DIY Project, Tracking Solar Panels

Discussion in 'Tech/Mech General' started by olley, Nov 30, 2009.

  1. olley

    olley Funster

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    Hi guys I have had a bee in my bonnet about making my own tracking solar panels for a few years now, and a few weeks back decided to give it a go.

    Basically because of where mine are, either side of the sat dish, I need to make them slide out either side of the RV before elevating and rotating. I have made a frame that goes the full width of the RV with two sliding frames either side, mounted a lazy susan onto it which will be driven by window winder motor, both the sliding frame and the elevation will be achieved with electric actuators.

    Now an immediate problem is the drive between the motor and the lazy susan, I have tried nylon cord but it slips to much, next idea is 1mm galvanised wire rope, as it has a rough surface, but open to other ideas.

    I also need a source of cheap 12v actuators minimum 12" extension and 100kg push.
     

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  2. scotjimland

    scotjimland Funster Life Member

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    Boy, that's some project Olley ..

    Have you considered a round rubber belt ? ..

    if nothing 'off the shelf' make one up from an "O" ring cord ?

    'O' ring cord - James Walker Group
     
  3. olley

    olley Funster

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    Hi Jim, I did consider that but its very elastic, which I think will cause problems. As the wires pretty cheap I have order 3 metres of S/S nylon covered, galavanised and S/S extra flexi, all around 1mm for a tenner, from here: Stainless cable wire rope assemblies & cable fittings. Tecni-Cable UK. So I can have a play and see if any are suitable. If not another idea is to glue emery cloth to the pulleys.

    Olley
     
  4. scotjimland

    scotjimland Funster Life Member

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    Hi Olley

    The lazy susan will be under a lot of stress if it's windy .. is there a locking device/pin or does it rely on the belt to keep it in position ?

    If no lock, maybe V or toothed pulleys would be better

    jim
     
  5. olley

    olley Funster

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    Hi Jim, no it relies on the belt, the window winder has a worm drive gearbox, nice bit of gear, I had to strip it to modify it. Bought 2 for £20 of ebay.

    Belts from what I can find out come in fixed sizes, I used brammer belting years ago, which buttons together in what ever length you want, but I have only ever seen larger sizes of it.

    Tumble dryers use a multi vee belt design, which would be good but they are miles to long.

    Also looked at chain drive, but its getting hold of sprockets the right size, push bike ones seem one possibility, which I may investigate further if the wire is a failure.

    Lazy susan is rated at 750kg vertical load.

    Olley
     
  6. Terry

    Terry Funster

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    Hi Olley, nice project :Rofl1: what about using O ring rubbers from soil pipes etc ? you can get different sizes and they streeeeeech good
    terry
     
  7. hilldweller

    hilldweller Funster Life Member

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    Two solutions - bicycle chain or timing belt.

    Actuators - sounds like sat dish rotator or gate actuator, neither of which hit the cheap category.

    But once again timing belt is the answer, it's the garage door opener scenario.

    PS: Impressive bit of engineering.
     
    Last edited: Nov 30, 2009
  8. spindrifter

    spindrifter Read Only Funster

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    WOW Olley, what a project.

    Could we have progress pictures please. I would love to see it installed and working.

    Thanks

    David
     
  9. hilldweller

    hilldweller Funster Life Member

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    That makes two of you.
     
  10. scotjimland

    scotjimland Funster Life Member

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    We used to stock this sort of belting off shore for emergencies..

    the belt had holes along it's length, it was cut to size and joined with a steel link with two pins.. came in both A and B section , I've had a ~Google .. don't actually see it, maybe this is a more modern version .. the yellow belt in the picture.
     

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  11. Douglas

    Douglas Read Only Funster

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    I am at the drawing board stage of an identical project, I at the moment I am working to a manual version as I only have a few months a year when I have access to my workshop. the motorized version may come later.

    Brahma belting would have been one of my choices but its terribly expensive, Would it be possible to reduce the gearing to a point where it would be possible to use a rod to pull/push the rotating panels, this would mean the the relative positions of the panel would have to be reset every time the MH was moved relative to the sun. No on second thought forget it, to complicated and not enough KISS.

