pvc frame? What will support them overall and keep them from dipping in between the frame? A ton of pvc pipe would end up too heavy?
Something lightweight but not solid like plexiglass. Needs to stay cool and not hold heat on the bottom. Plexiglass is too heavy too.
I think you mentioned reflectix(?) The refletix would probably help even if it was flat on the roof under the panel? The edge would have to be sealed to keep it from being a mess of mold? So the chore is to keep a floppy panel supported off the roof? Huumm?
I need to go look at the part where you mentioned the panel manufacturer . Are they sort of rigid yet bend for curved roof or are they very flexible and could be rolled up. I have never handled any like that.
Would laying them on several piece of pvc tube work? May end up being a mess underneath between all the tubes.
Expanded mesh type lightweight plastic that would form a sturdy flat surface yet let air and heat move.
How about many pieces of pvc pipe cut about an inch or inch and half long stood on end forming a grid? the lengths could be varied from end to end to provide run off from back to front or side to side? Dicor them to the roof then dicor the tubes and lay the panel on? No holes in the roof but crud could accumulate under them. Power wash gently or hose under them?
I disagree with that “be quiet” thing, Ron. I did look at liquid cooling, and/or finding something with a high thermal mass that’s thin and light enough to not add in more problems. Looked at Reflectix too, which is not so much an insulator as a radiant energy reflector.
The panels in question are sold now by WindyNation, and are categorized as semi-flexible. The degree of flex combined with heat is one of the things that spooked Renogy with their version. Prior to the point that they pulled their panels off the market, they cautioned against bending the panels at all, and all sellers of all types warn against allowing such panels to actively flex, as in vibration or flex movement. They also promote getting airflow to the rear of the panel, something which cancels the main mounting method used by their customers. In fact, 3M 5200 adhesive works so well that most folks can’t possibly replace a fried panel without damaging the roof – they have to glue the new panel on top of the dead one. Roll-up solar is a different animal, supremely adaptable in deployment, relatively rugged, but soberingly expensive and needing a large surface area to generate limited wattage. If you’ve got the bucks though, they offer an unmatched ground system that is not what you would call finicky.
I thought about adding insolative rib supports under the panels just as you describe in this and later comments, then realized that my willingness to permanently gunk up the roof with adhesive caulk residue etc for a panel which must be easily replaceable and may have to be abandoned for a different type, size and placement, well, matched my willingness to drill holes in it for screws.
I feel that you briefly hit the solution on the nose when you wrote “Expanded mesh type lightweight plastic that would form a sturdy flat surface yet let air and heat move.” Then you quickly moved on to support rib grids and how to best place and fasten them down. I think a sturdy, full-support pad that also allows for air circulation is a brilliant idea! However, I think that because I’d been pursuing it for a good chunk of the day, and was impressed that that you sensed the ideal kind of support, but simply lacked a familiarity of what materials existed that might be able to offer those qualities.
That material is called “reticulated foam sheet”, and in its denser forms is used in air filters and speaker face covers. The material itself takes up only 3% or so of its volume, leaving the rest available for air flow. What I’m interested in is rated as 10PPI, which is almost skeletal in appearance. It’s expensive because of the process used to make it, but is available in 1/4″ thickness sheets, which just happens to be the same latched thickness of the reclosable 3M tape squares that I want to use to lock the panels to the roof. With the flat roof and matching device thicknesses, that means no bending for the panels and a reasonable freedom for air to circulate underneath. My only regret is that there isn’t enough space available for something resembling a cool air intake on this setup. A 1/4″ air gap isn’t much, but it’s a lot better than letting the panel sag down onto hot roof contact.
I’m also thinking of adding an aluminum foil sheet to the back of the panel in an attempt to equalize heat distribution across it. Some panel descriptions note an “aluminum backing”, but I have no way of knowing whether this is internal or external at this point, or whether the WindyNation/Renogy panel has this at all. The black center of each cell is the first to heat up and begin distorting – either the clear overlay above is shrinking or the cell underneath is expanding – and it might be possible to shuffle a little of that excess heat away toward the cooler areas of the panel. If nothing else, the foil and air gap combo should cut off a lot of the heat radiated up by the roof itself. How effective will this whole approach be to stave off panel damage and heat-induced failure to somewhat higher temperature levels? Hard to say. I are not a engineer.
