DIY LED for 1 auto plant - advice needed

Discussion in 'Indoor Lighting' started by bzz945, Mar 1, 2017.

  1. bzz945

    bzz945 Registered

    I want to make it the most basic and most efficient.
    I plan to grow 1 plant, autoflowering under LED (these are freebies my friend got from seed shop named auto diesel x auto AK feminized) also gonna go with DWC setup.
    So most basic design, crapton of small low power LEDs and simple efficient circuit resulting with smoothened 230V DC and LEDs in long chains. No fancy billions of colors, just red and blue.
    What I wondered is:
    What wattage should I aim at? (looking at upper limit)
    Should I use resistors? or just lengthen LED chain (highest efficiency possible is what interests me the LED is most efficient within 10-20mA range, however I have no measuring equipment, so no idea how LED reacts on undervoltage)
    Should I add an option to modify red/blue ratio for different grow stages?
  2. Weezard

    Weezard Registered+

    There is a single chip solution for that.
    The parts are available from Aliexpress dot com
    A 77 mm. 100W. R:B 660nm.:450nm. -- $43
    It fits on a heat sink, lens, fan combination that runs ~$35.
    A constant current driver that runs on 250V is also available from the same source.
    for $23 .
    I slapped this one together in a half hour and am very happy with it.
    It will grow 3, 3' tall plants easily.
    Runs about 90°F. with an ambient of 83°.
    Same company has waterproof bi-color grow lights assembled for excellent prices.
    Their 50W unit runs $67. Just plug n grow.

    Wee 'zard
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  3. bzz945

    bzz945 Registered

    Thanks for these, however simplicity or low cost is not what I am looking for, I want highest efficiency possible.
    I see your approach here is making things simple, however using 12V power supply is first inefficient part, you can run LED in long chains off 230V, just gotta make it DC and stabilize (electronic stabilizer is better than large caps)
    And you can't avoid physics, modern LED producers pump 30-300mA and 12V+ trough because they made LED capable to not break at high temp, however efficiency curve shows LED is most efficient at 10-20mA range (concluded from data data sheets provided by multiple LED producers, like Cree), so my approach is classic: 1000+ LEDs I have soldering skills and lots of time, don't worry.
    PS. Having multiple tiny sources will help for even distribution of light instead single beam that might burn plants.
    PPS. multiple LEDs will make light band more stretched as my theory is: narrow band spike - overload, using many cheap LED whom light band differs a little one from another would allow higher margin of error because of lack of said spike.
    PPS. It's too late to edit opening post and adding "most efficient" on title and within text.
    Last edited: Mar 2, 2017
  4. Weezard

    Weezard Registered+

    Yeah, did all that years ago. :)
    HGL14bottom.JPG LEDboard front.JPG
    What I found is not what I expected.
    "In theory, theory and practice are the same. In practice, they are not!"

    Wide, weak arrays fall victim to the inverse square law and can not grow big.
    They are fine for SOG or SCROG, but not so much for big bush.
    So I went to 3, and 5 W. arrays. cooler brick.JPG
    Worked very well but still lacked "penetration, so I tried lensing.
    Still left bottom leaves wanting on >2' plants.
    Then high power leds arrived.
    Those are 15 Watt emitters. This 10 year old build is still in service. :)
    I wanted 4' plants so. . .
    That's 150 Watts of high power emitters and it works a treat.
    The reds are 660 nm. at their peak.
    Peak absorption in cannabis is 657 nm.
    635 nm. leds waste a lot of photons.

    And the new tech is easily adjustable for beam angle with a single lens adjustment from 180° down to 60°.
    And that 100 W. chip driven to 70 Watts is extremely efficient in targeted photons per watt.

    Oh, and that 12v. power supply in my newer build is just for the fans.
    The led chips take 36v. current limited to 3,500 ma. Not shown because I remote it to keep heat out of the grow room
    I drive them at ~3 amps for efficiency and cool running.

    The first thing I learned, right away, was that a current limited supply is a must.
    Turned a few expensive emitters into slag playing with V.R. and limit resistors. :(

    So, go ahead and do what your theory seems to indicate. It's fun! And educational.
    And I'll meet you back here in about a year. :)

    Wee 'zard
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  5. bzz945

    bzz945 Registered

    Okay mate I wont experiment much then as I briefly browsed trough your stuff and will assume you are an expert on this matter, just advice me what I should go for.
    Max yield for least watts is my goal.
    Assuming you are advising me single chip solution.

