Planning a Solar Rack - Part 1: Building a Model & Our Plans
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- Опубликовано: 29 сен 2024
- Our bus is off in Mexico for paint! The biggest challenge remaining on our bus build is the solar rack. We share a brief overview of our plans for installing 3500 Watts of solar panels onto a space about 27.5 feet x less than 4 feet.
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A family of six dreaming, planning, and preparing to full-time RV around the country. Renovating our '64 GM PD4106.
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I went through a similar thought process. I'd consider revisiting the id of mounting sideways. 1) It's simpler, less to go wrong, and oh boy will things go wrong, always do. 2) You could build a side skirt like many modern coaches do. s3.amazonaws.com/mot-production/vehicle_images/images/5537/full/2006-Country-Coach_Magna-42_-23.jpg?1364257920 (search country coach in google if this link breaks)
I Had grand ideas about tilting and maybe even a solar tracker, but in the end, keep it simple, keep it safe and then make it look good. In the end it might just look like a roof raise.
Or, if you're as stubborn as I am, you'll make the slide system work hell or high water, and if you make it work, I've got nothing but praise and admiration. Keep up the good work and thinking outside the 35' box.
Thank you - we considered the skirting too - that is what "Life is Joy" ended up doing and I think it worked out really well for him. (after a couple panels broke in a freak microburst before he could get them skirted). I had tilting fantasies too but those already went out the window because I couldn't figure out a good way to secure them and have them tilt. LOL, I have been known to be a little stubborn - we are going to give this slide design a good try! Thanks for following along
Looking forward to seeing what you come up with. Guessing you might have already seen this guy’s amazing build (he’s a genius), but if not, check out this video: ruclips.net/video/cM5s4F-7AOk/видео.html
Obviously, your application is complicated by the curvature of your roof, but I thought perhaps you’d find some inspiration, if nothing else. As others have already pointed out, and as I assume you are already well aware, those large panels are going exert a lot of force when extended. Have you considered having the upper panels slide as well? That way each level only has to extend half as far. More slides, of course, but a lot less stress on the structure. Just thinking out loud. A challenging project and I look forward to seeing you tackle it. Cheers!
yes! We love that guy's build! He even commented on our Instagram photo!
Yes, we considered doing both slides or even a triple layer approach but kept running into the problem of supporting huge panels (almost 7ft long!) on only the sides seemed like not a good idea. Stay tuned to see how we got the panels to slide while supporting them in a little stronger way.
Smart minds think alike lol Just got pointed to this video. have for months been considering same thing with 5 stacked on 5..... maybe 3 on 5..... with two extra of my 10 on the truck cab instead of camper roof.
Awesome! Thanks for joining along - We are getting the bus back this week - his solar rack is among the first items to go on the freshly painted bus - we'll see how it goes :)
Sorry, but to be honest, this seems very complicated and has too many moving parts. Would be great if you could make this, but wear and tear will give you problems in the future i think... As mentioned earlier by someone, look at the ‘life is a joy’ channel for Jim’s problems and solution. Thank you for making these videos. Love how you two make a great team and are passionate about this project.
Hi Freddy - I did watch "life is joy" - love that guy! his video was one of the reasons I decided to mount these with less surface area exposed to the wind. Thank you for the kind words and tuning in - let's see where this rabbit hole goes :)
good idea but you're thinking small . If you're gonna do something do it right and do it big or go home lol . Why are you planning for only 8 panels why not go for 12 ? Instead of doing 2 layers and do 3 . have one slide open to the left of the bus and then have another slide open to the right of the bus so that you have four panels left four panels right for panel center . And then if you really want to challenge hey you really wanna be unique and they only wanted a country with such a rig then put the entire rack on a hydraulic lift so that you can pivot the entire array up at an angle to better soak up the sun. You can lift the array with hydraulics or you can do it again with actuators . And then once I had the whole thing set up I would plug the entire system into a remote system so I could stand on the ground and control it my remote control . Not only would that be freaking cool as hell but it would also be a technology that you could market and sell .
Thanks Rocky. 3500 Watts of solar should be plenty for us while we are on the road. We had considered doing 3 layers (two slides) but opted to make the bottom layer more stout instead. 3 slides would have been great if we opted for smaller/lighter panels - but with the commercial panels we thought it might be more valuable to create a stronger solution. One and half years later they are still working very well and have survived several wind gusts that have blown down nearby trees.