I should have followed my comment with a smiley face.
The stub pipe idea would be dirt cheap and provide a lot of air space but it would be ugly as far as Dicoring it all in place. It’s probably overkill too. As you said in your comment about going from 90 to 100 degree threshold. You are just looking for the “edge” that lets this product live longer.
I looked at the reticulated foam and it seems like a good idea. In the 1/4 inch thickness it would keep a low profile to the whole set up. As I mentioned before, what conditions are the Winns in? I noticed that they mentioned extremely hot conditions in Florida so maybe they are typical of the worst case example?
We are not engineers and we cant mock any of this up in high temperatures so it’s just a matter of taking a stab at it. I didn’t read every bit of it but I did see Technomadias comments and the AM solar rig issues. I did notice that AM solar had an older generation of panels?
There have to be a ton of these flex panels in use so how many people aren’t having a problem?
Are the windy nation panels better than others as far as not having this problem?
Is the idea of using solid panels up there 100% dead?
400 to 600 watts of flat panel up there is just such a beautiful thought. Flat, smooth, cant be seen, aerodynamic…..just seems like it has to happen. 🙂
Just thinking.
Beats me what conditions the Winns camp in Ron, but the two times temps were mentioned, it was ninety and summer. To me that means the high sun arc got the roof nice and toasty, and ambient helped keep it from losing heat. One was actually just keeping the batteries topped off in the Chicago area. I think it was Technomadia that blamed thin 3mm panels, feeling that 5mm units survived better, but AM Solar no longer lists those either, so that apparently was not felt to be enough. The impression I have is that ground panels have no issues, apart from fragile junction box attachment. It’s the glue mount to the roof that gets as bad as 1/4 to 1/3 of failures. WindyNation panels are the same as Renogy’s, which means that they are no improvement as far as I’m aware. Panels are a sideline to them, since their main market is wind generators. Renogy gets the press, since they market much more aggressively as a system approach, and collect the bulk of people who are less technically oriented.
I’d love to make the challenge go away by using framed panels, but that introduces so many significant side issues (on a large system in this rig) that I’m thinking I’d rather try to make lightweight panels live than have to deal with the fallout of using lots of framed ones. When you’re already sitting on 500Ah of the best AGMs money can buy, it’s kind of hard to let them go to waste. Several days of dark overcast are worth a shrug.
I see the windy nation panel is only 4 pounds. That’s real nice. It appears that it could possibly be supported at the intersecting grid lines on the panel. 9 rows x 5 rows=45 spacer tubes weighing a few ounces. $800 for 400 watts isn’t too terrible. Something to think about and perhaps play with some pieces of tube to mock it up????? Having it sit on the ends of the tubes would give it any amount of lift desired off the roof and perhaps keep the supporting contact surface area to a minimum. Also with the tubes being at the grid intersections it may be better than having beat blocking material directly under the crystal areas?
3M makes a good adhesive called 5200 although it may be too permanent vs dicor. If the roof is a hard plastic like surface it would seem that Dicor could always be cleaned off or pretty much so. I think it’s tough to get it completely off an epdm roof. Mineral spirits can be used sparingly on epdm but a hard panel roof would probably be much more forgiving.
Another thought is what dynamic would the air flow at 60 miles an hour have on any mounting method? I have used electrical conduit with open ends on a Jeep home brew roof rack and it whistled at times. Flat tubes may do the same. Stubs of pvc wouldn’t have open ends so that’s not a problem. Air rushing past the tubes stood on end shouldn’t be a problem?
The front edge of panel would need to be tipped down slightly so it doesn’t funnel air underneath.
Maybe pieces of pvc laid flat and lining up with the grid lines on the panel would work? It does the same thing as the stubs but just has more contact area and lift clearance is limited by pvc diameter. It would be easier than the stub idea. Might need to semi mock it up. Maybe tristar solar(?) in Yuma has a flexible panel to “look” at. Putting a slight curve in the panel with the stub method may also make it more rigid?
