Slide out solar panels

calbiker

Well-known member
Exactly! What's the risk to reward ratio? What's the effort to build it to reward ratio?

The whole thing looks like a big lever arm. How much wind can it handle?

Of course the first step is to determine if two panels are required for your application. Do you need that much solar?
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Here's a relatively simple design for slide-out panels which I mocked up using 1" t-slot extrusion and the matching double-keyed bearing pad. Since the bearing pad is UHMW plastic, there are fewer moving parts than a standard extension slide. The bearing pad is 50% of the panel width, which should provide enough stability for the panel. This allows 4x full size (300W+) panels on the roof with room at the rear for a fan and/or air conditioner. When retracted for travel, 2 of the 4 panels are still usable for battery charging.

It may be possible to use single-keyed bearing pad directly attached to the solar panel, rather than the doubled t-slot I used here, depending on the rigidity of the solar panel frame. This design still needs a locking mechanism to ensure the panels stay retracted while driving. The aluminum blocks between extrusions need some work to refine their design too.

Like HarryN says above, this is something which needs some additional prototype work before trying to install it on a van.

Retracted Panels render
Great work! With 50% extension 1” 8020 should work because it would be attached to the solar panel frame so it is the strenght of both. As an example, see how I attached my 35” projection screen and the projector at the ceiling using 1” 8020 with https://8020.net/shop/6710.html. Regarding the strength of the 15-series glide could be better.
 

Attachments

dttocs

Member
Of course the first step is to determine if two panels are required for your application. Do you need that much solar?
That is always the question. I'm looking into whether it is feasible to run an air conditioner from batteries/solar panels without the need for a generator when it's warm/humid overnight. This may end up requiring a crazy amount of battery capacity and solar, but it's interesting to explore.

Judging from my application, I do not think 1" 80/20 is rigid enough to be used for solar panels. 1 1/2" series 15 might work.

There are different extrusions designs used for solar panel frames. Select a tubular frame instead of a channel frame to get additional rigidity in the panel.
I used standard 1010 t-slot in the diagram, but it could be made more rigid using 10-series monoslot, which is more rigid (Moment of inertia 0.057 in^4 vs. 0.046 in^4). Typical solar panel support designs do not have any additional support beyond the panel frame itself in at least one dimension (example), so I'd expect that the t-slot bolted directly to the panel frame extrusion should be sufficient. That said, I plan to do some modelling and look at whether the 30" of UHMW PE is sufficiently strong before actually building anything - I think that's the weakest point of the design.

Using a mix of 10-series and 15-series could simplify the design - replace the fixed 80/20 beams with 15-series, and there's no need for the spacer pads. Some machining of the 6812 bearing would be needed to fit the 10-series on the one side though.

The whole thing looks like a big lever arm. How much wind can it handle?
At a guess, a lot more wind than your average awning, given the structure and support. And the panels can be slid in and locked the same way you do with your awning in high winds.

Great work! With 50% extension 1” 8020 should work because it would be attached to the solar panel frame so it is the strenght of both. As an example, see how I attached my 35” projection screen and the projector at the ceiling using 1” 8020 with https://8020.net/shop/6710.html. Regarding the strength of the 15-series glide could be better.
Thanks George. It's unfortunate there isn't a double-sided version of the 6710 - that would be ideal for this application. (Yes, it's possible to make one, but is it worth it?)
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
........
Thanks George. It's unfortunate there isn't a double-sided version of the 6710 - that would be ideal for this application. (Yes, it's possible to make one, but is it worth it?)
Indeed, I searched for it on Bosch and Misumi site but didn’t find a double-sided slider.
https://us.misumi-ec.com/vona2/detail/110301962560/?Inch=0
https://www.boschrexroth.com/en/us/...motion-technology/linear-motion-systems/index
A double-sided profile could be done on a CNC machine, it could require a flip but registration wouldn’t be critical.

George.
 

Eka

New member
google "Heavy Duty Stainless Steel Over Extension drawer slides". They should be able to easily be found up to around 32". I've seen steel ones longer.

I checked my design, could add 300W (total 600W) but would need to lift the panels above the awning. If I would do conversion over again, which is not in my plans, I would forgo awning. Sliding panels to both sides would also serve a second function of keeping the van cool by blocking a lot of IR.

Doubling solar harvesting has value for camper vans with limited roof real estates.

George.
Interesting idea. It would be very important to have a "remove before departure" tag/notice etc on the steering wheel. It would be VERY easy to drive off with the panels deployed. The results of which would be not pretty.
Here's a relatively simple design for slide-out panels which I mocked up using 1" t-slot extrusion and the matching double-keyed bearing pad (80/20 6702). Since the bearing pad is UHMW plastic, there are fewer moving parts than a standard extension slide. The bearing pad is 50% of the panel width, which should provide enough stability for the panel. This allows 4x full size (300W+) panels on the roof with room at the rear for a fan and/or air conditioner. When retracted for travel, 2 of the 4 panels are still usable for battery charging.

