Cheap and Cheerful DIY using Citizen cobs

CobKits

CobKits

Well-Known Member
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
 
Dreddd

Dreddd

Well-Known 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:
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?
 
CobKits

CobKits

Well-Known Member
ilam said:
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?
Click to expand...
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
 
Dreddd

Dreddd

Well-Known 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?
 
CobKits

CobKits

Well-Known Member
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
 
CobKits

CobKits

Well-Known Member
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
 
Dreddd

Dreddd

Well-Known Member
CobKits said:
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
Click to expand...
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..

CobKits said:
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
Click to expand...
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?
 
guy_incognito251

guy_incognito251

Well-Known Member
CobKits said:
1000 mA in the sphere

3000k 90 cri gen 5 vs gen 6. and just to confuse things i thru the "H6" below BBL 90 cri gen5 version in there
definitely a slight shift

gen5 "H5": blue peak 449 nm, red peak 627 nm
gen6 "H5": blue peak 451 nm, red peak 620 nm

considering mccree YPF is 100% from 590-625 nm i wouldnt worry about it. the additional 5-7% PPF of gen 6 more than makes up for it
Click to expand...
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.
 
CobKits

CobKits

Well-Known Member
Dreddd said:
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..
Click to expand...
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
 
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?
 
CobKits

CobKits

Well-Known Member
Redoctober said:
@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)
Click to expand...
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
 
You must log in or register to reply here.
Top