Worst case in guaranteeing that hey dont blow off is to use the six mounting holes with stainless screws. then you have 24 small holes in the roof. :0
In theory the adhesive should be the adhesive but just thinking of problems that could occur.
Chinese fire drill?? Not having come across the term before, I looked it up. While at first blush it seems to describe a humorous situation, I then came across this:
“Historians trace Westerners’ use of the word Chinese to denote “confusion” and “incomprehensibility” to the earliest contacts between Europeans and Chinese people in the 1600s, and attribute it to Europeans’ inability to understand and appreciate China’s radically different culture and worldview.[5] In his 1989 Dictionary of Invective, British editor Hugh Rawson lists 16 phrases that use the word Chinese to denote “incompetence, fraud and disorganization”.
[Wikipedia]
This was a total bummer which colored my usual enjoyment of your excellent posts. Surely you didn’t intend any insult? You’ve never said anything that could come across that way before.
Anyways, back to the main problem at hand. When I originally came across the Technomadia reports of lightweight solar panels failure, I assumed that they were caused by heat buildup. My theoretical mounting of such panels on a dream FWC then changed from roof adhesion to mounting them to steel wire frames (the ones with 2″ squares), which would then be mounted onto Thule racks. That would provide the airspace, make for easy replacement, and allow for tilting using the proper hardware. What I don’t know is what the effect of the wire frames would have on weight. If the panel manufacturer is good on replacing failed panels, you don’t lose out on the cost, just pop in a replacement when they fail.
I would also add a wind deflector to the front of the rack to protect the panels from the wind at highway speeds.
I have come across some peoples’ ideas of using solar to heat water. That led me to think – why not combine power with water heating? On the ground deploy panels, one could mount the panels to a copper or plastic tube system that would carry water which would circulate into your “hot water tank/ bag” thanks to a small pump. You would get increased panel efficiency and longevity along with hot water for your household use.
Well you certainly have a lot of suggestions to play with at this point, I’m interested to see what you ens up doing, and relieved that you stopped the process before adhering the panels to your roof!
Political correctness smacks you upside the head!
Speaking for myself, it’s a lifestyle, Rob.
You are correct, Ming, no insult is intended. My sole knowledge of “Chinese fire drill” is the 1960s reference to hurried rearrangement of vehicle seating accommodations, and that reference was just what it was, with no known backstory. I’ve carried that with me, unaltered by what appears to be a shift in meanings into a racial or political or nationalistic slur, which your research claims to be its origin. My daughter-in-law pointed out some time ago that “retarded” is no longer a clinical term, has been replaced, and is now considered derogatory. I will adjust with the times as I find these things out.
Actually, I’ve worked most of the way off and on through a free Gutenberg Project e-book called “As a Chinaman Saw Us: Passages From His Letters to a Friend at Home”, letters written from 1892 to 1902. The author’s name was not revealed, as he was a highly educated and well-connected Chinese national who sounds like he may have been in diplomatic service. It is both insightful and thoroughly caustic, and lends a bit too objective a view of sometimes-unreasonable American foibles and biases of the time, many of which have stayed present. It’s an interesting read, to say the least, as both cultures of the time, as he describes them, would be considered mucho politically incorrect today.
Your wire platform on a Thule rack sounds like it would completely solve the heat issue. You might come across an aluminum rack or something like expanded steel or some similar form of aluminum that decreases the weight penalty. I have considered cooling the underside of the panels with water, and so be able to use it for showers or dishes, but wondered at the weight and complexity of doing that. I suspect it could be made practical, but I’m not the guy to try it. There’s a form of food-grade plastic tubing at most hardware stores, and it’s very light. My issue with it is that I’d expect to need a “hot box” under each panel to heat the tubing, with all connecting tubing being insulated. Whatever’s up there, you have to lift. Used only on ground panels as you note, why not? But I suspect that the panels without the hot surface behind may not develop the temperatures needed. Don’t know.
On a pristine new camper fresh from the factory, there are no such things as drills, screws or lathered-on adhesives. It’s a respect thing.
