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Thread: DIY Solar Thread...

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    New Member Array
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    Fyi DIY Solar Thread...

    Building your own solar panel grants you autonomy from purchasing one off the shelf. Bought commerically these can cost a fortune but by being able to make one yourself you can save yourself money, learn and gain knowledge instead of being lazy and having someone else do the work.




    The Suns rays are free, in Thailand there's an abundance of solar energy compared to the cloudy islands and nations of Europe.
    Yet, to harness them adequately, takes some work. Here's how you do it...

    Firstly you'll need a small workshop or area where you can work uncluttered. A flat surface is essential. In the shade is important, not only for comfort but you don't want your panel it 'go live' while your working on it. Especially in the case of a very large panel.

    The right tools are also necessary.

    Solar cells - 0.5 volt 3.6 amp polycrystaline.

    At least enough for 7 - 10 volts per array. If you're wanting to charge up a lead acid battery you'll need to build two or more of these. Otherwise re-charging it will be difficult. SOURCE: Ebay

    Stuff you'll need for one array / panel.

    1. Soldering Iron

    2. Thin Solder

    3. Clear, see-through perspex in a minimum of 2 equal sections.
    Make sure you have the dimensions of AT LEAST 350mm x 750mm x 4mm. Any less and you're cutting it fine for margins to the edge with a 2 column displacement on your cells.

    4. EVA (ethal vynal acetate), this what you need to seal in the cells to one another so they are crack resistant and will hold them together if they do crack (thus retaining conductivity.

    5. A method to raise the perspex clear of each other. This may involve wooden
    beading (you'll need a table saw for ultra accuracy). DIY methods or use fine sections of perspex.

    6. Araldite glue (plenty of it!)

    7. Surgical Gloves.

    8. A heatgun (used for paintstripping) or a hairdryer.

    First thing you need to do is order in some perspex and source your solar cells.
    I used Plastic People (URL at bottom of page) for my clear perspex and ordered 2 sheets of equal dimensions.

    For the cells you can get these off eBay and they are quite cheap too.
    Roughly $0.75 per cell which is 0.5 volts each at peak power.
    Be VERY gently handling them as they snap with ease.

    Solar Panels being soldered



    So by the picture above you can see that I've soldered a fair few and am coming to the end of the main soldering.

    You want to have the 2 rows (or more) in a configuration where it runs like a railway track. One-way from top to bottom; The top being where you'll be making a 'bus' wire bridging the contacts, the bottom where you'll have the + and - wires running out of the array to be heatshrinked and joined by your voltage regulator wiring.

    Once the soldering is done you need to sort the EVA out.
    This needs to be laid out on top of and underneath the cells. Be careful as you'll have to move them back and forth as you go about soldering and placing the eva underneath etc.
    You can't solder the cells with the EVA in place though as the heat will melt it.
    Once you've got the EVA laid out you need to first get the feel on a sample section by heating it up and seeing how much heat you need etc.

    So by the picture above you can see that I've soldered a fair few and am coming to the end of the main soldering.

    You want to have the 2 rows (or more) in a configuration where it runs like a railway track. One-way from top to bottom; On one end you'll have to make a 'bus' wire bridging the contacts.


    Attachment:





    At the other end you'll have the + and - wires running out of the array to be heatshrinked and to wherever you are having them go. These are the OUTPUT WIRES.

    An easy way is to wire the output wires direct onto an appliance, but that only works as long as there is a sunlight. You'll need a lead acid battery and voltage regulator wiring for power-on-demand.
    That's for another day though...



    Stage 2 - EVA Encapsulant.

    Once the soldering is done you need to sort the EVA out.
    This needs to be laid out on top of and underneath the cells. Be careful as you'll have to move them back and forth as you go about soldering and placing the eva underneath etc.
    You can't solder the cells with the EVA in place though as the heat will melt it.
    Once you've got the EVA laid out you need to first get the feel on a sample section by heating it up and seeing how much heat you need etc.

