My Portable Solar Tracker (single-axis)

Discussion in 'Power - Site Power/Batteries/Generators/Solar' started by Dubbya, Apr 27, 2015.

  1. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    I've been trying to convince the DW to try dry camping but she's not too keen on "roughing it" any more than we already do, so anything I can do to make sure we've got a few 12v amenities is well worth the effort. Given that we only have space for one Group 31 battery, whatever I did would have to be reliable and efficient. So much the better if one the solution doesn't cost a ton and it's easy to use.

    I'm a "set-it-and-forget-it" sort, so if we're going to use 12 volt power, we'd need a way to recharge the battery and I wanted to take the guesswork out of positioning a solar panel to maximize it's power generating capabilities throughout the day.

    I wanted something that was portable, easy to set up and store and that took most of the guesswork out of using a solar panel. I needed something that was reasonably weather resistant and that didn't require much more intervention than picking a sunny spot, positioning the panel so it faced south and plugging it into a charge controller.

    There are simpler ways to control the direction of the motor but I opted for ease of installation and convenience in choosing the LED-based tracker controller. They come in many different shapes and sizes, each with different options but you can pick these up on eBay for between $20-$54US.

    Mine cost $19.99US + $10 shipping from China and it arrived at my door in about 2 weeks. In the end, mine came with an enclosure roughly the size of an average round snow globe though it'll definitely need some work to make sure it's weatherproof.

    Along the way, I though I'd share my progress in the construction, assembly and testing of a portable solar panel mount with built-in solar tracker.

    Materials:
    • Qty: 2 - 24" x 24"x1/2" G1S plywood
    • Qty: 1 - 2" ABS Shower drain
    • Qty: 1 - 2" x 30" ABS pipe
    • Qty: 1 - 2" ABS pipe cap
    • Qty: 1 - 4" round junction box cover plate
    • Qty: 2 - 10 tooth plastic derailleur sprockets
    • Qty: 1 - 44 tooth x 1/8" chain ring (sprocket)
    • Qty: 1 - 1/2" x 1/8" 112 link bicycle chain
    • Qty: 1 - 4" lazy susan bearing
    • Qty: 2 - 22mm skateboard bearings
    • Qty: 1 - 2" circles cut from 1/2" thick nylon cutting board
    • Qty: 1 - 9.6v cordless drill with battery pack
    • Qty: 1 - Single Axis Solar Tracker Controller unit (6-24v, 4Amp)
    • Qty: 1 - 12v on/off toggle switch
    • Qty: 3 - Top-Mount Deck hinge
    • Qty: 3 - 1/4" x 1" Pull pin (detent pin/cotterless pin)
    • Qty: 2 - 1/4" x 1" Clevis pin (adjustable)
    • Qty: 2 - small hitch pin clip
    • Qty: 1 - 1" x 4" x 1/8" fabricated steel chain tensioner bracket and spring
    • Qty: 4 - 1/2" solid rubber caster (non-swivel)
    • QtY: 1 - 12" x 5/16" Allthread (ready rod)
    • Qty: 2 - 5/16" (fits 7/16" socket) joiner nuts (for spacing bearings and as drive nut for drive sprocket assy.)
    • Qty: 1 - 1/2" x 2-1/2" spring (for chain tensioner)
    • Qty: 1 - 5/8" x 3/4" nylon bushing(for chain tensioner)
    • Qty: 2ea - 1/4" Tee nuts and 3/16" Tee nuts (for mounting top mount hinges)
    • Qty: 2ea - 1/4" x 1/2" stove bolts, 3/16" x 1/2" stove bolts (for mounting top mount hinges)
    • Qty: 1 - 1/4" socket drive adapter
    • Qty: 1 - 7/16" x 1/4" drive deep socket
    • Miscelaneous 10/12 gauge automotive wire and connectors.
    • Miscellaneous screws, nuts, bolts and washers
    • Qty: 1 Quart - Killz Premium exterior primer
    • Qty: 3 - Spray cans Duplicolor spray-in bedliner


    [​IMG]

    This is the 24" x 24" x 1/2" G1S plywood base of the portable solar tracker. The corners were rounded using a 2" radius and 1-1/4" x 4-1/2" handholds were cut out to facilitate carrying the apparatus. The base has been primed with Killz Premium exterior primerA 4" lazy Susan bearing and 44 tooth chain ring (bike sprocket) are attached to 5" x 5" x 3/4" plywood centered in the middle of the board.