So the brain storming is over. The options seem pretty clear but let’s just chew the fat a little more . I like to try to use a trouble shooting flow chart approach to keep my head from spinning. I’ll try to not ramble on too long. 🙂
First, regardless of how shiny and new the toy is it seems like you will have to drill at least one hole for the panel wires to get to the controller. That or they hang down the side? I think I’d rather see them in the interior rather than flopping on the exterior. That’s not even an option is it? A virgin is a virgin. Yours isn’t going to be a virgin or remain pristine. There is a tree branch out there somewhere with each of our names on it.
Number one way to install is just tape them on and see how long they last. They are warranted for 5 years unless they find wiggle room out of honoring it.
If they do find a way to not honor the warr at all you then start dividing the cost by the time that they last. I have no data to go by but if I had to put money on it I would bet 2 years for sure. At that point we are looking at a built in cost of $400 or so a year.
From there we would next install them with your 1/4 gap idea and hope to stretch the life span. I wont say it wont help but I would also say I dont think it will provide a big difference in temperature effects on the panels. The roof isn’t the heat problem. The lack of air under the panel is the problem. The farther away the more air. Yes some heat is not avoidable because of the shear temp hanging around the hot roof but air gap still makes the biggest difference.
Next and more trouble to accomplish is to use pieces of pvc pipe in various diameters to create a slight arc in the panel from side to side. These pipes would run from front to back with possibly 1″ diameter in the center and 3/4″ next and 1/2 ” at the outer edges. This would provide a lot more air space under the panel and also create a self flushing effect. Just like hard framed panels the rain is more of a friend rather than enemy who helps to pool the dirt in the dipped area. Even a dip wont hold water if tilted enough. The pvc can be fastened with Dicor and not lathered out all over. Simple strips of non leveling dicor with the pipe laid in until dry. Then use dicor or 5200 to fasten the panel to the pvc. Surely more trouble and not as pretty as flat but more likely to cut temperatures. OR do the same thing without the arc and get them an inch off the roof. Is it worth doing? I don’t know? We have no way to mock it up and compare temps but I would bet it’s better this way. Sounds like a pain to me compared to dividing the risk vs cost of just laying them on flat.
I would add that if you ever wanted to remove everything from the roof, the dicor would be better than holes all over. As I mentioned before I would give it a pretty good chance of being removed from a hard surface as compared to epdm. Of course your tape/3m idea is ideal as far as ease of removal.
Without drilling holes and adding weight those seem to be the only roof options.
I dont need to go on about ground panels. They can be stored under the cab over or in the back seat. It sort of makes me want to throw up when thinking of building in such a pita system. You been there done that, in fact you need a tee shirt that says that.
Others please add in whatever I’m missing. I like all the ideas and learning.
So…..is it door number one or door number two or…………..:)
Nay on despoiling my virgin beautious camper for solar, marauder! It’s prewired for solar, meaning that there are SAE terminal connectors located both on the roof and on the rear exterior wall. You get that whether you want it or not. Those wires join behind a panel in the cabinetry before they lead to the battery compartment where a solar controller can fit (another reason why AGMs are recommended). FWC has gone to great trouble and expense (out of my pocket) to eliminate as many potential leak points as possible with their one-piece roof, and far be it from me to undo that.
I’ve been mulling over the 1/4″ gap and have to admit, a 1/2″ gap or more would allow more airflow and work better overall. Sticking with reticulated foam, the greater thickness tends to be the same price as the lesser. The 3M mounts can be either doubled up to match the rise, or spaced up with sheet squares and double-sided tape. Or, leaving the low mounts in place, correctly spaced apart, would tend to create a fairly even slight bend in the panel to help runoff, since the foam tends to be more supportive than stiff. There’s no real limit as to how thick the foam can be obtained, so the limits are more determined by how it is held down. My imagining is that, with the roof underneath the panel now in shade, that section would be heated mainly from conductive transfer from surrounding areas, and whatever decreased heat transfer there is, is all radiant. Much of that can be reflected back by adding aluminum foil to the panel’s backside. The roof’s enamel is pretty tough, but the nature of 10PPI reticulated foam is such that it may be worth adding a very thin sheet of suitable plastic underneath the foam to prevent any scrubbing long-term. All of the adhesives/sealants I’ve used and read about would be a nightmare to get back off, and be likely to damage the thin aluminum sheet in the process, so I’m squeamish about even that, especially on an experimental system that may need a major revamping later. Like the Defiant, it’s not a “walk-on” roof. It’s more of a “lean-over it” roof.
