Sliding Solar Panel Rack Systems by Orion Designs

OrioN

2008 2500 170" EXT
Both of these DIY projects, like many others, used ball bearing drawer slides. Everlanders washed out all the lube from the slides so they would not collect dirt. But they still needed to clean them with a pressure washer regularly. Using Unibearings as Orion is doing should work much better.
Steel ball-bearing sliders were never a consideration for my systems.

Lube them, even with dry lube, and they 'grit up' quickly.
Without lube, even chrome plate will wear off and corrode.
If snow or ice gets in a bearing slider.... get out your blow-dryer.

Mine do not require lube, nor is it recommended that you do. To clean them, just use a garden hose or pressure wash just like you do when you wash the van.
 
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hein

Van Guru
My prediction is that reliability will be the achilles heel of these systems. Thermal expansion, weathering, dirt/debris, twisting/racking, g-forces, lack of lubrication and component wear will be continual problems. I would do some accelerated product testing (500-1000 cycles in an environmental/dust chamber on a shaker table) before releasing this to unsuspecting customers. They are pretty renderings but I see some blatant design mistakes.

All the best,
Hein
DIYvan
541 490 5908
 
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Agreed, statements like "things look wrong" are way more helpful when they are specific. Without understanding the inner mechanism (just looking at the renders on page 1), a couple of things stand out to me. Anytime there is a single screw going through a bracket that could potentially see a moment (especially in plane normal to the screw), it would be better to use two screws instead of 1, to support that moment. The further apart the screws are, the better. Otherwise the bracket is likely to rotate. Surfaces moving relative to each other (even small displacements such as from thermal expansion or vibration) can wear out, bolt loses preload, falls out, etc.
I'd also be interested in the wind force calculations (what the assumptions were), as it just doesn't look very strong in the extended position. I would try to include the fasteners and the roof in a stress analysis to make sure I hadn't accidentally overlooked the weakest link- want to know what fails first if a 300 pound person tried to do a pull up off the end, or if that same force pushes up.

Environmental, dust, shaker testing seems cost prohibitive for a niche product like this, but I agree that the odds of the first untested prototype being acceptable for final use are zero for something like this. The odds improve with group design review, but still better to do some kind of cheap testing. I have solar panels that tilt towards the sun (much simpler than this and for personal use only) and had to ask myself similar questions

Edit: "There are 6 prototype setups roaming around the continent, until recently under an NDA program."
Appears this is already happening..
 
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Midwestdrifter

Engineer In Residence
I would be very curious to see a teardown of a few in-service prototypes. Even the best design will have tweaks or weak areas. Hopefully the OP has done their due diligence. It can be very difficult to predict how the roof will flex when loading the rack, or the as the van drives, hence the testing. I do share some moderate concerns about fasteners loosening, or chafing at the joints due to localized micro movements. I will give the designer the benefit of the doubt based on the limited information at my disposal.

With regards to Hein's lack of detail. His primary income appears to be engineering and selling products relating to conversion vehicles. Providing this type of advice for free on a forum, while other customers are paying good money for it, is generally not good form. Especially when its to another for-profit service provider.
 
I hear ya but this ain't rocket surgery, it takes all of 2 minutes to jot down what looks questionable, not looking for a full report ; ). It's for the good of everyone.
 

Midwestdrifter

Engineer In Residence
I hear ya but this ain't rocket surgery, it takes all of 2 minutes to jot down what looks questionable, not looking for a full report ; ). It's for the good of everyone.
I agree, its easy for the expert to do. But that knowledge and experience is quite expensive to buy or earn. I have been paid significant sums to identify simple problems (sometimes in mere minutes) that eluded those without the requisite years of experience. I have been in the reverse position of paying good money for experts to solve a problem in minutes. I would be a bit miffed If I could have gotten said expert to do it for free on a forum!
 

vanski

'05 Box Snow Camper
i'm sure many of you guys have seen this

wonder how his design has worked out over the long run.. after his little wiring snafu..
 

