connecting 6pin RGB leds-help needed

Discussion in 'The Projects Forum' started by raidod, Dec 21, 2009.

  1. raidod

    Thread Starter New Member

    Dec 21, 2009
    4
    0
    Hi,

    I need help for my fish tank lightning panel.
    RGB leds that i use:

    [​IMG]
    Forward Voltage : 3.2V~3.5VForward Current : 700mA

    Controller

    [​IMG]

    Input voltage: 12V/24V DC
    Maximum load current; 3A each color

    I want to connect 6x these leds in series and im not sure how to do this.

    Attached is my nice :) drawing how i was connect the leds but im not sure that this will work so i need your help people.

    Thank you in advance.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Your controller should have documentation that describes how to connect it up like this. There is a chance it can not control 6 LEDs, though, again the documentation will tell the tale.

    My interpretation of the LED itself is the +B is the anode of the blue LED, -B cathode, +R / -R Anode / Cathode Red, and +G / -G Anode / Cathode Green. The power supply might not be able to handle 6 in a row (which is how I think it may need to be done), the blue is probably around 3.6V drop, which means it would need 3.6V X 6, or 21.6V. Hmmm, maybe it might work after all.

    I'm thinking in series similar to this.

    [​IMG]
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    If you are not careful, you will burn up your LEDs using that controller.

    3A is far more than your LEDs are rated for.

    You need to provide links to documentation for your LEDs and your controller.

    Note that your LEDs will have to be mounted on heat sinks. Otherwise, they will get much too hot and melt.
     
  4. raidod

    Thread Starter New Member

    Dec 21, 2009
    4
    0
    Thank You guys so much for this :) You have been really helpful.

    SgtWookie - 3A is far more than your LEDs are rated for.
    I thought that this means the controller can handle 3A each color - but once again im not sure about this as there is very little documentation. Thank You for bringing this issue up.

    Bill_Marsden - thanks for the shematic. looks much nicer than mine :)

    Leds will be glued on aluminium sheet 3mm with Artic Silver thermal adhesive. I even bought a infrared heat gun for measuring the temps ( i have worked with luxeon 3w leds before but not with RGB )

    Power supply is a old laptop adapter rated for 4900mA 19V -
    how is it with RGB leds - does the 700mA means the whole current for one led? 6x 700mA = 4200mA so my power supply should handle this?
    If they get less V - lets say 3.2 from the power supply 6x3.2 = 19.2V..less lumens but they still gonna work or they wont work at all ?


    controller came from China and the seller did include one sided spec paper but that's all there is :
    Input voltage: 12V/24V DC
    Maximum load current; 3A each color

    other information is about the color pattern modes..
    I will ask the seller.

    Same with leds - no other spec than
    Forward Voltage : 3.2V~3.5V
    Forward Current : 700mA

    e-mailed the seller and waiting for respond.

    edit: i just got email from the led seller. not providing me with pdf data sheet but just in writing:
    The red work voltage 2.2-2.4v current 350mA
    The blue work voltage 3.0-3.8v current 350mA
    The green work voltage3.0-3.8v current 350mA
    :)
    Now where did the 700mA came from at first place? just missleading information or do we sum up the mA for rgb leds as there is 3 colors ? now im pretty lost here....:D
     
    Last edited: Dec 22, 2009
  5. SgtWookie

    Expert

    Jul 17, 2007
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    1,728
    I don't know where you got the 700mA from, but those are 350mA LEDs.

    They won't be powerful enough for an aquarium, unless it's the size of a coffee cup.

    Your controller is not really appropriate for your lights.

    Good aquarium lighting is not cheap.
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    The 700ma to 350ma sounds bait and switch to me.

    Don't know about the controller, but I suspect you'll need a 24V power supply, though I could be wrong about this.

    They may be thinking of running the LEDs in parallel. This opens another can of worms, though it works on the short term.

    I'm guessing that the controller is programmable as to it's maximum current.

    How much did you spend on those LEDs?

    I tend to be one of the draftsmen for this site, you can get my templates if you want them, I use M/S Paint.

    Introduction and PaintCAD
     
  7. raidod

    Thread Starter New Member

    Dec 21, 2009
    4
    0
    Bill_Marsden - How much did you spend on those LEDs? The 700ma to 350ma sounds bait and switch to me.

    700mA was advertised by the seller - and now after asking data sheet he stated that leds are 350mA - Ebay link. Seller did gave me a discount so price for one led was 6$. Another valuable lesson from Ebay.

    SgtWookie - They won't be powerful enough for an aquarium, unless it's the size of a coffee cup.

    You might be right but i have to try - if i get them work i will post some pictures.
     
  8. JMD

    Member

    Dec 9, 2009
    96
    0
    Well, something is messed up with your drawing. You cannot connect the LEDs as you want in your drawing, thats for sure.

    If you want to connect them in parallel, its positive to positive between the LEDs. If you want to connect them in series, its positive to negative between LEDs.

    What youve done, is a mix of parallel and series.
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    I doubt you'd be able to run 6 in series with that controller due to the sum of the Vf's.

    Need to know more about the specifications of the controller.

    Anyway, here's how to wire three of them in series:

    [​IMG]

    I've attached a single "cleaned-up" LED image for you to experiment with.
     
  10. raidod

    Thread Starter New Member

    Dec 21, 2009
    4
    0
    I really appreciate all your help. Thanks to you its working now. Only the RED color was missing - i think this can be fault of my bad soldering skills or some bad led. As it was late and i was tired i thought its better to sleep on it and continue next day with this project.

    Thanks once again and Merry Christmas everyone :)
     
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