    The dark circle surrounding the sprocket is the result of the caster wheels (attached to the underside of the top deck @ 16" o/c) rubbing as the top deck rotated during testing.

    [​IMG]

    The base and assembled top deck with drive sprocket assembly, casters and chain tensioner mounting post which has since been repositioned closer to the edge (top edge in photograph) to support the slack side of the chain and to make the tension spring more effective.

    Note the Tee-nuts installed on the underside of the top deck on the right side of the photo. These are the mounting points for the top-mount deck hinges which have had one mounting tab (with 1/4" bolt hole) removed so that they can be mounted as near to the edge of the deck as possible. Additional 3/16" holes were drilled and countersunk in the centers of the top mount hinges.

    [​IMG]

    The drive post consists of a 2" ABS pipe section cut to approximately 24" long. A 9.6v cordless drill motor, clutch assembly and 3/8" chuck has been placed inside the pipe (to be secured later).

    Note that the handle of the drill and battery charge display have been inserted into the side of the pipe and secured in place using Marine Goop UV resistant urethane sealant. This will be the rear side of the drive post.

    On the opposite side, another 1/4" top-mount deck hinge has been screwed in place. This will be the top mounting point for the solar panel.

    2 wire x 10 gauge double-insulated wires run from the battery and motor out through the top of the post. Both will later connect to the Solar Tracker control unit.

    [​IMG]

    A 1/4" socket drive adapter was locked firmly in place in the drill chuck and a 7/16" deep socket placed on the end of the drive adapter.

    "C-shaped" bands of 2" ABS pipe, 1-1/2" pipe were glued together with Marine Goop and a 1/8" thick piece of rubber mat was placed inside them. These layers slid over the drill motor (cut and placed so as not to obstruct airflow of the motor) prior to inserting the assembly inside the 2" pipe so that the motor could later be removed/replaced if necessary.

    Note that the open end of the deep socket is recessed approximately 1/8" from the end of the 2" pipe so that it will later slide as far down onto the sprocket drive nut as possible.

    [​IMG]

    The drive sprocket assembly with 10 tooth derailleur sprocket mounted to 5/16" Allthread (ready rod) drive shaft.

    Skateboard bearings were inserted in 2" x 1/2" think nylon cutting board circles with a joiner nut and washers placed between the nylon circles.

    This was then mounted to the junction box cover plate using #10 - 24 bolts, washers and nuts. A second joiner nut is placed at the opposite end of the drive shaft which is where the 7/16" deep socket connects to.

    [​IMG]

    Here you see the nylon cutting board cicles with the skateboard bearings, the joiner nut and washers separating

    them and the mounting bolts which secure the assembly to the mounting (junction) plate. Note that the 5/16" Allthread (ready rod) has been trimmed to allow the drive socket to rest as far down on the drive nut as possible.

    [​IMG]

    The drive assembly was test fit through the underside of the top deck through a 2" hole. Note the chain tensioner in position a few inches behind the drive sprocket. The mounting post for the tensioner was later relocated toward the left edge of the top deck in order to support the chain, to make the tension spring more effective and to make positioning the tension spring easier.

    [​IMG]

    This is the top view of the drive sprocket assembly inside the 2" shower drain fitting. Note that the 5/16" drive shaft and #10 screws which hold the assembly together have been trimmed. You can see the top of the skateboard bearing which was partially recessed in the nylon using a 7/8" spade bit, shaved down to 22mm.