I’m now sitting on a couple of rigid 100W panels, so I’m agonizing over whether to mount them under the overhang and put just 400W on the roof, which would be helpful in the few forest situations I’ve had, and save money up front. My existing MPPT controller tops out at 600 watts, so I can’t have it all. Any ground system I use would require goofing with the camper’s wiring to convert it to series instead of parallel, and then keep a crosswired SAE plug in the rear port to keep solar working when ground panels are not being used. Then again, the lift struts could certainly take them being on the roof as part of the total roof system, at the front and rear edges. I do have an unusually low PITA threshold, so it’s not an easy decision. Decisions, decisions.
Doug…I know after lugging around the defiant . The last thing you want to do is think of towing something again. However….(having towed a 6×12 trailer with motorcycles) the inconvenience of having it behind me is easily outweigh by the pleasure of having the bikes when I need them. My limitations to going to very remote areas will be restricted by my truck (2×2 dully) a problem you don’t have and from photos I have seen with jeeps in extreme off road conditions, towing a small trailer I don’t think it would inhibit you from going to the areas you wish to go to.
So just for fun consider for a moment a small, (maybe 5×8) enclosed trailer with high ground clearance. Multiple panels (that you already have) on top, additional batteries (that you already have) inside along with additional water and supplies.
Start throwing in some of the stuff you thought you couldn’t carry with you and soon you may start to see the negative aspects of towing a trailer begin to diminish.
Just a thought ……. 🙂
David, you’re appealing to my packrat side, which is very naughty! Being so, I have given serious thought to doing just what you say, storing all my crap and transferring solar and battery duty to the trailer. But it all comes down to this, I guess: The Mighty Furd is no Jeep, and its overall length at 24 feet, width, and extended wheelbase with its terrible turning circle have worked against me while exploring solo. Many’s the time when I’ve run out of passable trail, backed up and just squeaked an awkward five-point turn at the first opportunity, deeply grateful that I wasn’t pulling anything. The latest was right here in Wellton, atop a sort of canal access ridge with a dirt road on top. Had to back up nearly a mile, as the Ford alone was just too long to get sideways without risking an edge collapse and an interesting forty-foot descent. Thanks for the thought, but I think the feasibility comes down to what the vehicle is, and where you tend to go with it. I like taking Jeep trails and sometimes find they’re actually ATV trails, but since I’m not in a Jeep, I’m kind of pushing the envelope at times.
I thought so, I find that most people are kind, just uninformed. The same thing has happened to me several times. As you say, times change and we change with them. The world is more heterogeneous than it used to be and people are more equal now than they used to be, which is a great thing. Not that long ago, I would not be allowed to vote, and racial slurs were still hurled in the street at me a up to few years ago.
I will have a look at the book that you mentioned. I don’t have great hopes for being able to make my way through it, the age of the internet web page has really made a dent in my patience for long, wordy texts written in older English.
I’m not aware of any aluminum version of the wire rack that I mentioned, but if it did exist, it would be ideal. Dawn’s suggestion of a custom aluminum rack would fit the bill well for lightness and support above the roof with a good air gap. I did consider the water cooling for rooftop use too, but now that you have mentioned the limitations of what the roof can carry, I would not do it unless some guinea pig went first!
I don’t think it has to be elaborate – a simple tubing run snaking back and forth sandwiched between the panel and the rack would probably work well enough to get your water warmish. I would not bother with the hot box, as it would get in the way of the panel cooling function.
I would also save any water that has run through heated plastic for washing purposes, as I think you are aware. All plastics leach into the water, and even non-BPA compounds have estrogenic properties in the body. It will just take another 20 years for the next culprits to be officially recognized.
One issue that occurs to me is that the lightweight panels are secured by grommets. Do you think that there is a way to bolt them down solidly enough to deter theft from your roof rack?
Ming, if you Google “expanded aluminum sheet”, you’ll come up with things like this. As for weight on the roof, the shorter FWC models are better at carrying loads, but I seem to remember you as having a full-size bed.