Wow that's a ton of work buddy but I'm sure you'll figure it out I'd be worried about the wind and the vibration issues very interesting to say the least, very.
Thank you Brian - we appreciate your kind words. Yes, wind is a huge consideration and one of the main reasons we felt we needed to orient the panels like we did (creates less area for the wind to push on when underway). We are working through some ideas - the next video should be more interesting :)
Not sure I understand why the need to make them flat. If you have a mppt controller ?
Sorry hadn't finished listening..
Don't layer them because a solar panel is a collective of small photovoltaic cells connected in series. If one of these cells is shaded, it reduces the efficiency of the *whole* panel. That's why you have to consider anything that can throw any shade (antenna pole, etc.) at them when designing the placement. Building this shade in the system to begin with is a bad idea.
Hi Simon - good point - this is something we forgot to mention in the video. Shading is a huge issue but with how we wire them we should be able to still get a full 50% (1700 Watts) as we travel down the road. We intend on wiring these panels in a 2s4p configuration. two panels on top will be wired in series and two panels on the bottom will be wired in series - all 4 of these will then be wired in parallel which should eliminate the loss you describe.
Wiring things in parallel still have its limitations. Here is what I experienced: I wanted to circumvent the fact that I would be dry camping possibly under trees, eliminating much of my solar array on the roof of my RV, and alleviated that with and additional portable solar panel that I would carry and move further away from the RV and chase the sun spots with it. I had connected this panel with the rest of the array in parallel. In series, each panel would see a different voltage, but current is limited by the overall resistance of the whole circuit - hence if you have a shaded panel it would affect *all* of the circuit. In parallel, all of the panels would see the same voltage, and the current that each panel is sending will depend on the amount of sun it's getting, and the current that the solar controller will see is the addition of all the panels' current. The problem is, if a solar panel is fully shaded, the voltage that it's able to produce is very limited - and possibly under the effective voltage. So what I saw is that even though my portable solar panel was in the sun, the voltage of the overall panel collections connected in parallel was somewhat limited by the shaded panels on the roof, and the solar controller never was able to "see" enough voltage to get into the effective charging range.
I will let you figure out if this problems affects you because I don't know all the particularities of your system, especially since you're using lithium batteries on a 48V system (if I remember correctly), so the numbers will vary from mine.
I just wanted you to factor all these in prior to investing a lot of time in this setup since you guys are already putting a lot of effort and money in this project!
Have you considered micro mppts? That way each panel will be independent and you can parallel it all as AC and hook it up to your regular victron charge controller. Thereby you can also eliminate the need for high gauge cables from the roof. I don't recall if your charge controller can handle 3-phase, but mppt's build for 3-phase last for ever (no need for local storage in capacitors while the current switches polarity). Not sure they are available in 435 W, though - but how often will you get full capacity from your panels anyway :o)
Sunpower is not affected by shading as other panels are. They dont even have blocking diodes!
Well. More accurately, the Maxeon panels from Sunpower are less affected than most other panels. According to Sunpower's own studies, at least :o) Sunpower panels are very good; but not magical... Shade still sucks. Given the limited area of RVs, high quality panes with high yield, micro mppt and various shade and heat technologies are worth the investment - and the 22% Equinox system from Sunpower (for instance) is very neat looking on top of meeting those specs, so I'd definitely recommend Sunpower. But they are still affected by shade.
Really a cool idea...can’t wait to see it happen...
Thanks Joe! Me too - we are still playing with some designs - stay tuned.
Wow Juan and Michelle! That is really ambitious. I'd be concerned about a lot of things, like wind, tree limbs and other UFOs. Is is not possible to get smaller panels? If you had 2' X 4' panels, you could mount them lengthwise and three across (so they are positioned the long way front to back). They would contour to the roof arc a little better. Then you could try to work around your vents, follow the arc of the roof and tie them down tight to the rails. You would also have 6' across of surface area rather than 4' even though overall, the collector surface is slightly reduced from your ambitious 8' across movable panel plan. I'd be really concerned about anything that is not firmly and permanently. The roof takes more of a beating than you might think. Just a suggestion. Seems like an uphill battle, but you obviously know more about it than I do. Good luck. Can't wait to see what you come up with!