    A 5/8" spade bit was then used to finish drilling through the nylon so that the drive shaft could spin freely. The same process was used for the bottom bearing.

    NOTE:
    It's important to note that all holes drilled in the drive sprocket assembly were drilled using a drill press in order to help maintain balance and alignment in the assembly.

    [​IMG]

    The end of the 2" ABS drive post has been sanded and polished so that it more easily inserts fully into the 2" ABS shower drain fitting. 1/4" holes were drilled through the sides of the fitting and the inserted drive post. Hitch (pull) pins attached to lanyards which are mounted to the underside of the deck are inserted through the holes to keep the post in place.

    Using an awl, alignment marks were made in the top edge of the shower fitting and in the drive post directly above it.

    [​IMG]

    The 10 gauge power leads run through a 2" pipe cap into the base of the controller enclosure where they're connected to the controller's power connection.

    On the right of the power post, the leads for the motor are reversed so that when power is supplied, the motor turns backward to rotate the top deck properly. The leads from the battery connect on the left.

    The enclosure base is screwed to the pipe cap, then the controller's logic board is mounted to the enclosure base.

    The wires are pushed inside the drive post, the cap is placed on the pipe end and screwed in place on either side of the cap.

    Note that very little adjustment of the clear LED's is required since, even with the clear enclosure cover in place, they're very sensitive to sunlight. Behind the LED's is the heatsink. Though it will accommodate up to 24 volts, this unit limits power output to 4 amps, more than enough to turn the 9.6v drill motor.

    [​IMG]

    The fully assembled 2" ABS drive post with solar tracking controller enclosure, top-mount deck hinge, 9.6v battery and top deck.

    Here's a video of the cursory test after initial assembly:
    https://youtu.be/qd3gPZm1Fxw

    I later adjusted the LED's so that the top deck would center perfectly with the sun then set the unit out on the deck behind the house and let it do its' thing for the afternoon. I have to admit that there was some pretty satisfactory giggling from yours truly when the controller would automatically reposition accordingly every 3-6 minutes. Just a quick little adjustment and that's it... sweet! [:D]

    At this point, there's little left to do but paint, reassemble and mount the solar panel. It's all ready to go and the DW will be out of town, so I'm hoping to have everything done by the end of this coming weekend.

    Left to do:
    • Install weatherproof 12v On/Off Rocker switch
    • Finish painting
    • Reassembly
    • Weatherproof controller enclosure
    • Testing

    I've already disassembled everything for painting but will continue to update with more photos as things progress.

    If you have any questions or would like to see an additional photo to help explain something better, please let me know and I'll see what I can do to help.
     
  2. ~erik~

    ~erik~ Active Member

    289
    40
    Jan 19, 2015
    North Georgia
    Very nice. I'll have to re-read and ponder your description a few more times, but it looks really nifty.

    Thanks for sharing.

    I was going to do something similar using our cat, as she moves around as needed to stay in the sun, but my wife shot down that idea. Just kiddin!

    Great work!
     
  3. Touring Kiwi

    Touring Kiwi New Member

    27
    0
    Apr 23, 2015
    Great work, thanks for sharing.
    The speed of response is much greater than I imagined, how are you securing the panel?
     
  4. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    my wife said I should post a video with one of our cats laying on the top deck and call a portable automatic sun chaser for cats. It'd go viral in a couple of minutes! [LOL]
     
  5. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    I was looking for a 54 or 58 tooth chain ring but wasn't able to find one for under $20. I'll keep looking for one though. It's just a matter of time before I can find one at the thrift store or at a garage sale.

    I'm using 1/4" eye bolts with nylon bushings clamped inside the eyes. The bushings have 5/16" holes in them that I can insert the clevis pins through. The eye bolts slide into the top mount deck hinges, two on the top deck for the bottom of the solar panel frame and one on the drive post with another eye bolt on the top edge of the solar panel frame.
     
