DIY Solar panel setup on a budget

Discussion in 'Hobby Engineering' started by Mathuisella, Oct 15, 2013.

  1. rainwulf

    rainwulf Member

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    Heh, thats completely automated for me.

    I will be rebuilding the switch box tonight, and will be adding a web interface to allow direct switching of things from a webpage. Means i can turn off lights and shit from upstairs if i forget.
     
  2. shane41

    shane41 Member

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    It's called exercise :lol: man I wish I had stairs to run up. Make it too easy & we get lazy complacent in out lives

    Maybe we can strap a generator/ dynamo on your legs somehow :confused:
     
  3. rainwulf

    rainwulf Member

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    ha yeaa

    On a very shitty note, i lose nearly my entire solar array at 1:30pm due to the palm trees on the border of the property.
    Fucking shit.
     
  4. shane41

    shane41 Member

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    How tall are they if your on a second story building?
     
  5. rainwulf

    rainwulf Member

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    Not really second story, more of an undercover garage that goes under the house, so 1.5 stories.

    They are probably at least 2.5 stories tall.
    Its on the neighbours property line too.
     
  6. shane41

    shane41 Member

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    Bring the Magnum Farm Boss up but it may alert them @ midnight. Buy him a gift hammock & his weight will pull the ferns over :leet:
     
  7. rainwulf

    rainwulf Member

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    Annnnnnnnnd the rain is back, OH and i accidently put 12 volts on the 5 volt rail of my power switching control unit.

    all the smoke fell out.
     
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  8. shane41

    shane41 Member

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    Did you upset another gypsy?
     
  9. vk2fro

    vk2fro Member

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    rainwulf, we know this is ocau, but pushing 2.5x the voltage through a device isn't overclocking, thats overvolting way too far :p
     
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  10. OP
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    Mathuisella

    Mathuisella Member

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    Funnily enough through a conductor, the voltage doesn't matter, it's the insulation around it that's the limiting factor to voltage, however current on the other hand, that's what creates the heat with potential hot issues ;)
     
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  11. rainwulf

    rainwulf Member

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    5 volt arduino doesnt like 12. Okts, thats all that matters, so now im out a freetronics ether10. They arent cheap either.

    Oh well, will be upgrading to a mega with an ethernet shield.

    After i build a decent enclosure for the 240volt side. It will also do the remote switching of the 12 volt house power, lights, and the ir movement detector that will turn on lights as i walk under the garage. Will also do emergency lights too, so its going to be an all in one super control unit.
     
  12. shane41

    shane41 Member

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    Pulling 250watts last night. Stopped @50v 70% DOD. So this morning measured 50.6v across the pack that have been disconnected overnight.
    What's up with that? How long to stabilize for measurements?
     
  13. OP
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    Mathuisella

    Mathuisella Member

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    voltage sag

    think of it this way, You're pulling current through the wires ect: according to the load, and when you stop, think of it like an elastic band that's being let go once stretched, it bounces back a little bit, not much but some.

    It's the same when you start your car, it's drawing such a load that the voltage on the battery dips down a point or two
     
  14. vk2fro

    vk2fro Member

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    Yep once you remove a load from a LA battery, it bounces back a little. Think of it like putting 5 bowling balls on a trampoline and leaving it overnight. Remove the balls in the morning, and the trampoline will spring back to its original shape but some of the springs will be stretched. To fix the springs, we recharge the battery, which makes the springs all nice and taught again.

    If you over discharge your battery (e.g. 20 bowling balls), all of the springs will be stretched, and it becomes very difficult but not impossible to get all the springs back into shape. Some of the springs will remain deformed; no matter what you do to try to fix them, so the trampoline won't have as much bounce in it as it did when it was new (the battery won't perform as well as when it was new).
     
    Last edited: Apr 20, 2018
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  15. rainwulf

    rainwulf Member

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    Rebuilding the automatic switch box after i let the smoke out of the other arduino module.

    [​IMG]

    Thinking of safety, i have the "earth loop breaker" on the right hand side under kapton high temperature tape. This maintains a small but discrete isolation from the mains in the house. It means fault current will still flow, but low level voltage differences wont. Also using X2 rated mains capacitors of course.

    The house mains and solar mains are on opposite sides of each other, the outputs of the relays go up and then down the side of the relays maintaing at least 1cm clearance. I also used high temperature silicone so that if the solder lets go the wire wont go bouncing around. I will also be cable tying anything thats loose.

    The arduino is at least 2cm away from the closest 240 volt, and its also completely isolated inside the box, as the only output to the real world is via ethernet, so is 1500volt isolated.

    The solar inverter detector relay allows me to detect the inverter running with no actual galvanic connection, so in essence, everything is isolated from everything house, and the chances of solar and mains coming together is very very low.
     
    Last edited: Apr 30, 2018
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  16. OP
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    Mathuisella

    Mathuisella Member

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    in your gearbox...grindin
    I have to ask man, what's your electrical background? , as it's pretty good and far from common hobbyest
     
  17. rainwulf

    rainwulf Member

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    Cert 4 Electronics from RMIT - Trained in the army as optical-electronics repair. Laser, radio, night vision, optics. Spent years doing programming on 8086s and 80286s.

    Was very happy when i first had a machine with a floating point unit!

    Mainly electro-mechanical/electro-optical with computing on the side.

    Materials science - model solar car mechanical design winner!

    That unit isnt that clean, still have to tidy up the 240 wiring and cable tie it.
     
  18. OP
    OP
    Mathuisella

    Mathuisella Member

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    I asked because what you've done is a bit beyond me at the moment. But Damn man, I'm sure you could go into Uni got a short time, have most of the uni degree accredited to you from experience and walk away in a year with a degree in Electrical/electronic engineering
     
  19. rainwulf

    rainwulf Member

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    maybe.. but its not like its going to make me anymore money.
     
  20. HSV_Enigma

    HSV_Enigma Member

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    I don't want to seem negative but it looks like you are using the relays as individual changeovers with both a solar and mains supply going to each. This is not the best approach because if somehow the contacts fail and cause a backfeed into the grid and cause all sorts of issues. The way this is normally done is with 2 rated contactors, with the supply for each contactor having a NC contact of the other, this ensures a zero state before switching and mitigates against welded contacts, mechanical interlocks are probably overkill for this. Why are you interrupting the earth? if the cap is in series with the earth it could prevent an upstream RCD from functioning. You should so also remove the pigtails in the mains cable for inductive reasons.
     

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