    How about using a thin plastic tubing, (for the friction) and a strong inner cored to carry the load

    Doug...
     
  12. olley

    olley Funster

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    The problem with most belts is the minimum bending radius, the little pulley on the motor has an inside dia of 1 1/4" the big one on the Suzy is about 8" I need to keep the gearing as low as possible, ideally 1 rpm for the panel, but I am way over that at the moment.

    At a guess the panels weigh around 12kg each, so you are looking at quite a bit of momentum if they are turning quickly, the worm drive motor will come to a dead stop as soon the power is turned off, so I need them to turn as slow as possible, otherwise I will be ripping the motor gears to bits or tearing the pulley of, one reason to use something that has a bit of slip.

    I can only see two ways to slow the panels, another reduction in-between the motor and the panel, which will add weight and complexity, or electronically, maybe just a big resister would do it? What do you think Brian?

    Hi Doug, I have ordered some nylon covered wire rope to try.

    Olley
     
    Last edited: Nov 30, 2009
  13. Douglas

    Douglas Read Only Funster

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    I think that unless the pulleys are big enough so that the joint in the wire does not course a loss of friction it may be a problem, IE a compression Ferrel would be a problem unless the joint never touches a pulley!

    Doug...
     
  14. hilldweller

    hilldweller Funster Life Member

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    1.25" outside diameter ( I assume ) is no problem for the size of timing belt you'd need.

    You want proper speed control - PWM are the magic letters - you can run the motor at a tenth of max speed with decent torque. Look at ebay #170412731121
     
  15. olley

    olley Funster

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    Hi Doug as I am not using commutators for the panels, they will only ever do at the most two complete turns (hopefully :BigGrin:) so I can loop the wire more than once around the big pulley and hide the join in the there, or even screw the ends to the pulley sides, so theirs no chance of slippage on the big pulley. I am already looping it twice around the small pulley to improve grip, but theirs only so many times you can do that before one wire starts to lay on top of another causing problems.

    Olley
     
  16. olley

    olley Funster

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    Hi Brian, your a star :BigGrin: just bought two, just have to hope SWMBO doesn't find out what this is all costing, or I am likely to end up wearing the panels :Doh: :Laughing:

    Olley
     
  17. pappajohn

    pappajohn Funster Life Member

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    hi Olley,
    have you considered notched V belts of the car alternator/water pump variety.

    due to them being notched they will bend round very tight radii and the V will provide the grip.
    would it be feasable to fit a tensioner pulley on the 'slack' side.
    maybe a simple small bearing on a stud running on the 'back'
    side of the belt.

    at 1 1/4" and 8" you wont be far off gear sizes from a multigear bike.....largest possible crank gear and smallest possible hub gear.
     
    Last edited: Nov 30, 2009
  18. olley

    olley Funster

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    Hi papa a vee belt would have to be in the region of 5-6' long, I could of course move the motor closer, but would prefer to keep it in the corner out of the way.

    Bike sprockets sound like a definite possibility now I have bought two speed controllers from Brians link, but going to try the wire first as I have already ordered it.

    Olley

    found a 12 and a 72 tooth on ebay both under a fiver so a definite poss.
     
    Last edited: Nov 30, 2009
  19. pappajohn

    pappajohn Funster Life Member

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    a vee belt would have to be in the region of 5-6' long,

    3 blade ride on lawn mower blade drive belt:thumb:

    just the thing mate. various lengths from around 4ft to 8ft and notched V belt as well.

    only thing.....my last one cost nearly £40
     
    Last edited: Nov 30, 2009
  20. olley

    olley Funster

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    Hi papa vee belts need "V" grooved pulleys, without a lathe that's a lot of work. If the wire doesn't work, I think a chain is probably the best bet as I can easily and cheaply buy the sprockets and chain, just need to find the link splitter that I haven't used in 30 years. :Doh:

    Olley
     
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