elemental

Wherever you go, there you are.
I agree, its easy for the expert to do. But that knowledge and experience is quite expensive to buy or earn. I have been paid significant sums to identify simple problems (sometimes in mere minutes) that eluded those without the requisite years of experience. I have been in the reverse position of paying good money for experts to solve a problem in minutes. I would be a bit miffed If I could have gotten said expert to do it for free on a forum!
I give away my knowledge and expertise (in areas where I am skilled) for free when asked to casually comment on something (whether on a forum or not) that I would normally bill $$ for; but I limit my statements to just casual comments and suggestions. It comes without any warranty for fitness of purpose, of course. That warranty, along with a lot more intensive review and analysis of requirements, is what one gets for their $$, and what makes the experience worthwhile for the person who pays the big bucks.

The folks who can afford to pay the big bucks aren't hanging out in forums trolling for design expertise, and the onus is still on the person who receives casual advice in a forum to investigate, determine suitability, and act (if the advice is sound).
 

Zundfolge

1-2-4-5-3
I subscribe to engineering codes and practices of making everything sex-proof. If it survives any imaginable interaction with humans engaging in said act, it's certified.

Furthermore, any warranty or liability is expressed and limited to this sole act of nature.

:smilewink:




.
In my circle of contractors and carpenters we refer to this particular engineering principle as:

SETFO

Y'all can derive meaning from that acronym with just a little of your creative thinking...

;)
 

hein

Van Guru


You can't form aluminum like that. And these brackets support the whole weight of the system. A basic design error like that does not bode well for the rest of the design. That will be $800, please.

All the best,
Hein
DIYvan
541 490 5098
 

OrioN

2008 2500 170" EXT
You can't form aluminum like that. And these brackets support the whole weight of the system. A basic design error like that does not bode well for the rest of the design. That will be $800, please.

All the best,
Hein
DIYvan
541 490 5098
The website renders first and foremost represent the design intent and practical applications and are intended for marketing purpose only. They do not represent the current or final designs verbatim nor 100%, nor are they shop drawings.

Some components have been 'sanitized' for specific reasons, others have undergone the requisite design or engineering upgrades.

For example, after testing, the Uni-legs are now 12mm thick with a 3.0t bend radius. If you look further down the thread at Post #49 you will see a previous & tested prototype using 10mm thick aluminum which always had the requisite 2.5t min. bend radius. Lastly, some parts have undergone design changes to facilitate the fabricators' machining processes. :thumbup:





Ps... I'll can send you $8 for a latte and biscotti for your astute eye and great question.




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Boxster1971

2012 Sprinter 3500 Ext
Those 12mm Uni-legs are certainly strong enough. But they are attached to the roof rails by a single bolt at each corner of the Sliding Solar Panel Rack unit. This could be problematic as pointed out by “markxengineering” in post #64 above. Are your prototypes using the same roof rail attachment scheme?

The Uni-Legs also appear to be attached to the T-Slot rails by screws into tapped aluminum holes at ends of the T-Slot rails as marked in attached image. In the renderings they look like stainless steel machine screws. Are those SS screws into threaded aluminum attachments going to be strong enough to deal with the vibrations and loads? Or is there some other attachment mechanism not revealed in the renderings?
 

Attachments

OrioN

2008 2500 170" EXT
Those 12mm Uni-legs are certainly strong enough. But they are attached to the roof rails by a single bolt at each corner of the Sliding Solar Panel Rack unit. This could be problematic as pointed out by “markxengineering” in post #64 above. Are your prototypes using the same roof rail attachment scheme?