Hi John - Thank you - yes, this is really ambitious a maybe out of our league? We intend on giving it the good college try though. To answer your question: It is possible to get smaller panels but it is hard to get the energy density and efficiency that these panels offer (each one is 435 Watts with over 20% efficiency and built-in electronics for dealing with shading). One of the reasons we opted to go with super strut as the base is it allows us the ability to play with different configurations and mount points without needing to drill new holes in the bus (once the rails are mounted). We are trying to consider as many things as we can think of and one of the ones that scares me most is the power of the wind. While we are traveling I want to reduce the area exposed as much as I reasonably can and this seemed like a decent way to do that. Let's see where this rabbit trail takes us :)
You will have to design a preety ingenious slide to prevent it casting a shadow on the lower panels. Otherwise you will loose performance on those. I understand you bought 72 cell panels which are 6 ft long, right. 60 cell panels, 5ft long would have been a better choice i guess...
Hi Hillside - I believe our panels are 128 cell panels. They measure 81.5 inches long (almost 7 ft). 5ft panels may have been easier to mount, but we thought it was a good trade-off to get more energy density. Hopefully we can make it work
Great channel! I have been planning on doing the same thing for quite a while with the same type of battery/AC/solar setup. I am planning on having three layers of panels with slide outs on each side for 11.7 kW total. There's no success like excess! Haha! I'm sure you already know this, but 8020.net and openbuildspartstore.com are good (but expensive) sources for useful hardware for this kind of stuff. Looking forward to watching your results and best of luck!
wow!! 11.7kW - that is insane! 3 layers are totally do-able. The 80-20 stuff is great but it is very expensive. Thanks for following along!
Gotta b a less complicated, less likely problematic way. I wouldn’t want to worry about all that hardware and mechanical stuff. You’re gonna have plenty of other stuff to maintain. Plus that much hieght and hardware will create a lot of turbulence which will probably require a serious spoiler. Trade those panels for different size to fit them side by side. Save yourself a lot of time and aggravation. Just sayin. It’ll b way cool though if you pull it off.
We'll see where this rabbit trail takes us ... we are still experimenting and playing with configurations.
Once again I am impressed with your ability to over come obstacles that you encounter as you progress. This is a process that brings answers by doing. My wife and I know that this is a testimony to the strength of your relationship. Don/ MC9
Thank you Don - Michelle and I consider this as being one of the harder problems we are going to need to solve. Thank you for the kind words and encouragement. I would love an update on your MC9 conversion.
Slides are complication you don't need when you can just make a 1x1 inch steel frame to support the panels in the original layout giving you lots of room to skip vents. 1x1 box steel for the vertical and horizontal then 1 inch flat stock to match the curve of the roof (can get a cheap ring roller from Harbor fright for around $80 to make the curved metal easier)
We are going with a foundation based on superstrut on the bottom. We figured this would give us a solid base to build up off of as well as some versatility if we decide to change our minds in the future. The structure you describe certainly sounds strong enough. One of the issues is we only have about 30 ft of space to work with because of the shape of the roof - all the panels butted up end to end is almost 28ft long so skipping the vents (they are longish at about 24" each) would only allow 6 or 7 panels
I've been giving the concept of one or more sliding layers quite a bit of thought. It's fairly easy to push the layer back and forth (for instance a scissor jack like thingy, which has a lot of pulling force from its extended position where you need it to pull the layer back in/up and will provide a way to manage cables/cords). It is also manageable to build the rails for wheels to run in - assuming you prefer the panels to tilt into an angle as they slide out (same principle as a tilting drawer), especially with your curved roof. The main obstacle, however, is the immense pull on brackets and panel frame along the edge of the panel facing inwards. Effectively the panel will act as a lever, so the frame the panel rests in and the opening of the housing for the sliding layer will need to be very, very sturdy. And thus heavy. The only way to fully avoid the weight of the panel being multiplied by leverage, will be to have hinge-like brackets on the side of the bus with rods connecting to the outer side of the sliding panels. This triangular structure can easily manage the weight of the panels, but makes it slightly more complicated to build (and less appealing to look at, unfortunately). The triangle will work best if the panels are close to the side of the bus, which is not what you plan for; but will enable a much more simple and light construction on the roof - something that you can certainly make at home.