    This all sounds complicated, but once you get your head around the mental gymnastics it's not that difficult. The soldering of the cells isn't for a clumsy hand though, take your time with this.

    The video guide at the bottom of the page will help you understand better.



    The EVA is like soft and slightly squigy rubber that you order in rolls.
    Cruicially it's see-through and when direct heat is applied it shrinks and bonds to whatever it's in contact with.
    In our case the solar panel cells, being very flimsy and delicate will be strengthened greatly by this material being used to bolster the structure.

    Attachment:


    The EVA needs to be laid out on top of and underneath the cells. Be careful as you'll have to move them back and forth as you go about soldering and placing the eva underneath etc.
    Once you've got it laid out (ensure it overlaps slightly.)

    You can't solder the cells with the EVA in place though as the heat will melt it so this is why you've already got your soldering out of the way.
    Once you've got the EVA laid out you need to first get the feel on a sample section by heating it up and seeing how much heat you need for when you go to put the heat on the main cell array.
    It'll take you about 15 minutes to do, don't over heat the EVA material, you are after a bond, not a melted mess.

    Stage 3 - Encasing the Cells in Perspex

    At this point you want to have your Perspex sheets that you ordered from your supplier. There are two you can use. One is the Plastic People in the UK. Another is a firm in Oz. If you need their urls let me know.

    With the EVA bonding the cells together they will not crack or break easily. With the perspex sheets encasing the panels, you make them much more robust and able to stand up to the rigors of outdoor use and operation.

    Even so, directly applying the sheets onto the soldered and bonded cells is not wise, the slight flex-effect may crack cells during transport and installation. What you can do to maintain rigidity is to have 'beading' or a 'spacer' to keep the perspex raised off the cells slightly.

    In the picture to the side you can see the beading for the long lengthways sections. You don't need much height on them, a couple of mm should do it.

    It is essential your perspex measurements take into consideration any 'spacer' or beading along the sides as otherwise it could mean you've not enough space for your cells.



    Perspex Application

    Final Phase

    After first laying the EVA cells down on the bottom perspex we lay the beading onto the edges.
    Then use the araldite glue for sticking on the beading.
    As it's long lengths you may find the beading doesn't want to fully flatten down, you ought to give it a helping hand while the araldite is curing...

    In the picture here you can see that we're using clamps, weights and the like to keep the beading pressed down.



    After giving this about 8 hours to fully dry onto the bottom sheet apply more araldite to the top of the now-glued on beading.
    Onto this put the top-sheet of perspex. Allow about half a day for the the glue to dry.

    Your panel is now complete and ready for testing.



    This Solar Panel that a friend and I built kicked out nearly 10 volts. With several of these together you'll easily have enough to recharge a 12 volt lead acid battery in Thailands weather

    Thanks for reading, hope it's interesting to those of you interested in solar projects out in LOS

    Materials such as the EVA, Extra tabbing wire, solar cells and Perspex is best ordered in from outside Thailand...


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  2. #2
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    Nice post - I'm going to read through it all very carefully.

    Quote Originally Posted by Sphere Vision View Post
    in Thailand there's an abundance of solar energy compared to the cloudy islands and nations of Europe.
    I keep banging on about this to friends. I cannot for the life of me understand why Thailand hasn't got millions of solar panels all over the place.
    "Take this, brother; may it serve you well."

  3. #3
    New Member Array
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    I know, it's mind-boggling the apathy on solar power in this land. Is it lazyness? Is it Laissez-faire combined with the boon for hydrocarbon benevolence?
    Who can tell?

    Here's a buzz on my Solartron to cheer you up :D

    Another Mini project That I carried out was the Solartron.
    This is basically a Solar Generator.
    This is only a 75 Ampere Hour battery but it kicks out plenty of power, even when being drained by the inverter...

    Here's the buzz:





    Early verion, without DC outputs:






    It's important that your battery is a not maintainance-free one, so that you can top off the battery with distilled water when necessary.


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