  6. BrianRosenthal

    BrianRosenthal Member

    55
    3
    Feb 23, 2011
    You do nice work!

    I'll point out that chain rings get rare over 52 teeth. I think I've had a 54 on a tandem.
     
  7. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    Thanks, Brian! I've seen 48 pretty often but yeah, 52 would slow things down a bit more. So far, a 3/32" chain sprocket has been hard to find but only because I work during the day and because I don't want to spend money on one. Once I quit looking, I'm sure I'll be tripping over them! [;)]
     
  8. R00

    R00 New Member

    1,301
    6
    Aug 10, 2014
    Streamline the process, source parts at a wholesale discount, and you've got a profitable business.
     
  9. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    As requested, here are the eye bolts mounted to the bottom of the solar panel frame.

    Clevis pins with washers and hitch clips secure the eye bolts to the top-mount deck mounts on the front edge of the top deck. Though hard to see here, nylon bushings (partially hidden behind the washers) were inserted inside the lot eyes then pinched in place by closing up the eyes. Since the bushings already have 1/4" holes in them, the clevis pins fit snugly.

    [​IMG]

    The third mounting point is located on the drive post with the corresponding eye bolt mounted to the top of the solar panel frame. A removable pull pin with attached lanyard will secure the eye bolt in place giving the solar panel 45 degrees of tilt.
     
  10. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    If I had a nickel for every time I've heard that... I still couldn't make a collect call from a pay phone! [LOL]
     
  11. inthedirt

    inthedirt Active Member

    839
    65
    Aug 28, 2012
    SW Montana
    this has me thinking.......
     
  12. Mr Zip

    Mr Zip Member

    519
    1
    Jan 2, 2009
    North Ridgeville Ohio
    Outstanding!!
     
  13. drosengrant

    drosengrant One Day at a Time

    1,193
    9
    Jun 14, 2008
    Mine Hill NJ
    Cool. Do you have a picture of the whole thing setup with panel?
     
  14. ~erik~

    ~erik~ Active Member

    289
    40
    Jan 19, 2015
    North Georgia
    Based on the dimensions of the base and height of the pole the solar panel must be about 2 feet square, or about a 50 watt panel? That answers a concern I had - too large a panel such that a gust of wind would knock the whole assembly down.... I guess the solar tracker could be scaled up to accommodate a larger panel, but would then need a larger or heavier base. Or one that's clamped to the camper in such a way that the solar panel can still swing to face the sun...
     
  15. shelmily

    shelmily Well-Known Member

    3,005
    87
    Jun 7, 2012
    Northeast Pennsylvania
    Another great invention from Dubbya. Can't wait to see the whole thing finished up. I have thought about doing something similar, but nothing ever came of it. I would have to go bigger though, as I have a 100 watt panel. Great job!
     
  16. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
    29
    Aug 2, 2011
    Steinbach, MB
    I've set it up to accommodate a 100 watt Coleman solar panel which, if I recall correctly is about 39" wide. The frame is more than strong enough to support itself when mounted with three eye bolts and I wanted to keep the footprint within 24" square. Thus far, it seems to work just fine.

    Given that it's so low to the ground (about 2-1/2" from the bottom of the base to the top edge of the top deck), it's quite stable and the 45 degree angle of the panel deflects a lot of wind. If a gust of wind does blow the panel off course, there's enough torque in the drill clutch that it'll correct itself immediately, so that's not much of a concern either. Worst case scenario, I may simply anchor the base to the ground with turn-in stakes of some kind. I also plan to add rubber feet to the base so I can situate it on a picnic table, gravel or concrete without damaging the surface it's on.