It may be possible to use single-keyed bearing pad directly attached to the solar panel, rather than the doubled t-slot I used here, depending on the rigidity of the solar panel frame. This design still needs a locking mechanism to ensure the panels stay retracted while driving. The aluminum blocks between extrusions need some work to refine their design too.

Like HarryN says above, this is something which needs some additional prototype work before trying to install it on a van.

Design details


Extended panels render


Retracted Panels render
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
I am not sure open roller bearing sliders would work, too much dirt could make them stuck.

George.
 

OffroadHamster

Well-known member
Indeed, I searched for it on Bosch and Misumi site but didn’t find a double-sided slider.
https://us.misumi-ec.com/vona2/detail/110301962560/?Inch=0
https://www.boschrexroth.com/en/us/...motion-technology/linear-motion-systems/index
A double-sided profile could be done on a CNC machine, it could require a flip but registration wouldn’t be critical.

George.
You can make something similar to a double sided 6710. I have some double sliding doors on an enclosure for an automated assembly fixture. Everything pictured is delrin except the spring washers and nut. Not pictured is a short piece of threaded rod trimmed to length. Set them so the spring washer on each side is half way to flat and you can assemble them together and everything slides nicely. I use green loctite to prevent anything from moving (ever). I double the length of the slides and double the hardware on horizontal sliding doors (where door is parallel to the ground versus perpendicular)






This was an early version. Subsequent versions have a standoff on the piece that slides internally to the 8020. Ill try to dig up a file.
 

OffroadHamster

Well-known member
Here is what I use these days. The internal pieces dont cock and the center can spin without repercussion (and it does). You could make the standoff longer and notch the center carrier and use a low SHCS on one side to effectively make a set it and forget it double sided 6710 without needing any CNC time.



note: Pocket for the nut has radiused corners (not modeled)

I make these out of acetal rather than uhmw of the 6710 because it is too gummy to work with. The acetal machines much better.
 
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HarryN

Well-known member
That is always the question. I'm looking into whether it is feasible to run an air conditioner from batteries/solar panels without the need for a generator when it's warm/humid overnight. This may end up requiring a crazy amount of battery capacity and solar, but it's interesting to explore
Some aspects of that are not too bad, some are more difficult. I have spent a lot of time on this challenge.

It takes around 1 kW on average to run air conditioning and the other misc items that go along with a van. Essentially you need to somehow generate 24 kW-hrs per day, which is pretty tough to do with solar alone on a sprinter size vehicle.

Potentially a better option is something like 4 - 8 hours of battery capacity and an auto engine re-start that uses a healthy alternator to re-charge the pack. Even 30 minutes of fast idle can do a lot of bulk charging to keep things going.

Solar can be used to supplement charging and a/c operation as available to reduce engine run time. The most solar I have seen so far on a class A is around 2 kW, not saying that is the most that is possible, but it gives you some perspective.

In theory I suppose you could make sort of a solar panel tent that shades both the top and sides of the van. Put the extra panels in a small trailer and set them up when you arrive.
 
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ToyQuest

Member
I've been working on a system to mount 960W (6 - 160W Grape Solar panels) for way too long. :idunno:

The design / implementation is similar to concepts discussed in this thread

Key points:
- The van is a 2016 170 Cargo with only a rear maxair fan to worry with
- All 6 panels are mount length-wise with the van
- The 4 top most panels are statically mounted
- The 2 lower panels are in pull out "drawers" deployed from the driver side
- A drawer wire management system is designed in
- The solar panel are configured with 3 parallel strings with 2 panels in series in each string. The panels feed a Victron Energy BlueSolar MPPT 150/70-Tr charger. All downstream components are all Victron Energy

Here is breakdown:

15 series rails are mounted on custom 316 stainless brackets. The rails slightly overhang on the driver side due to the Fiamma F65 S400 Awning on the passenger side. Rails are 52" long to accommodate the 26" wide panels


Drawer frames are built out of aluminum angle (2" x 1.5" x 1/4") mounted up to 80/20 linear bearing pads referenced in this thread. All framing is TIG welded. Here is the end profile mounted up to the 15 series rails


Drawer cable management is via cable drag chain:


There are a number of custom machined mounting plates. 9 for mounting the statically mounted solar panels. 3 load plate for the drawers. 4 linear bearing pads are equally spaced out on each drawer rail mounted up with 2 #10 screws on each pad.


The drawers are held in position with spring latch pins on each back corner:


A simple rope system is used to release the latch pins. The rope pull is on the outside edge of each drawer.


