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Cheap and Cheerful DIY using Citizen cobs

Discussion in 'LED and other Lighting' started by JorgeGonzales, May 17, 2016.

  1.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    heres just the H5 "on BBLs". i normalized the gen6 to 1.058x the response based on my par measurement difference at that current. as you can see youre not really missing out on any significant amount of red, but there is substantial extra photons in the very active 560-650 region
    upload_2017-3-20_15-41-24.png
     
    MrTwist1, Moflow, Joe34 and 1 other person like this.
  2.  
    Dreddd

    Dreddd Member

    Excellent post, thank you.

    i'm thinking about pulling the trigger on 8 90 CRI 1818's to build 2 lights with, one with an HLG240H-C and one with an HLG320H-C, i'm just not sure what mA i should go with...?
     
    Last edited: Mar 20, 2017
  3.  
    ilam

    ilam Member

    Hey @CobKits i have a question. It's not specifically related to CITI cobs but you're knowledge about cobs so yeah... I'm wondering about PAR measurements dropping with distance, obviously that's expected, and although theoretically it's supposed to follow the inverse square law, i've noticed that it really doesn't.

    I'm running Citi and Lumi COBS, and i can only measure in Lumens, but i've noticed my readings being a lot higher than what i've calulated.

    So i'm wondering what your experience has been with measurements over the usual 12'' point. Have you noticed how the PAR readings drop at certain distances like 2FT? Do your readings really halve at that distance? Or Become a third at 3ft?
     
  4.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    1050-2100 is best range for those imo
     
  5.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    inverse square law only works in an area with zero reflectivity. it will always drop off less than than in an area with any reflectance
     
  6.  
    Dreddd

    Dreddd Member

    I think i got it, with the HLG240 i can run 4 cobs at 200w and with the HLG320 i can run 4 cobs at 280w, both cases not really utilizing the drivers to their full potential, would it be possible to run 4 1818's @ 1750mA for a 350w total or will the 320w driver not be able to support it?
     
  7.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    which models that sounds low
     
  8.  
    Dreddd

    Dreddd Member

    the 1818's with CC drivers? i'm open to suggestions..
     
  9.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    yeah hlg240 is not an ideal fit for 50V cobs in CC- the CV drivers are better for maxing out. the discrepancy etween CV and CC is not usually this great but 240 CC series has wierd voltage cutoffs

    at full tilt:
    6 cobs:
    -C700B model dimmer leads open, 105%, ~735 mA >35.5W x 6 = 213W
    -C700A model, 754 mA>36.4W x 6 = 218W
    -48A model: 5.42A/6 = 903 mA = 44.2W x 6 cobs = 265W

    4 cobs:
    C1050B model dimmer leads open, 105%, ~1100 mA >54.5W x 4 = 218W
    C1050A model, 1.281A >64.2W x 4 = 250W
    -48A model: 5.42A/4 = 1355 mA = 68.3W x 4 = 273W

    3 cobs
    C1400B model dimmer leads open, 105%, ~1470 mA >74.6W x 3 = 224W
    C1400A model, 1.623A >83.1W x 3 = 249W
    -48A model: 5.42A/3 = 1806 mA = 93.4W x 3 = 280W
     
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  10.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    HLG320:

    4 cobs:
    C1400B model dimmer leads open, 105%, ~1470 mA >74.6W x 4 = 298W
    C1400A model, 1.626A >83.2W x 4 = 333W
    -48A model: 7.66A/4 = 1915 mA = 99.6W x 4 = 399W
     
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  11.  
    Dreddd

    Dreddd Member

    Hold on you're saying the HLG240H-C1050A can run 4 cobs for 250w while the C1050B only goes as far as 218w?, that's quite the difference..

    Thank you, which one of these three setups do you think would match a single ended 600w HPS? can i get away with the 298w?
     
    Moflow likes this.
  12.  
    guy_incognito251

    guy_incognito251 Member

    Thanks for the gen 5 90 CRI on BBL vs below BBL comparison - the graphs on the Citizen data sheets look identical which didn't seem right.

    It explains the lower lumen output of the below BBL cobs.
     
  13.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    they test closer than that on par
     
    guy_incognito251 likes this.
  14.  
    guy_incognito251

    guy_incognito251 Member

    I hope so - I have some of the 1212 3000K below BBL cobs
     
  15.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    just going by the test reports. havent tested thsoe specific models on the bench but the reports have always been spot on with ones i have tested.

    since they changed their datasheets, its hard to know what % of output 'open leads' corresponds to on the B models. 105-108% is pretty typical. A models always go higher in my experience. sometimes a little, sometimes a lot
     
  16.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    guy_incognito251 likes this.
  17.  
    Nutria

    Nutria Member

    I have 4x 1212 @1A in a 2x2 tent for 800ppfd
    If I add 1x [email protected] for 200ppfd (diy calculator)
    is the total ppfd a sum ? 1000ppfd?
     
    Moflow likes this.
  18.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    yes assuming coverage is even
     
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  19.  
    Redoctober

    Redoctober Well-Known Member

    @CobKits I'm assembling a Citi COB light setup I have noticed that you tent to favor the 1818 52v COB over the 1212 36v version , just curious as to why? (maybe better efficiency)

    My thinking was that having more COBs with slightly less output would give more even coverage and a slightly wider arrangement of possible spectrum combinations.

    i.e. if putting together a ~750w setup, two theoretically equivalent paths would be either ~ 14x 1818s... or ~ 21x 1212s and wind up with roughly the same wattage output.

    I've been thinking that more 1212s would be better even though I know the 1818 chips have more than double the amount of diodes that the 1212s do

    I wonder what your thoughts are on which direction you would go and why?
     
  20.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    1818 is probably my least favorite.

    1212 and cxm22 are the best bang for the buck that i have. if you want to go big (100+ W/cob), 1825 is a good choice
     
    Redoctober likes this.

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