I’m not real optimistic that tubing adhered to the bottom of a solar panel will heat water significantly, the panel heat developed being one issue and the effective transfer of heat to the tubing being another. The black solar panel may get enough heat from the sun to fry itself, but the “radiator” underneath is in shade and must get all its heat directly from the panel, so what heat there is must come from an effective transfer and then be preserved with fully insulated lines and tank. Whether by thermosiphon or electric pump, water must circulate continually, or all you’ll get is a gallon of warm water within a system of much greater volume. The “hot box” would be an insulated rear panel enclosure that would try to stop the tremendous heat losses to open air. After all, this concept is basically a solar water heater flipped upside down, then having its sides and Lexan cover removed. That flat square on top presents a limited heating surface, and suddenly relies on transferring that heat to the tubes below by contact or conduction, which are now hanging in open air. If you want warm water, you’ll need to stop that heat loss there and throughout the system. At the same time, as you note, the panel can’t be allowed to overheat once it warms that water underneath it, so the water must flow to carry that heat away. It’s a bit of an either/or: for maximum panel cooling, you’d leave the hot box off to allow as much heat leakage to air as possible, and for maximum warm water, you keep the box on and make sure the water circulates. On the whole, this concept seems much better at potentially cooling the panels than at heating water. A solar heater would be much less complex and more efficient, I think. The major stumper for me is how to get a ton of physical surface contact between the panel back and the “radiator” underneath. A thin flat bag of water is about all that comes to mind, or having the panel be the top cover for a five-sided water tank below. And then there’s the cost. I wouldn’t want to be the guinea pig on such a system.
As for theft, your use of the word “deter” is appropriate, since there is no preventing except by pure adhesion, which poses its own issues. The goal of securing anything is to make the removal process difficult enough to encourage the thief to move on to an easier target. That’s helped by making the removal process elaborate, making hurried removal likely to destroy the target, and/or require the use of tools which are less common – like Torx fasteners instead of hex bolts or phillips-head screws. Like using aircraft cable thick enough that wire cutters won’t do it and a hacksaw or bolt cutter is required. I don’t have a pat answer for that on flex panels.
More thoughts.
If you dont want Dicor on the roof and you like the idea of 3m tape products, maybe you could use 3m tape to mount pieces of white pvc lumber. I have used it on several projects and it’s available at HD. I rip it with a table saw and have used a router on it. It’s beautiful to work with and finishes off very clean. No splinters or rough edges. Lasts forever.
You could either use long strips running the length of the panel front to back or use sections of strips 6 inches or so long to create a honeycomb effect. Even if you went as far as smaller sq nubs of it you would get maximum air flow. More work but it’s not like shoveling dirt. 🙂
It would probably look very clean and neat also. If you ever need to remove it peel them off and clean the tape residue off the roof. The edges would all be nice and square and possibly look very cool.
The problem is no air under the panel. They all say keep the rigid panels off the roof. Give it air space without it being half arsed. Cheap, clean, easy to maintain, local availability, common tools, easy to remove, very lightweight, looks good.
Hmmm. PVC lumber sounds interesting. I wonder if Home Depot can rip it for me, since I have no way of doing that. For flex panels, that would allow screws in the grommets, and for framed panels, conventional mounts…
I picture the mesh product holding debris. Not a problem in Az but up north where we go there is a ton of crud from pine needles to bugs to leaves etc. The front edge of the mesh product will also catch insects like a car grill. Maybe not a huge problem but not easy to clean. It may seem extreme at first but you could raise the panels a couple inches and have even better access for hosing under there.
Oops, I hadn’t thought of that. A strip of window screen at the front edge might help, but I’ll have to noodle on that for awhile.
Some more thoughts
On the issue of using the web mat material, I agree with you that all those little poky ends or even smooth edges would be constantly rubbing on your roof and panel.
So the big issue is heat. Heat isn’t destroying all the ridged frame panels because we keep them off the roof. There is more to the whole durability issue between rigid and flexible but it seems the main issue is heat.