Here is the front drawer mounted up without the solar panels:


Here are the panel / MPPT calcs for those interested:


Current Status:
- Everything has been built and test fitted together
- Still need to mount the combiner box / poke a hole through the roof / complete the parallel-series wiring
- Currently building out the interior so there is no rush on finishing up the solar

I sure hope the 2 extra panels are worth it. The drawers definitely make the build much more involved than statically mounted panels.

Eddie
 

Mponton

New member
I've been working on a system to mount 960W (6 - 160W Grape Solar panels) for way too long. :idunno:

The design / implementation is similar to concepts discussed in this thread

Key points:
- The van is a 2016 170 Cargo with only a rear maxair fan to worry with
- All 6 panels are mount length-wise with the van
- The 4 top most panels are statically mounted
- The 2 lower panels are in pull out "drawers" deployed from the driver side
- A drawer wire management system is designed in
- The solar panel are configured with 3 parallel strings with 2 panels in series in each string. The panels feed a Victron Energy BlueSolar MPPT 150/70-Tr charger. All downstream components are all Victron Energy

Here is breakdown:

15 series rails are mounted on custom 316 stainless brackets. The rails slightly overhang on the driver side due to the Fiamma F65 S400 Awning on the passenger side. Rails are 52" long to accommodate the 26" wide panels


Drawer frames are built out of aluminum angle (2" x 1.5" x 1/4") mounted up to 80/20 linear bearing pads referenced in this thread. All framing is TIG welded. Here is the end profile mounted up to the 15 series rails


Drawer cable management is via cable drag chain:


There are a number of custom machined mounting plates. 9 for mounting the statically mounted solar panels. 3 load plate for the drawers. 4 linear bearing pads are equally spaced out on each drawer rail mounted up with 2 #10 screws on each pad.


The drawers are held in position with spring latch pins on each back corner:


A simple rope system is used to release the latch pins. The rope pull is on the outside edge of each drawer.


Here is the front drawer mounted up without the solar panels:


Here are the panel / MPPT calcs for those interested:


Current Status:
- Everything has been built and test fitted together
- Still need to mount the combiner box / poke a hole through the roof / complete the parallel-series wiring
- Currently building out the interior so there is no rush on finishing up the solar

I sure hope the 2 extra panels are worth it. The drawers definitely make the build much more involved than statically mounted panels.

Eddie
This gives me plenty of ideas. Thank you very much.

It's basically what I'm wanting to do but I'll be building a "patio" versus the extra four panels that you'll have.

Quick question on your drawers. How far does the panel slide? What's your overall travel, hangover the side distance, and what's the weight of three panel and each mount?

Sent from my Nexus 5X using Tapatalk
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Very nice work, I assume Fiamma awning is preventing the slide out on the passenger side. Instead a push pin latching could you make a rotating plate mounted on the stationary panel to prevent slider out?

George.
 

Eka

New member
I am not sure open roller bearing sliders would work, too much dirt could make them stuck.

George.
It's easy to position some rubber flap moldings to keep the dirt away. when stowed, and shed the rain properly when extended. Guide blocks can be used to get the molding to move into the right place when retracting. It does add complexity to the joint. With 80/20 you can clamp a plate of aluminum on top, and use it to hold the attached edge of the molding. The hard part is sorting through all the moldings out there to find the ones that will work.

As far as using the short tongue going into the slot, that will also have problems.The crossbar structures are only tied together by the flexibility of the van under them. As mentioned by others, the tongue would need to mushroom out inside of the 8020 extrusion slot so it can resist pulling out then falling when it gets pulled at a bad angle, or wind buffets it right on the highway. I'd make that slider piece out of derlin or nylon and t-nut bolt it to the side of an extrusion that then supports the panel. The sides of most solar panels are as weak as possible, and still be able to survive storms bolted to a rigid frame on the roof. Both nylon and derlin could be machined from solid blocks using regular carpentry or metal machining tools. Radius every inside corner to distribute stresses better. Thinking some more on that mushroom head, you could use a carriage bolt head as the retainer that keeps it from pulling out of the slot. It just needs to slide into the slot from the end. Those unibearing bearing blocks were made to be used when clamping a single extrusion from 3 sides. In that situation the tongue can be very short.

BTW, just a single square extrusion will be plenty strong for the application. I'd use 80/20's 25 series for the cross bar. Then I'd find a fully threaded carriage bolt head that will just barely fit into the slot. I'd then drill and tap the core of the other side of the slide to accept the carriage bolts. For the slots in 25 series I expect the bolt would need 20mm of length from head underside to the end of the bolt. That is so it doesn't stick out. It may still go into the opposite slot enough sliding in a t-nut can't be done. The reason for threading is tightening nuts down in that slot is insane hard and due to the diagonal walls it may be impossible. When the right depth is figured out it would be possible to partially back the bolt out, then treat the newly exposed threads on the carriage bolt with a thread locking compound, then screw it back in. Count the revolutions as you partially back it out, and then turn it back in the same number when restoring it's position. You might want, make a jig to check and set the depth. I'd use at least one every 6 inches or less.