    I have no plans to mount it to the camper roof. We usually park in the shade and the roof already moves around enough in a good wind. No sense compounding the problem with a solar sail! [;)]

    It's hard to see that in the photos unless the top deck is centered with the drive post between the handhold cutouts, but the top deck is offset by about 4" rearward so that the weight of the panel and drive post is transferred closer to the center of the base.

    [​IMG]

    Finally, the 4" of space will be at the bottom when the top deck is locked in position and the solar panel is laid flat for carrying/storage. This is where the drive post will be secured with latched straps (similarly to a fire extinguisher). I'll explain further as the project nears completion. Hang on!
     
  17. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
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    Aug 2, 2011
    Steinbach, MB
    I picked up an on/off rocker switch last night and cut out the opening in the drive post, I'll just need to pick up some female blade connectors to finish installing it.

    The hunt for the reasonably priced 54 tooth chain ring is over! I'm stoked to have found and ordered a used 54T 3/32" chain ring off of eBay this morning. $20US shipped! That'll increase the drive sprocket gear ratio from 4:1 to 5:1 and slow down the rotation of the top deck by 18.5%. Nice!
     
  18. dmitrym

    dmitrym New Member

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    Sep 13, 2013
    That is very cool, thanks for sharing.

    As I'm looking into solar for boondocking, I've never considered having to reposition the panel. What kind of efficiency gains are you expecting out of this setup? I'm curious, because a lot of people have panels mounted on the roof of the RV where they obviously don't move at all.
     
  19. Dubbya

    Dubbya Wherever you go, there you are...

    6,138
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    Aug 2, 2011
    Steinbach, MB
    Well, there are several variables that have to be considered. For example, parking your RV or camper in the shade is going to have a significant impact on the amount of power your solar panels can generate. That said, their efficiency actually degrades if they get too hot.

    According to what I've read on the subject, by tilting the panel between 40 and 50 degrees, one might reasonable expect to see an increase in output of between 16% and 18% but simply adding another panel to form an array would compensate for any losses. Same goes for setting up the panel in areas affected by shade as the day progresses. Add another panel to compensate.

    More on angle of tilt here: http://www.civicsolar.com/resource/effect-array-tilt-angle-energy-output

    There are also tilt calculators around that you can use to figure out the premium angle according to where you want to set up the panel. http://solarelectricityhandbook.com/solar-angle-calculator.html

    Since I don't plan to use the panel in spring or winter, setting it between 45 and 50 degrees seemed like the optimum angle for the time of year I'll be using it in my neck o' the woods (Winnipeg, Manitoba, Canada and surrounding area). Alternatively, if that's an issue, you can always set up a dual axis solar tracker as well and just have hardware tilt the panel to face the sun accordingly. In my case I felt it would require too much additional hardware and additional weight.

    Though convenient to store and transport, laying them flat or mounting them to an RV roof might be fine at noon but output declines during the rest of the day. Again, additional panels would compensate. Another problem is that a panel that is mounted flat gets dirty or obscured by rain and debris, further limiting the panel's capabilities.

    In my case, space is an issue so I'm using one panel and hoping to generate as close to 100 watts as I can for as much of the day as possible.

    I'm certainly no expert but based on what I've read on the subject, using a single axis solar tracker, though sellers tout 30-70% increases in output, I anticipate a more conservative increase of 30% over a stationary panel and I'd be more than satisfied with that.

    "Solar tracking is one of the most straightforward ways to improve the performance and economics of a solar installation. Compared to a fixed mount solar panel, a single-axis tracker increases annual output by about 30 percent and a dual-axis tracker an additional 6 percent. Other estimates say that solar panel trackers add between 25 and 45 percent to the efficiency of an average residential solar PV system." http://www.solartown.com/learning/solar-panels/beginners-guide-to-solar-trackers-how-to-increase-output-for-your-home-solar-panel-system/
     
  20. phoodieman

    phoodieman Active Member

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    May 18, 2009
    Hutto, Texas
    How much power does the tracking system consume?

    Phoodieman
     

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