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Introducing CobKits.com - specializing in DIY and Citizen COBs

Discussion in 'LED and other Lighting' started by CobKits, Aug 2, 2016.

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  1.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    are you vegging with the 4000K? not most peoples first choice for flower. ive got some 97 cri 4000k not up on site yet
     
    pop22 likes this.
  2.  
    Humanrob

    Humanrob Well-Known Member

    When I started building COB lights, most people were mimicking HID, so I had 5000k for veg and 3000k for flower (pretty much the widest spread readily available at the time). Over time it seemed the trend shifted to finding a middle ground so that a single light could be used from start to finish, and looking at the charts 4000k was a good compromise in terms of covering the plants needs. Others went with 3500k or even 3000k for their single light. People who compared 3000k vs 4000k (for flowering) said the 4000k plants had less volume but were frostier, that works for me. I never did a side by side comparison myself.

    I did a couple of grows with just 4000's and they were fine -- but now (in one tent) I'm mixing 4000k's and 5000k's for veg, and 4000k's and 3000k's for flower. My 4000k lights were stolen, so I need to replace them, that's part of what I'm shopping for.

    In my other tent I've been growing with 3500k and 4000k from start to finish. I might add a couple of 2700k to that set up to warm it up a bit more during flower.

    The discussions I've read regarding the impact of CRI seem to mostly be theoretical, and I don't have a lot of patience for that. I think I've read one or two threads on RIU where people have done side by side tests -- and what I took away from those were that with 3000k lights in flower higher CRI was preferred. I don't know if higher is always better in every kelvin range, so that's why I was asking.

    What is the benefit of 97CRI?
     
    Last edited: Nov 8, 2017
  3.  
    GrowLightResearch

    GrowLightResearch Member

    You may want to consider the Samsung F-Series Gen3 strips. At $14 for a 4 foot long strip it is very difficult to build your own for less than this.
    They come in 2 foot and 4 foot with a single row (FB22B and F562B) of LEDs or dual rows (FB24B and F564B). Although the dual row has a better cost per LED the single row strips will cost a bout $4 more to get 2 single row strips verses 2 single row strips. With the single row strips you can improve your uniformity across the canopy. The improved uniformity will allow you to position the strips closer to the canopy.

    The following post has a photo of a DIY fixture made with these strips posted by @graying.geek


    @Stone_Free recently comments about these strips as well.



    DATASHEET LINK: https://media.digikey.com/pdf/Data Sheets/Samsung PDFs/F-series_Gen3_Rev0.0_2017-01-05.pdf
     
    Stone_Free likes this.
  4.  
    Humanrob

    Humanrob Well-Known Member

    @CobKits -- how about a simple question: Is it OK to mix Citi 048-1212 and Cree CXA-3070 COBs in a serial run?
     
  5.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    yes you can mix any cobs or leds for that matter in series as long as the current is a match for both. in other words not running 1400 mA thru a single LED with max current 1000 mA
     
    Humanrob likes this.
  6.  
    Lost Green

    Lost Green New Member

    Hey CobKits,

    I've been reading through your threads getting ready to purchase a set-up for a 4x4x6.5 tent. I was all set to by Cree CXB3590s until I stumbled upon a thread or two of yours (so thanks for saving me some $$, I'll hit you back with some sales dollars).

    The new HLG-600H-54B looks awesome for my tent size. Does a constant current, constant voltage driver need to be wired in parallel? I thought I read somewhere that COBs wired in a series will draw Volts equal to driver volts/# of cobs, which would imply the answer to my question is yes. Is thermal runaway a concern with parallel wiring for the cobs?

    The main thing I am confused about is how Luminus cxm22s can run of 54V though? The Luminus cxm22 data sheet seems to show a maxium forward voltage of 37.5. I am sure I am missing something.

    upload_2017-11-8_21-7-53.png
     
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  7.  
    klx

    klx Well-Known Member

    Cobby, have you ever seen an issue with multiple drivers wired in parallel to a single power lead?

    I am having a problem where I can only fire 2 x 250W drivers from a single power socket and if I add a 3rd it will not light up. I would have thought 600W spread over 3 drivers would be no problem but maybe its too much for a single 10A 240V socket?
     
    pop22 likes this.
  8.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    yes

    not exactly. say your driver is 186V and 1400 mA.

    at 1400 mA your cobs are 34.5V
    the cobs use 34.5 X 4=178 V of voltage. the other 8V goes unused. As opposed to 186/4 = 36.5V per cob. Remember cobs can ONLY operate at the corresponding voltage in the datasheet (+/- normal variations)

    that datasheet is not gen3. gen2 cxm22 were 36V cobs
     
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  9.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    on the AC side?

    unless your wire is horrendously undersized you would trip the breaker before you dropped the voltage

    theres gotta be something obvious were missing. have you confirmed all drivers are wired the same (in-phase)
     
    pop22 likes this.
  10.  
    klx

    klx Well-Known Member

    Yes AC side. The wire is fine because I am using the cable from the drivers connected directly to an extension lead.

