Cheap and Cheerful DIY using Citizen cobs

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


    JorgeGonzales Well-Known Member

    So, this is my first cob build, but not my first DIY light. I built to a modest budget, and chose Citizen over Vero 29s after crunching the numbers and realizing Citizen is way ahead of Bridgelux at the moment, likely because they are a generation ahead right now.

    These are a minimalist design, meant to be easy to build in modular chunks, with aluminum angle, pre-drilled heatsinks, and hand tools.

    The parts for one lamp, not including screws and wire:

    4x Citizen CLU048-1818 $100
    1x Meanwell HLG-120H-C700B $52
    4x Mechatronix 9980 Xtra heatsinks $38
    4ft 3/4 x 1/8 aluminum angle $10

    Total with CLU048-1818: $200

    Draws 160W at the wall, ~167lm/W @ 3500k

    Same build with CLU048-1212 would be $150, and ~160lm/W. 1212 is a great deal, if it was easily available. It isn't. This type of build would work fine with anything smaller than a 3590, like a CXB3070 or Vero 29.

    I wanted one cob per square foot, so with the heatsinks that ended up being two 16" and two 12" lengths of aluminum angle, in an H shape like so:


    Honestly, single rivets and a dab of epoxy would have been just as effective as two screws in preventing slippage. I just wanted to be able to dismantle if I forgot anything, but it all went together fine.

    Then the heatsinks, which I attached with two thread rolling M4 bolts each. The holes are already drilled in the heatsink for a different cob holder. Test fitting the driver as well. The HLG-120H is a perfect fit for the 12" spacing.


    And the hard part was over at that point. I only snapped one bolt head, which is pretty good for me.

    Skipping to the finished light, I used solid core wire. If this was something that would be flexed a lot or taken apart and put back together a lot, no way. But I wanted something that stayed neat without being fussy, so it was perfect here.

    Editing to add, I forgot to mention the wire routing holes were sanded smooth to prevent wear on the insulation. Alesh shows safer and potentially neater routing aids here



    Love these cob holders. I ordered the Ideal to try as well, but they were fiddly as hell, and these allow an Angelina to attach directly.

    The only other interesting bit is the switch. A bit of magic with some resistors and a DPDT on-on-on, and et voila:

    Basically just putting one or two 24k resistors in series, using crap I had around the house. The 100% setting is an open connection between the dim wires, so it runs about 10W over the 150W it pulls with a 100k resistor.

    And that is about that. Some more pictures:

    image.jpg image.jpg

    Last edited: May 18, 2016
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    Evil-Mobo Well-Known Member

    Man that came out nice. So this would be used for a 2x2 space since you stated you wanted one COB per sq/ft?

    JorgeGonzales Well-Known Member

    Thanks! And yeah, I built two to go in a 4x2 space.

    Honestly even cheaper and more cheerful would be stepping up to an HLG-185 for like $4 more, and maybe some of the $12.50 Mechatronix mega heatsinks. That would give an extra 50W for $14 more, and a bit more weight. If CDI had those heatsinks in stock I probably would have.

    I built this around what I could get ahold of without a six week wait, but things are only going to get easier to build and buy.
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    Will Thayer

    Will Thayer Well-Known Member

    Mr Gonzales,
    A very clean build Sir. It is refreshing to see people using Citizens. I can get the CLU048-1212 over here for $11.90. Your post has nudged my hand closer to my wallet even though I promised myself to stop buying LEDs for a bit.
    I seem to be running out of grow space to put new fittings over. Perhaps in a month or two I will build the CLU048-1212 option.

    Thanks for sharing your build, great job.


    choomer Well-Known Member

    Nice build!

    I'm thinking of something similar to that but for individual 2'x4' stalls (8 COBs per at the moment but I have to buckle down and do some number crunching and I think I remember you posting specs for the Citizens in the "other COBs" post. Search looks to be my friend where Mechatronix specs are concerned).

    Did you go radial for any particular reason over pin/fin?

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    JorgeGonzales Well-Known Member

    Availability, cheapness, specs, and convenience. Or something like that.

    The 9980 had better slightly better specs than the Mechatronix pins (the ones in the Cutter kit), cost $9.50, were pre-drilled and ready to ship from CDI.

    Speaking of Cutter, the I think the CXB3070 is only $28 from him, might be a good choice, or the Nichia NFDLJ130B for $12 from Future Electronics looks decent. Decent being defined as better than a Vero 29 for half the price.

    There is also this place:

    Not to be confused with aka Mechatronix. China is rocking hard these days.
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    klx Well-Known Member

    Nice job mate. KISS at its finest.
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    Atulip Well-Known Member

    Very nice build. Wanted to build the 048-1212's myself if I can find them. The 038-1210's look comparable at 25w each or so. Haven't done the math though for the cost/w for those though, should be comparable. (going for similar design, but wanting 200w to spread over a 2'x4')
    JorgeGonzales likes this.

    BOBBY_G Well-Known Member

    sweet build seems like you could do a 3x3 pretty easily with that

    where did you find the clu048-1818 for $12.50 ea?
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    JorgeGonzales Well-Known Member

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    BOBBY_G Well-Known Member

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    BOBBY_G Well-Known Member

    So are you saying your cob cost was really $25 per for a total build cost of $250ish?
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    JorgeGonzales Well-Known Member

    No, the total was right, just can't multiply 4x25 apparently.
    Growmau5 likes this.

    BOBBY_G Well-Known Member

    bet you could multiply four times twenty, lol

    JorgeGonzales Well-Known Member

    Thanks Will, glad you liked it.

    Do you know if Marl ships outside of England?
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    Growmau5 Well-Known Member

    @JorgeGonzales awesome thread, amazing clean simple light! its very cool to see you break the Vero / Cree mold. I was actually going to PM you last night and ask if you could find the time to do a little write up on Citizen's offerings. I know there is a lot of discussion about them in the "COBs other than cree thread" Since you are pretty well informed about them, do you think you could do a post with a little rundown on their offerings, what the product codes mean, binning etc.

    cheers man.
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    alesh Well-Known Member

    Nice build. I suggest these for routing the wire through the alu angles. 6 mm hole required and the can take 2x .75mm2 wire (easily) or 2x AWG 18 wire (not that easily).
    And these ones for routing the wire on the angles.
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    Malocan Well-Known Member

    i asked marl if they would sell citizen cobs to germany, they told that they are not allowed to sell outside uk:/.
    they gave me the address for germany distributer, but the germany distributer only sell from company to company
    DankaDank likes this.

    JorgeGonzales Well-Known Member

    It's funny, I just finished a guitar amp build, and used grommets for the transformer wiring...

    I debated using grommets and guides on this build, but keeping in the spirit of cheap and cheerful I just sanded the insides of the holes smooth, since it will get jostled around a lot less than an amp. Glad you mentioned it though. Sharp edges will really do a number on wire insulation if given half a chance.

    I think I will add that to the top post before my edit timer runs out. Sigh.
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    alesh Well-Known Member

    Seems like you exactly know what you're doing. Might be useful, though, to have a thread about all these small useful...thingies.

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