Seed Spotlight

Positronics Seeds - Purple Haze #1

Purple Haze #1

Constructed from Mexican, South Indian and Thai variety up until the '70, this plant posseses an incredible resin development. Deliver a clear and energetic high.

Seed Spotlight

Positronics Seeds - Blue Rhino

Blue Rhino Seeds

Blue Rhino is the outcome of careful selection among numerous plants from a classical breeding procedure that makes positive that simply one of the most powerful and exquisite hybrids more knowledgeable growers were demanding.

Breeder Spotlight

Positronics Seeds


One of the first of the Holland seed breeders, Positronics has earned a solid and respected reputation. Positronics set out with the mission of ensuring that home growing supplies were available to everyone.

How to build your DIY LED array

Discussion in 'Lighting' started by knna, Aug 23, 2008.

  1. Offline


    So why dont I see more people using this route. Cheap and easy. Is it not worth the trouble or something?
  2. Offline


    Hi all,

    Long time lurker, first time poster! :lol:

    I'm in the process of designing an LED setup currently. I've read through (most) of this thread, as well as many others (lighting concepts etc) which has been very informative! Special thanks to KNNA, The Bong Master and others for sharing their hard-gained knowledge.

    From reading, it seems a good basic spec is something along the lines of:
    9 cree XP-E reds 630nm
    2 cree XP-E cool white
    1 cree XP-E royal blue 450nm
    2 660nm Ledengin "5W" for flowering only

    However, given the efficiency advancements made in white LED's over the last few years compared to the lack of progress in the red spectrum, does replacing all three types of XP-E with a top-bin 2600K XP-G make any sense?

    Looking at the spectral power distribution of XP-G warm whites, it doesn't seem too far off: A little too much at 450nm maybe and too much from 500-600nm also but there is still plenty of light from 600-660nm and this can be further supplimented with Ledengin 660nm's as required.

  3. Offline

    The Bong Master

    I myself like whites. Some prefer just blue/red.

    There really isn't a whole lot of data on what works best yet as far as spectrum and ratios. Rather than the 630nm reds, warm whites could replace them. Same for the 450nm blue. The only drawback is it is hard to calculate the radiant power from just one waveband of the white LED. The red and blue LEDs could still output more radiant power at that wavelength.

    KNNA could word it better, but that is the basic understanding. You do not get all the radiant power of a white in the certain wavebands you want to target, you only get partial power from that band.

    On the other hand cannabis loves light intensity, and whites provide the best intensity, so supplementing with more white only helps your garden. I would still not dismiss the far red and blue sides of the range though, the whites wouldn't output as much as a colored LED would in those specific bands.
  4. Offline


    hey guys, a novice question here, if I am to get a soldering iron for soldering LEDs, how much watts I have to look for? 40W? Many thanks!
  5. Offline


    40W is fine.. I have a 40W Weller that does well. An adjustable station is best.. adjust temperature from low to high using a dial. Some work requires less heat than what tinning/soldering a star/diode would require. If doing PCB work/rework using the same high temperature, it can actually result in the copper traces coming right off the PCB. Same thing can happen with copper pads on a project breadboard PCB.. too hot, the pads lift right off while trying to solder a part. But.. try to solder a star/diode at the same lower temp needed for PCB work, and you'll never get the damn thing soldered. My 40W station runs about $50.

    jubiare likes this.
  6. Knna.. u a electronics major? damn.. wasn't good in science.. I can't even understand 1/2 of that.. I am trying the lazy way...check out my little op.. would appreciate your expert opinion. I am doing my first grow with LEDs
    DAMN! I should have seen this thread before buying and setting up my shit.. but actually, it all seems too complicated. I would have to stop smoking to understand all this.
    [admin note: please don't post to drawn attention to another thread -PM the member]

    Attached Files:

  7. Offline


    I have a better picture how to go about with Golden Dragon + and double sided adhesive copper tape... but do you guys think it is a good idea to attach star leds to the heatsink by using a double sided adhesive copper tape? if not, presume I don't want to screw them up, what's the best bet? cheers folks
  8. Offline

    The Bong Master

    Arctic Silver Thermal Adhesive. Way better thermal conductivity. It can be removed by a quick tap on the Star with a flathead screwdriver and hammer.
    jubiare likes this.
  9. Offline


    I finally have a list of parts together for my DIY led and would love some feedback. I know there is still no perfect ratio for a veg or bloom lamp but after reading over a countless number of threads this is what I have;

    Veg Lamp:
    6 Cree XT-E Royal Blue (450nm)
    8 Cree XP-E Red (620nm)
    2 Cree XT-E Natural White
    4 Osram Golden Dragons Deep Red (660nm)

    Bloom Lamp:
    27 Cree XP-E Red (620nm)
    18 Osram Golden Dragons Deep Red (660nm)
    5 Cree XT-E Cool White
    5 Cree XT-E Warm White
    4 Cree XT-E Royal Blue (450nm)
    2 Ledengin Far Red (735nm)

    The lamps will both be used in separate grow cabs of 45 x 50cm. I am quite happy with the overall cost of the veg lamp but the total for the bloom lamp is a little more than i would like so if there are any areas you see i could cut back please let me know. Not sure if it might be worth holding off until more efficient red leds become available, a XT-E Cree would be fantastic. Another key concern for me is electricity usage as i hope in the future to run the system from solar panels so finding the sweet spot between good yield and power usage is important to me.
  10. Offline

    The Bong Master

    I think they are both OK. I wouldn't really skimp on anything on the bloom lamp.

    What you could do is plan the bloom light for all of the LEDs, but don't buy them all right away and leave gaps. Realistically you should use 40W/square foot. You have almost 2.5 square feet there. All together you will have 65-70W depending on drive current, which is about where you want to be. If you are using one huge heat sink, you can allocate space for all LEDs and just install them when you can buy them. Maybe throw a couple CFLs in there to supplement in the meantime.

Share This Page