COB Leds for a2x2 closet?

Discussion in 'LED and other Lighting' started by Fawkes420, Feb 7, 2018.

  1.  
    InTheValley

    InTheValley Well-Known Member

    Yeah, I did a strip build, and made my own enclosure, and that was the exact problem i had with it. Here is a pic.

    the 2 fans were enought to cool the inside, but the underside, no air flow to the top.

    I tore all the wires, and strips out, and putting in 4 cobs ( luminus-cxm-22s), and adding 2 more holes for fans to suck the hot air up and thru the enclosure. Im using a perfect Sun mini right now to veg out my FireOG, and not flipping till i get this cob build done,. Poor plant is on day 88 of veg, lol, starting to preflower, YICKs. Going to top one more time tonight, then 2 weeks about to recover before hitting her with the cobs. She has around 50+ good cola branches to flower off right now, but she is a tiny shrub, just many branches. Going to look like a giant tumble weed if she dont stretch.
     

    Attached Files:

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  2.  
    Rocket Soul

    Rocket Soul Well-Known Member

    Hi. Nä, tror inte men man kan alltid hälsa :)

    Your completly right about airflow, in fact about an hour after posting i went "Doh, airflow!!!!" But already busy with something else. Boards are nice for simplicity but [email protected] is going to give you same probs as 2 veros @80 each, you need about 50 cm clearance. Good luck
     
  3.  
    G84

    G84 Well-Known Member

    I am actually using 1 board in a 60x40cm small tent at 100watt.No problem with airflow or temperature.Fixture is 33cm from canopy
     
  4.  
    wietefras

    wietefras Well-Known Member

    Strips don't have this problem. You put every strip on a lenght of aluminium U-channel at more or less the same width as the strip. Plenty room between the strips for the air to flow. Put an alu angle at the outer ends of the strip and you're done with the frame. Or a wood bar at each end if you must, but alu is sturdier and easier I would say.

     
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  5.  
    Fawkes420

    Fawkes420 Member

    Yes! Thats exactly my plan.
    One thing that came to me...
    If i mount like,,,
    strip28mm-space15mm-strip28mm-space15mm etc.
    OR...
    Strip,strip56mm - space30mm - strip,strip56mm - space30mm-
    Which would you think is better? Or is both equal regarding heat transport, airflow?

    And... Would it be sufficent to use L-profile (40mm high)instead of U-profile (24mm highx2)(half the price)?
     
    Last edited: Feb 9, 2018
  6.  
    1212ham

    1212ham Well-Known Member

    Strips are not the problem, It's the enclosure blocking airflow. Strips should be mounted "naked' by the ends, or attached to aluminum angle/channel with gaps in between for airflow.
     
  7.  
    wietefras

    wietefras Well-Known Member

    @Fawkes420 , Are you going to run that many strips? I'd say normally you'd have something like 10cm space between the strips? Or more for double row led strips.

    I used 25mm wide and 15mm tall U-channel for single row strips (19mm wide). Seems to work fine:
    LedStrip_FLIR.png

    The U-channel is around 35C, the PCB backing of the strip (where the cursor in the center of the FLIR image is) around 45C and the hottest bits are the SMD's running at something like 50C. Normally I have some airflow over the frame and it runs somewhat colder, but even without any airflow it's doing fine.

    The FLIR image is from the bottom of this VEG light :
    2x24W_5000K_Boven_DSC3956.jpg

    Because this is a VEG light, the strips are spaced about twice as far apart as one would use for flowering.
     
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  8.  
    Fawkes420

    Fawkes420 Member

    Well. I just might need to reconsider my design.
    Now i'm leaning to a 2-row design with 6 strips/row. With a total lenght of 500mm and with 6 strips leave approximately 65mm space between strips.
    I also lean to a contruction in aluminium L-Profiles as described earler by Weitefras (good idea).
    Maybe comes more changes before finished but hell,,, thats part of the fun of DIY :eyesmoke::eyesmoke:
     
  9.  
    wietefras

    wietefras Well-Known Member

    What do you mean a 2-row design? a 2ft (56cm) strip covers the whole widt/depth of the space already doesn't it?

    With the efficiency of these strips you need about 320W/m2. So you;d need about 320W * 0.36m2 = 115W for the whole 2x2 space.

    Those 2ft led strips with a single row of leds consume close to 25W each. Making 150W for 6 of them. That would still work, but it's getting kind of high.

    It's really incredibly easy to make a led strip light.

    I wouldn't copy the hanging design though. That's supposed to be temporarily. Still waiting for parts to replace that.
     
  10.  
    Fawkes420

    Fawkes420 Member

    I have the 1ft ones since i was planning to have a design of 12 in a row, but now i will put 2 1ft strip at every 56cm heatsink x6.
    The frame will be 560x500mm, and my closet is 600x600.

    * System Specs:
    Type: C.V./Parallel

    Diode Count: 672

    System Voltage: 19.6V

    System Current: 6,000mA

    System Power: 117.6W

    Lumen Estimate (3000K): 20,160

    Efficacy: 171 lm/w

    *= From Ledgardener
     
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