How to run 10 1w led in parallel?

Discussion in 'Digital Circuit Design' started by shark669, Jan 30, 2017.

  1. shark669

    Thread Starter New Member

    Jan 30, 2017
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    Hi
    I have 10 1w led bulbs, I would like to run all of them at max output possible,
    This is the led:
    http://imgur.com/a/X6jME

    I am not an electronics expert, how to calculate the power source and current needed?
    Thank you
     
  2. spinnaker

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    Embed your image in the post. It is easier for others and people are reluctant to click on unknown links anyway.
     
  3. ErnieM

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    Apr 24, 2011
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    Will we be able to see the part number from the picture? Why not just post a link to the part itself?
     
  4. shark669

    Thread Starter New Member

    Jan 30, 2017
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    Sorry there is no caption on them, got them a while back, the bag says 1w
    Here are the pics:

    Bq6e8kl_800x450.jpg
    Am19twM_800x448.jpg

    http://i.imgur.com/Bq6e8kl.jpg
    http://i.imgur.com/Am19twM.jpg


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    Last edited: Jan 30, 2017
  5. GopherT

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    These are generally 3.1V at 350 mA to get about 1W.
     
  6. shark669

    Thread Starter New Member

    Jan 30, 2017
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    So is it simple as connecting 3.1v dc power supply capable of 3.5A?
     
  7. GopherT

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    No, the best thing to do is connect something that will supply 350 mA and the voltage drop of the LED will take care of itself. Unfortunately, you don't likely have a 350 mA constant current source.

    To get an approximate current source, we'll need to know what type of power you plan to use. Batteries, wall power adapter, ...
     
  8. spinnaker

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    No you need to limit the current somehow. The method is going to depend on what is driving it. If you don't care about efficiency then the appropriate current limiting resitors will do. If it is a battery supplying the power then you will want some form of switching current regulator.
     
  9. shark669

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    Jan 30, 2017
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    I am going to use a wall power adapter, I have three available:
    12v 1.2A
    12v 2A
    12v 500mah


    Since its a wall adapter I don't care about efficiency
     
    Last edited: Jan 30, 2017
  10. GopherT

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    Well, 10 x 1W means you'll need 10 watts of power (minimum) so the one that has a max output of 6 watts won't work.

    The next challenge is your desire to connect them all in parallel is an issue. Doe that you would need 10 X 350 mA = 3500 mA. None of your supplies are set up well to do that. Would you consider another combination of series (three groups of three bulbs, and an odd one.
     
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  11. shark669

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    Jan 30, 2017
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    Yes sure, I am trying to build a simple light box, the configuration is not that important, thank you for your help!
     
  12. GopherT

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    Use the 2 amp X 12 volt supply

    The six resistors are each 10 ohms. You need some fat ones capable of handling 2 watts or more each.

    Each string will be well matched in brightness if the LEDs are 3.1v at 350 mA. It is never a good idea to run them at max so these are set to 300 mA. Make sure they are mounted on a heat sink.

    image.png
     
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  13. shark669

    Thread Starter New Member

    Jan 30, 2017
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    Great! I appreciate you taking the time to sketch it!
    One thing I am missing here, is the direction of the LED relevant?
     
  14. GopherT

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    ⊥⊗

    Yes, LEDs are one-way devices. Look for a bar printed on the bottom of the LEDs. That will be the negative side. It is also possible that there is a line aligned with the negative lead (closer to the negative side) and a bar traversing that line (to look like a capital T). Actually closer to this with the unique line pointing to the negative lead (the cathode). ⊥
     
  15. SLK001

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    You would be much better off operating all 10 in series. A 36V, 500mA supply would work just fine. Operating in parallel would require each LED to have EXACTLY the same forward current and voltage to equally share the power.
     
  16. GopherT

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    The only need for EXaCTLY is if one wants EXACTLY the same light intensity out of each. The resistor in each string compemsates for any differences in Vf. Also, if you'd bother to read, the OP doesn't have a 36v supply laying around.
     
  17. dendad

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    You probably can check the polarity if you have a multi meter with a diode test on it. Most will light an LED ok and it will not harm the LED if you get it reversed. Otherwise, use a 5V supply AND a series current limiting resistor, maybe 1K or 470R. Don't go for a high supply voltage as most LEDs have a fairly low reverse breakdown voltage and it would be a shame to pop them.
     
  18. spinnaker

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    Assuming one has a 36V supply. The OP does not have said supply so it is moot.
     
  19. SLK001

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    A 36V supply is easily obtained. Much better than paralleling various strings of LEDs with high power resistors balancining the current. The LEDs will illuminate just fine with 250mA, so a 36V @ 250mA supply will be all that is needed to operate the series string.
     
  20. spinnaker

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    "Easily" is subjective. We have no idea the OP's location in the world or financial position. We have no idea how "easily" the OP can obtain a 36V supply. The only facts that we have are the list of choices presented by the OP and that is the OP has the 3 supplies listed in post #9..
     
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