Thinking about that design, it could be made to extend fully. Take a look at the half wide extrusions with only one side having slots. 25-5013 is an example. Have the bottom track slide on a crossbar track, and the top one on the panel. Between them full extension is possible. The smooth side of the 25-5013 also provides a nice face to the world.
 

Midwestdrifter

Engineer In Residence
Stainless roller slides with no grease and a dust flap would likely be okay. A regular clean out with a pressure washer may be needed.

Only dry film lubes can be used. Any grease or oil will invariably become a dirt and debris magnet.
 

ToyQuest

Member
This gives me plenty of ideas. Thank you very much.

It's basically what I'm wanting to do but I'll be building a "patio" versus the extra four panels that you'll have.

Quick question on your drawers. How far does the panel slide? What's your overall travel, hangover the side distance, and what's the weight of three panel and each mount?

Sent from my Nexus 5X using Tapatalk
The drawer extends 30", 4" more than the panel width. This should allow for some shadowing of the static mounted top panels without negative impact to the lower panels

The weights are as follows:
- Per GS 160 panel - 26.4 lbs
- Per drawer framing - 11.8 lbs (per Fusion360 CAD)
- Total per drawer weight - 38.2 lbs
 

ToyQuest

Member
Very nice work, I assume Fiamma awning is preventing the slide out on the passenger side. Instead a push pin latching could you make a rotating plate mounted on the stationary panel to prevent slider out?

George.
Correct - the awning prevents the slide out on the passenger side

I could of absolutely used a rotating plate from the static upper panel to lock the panel in the retracted position.

I went with the pin latch to give me a positive position lock in both the deployed and retracted positions. The rail is notched for the pin latch engagement in both positions
 

Mponton

New member
Sorry for the lack of response for a bit. Wife and I were hiking Utah and Arizona followed up by a trip to Vegas with friends.

I measured everything out and will try to get another diagram together. The Vantech Cross bars I have now are 65"x3"x1.5". I'm thinking about building the rack in line with the existing bars to save on some pieces and give it a better more streamline look. I decided to also use the 15 series to increase strength and cost will be similar to the 10 series after I remove the three larger cross bars. Having the Aluminum plate on top will provide any extra strength required so it'll all be strong enough and of course having brackets on the bottom. What I did measure out though is overall dimensions.

From the center of the front brace to the rear is 102" separated into the front section being 46" and the rear being 56". I plan on having 15" of overhang on the rear from center of cross bar to the rear corner of the van. I also plan on putting an angled piece on the front to direct air/bugs/rocks/etc. above the solar and roof rack. So I will also have 13" of overhang in front of the front crossbar. This will give me 130" x 65" overall space on top. Using the 15 series we should be able to use the 15 series sliders and have the two solar panels slide off the rear and have approximately 18-20" of 15 series as the section still on top. I will also have the two other panels stacked and slide out on each side same as discussed before.

After looking at everything regardless if using the 15 series slides or whatnot is what I go with or if I go with super long extensions with covers. I'll also do these panels as two sets of two. I really want to use the panels as awnings, regardless of the engineering involved. I want to have each side slide out and provide three sides of shade and the roof will have the air gap with the rack to provide a heat barrier for the roof.

Couple quick questions. By using that extruded material (previously shown) from 8020.net on the side and the top of each slide out will the be enough support to allow the frames to slide out 48" with a 17" section still in the sliders. If not I'll have to figure that out. Another idea for the side panels is to be on a swivel. With this setup the panels would be stowed front to rear under the rear section of the rack and then swivel out to each side. Would provide a very easy and clean mounting and deploying option. Last but not least...... flat plate with non-skid stickers or diamond plate aluminum so we actually have some traction up top?
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
……………………………will the be enough support to allow the frames to slide out 48" with a 17" section still in the sliders. If not I'll have to figure that out. Another idea for the side panels is to be on a swivel. With this setup the panels would be stowed front to rear under the rear section of the rack and then swivel out to each side. Would provide a very easy and clean mounting and deploying option. Last but not least...... flat plate with non-skid stickers or diamond plate aluminum so we actually have some traction up top?
So, 48” hanging on 17” long slider during erected state only, maybe, perhaps calling 8020 could help. I called them a few times. Rotation on corner could be heavy. Looking forward to see some pictures.

George.
 

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