I have never paid any attention to flex panels so I’m learning as we look at your problem. The other obvious issue is weight with the difference being very large between flex and rigid. 4 lb vs 18 lb. So it would seems that the next generation of flex panels should be built with some method of holding them off the roof. Given today products and various manufacturing techniques it seems like they could integrate a riser design that may also be flexible enough to comform to the various roof radius. It may also have the ability to have easily cut off or snapped off segments so self flushing could be achieved if desired. A radius or self flushing angle could be built in. It could have zip strip adhesive mounts. Zip the tape, position, plug in, DONE. Seems to also fit right on with the new 3D printing methods.
Heck, why not add some simple tilt mechanism. They may still be able to keep it very lightweight. Someone better run out there and patent this idea. I’d go do it but I’m still in my pj’s drinking coffee and watching the humming birds. 🙂
I’m trying to word the patent application now. 😉
I’m kind of letting things soak before I commit. As of last night, I started having second thoughts about the cost of flex panels, the failure rates, and all the problem solving. I’ve decided in the interim to cut out some butcher’s/builder’s paper I have to panel size, both flex and framed. I need to ensure that the happy dimensions the factory gave me long ago are actually valid for my camper, so I have the needed space. But before I do that, I think I’ll Gorilla Tape my two framed 100W panels to the front end of the roof in some believable position, and see what lifting is like. That’s the clumsy end compared to the back, and I’ll be able to put the high-rate lift struts to the test. If the effort to lift the front is tough, that means stick with flex. If it’s workable, I’m thinking I may just install four total (framed) on the roof toward the front and rear supports, and stow two over the cab for overcast weather and overhanging trees. That will get me the standard 1/1 watts/amp-hours ratio daily, and 1.5/1 when I need it. And I’d save a bundle on the panels. Four panels at 68 pounds plus wires is do-able at the edges as long as I can get the roof up. Actually, the test will be mine to fail, not the roof’s.
If the PITA factor in the field proves excessive because I’m breaking out the panels more than I figured I’d have to (because they’ll be horizontal), I can figure out what I want to do from there, since the real estate should still be available for something. 102 pounds of framed panels would be a bit much (made the factory rep flinch, too), since the last two would have to be at roof center. I’ll do the test to see whether I have this framed option or not.
There you go. Keep the ideas going. I’m just sort of stuck on never doing ground panels. It’s just me. I have to do the water thing and the dump thing but after that I’m real set on not building in anything like panel moving over and over. I know, I sound like the broken record but this is it. This is no time to compromise. 🙂 Well, unless mandatory.
If you do 4 panels at 68 pounds maybe you can just tape the aluminum mounts on. No screws. In it’s simplest form you could use 2 inch aluminum angle from HD. That’s all I did but I also had rivnuts that I inserted in the panels to allow tilting. If kept flat all you need is one angle bracket at each corner screwed to the panel, no tilt
I guess the next step is buying aluminum mounts but they could still be taped on. If we were to guess, the 4 flex panels and the needed vinyl spacers would weigh a total 28 pounds so you are really only going over that by 40 pounds if doing four 100 rigid. It’s good that you are mocking it up. Any item that gives you the approximate weight will work.
I guess it’s then a matter of knowing that the weight while going down the road doesn’t have a resonance or humping effect and fracture the aluminum over time.
Another thought would be to span the roof with light gauge aluminum angle, taped on and mount the panels to that. It may be 10 more pounds total but it would keep the mounts from having a small contact patch on the roof. May also help the roof not dip in the center. I’m sure that roof has to be a pretty light gauge to keep the weight down.
http://www.homedepot.com/p/Everbilt-2-in-x-96-in-Aluminum-Angle-with-1-16-in-Thick-802607/204273998
Putting the mount holes nearer to the edge of the alum angle will give the back side of the panel about 2 1/2 inches of clearance from the roof. The panel frame edge will be closer of course but the actual backside of the panels will be 2 1/2 or so.
So, it seems that 4 100 watt rigid with 4 pieces of 8 foot 1/16 in alum would weigh about 80 lb
Another thing, if the aluminum runs from side to side will it whistle? Its not aerodynamic. Just trying to throw every idea in there.
Ron, I think you’re enjoying this more than I am! Some good ideas in here.
I saw something driving around today that might work for you. Or something like it. That is, if you are absolutely determined not to use suitcase panels.
