Cheap and Cheerful DIY using Citizen cobs

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mduke

Well-Known Member
JorgeGonzales said:
Wish I had an easy answer to that. If optics were sorted, it would be easy. 1825 @ 1050mA, 53W each. Crush it.

4 1825s for a total of 200V, 212W on an HLG-240H-C1050 or equivalent. 85% load might annoy some people, I don't mind running drivers cooler as long as they are in the efficiency sweet spot.

Alternatively, the 1818 @ 700ma like I did. 35W each, fits 4 cobs well on an HLG-120-C or 7 cobs on a 240H-C. 700ma is a good Meanwell match for the 52V versions.

Practical answer might be 1818 @ 1050mA, which @robincnn shows ahead of 3590 CD at 50W. It has holders and reflectors and you can do a 1:1 cob ratio, for literally half the cob price as Cree. We are still figuring out real current droop, "we" being robin and @BOBBY_G , so who knows.

------

But!

It's a great question that really makes me learn answering it. The way the lineup is arranged you could replace one 1825 with two 1812s and have nearly identical perfomance across the board. Heat dissipation per area, efficiency, the whole nine. Then you have twice the spread, and twice the pain in the ass to build.

But I guess that's the really cool thing. 3x 1212 (432 die), 2x 1812(432 die), 1x 1825(450 die) are all roughly equivalent and cost the same to buy. It's a brilliant lineup. 1818 is a Goldilocks cob.

Sorry, I have a hard time not giving nuanced answers with lots of qualifiers. Maybe somebody else can help.

A more fun answer would be 1812s replacing Cree at a 2:1 ratio running at 500mA/25W each. Unfair? Maybe not when you can buy two 1812s for every CXB and still have money left over for you and your gal at In-N-out.

Anybody else?
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do you know what efficiency of each of these cobs would be? so the 1825 @ 1050ma, 1818 @ 700ma, and the 1818 @ 1050ma?

do you mind explaining how you calculated said efficiency and point to any data sheets that were used. I barely wrap my head around the whole Cree COB and without supra's spreadsheets i don't think I ever would have, hence all the rudimentary questions.

like GM i'm interested in building a DIY led fixture that has similar to better PPFD values and efficiency to cree cobs but it would be nice to make a fixture for 30-40% cheaper
 
JorgeGonzales

JorgeGonzales

Well-Known Member
nevergoodenuf said:
That duel input might be throwing it for a loop. So for me 243 watts @ 135 lumen per watt with the 3500K 80 cri
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OK, I think you must be right. Well, we both are. I'm pretty sure the data sheet for the CLU058-3618 is incorrect, because of the error I pointed out.

I was mistaken that the CLU550 was last generation (I think?) even though they stuck it in their Version 4 cob simulator.

So the CLU058-3618 will be more efficient than half of a CLU550 at the same watts (36*18 vs 36*13), but the two halves of the CLU550 running at an equivalent wattage of one 3618 will be well ahead.

Christ.
 
weed-whacker

weed-whacker

Well-Known Member
JorgeGonzales said:
Fuck, why are the CRI and Phosphor codes in the CLU550 model code the same as version 4 then? I give up.
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when i first looked at it i thought that indeed the 58 was better, i think u just get more bang for buck because you drive the 550 in parallel, although its unclear if the data sheet is per channel or combined as far a the current goes, at least to me its unclear
 
JorgeGonzales

JorgeGonzales

Well-Known Member
mduke said:
do you know what efficiency of each of these cobs would be? so the 1825 @ 1050ma, 1818 @ 700ma, and the 1818 @ 1050ma?

do you mind explaining how you calculated said efficiency and point to any data sheets that were used. I barely wrap my head around the whole Cree COB and without supra's spreadsheets i don't think I ever would have, hence all the rudimentary questions.

like GM i'm interested in building a DIY led fixture that has similar to better PPFD values and efficiency to cree cobs but it would be nice to make a fixture for 30-40% cheaper
Click to expand...
https://www.rollitup.org/t/if-you-are-new-to-led-and-want-help-choosing-what-to-buy-post-here.633304/page-280#post-11416189

This is a good explanation, also here:

https://www.rollitup.org/t/math-behind.868988/

As far as efficiency, who knows what the real numbers are. Might be that every combo you named matches or beats the CXB3590 CD.

On paper:

1818@700 49.5%
1818@1050 47.5%
1825@1050 51.6%

But see this post, for example, and draw what conclusions you like: https://www.rollitup.org/t/top-bin-cob-comparison-2.897765/page-5#post-12726618
 
OldGrower

OldGrower

Well-Known Member
@goofy81 no it does not use the current just measures it, but you do need some dc voltage to run the meter mine was
in a range of 4.5-40v or so. Gl OG
 
G

goofy81

Well-Known Member
Excuse my noobness. But is it wired in series just as if there was another COB? If so, did you position it at the beginning or end if the series?
 
OldGrower

OldGrower

Well-Known Member
@goofy81 , yes in series and I put mine as the first thing on the positive lead but it really does not matter.
If you don't have dc power you could always use batteries, a 9volt would last a long time. Gl OG
 
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