The Uni-Legs also appear to be attached to the T-Slot rails by screws into tapped aluminum holes at ends of the T-Slot rails as marked in attached image. In the renderings they look like stainless steel machine screws. Are those SS screws into threaded aluminum attachments going to be strong enough to deal with the vibrations and loads? Or is there some other attachment mechanism not revealed in the renderings?
5/16"x18 screws are a min. 0.75" deep with supplied Loctite Blue 242.... None have loosened yet. :thumbup:
 

marklg

Well-known member
5/16"x18 screws are a min. 0.75" deep with supplied Loctite Blue 242.... None have loosened yet. :thumbup:
You might consider Loctite 243. It has higher oil resistance and works better on surfaces such as stainless steel and aluminum, not needing an activator. I switched a few years ago and have had good results.

Regards,

Mark
 

Boxster1971

2012 Sprinter 3500 Ext
Thinking that using bifacial solar panels with this type of Solar Panel Rack System might offer several advantages. When the lower panel is extended it would provide additional power as it would have more light reaching the back side. Also the semi transparent design of bifacial solar panels would allow some light to pass through the upper panels and reach the lower panel when retracted. Thoughts?
 

OrioN

2008 2500 170" EXT
Thinking that using bifacial solar panels with this type of Solar Panel Rack System might offer several advantages. When the lower panel is extended it would provide additional power as it would have more light reaching the back side. Also the semi transparent design of bifacial solar panels would allow some light to pass through the upper panels and reach the lower panel when retracted. Thoughts?
Interesting....

...bifacials will certainly increase harvesting, and as by the methods you described. The only caveat is that dual controllers are required now, one for each array, and wired in parallel between arrays and battery bank, as each array, especially in the retracted position, will exhibit different output voltages. These different voltages will negate any advantages no matter how you wire it into a single controller.

Non-bifacials panels used in both upper and lower arrays can be wired into one controller and in any series/parallel manner. It is recommend or required really, that the lower arrays input be switched off when retracted, regardless of how they are wired up.




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GeorgeRa

2013 Sprinter DIY 144WB
I think back sides harvests reflected not transmitted light. So, uniformity of back side illumination could be problematic because panels are very close to each other so only edges would be illuminated. The key question would be what is the predicted gain, and I don’t know.

added:

"Bifacial PV modules can produce additional output energy in comparison to conventional mono-facial modules because both sides of the cell/module, front and rear, can absorb solar radiation, utilizing the scattered light from the ground and surroundings." https://www.sciencedirect.com/science/article/pii/S0038092X18311514
 
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Boxster1971

2012 Sprinter 3500 Ext
Interesting....

...bifacials will certainly increase harvesting, and as by the methods you described. The only caveat is that dual controllers are required now, one for each array, and wired in parallel between arrays and battery bank, as each array, especially in the retracted position, will exhibit different output voltages. These different voltages will negate any advantages no matter how you wire it into a single controller.

Non-bifacials panels used in both upper and lower arrays can be wired into one controller and in any series/parallel manner. It is recommend or required really, that the lower arrays input be switched off when retracted, regardless of how they are wired up.
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Are you saying one would need separate controllers for bifacial panels to handle the voltage difference from retracted panels? I thought wiring panels in parallel to a single controller could handle the voltage difference from a shaded panel. If parallel wiring won't handle the voltage difference I can understand why normal lower panels must be shut off when retracted. Including a shut-off switch for the lower panels will complicate the installation a bit.

I was thinking of a four panel system with each layer of two panels in series and then the series pairs paralleled to the controller. Think I might need to get smarter on solar installations.
 

HarryN

Well-known member
Are you saying one would need separate controllers for bifacial panels to handle the voltage difference from retracted panels? I thought wiring panels in parallel to a single controller could handle the voltage difference from a shaded panel. If parallel wiring won't handle the voltage difference I can understand why normal lower panels must be shut off when retracted. Including a shut-off switch for the lower panels will complicate the installation a bit.

I was thinking of a four panel system with each layer of two panels in series and then the series pairs paralleled to the controller. Think I might need to get smarter on solar installations.
Two controllers is a small price to pay for extended vs non extended operation.

I just did a project with 3 controllers to optimize a customer's special requests / ideas.

Nice to see the project moving along.
 

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