    These are available on my local online market:
    And single grow chip modules 32V , 20W 30W 50W 100W narrowest lens for it 60deg then 90, 120
    Claimed producers from auction: epileds, epistar, bridgelux, all claim to be full spectrum, with traces of UV band as well

    PS. is there private message option on this forum?
    PPS. I have close loop water cooling lying around. Corsair H70 driving overclocked 130W CPUs at 74C (55C no OC), Do you think it would be good cooling? Also liquid metal thermal compound, but not sure what back of the chip is made of, if aluminum compound would eat it. So might use other, less extreme quality paste.
    PPPS. Reminder it's gonna be for auto plant, and only single one, grown with DWC
    Last edited: Mar 2, 2017
  6. Weezard

    Weezard Registered+

    I have done side by side grows to test the need for UV.
    I found that it does more damage than good.

    It does not increase resin production, or quality.
    It does damage surface cells and ages the capitate glands to the point where I had a lot of un-capped trichomes.

    I now use UV filters on the greenhouse roof for the outdoor flowering.
    And my arrays contain 0 UV.
    The commercial units touting far red that come on and off with the rest of the light are clueless.
    Far red is only useful when applied at lights out for a short time.
    that and all the rest of the "full spectrum" hype is marketing.
    The single chip I use has a copper base and works fine with most thermal pastes.

    Sounds good, you know how to find out, yah? :)

    It's the best I've found so far. 660:450 in a 4:1 ratio is an ideal compromise.
    I would prefer a little control over the ratio, but I have some stand alone blue emitters that I can use to tweak it for tighter internodes in the seedlings.

    Blue Phil.JPG
    It's a workaround, but whatever works, yah?
    I do this because we get gouged by the power company.
    We pay 4X what the mainland does.
    I need the most efficient system I can get for the least effort and cost from me.
    Because I'm lazy and I'm broke.

  7. bzz945

    bzz945 Registered

  8. Weezard

    Weezard Registered+

    I'm using their 100 Watt with a 90° lens because I like to veg to 2 or 3 feet and then put them out to about double in height.
    Also just built a 2, 50W. 660nm. chip array but have not put it in service yet.

    Still waiting on a blue companion chip.
    The early ones are getting long in the tooth.

    You found the right vendor in spite of the typos in the ad.
    While I was looking, I spotter some E27, 18W. 660/435 floods for $2.83 ea. w/free shipping.
    The ratio is blue heavy.
    Zackly what I need to pop some seed.

    Bought 4 for my new seedling rack.
    72W. for less than $12?!
    Ordered them partly to see if it was an error. :)

    This DIY used to be arduous.
    Now, it snaps together from trailing edge surplus like legos.

    I love livin' in the future, pickin' up techno crumbs to play with. :)

  9. bzz945

    bzz945 Registered

    Hey it is growing well, I have built smaller light for sapling from intel stock cooler, 9x3w LED
    to not bother with problematic commercial mylar I went lazy route.
    Bought training mat with aluminium shiny side on one end, built 40cm tall tube and it is 15cm diameter. Enough for sapling.
    But to the point, this small light runs at full power - 27W it is about 30cm from plant, I am afraid burning it, is there cheap plant I could test light intensity on?
    Different plants have different light needs. I did wonder, what popular plants I could burn for test instead risking burning precious little baby.

    DWC seem to work well BTW plant is intesily green, however after few days nute water starts to give specific smell, not sure what might be the cause, high class airstone (that is actually woodden) or clay pebbles I never used, washed it like 10x before use.
    Other thing that keeps wlrrying me is constantly rising PH, gotta use PH down all the time and keeping stable PH between 12h time is a nightmare.
    I planned to use automated PH station on bloom final container, but if I will get mad I'll install it in this tiny start setup.
    Also since I wont use chip water cooling I gonna use old graphic card cooler for my big light.
    I think you will be interested in build process as it uses recycled parts.
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  10. Weezard

    Weezard Registered+

    Indeed I would.
    I love to see creative constructs. :)

    A follow up on those 18 Watt mini spots.
    My Watt meter says ~ 5 Watts per bulb.
    So 20 Watts for under $12.
    Not as big a bargain as it seemed. :(
    But, wait, it gets worse.
    After just 15 minutes they were too hot to touch!

    Meh, too good to be true, is usually just that.
    However, the 100W. bicolor chip is working very well.


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