I was driving behind a pickup with a camper shell, and he had an overhead rack that was fastened to plates at four corners that stuck out about 6 inches from the sides of the truck. The flat plates were installed on the bed rails and the camper shell fastened on top of them. Very much like the anchor points you used to see on truck campers that held the jacks, two to a side. Coming up from these plates were the 4 uprights that supported the overhead rack. Any welder could make you something like this out of 1 inch square tubing. Of course, you’d have to lift your camper back up to install it.
You wouldn’t need a very strong overhead rack to hold a number of solar panels. And you’d have to make the rack tall enough to raise the roof beneath it.
Alternatively, you could skip the overhead and just hang the panels from the side in travel and raise them up like gull wings when parked. They would thus also serve as shade for the side windows. One long flip-up panel on each side.
Or you could just forget about all this bother and get a couple of suitcase panels to carry behind the driver’s seat. :o)
And then there’s the possibility that perhaps I shouldn’t let my brain out in a storm like that. It may not be wash and wear.
Bob, about as far as I’d go toward suitcase panels is to use hardware store hinges to tie two framed panels together face to face, and wire them in series toward a remote controller in the camper. I’m already sitting on an MPPT controller and am loathe to pump lots of amps at 12-14V over long wire distances to get to batteries inside the camper, which is what a suitcase setup would do for me. I’ve already observed it to drop plenty of voltage firsthand. I’d rather have much higher voltage and fewer amps, since 10AWG wire can only carry so many amps for a given length. I’m not much tempted to decide between 20 feet of 2 or 4 AWG cable, or longer charge times.
With apologies, I’ll have to write off the overhead rack idea as well, as it undoes the basic purpose of what a lightweight pop-up truck camper is for me. Low profile.
I’d also have to debate that I wouldn’t need a very strong overhead rack. Unlike a shell, the Grandby overhangs the truck bed by five inches on each side, so the bed plate would have to project out considerably more than that, and be stiff enough that the verticals never, ever contact the camper even when the F-250’s suspension is racking the truck violently from side to side. With the panels held at least two feet above the camper roof lowered for travel, I’d be concerned that the bed plates themselves, which are not trapped by the camper body, would create some interesting flex issues in themselves or the bed mounts. It sounds like one of those things that works well for what it’s for, but is not suitable for just everything. Having been thoroughly introduced to the issues involved in using hanging panels from the side of a roof (the Defiant), I would do that only as a last resort, particularly on a roof that must change heights. Those suitcase panels are starting to look pretty good! 😉
But you are in brainstorming mode on this thing, and I appreciate that you are percolating on this project in the back of your mind.
I didn’t realize the Granby over hung the side rails 5 inches. The picture above doesn’t do that justice, and it looks like it is almost flush. So my idea of just welding up rail-supported side racks to hang them on (without the overhead cross members) probably wouldn’t work due to flex. You’re right. I don’t suppose the side wall of your camper is strong enough to support them either.
FYI, take a look at the formatting of your reply. I couldn’t read a portion of it because it was cut off on the right side. But I got the gist.
Bob, fresh out of ideas.
Sometimes ideas come whether you want them or not! Actually, the sidewalls of the camper have jack mounts at each corner, which could be used to mount structural verticals! But hiking up so high with panel weight wobbling around, the effect on the camper frame over time, or the rack itself, is a big question mark in my mind. Still, you may have found what might be the best way to mount an overhead rack or side-hanging system. Now, is anyone going to suggest telescoping electro-hydraulic legs? Maybe mounting camper lift jacks upside down to push a rack up? Hmmm… 😉
If your side wall is solid enough , you could mount uprights down low for weight bearing purposes and then anchor them at the top to prevent flex. The high anchors wouldn’t have to be all that strong. Their purpose isn’t to support weight, but just to keep the frame from flexing. Also, the tilt-up or -out panels would not be tilted in travel, but just hang straight down and probably lock in place, which would limit torque effects. With a little ingenuity they might not rattle. :o)
The suitcase idea seems simpler and less trouble. You know you can buy them sans controllers and wire them to the one you have? And they come with nice connectors that let you hook them up without uncovering your batteries (or your controller) . Just open them up, “click” , and you’re done.