Your particular curved roof may not need the complicated outer edge support if you let the panel rest on the roof all the way to the side of the bus and have the house as far as possible towards to the opposite side - the leverage effect will decrease the longer the distance between resting points for the sliding panels. If only half the panel is floating then all of its weight will rest on the outer wheels(those on the frame) - which should be fine. Any extension over the side beyond 50% will increase the weight on the outer wheels and will cause the inner wheels (those on the panel) to provide an upwards force which need to be contained. The closer the wheels get the more sturdy you need to build.
I'll be following tour experiments with even higher interest than usual!
Thanks Claus - excellent observations and suggestions as always. We are still testing and figuring things out - the next video should be more interesting!
Very cool idea for getting all that solar. For attaching the frame for the solar check out rivnuts. It is a little bit expensive but you can put a blind nut into any material. You would be able to put the insulation and inner paneling in and still be able to attach the solar rack.
Thank you Hill on Wheels - we just bought a proper rivnut tool (last time I used an alen wrench, a spacer, and a washer) - but now I actually have the right tool :). We thought about doing it this way and we may still end up doing it this way but we really want to try to get some U-bolts around some of the ribs for a more secure fitment ... we'll see what happens. Thanks for tuning in
I am excited to see the bus painted and I have never done solar before so I have no brilliant ideas for you so I will just keep watching and see what you come up with :)
Thank you Jerry - we are excited too - last news we had is that they were stripping it down to the bare metal to get it ready for the first coat of "heavy primer". The next video should be a little more interesting as we try to make the sliders ...
Interesting. Do consider wind forces. Channel "Life is a Joy" has similiar panels on a skoolie.
Thank you Dennis - We saw what happened to his panels and it was one of the factors that made us decide that we wanted to have less of a "wing" to catch the wind.
That is an interesting problem. What about clearance between the panel and the vent for air movement? Just a thought, and I will try and describe my thought. Mount the panels length wise as you planned, offset them to each side as far as makes sense with the curvature of the roof. one side slightly lower than the other side so when they lay flat and overlap in the center. Hinge the outside edge. put a linear actuator in the center. when you reach a destination push a button on the inside of the bus which would push the centers of the panels up into a "tent" (triangle shape as you look from the front of the bus,) until the two center edges met and there is no overlap? When ready to leave, push the button again and the fold back down. Although one panel is over laped on the other, you still might have more surface area exposed when traveling then ife one pane is stored completely below the other? Do you understand the concept I am trying to describe? Glenn
Hi Glenn - I love the idea you have. A couple of things that tripped me up with it are that we still need to clear those rooftop vents and also be able to clear the black tank vent we just installed. I love the idea of the linear actuator and we are incorporating that into the slides we are building. The part I am having trouble with is how to secure the floating piece (at least I am not clever enough to have come up with a solution I think I could manage).
Maybe send me your phone number by e-mail and we can talk about it? autoshop@rochester.rr.com If you want I could add you to my mailing list (I do not send out cat videos, only things that are of "great" interest).
as always good team work is good engineering too.. you 2 are rocking...!!
Thank you Anura - The next video should be a little more interesting as we attempt to make the sliders. Thanks for tuning in.
Hi Juan. That seems like a complicated build. I don’t know how far along you are but have you considered building up from the side rails of the bus and putting a steel platform all the way across the bus. Not only would everything be even but it would shade the entire top of the bus. If you make them so they can be tilting you would then have access to the entire roof when they are tilted. If they were hinged both in the middle and the outside they could tilt in both directions. Just my thoughts. Alan
Hi Alan, thanks for the feedback. Interesting ideas - we would still need to clear the roof vents (5.5" tall) but the idea could work. I like the idea of the big hinge in the middle to tilt both ways but this might be outside my skill level :)
Juan, I’ve seen you weld. I don’t think you would have any problem with that. Especially if you bought weldable hinges.
What a wonderful approach to this challenge! We love your ingenuity.
Thanks guys! How is your conversion coming along?
Of course! Your model looks great and I get why you're doing it. I like the slide idea and know you can figure out a good way to build it. I know we are planning on using a fair amount of 300# full extension drawer slides on Penny.
She's going way slower than we thought, dreamed, wanted. But we're just now really figuring out why. It's an accountability issue. Other life and living gets in the way and we don't end up going over to the bus lab when we said we wanted to.