    I have confirmed the wiring about 10 times. I have redone it, I have run them on their own. Weirdly, when I hooked up each driver with its own power lead and plugged them into a powerboard, only 2 would light up. I can also rule out the house wiring because I hooked it up to a dedicated 15A line and still only 2 would light.
     
    pop22 likes this.
  11.  
    pop22

    pop22 Well-Known Member

    Do you have the new type breakers with the" fire prevention" circuitry? They can do funky things.........

     
  12.  
    klx

    klx Well-Known Member

    Thanks for the suggestion but I figured it out. It was the potentiometer causing it. As soon as I removed it, everything lit up fine.
     
    pop22 likes this.
  13.  
    pop22

    pop22 Well-Known Member

    Ahh I had the same problem!
     
  14.  
    GrowLightResearch

    GrowLightResearch Member

    A single 600W driver is often not the best fit. The HGL with the best cost per watt is the mid-power 185 and 240 watt. You have to look at the combination of supplies with the number of watts being used.

    CoBs should NEVER be wired in parallel. You should use the high voltage output HGL-xxH-Cxxxx Type A.


    Wire them in series.

    I would run them light at 1000 mA driving five CXM-22s with a HLG-185H-C1050 Type A.

    I would not run these CXM-22s at more than a maximum of 1400mA. Drive four of them with each HLG-240H-C1400 Type A.

    The HLG driver automatically adjusts the voltage output to the forward voltage required by the CoBs.

    In the case of driving five CXM-22s @ 1000mA, the voltage will be about 5 x 35 = 175V (188V max). the voltage range of the HLG-185H-C1050 is 95V - 190V.

    Possibly.
    The real problem is the forward voltages of the CoBs are not all identical. When wired in parallel they will all be running at the same forward voltage. They each should be run at their own forward voltage.
     
    Last edited: Nov 9, 2017
  15.  
    burnpile

    burnpile Member

    If making a linear fixture with these what is a good spacing? They will be run at approx 60 watts ea, the fixture is similar to a tube, one side is a heatsink that the cobs are mounted to. There is a fan at one end to move air over the heatsink. I was thinking about 10" c-c, the whole fixture would be approx 36" long.

    Meant to say Luminus CXM22 Gen3 3000K 90 CRI.
     
    Last edited: Nov 9, 2017
  16.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    the larger "HLG" drivers do cost very slightly more per watt (~2 cents/W) but are also substantially more efficient so thats a quick payback. also easier wiring for some setups if its a fit


    That is false. there are numerous ways to wire cobs safely in parallel. using more than 3 cobs per driver, using drivers with the proper voltage range and limits, etc.
    not sure where this suggestion is coming from but there is no reason cxm22 cant be run above 1400 mA with adequate cooling. Their maximum rating is a (very conservative) 2400 mA. That said 1050-1400 mA (50-75W) is a great range and very popular for these chips

    Constant current drivers do no form of "voltage adjustment", they control current to the cobs which operate at the proper forward voltage for that current
    with all due respect, please stop posting information in my thread on things you dont fully understand. the CXM22s i sell are not 36V cobs

    not a "problem" per se. about a max of 1/2V spread in most lots of chips which is less than 10% on a flux basis which is essentially irrelevant in an array. flux per chip is not the same in a series array either as each chip is running at a fixed current but independent voltages
     
    Last edited: Nov 9, 2017
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  17.  
    Lost Green

    Lost Green New Member

    that datasheet is not gen3. gen2 cxm22 were 36V cobs[/QUOTE]

    Thanks - I was definitely looking at the Gen2 datasheet. One last question for you:

    If I am wiring 16 cxm22s to the HLG-600H-54B, can I use the Wago 5-wire connectors to do the parallel wiring? First Wago would have the positive in from the driver + 3 cob positives + 1 wire to the next Wago, second - fourth would have the positive in from the prior Wago + 3 cob positives + 1 wire to the next Wago, fifth and last Wago would have the positive in from the prior Wago + 4 cob positives (3+3+3+3+4=16 Cobs using 5 Wago 5-wire connectors). Negative side would just be the reverse of that.

    The reason I ask is because I'm not sure if the Cobs on the first Wago connector would get more Volts/Amps than the cobs on the last Wago. Might be a dumb question.
     
  18.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    you just ordered that yesterday?
     
  19.  
    Lost Green

    Lost Green New Member

    Yessir - I like to get my research done beforehand haha
     
    Last edited: Nov 9, 2017
  20.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    packed up and ready to go.. i threw in 8 5-slot wagos, thermal paste and a 100k pot

    ill throw in 2 more wagos, look for them separately just gonna cut a small hole in the box and insert surgically ;)
     
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