Help needed for LED/Solar

Discussion in 'General Electronics Chat' started by daktari, Apr 30, 2010.

  1. daktari

    Thread Starter New Member

    Apr 30, 2010
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    I run a charity educating under-privileged children about the environment (www.daktaribushschool.org). We live in the remote bush near Kruger Park in South Africa and have no electricity. Most of the project is run on solar power.
    I was donated about 15 solar garden lamps, however the animals have broken them. I have saved the pieces.
    They run on a small (60mm x 60mm) solar panel which charges 2 x 1.2v rechargeable batteries. There is a small circuit board and they have 2 LED lights. Each panel seems to give out 4.2v in direct sunlight.
    I was also donated about 30 LED bulbs, with 30 resistors, and about 10 x 3.6v batteries.
    I thought I could connect all the solar panels from the garden lights, in parallel, then connect them to the batteries (also in parallel) then make a 30 x LED array to provide light.
    I know nothing about electricity, so I do not know where to wire in the resistors, how many I will need etc. The resistors are marked RE5CF27R, and have three bands, Red, purple, black then a space and a gold ring. This means nothing to me.
    Can anyone help me with the wiring, and maybe explain why I need the resistors?
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Sorry to hear the solar lamps were broken by the animals.
    Do you have more details on the leds?
    Do you also have more details on the batteries?

    The resistors are needed to limit the current for the leds.
    Whitout resistors the leds would burn out almost immediatly.

    Bertus
     
  3. retched

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  4. daktari

    Thread Starter New Member

    Apr 30, 2010
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    The LEDs are white and the packet says only 5mm. The batteries are sets of 3 circular batteries (blue wrapping) and the label says "Cellular phone" batteries. They are marked 3.6v
     
  5. retched

    AAC Fanatic!

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    Friend, I think what you are doing is commendable. A Very good thing.

    I will try my best to give you the information you need to get things together, in a teachable form for the kids.

    I, and others here, can only help you with what you have, if you can give us specs. Which you have done well so far.
    Is there a brand name on the solar lights? I may be able to get a schematic of some more part specs online from the name and model numbers.

    Are there any other markings on the batteries? Maybe a number with an 'mAH' after is.. Like 3300mah ?

    That will tell us the amount of current available to your leds.
     
    Last edited: May 2, 2010
  6. daktari

    Thread Starter New Member

    Apr 30, 2010
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    OK I went to the workshop and checked. I have 17 similar solar panels. I have 15 batteries. They are in a sealed pack, branded "Circuit Centre" and labeled r"rechargeable cordless phone battery" Each pack has a number 3XN280BC No 2P373 3.6V 280MAH
     
  7. daktari

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    Apr 30, 2010
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    I also have about 60 LEDs, just labelled "white 5mm"
     
  8. retched

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    OK, do you have shop standards? A multi-meter, soldering iron?


    Im guessing a yes on the meter, you said you were getting 4.2 in direct sun. How about current? Can you measure the amperage (mA) in direct sun?

    Once we have that number, we can calculate the total series or parallel (or a mix of both) for the system we can build.
     
  9. daktari

    Thread Starter New Member

    Apr 30, 2010
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    Thanks. We are at GMT +2 (South Africa) and it is dark at the moment. I will try and measure the mA on my meter tomorrow (if the sun is shining - it has been overcast for about three weeks - very unusual!) Yes, I do have a soldering iron, when I run the generator.
     
  10. retched

    AAC Fanatic!

    Dec 5, 2009
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    Ok, good, You wont DEFINITELY need to solder this all, but it would be the way to go.

    Is this your battery?
    [​IMG]

    It is a NiCd battery, and we will be using low currents, so we can make a charger without too much hassle.

    Do the broken solar lights have a circuit board in them? There may be a charging circuit we can salvage from a few of them. If not, we will figure it out.

    Do you have a digital camera to show us your parts? A cell phone camera will do.

    We are really going to have to have that 'current' reading from the panel to get moving, but this will get things churning.