Our relatively obvious yet new to us realization is that it's going to take being committed to something/someone other than ourselves. So we are starting to engage with the online community as a source of that accountability partnering. It's not going to be hey let's make a schoolie for us. It's going to have to also include the lifestyle change and investment in the community, because if we make friends, and then those friends help hold us to a declared production schedule, then that's likely our best way of keeping to a build schedule.
Marie and I spent around six hours yesterday in a local coffee shop away from home chores so that we could start a spreadsheet of roughly sequential building video topics as a project map to organize our thoughts and actions around. Sure, it will change and grow as our experience does, but for now we've mapped out 86 videos, and how they fit into themed playlists. We think that's about half the total build, but it's a darn good first wave of planning.
Speaking of planning... I'm planning on finishing video number three tonight and publishing before the sleeps can happen. (also a learning curve)
Thank you both for the efforts you're putting into both your bus and your videos. It is greatly appreciated.
An interesting way to do it...can't wait to see the results!
You would need to be able to disconnect the panels underneath to be able to use the upper ones when the lowers are retracted or while in motion.
As far as the ability to extend/retract them you may wish to investigate using electric seat motors...they have fantastic torque...so should be able to work.
PS> Love picture #2 with the posing...hehehe!
LOL thanks Gregory - We sound really serious on our videos but we are constantly messing around and doing goofy stuff. This is and has been a really challenging problem but it has been fun so far. electric seat motors are an interesting choice - I was leaning more towards a linear actuator. I will have to do a little more reading - thank you!
It is a linear actuator...just one that has an open screw drive...which makes it easier to work with in some ways.
You might have to switch out the original screw drive...it just depends on the rest of the build.
I have even seen them used for homemade "popouts" though they are not very fast.
wow homemade popouts! I will definitely take a look at these - thanks!
Unless your are going to build a Mad Max roof top solar cage and mount system and spend hundreds of hours and thousands of dollars I would just mount the panels sideways and skip over where the roof vents are. I wouldn't worry about clearing them as they still have to open.
Thanks Alex - This was our original plan and it just seemed really risky with so much panel exposed and out in the open for the wind to catch.
You can widen the stance width of the rails running lengthwise on the roof by running some cross beams underneath them. It wont feel like there is so much exposed to the wind if you even went a foot wider.
Now that I think about it. You don't even have to attach to the existing roof lengthwise beams do you? I mean your roof is strong enough to just mount directly through it isn't it?
Have you thought about having portable panels so you can park in the shade? I'm going to have a few on the roof, but some on an extension so I can use shade if available.
Hi - Yes we considered that and watched a few videos of folks who do that. It seems like a very effective way to get more power but it seemed like it could be pretty cumbersome (not that this isn't cumbersome as well). We also worried about damaging the panels or the wiring. Thank you for he suggestion.
I've actually been working on something similar for a vintage '78 GMC motorhome, primarily because the aesthetics of a big flat rack are so poor on a curved roof, same issue you have. The attraction of a GMC, to me, is the styling so I don't want to mess that up. I've been looking for the latest greatest viable panels which to me would appear to be the LG 405w NeON2 panels. These coaches have a factory storage pod on the roof, so a pod of sorts being up there is not unnatural looking. I'm shooting for three stacked with the center panel being static, top pulling to driver's side, bottom pulling to curb or passenger side, these would latch to the factory roof rails for security in wind. Outside would be fiberglassed to mimic the appearance of the stock storage pod with gaskets on the seams for each panel, not to keep water out but stinging insects which are a problem here 9 months out of the year. The GMC is 26 ft total so front to back two panels, three vertically, six total. One benefit of such a rack system will be shading the roof with an air gap, so that will decrease the load on the A/C system or heat pump when parked and deployed. You're bringing your own shade for the roof with you. I'll be watching closely, glad to see someone else embarking on the same or at least a similar path beforehand, you guys are going to save me a few headaches I suspect, so thanks.
Hi Michael - Thanks for following along - sounds like a great project. We considered 3 layers but we did not feel comfortable supporting panels as large as ours solely on the sides. This would be much easier to accomplish with smaller panels. The LG 405w are GREAT panels but they are basically the same size as our SunPower e20 panels which are HUGE. You may have an easier time with a configuration like this: ruclips.net/video/cM5s4F-7AOk/видео.html - I hope you do some videos on your build - It would be neat to see what you come up with! Best of luck!