    The resistors you have, (the red, violet, black) are 470 ohms, Did you have a chance to look at the link I posted in POST #3?

    It has the color codes to decode the resistors. You should bookmark that.
     
  11. daktari

    Thread Starter New Member

    Apr 30, 2010
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    Hi there. Today the sun is out, but varies. Clouds every now and then. I have tried to take the measurements in similar light, but not really possible. Perhaps these readings will help you anyway.
    With a resistor between the + and - on the panel: Meter readings: 200mA 36, 9VmA 2.6, 1.5VmA 16
    With a resistor just on the (+) : 200mA 39, 9VmA 12, 1.5VmA 38
    With no resistor : 200mA 10.3, 9VmA 0.8, 1.5VmA 3.2
    With the panel half covered, and a resistor between (+) and (-) : 200mA 10.3, 9VmA 0.8, 1.5VmA 32 (a bit more cloudy for this one)

    Double check of quantities available: 67 x 5mm LEDs (white)
    30 x resistors
    14 x batteries
    17 x PV panels
    ideally I would like to make a circular array of all the LEDs to provide quite good light in one area.
     
  12. daktari

    Thread Starter New Member

    Apr 30, 2010
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    I thought I posted a reply, but it is not here. Will try again. Three different settings on my meter for mA! The weather does not help. Sun comes out then disappears in clouds. I have tried to do all readings in direct sun, but not really possible.
    With a resistor between (+) and (-): 200mA - 36; 9VmA - 2.6; 1.5VmA - 16
    With a resistor just on (+) : 200mA - 39; 9VmA - 12; 1.5VmA - 38
    With no resistor : 200mA - 38; 9VmA - 0.8; 1.5VmA - 38
    With half panel covered, and a resistor between (+) and (-): 200mA - 10.3; 9VmA - 0.8; 1.5VmA - 3.2 (more overcast for this reading)

    Update on supplies availabel: 67 x white 5mm LEDs
    30 x resistors (red, purple black gold)
    15 x 3.6V 280MAH batteries
    17 x PV panels
    Ideally I would like to mount all the LEDs in one circular array to provide better light in one area only.
     
  13. daktari

    Thread Starter New Member

    Apr 30, 2010
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    I have 10 of the old garden light circuits. They have 2 x LEDs and charge 2 x 2.2V rechargeable batteries. I have taken photos of everything and will try to attach here. If it doesn't work, have you an email address?
     
  14. daktari

    Thread Starter New Member

    Apr 30, 2010
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    I dont know how to download the pics. It says URL of image. There isn't one. It is on my computer! (You see electricty is not the only thing I dont know about!!!!) I can send them by email to you?
     
  15. daktari

    Thread Starter New Member

    Apr 30, 2010
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    my email is : <snip> attn Ian
     
    Last edited by a moderator: May 3, 2010
  16. bertus

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    Apr 5, 2008
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    Hello,

    You can post images using the Manage Attachment button below the edit field.

    Bertus
     
  17. retched

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    You can also press the 'Go Advanced' button which is next to 'Post Quick Reply' that will take you to the area were you can find the 'Manage Attachments' link below the box you type you message into.
     
  18. Bosparra

    Member

    Feb 17, 2010
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    Daktari, I might be able help with some info. I am Johannesburg and I have two of these solar garden lights at home. They are quite common and chances are they're from the same manufacturer.

    I will try and open one of them tonight, perhaps that will help at least identify the components we're working with here. I will get home in about 4 hours and will see if I can post a photo of pcb board, then you tell me if this is what you've got.
     
  19. daktari

    Thread Starter New Member

    Apr 30, 2010
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    First of 10 pics

    Taken in high res so you can see the parts etc and markings
     
    Last edited by a moderator: May 3, 2010
  20. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    I merged the posts.

    You can have upto 6 pictures per post.
    Just fill the lines at the "upload from my computer" with the locations of the pictures.
    (there are three lines you can fill in at once).
    Resize the pictures to about 800X600, this will make the up and download quicker.

    Bertus
     
    Last edited: May 3, 2010
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