LED FAQ) Building and DIY

[Dion]

that's the cxb 3070 at different k° and cri:

[URL=https://www.icmag.com/ic/picture.php?albumid=64409&pictureid=1576531&thumb=1]View Image[/url]

hold on, is useless dedicate a mono for that red, the 600-660nm are well covered by the cob. imho.
i meant this when i said useless.
what we should play with are the 700-730 nm and the uv-a and uv-b.

look at the 3000°k 90 cri, a little early than 600nm and a little after the 660 nm the spectral power is still equal or higher than 60%, which is higher than a 3000°k 80 cri and way more higher than a 4000àk, and i do think even than a 3500°k.

i'll say again, imho, with a 3000° and a 5000°k you've the PAR well covered, on both the external pick, red and blue, what is lacking, according to the graph is a boost on the 730-680 nm and 450-380 nm, where i see a spectral power lower than 60%.
my point is to get the all the spectrum needed covered, not increase a pick value.

that graph is relative spectral power aka how many watts dedicated to each wavelenth not how much light it being put out

 

[jikko77]

In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength.

Spectral Power Distribution, SPD. IESNA Definition: A pictorial representation of the radiant power emitted by a light source at each wavelength or band of wavelengths in the visible region of the electromagnetic spectrum (360 to 770 nanometers). Lamp manufacturers publish SPD curves of specific light sources.

What is a spectral distribution?
In radiometry, photometry and color science, a spectral power distribution (SPD) measurement describes the power per unit area per unit wavelength of an illumination (radiant exitance).

 

[ballsack]

reparing a cheap cob light

reparing a cheap cob light

I bought a broken 6x 50 watt cob 300 fixture on ebay. All 6 cobs are doa.
I’m adding a lot more heat sink to it cause like most of these they use cheap cobs,overdrive them and have very poor cooling. So just to get my feet wet and understand how how they work so I can build a nice cree 3690 light later.
My question is using 1 driver for each cob what cob should get. The driver has 40v
Output at 1500ma. I want a 50watt cob that I can under drive 750ma instead of 1500ma which would probably fry. Would 2 chips on 1 driver in parallel cut the 1500ma
Down to 750ma ea. I’m still going to use the cheapo cobs on the first test.

 

[Dion]

I bought a broken 6x 50 watt cob 300 fixture on ebay. All 6 cobs are doa.
I’m adding a lot more heat sink to it cause like most of these they use cheap cobs,overdrive them and have very poor cooling. So just to get my feet wet and understand how how they work so I can build a nice cree 3690 light later.
My question is using 1 driver for each cob what cob should get. The driver has 40v
Output at 1500ma. I want a 50watt cob that I can under drive 750ma instead of 1500ma which would probably fry. Would 2 chips on 1 driver in parallel cut the 1500ma
Down to 750ma ea. I’m still going to use the cheapo cobs on the first test.

hi welcome

so you can run 2 cobs per driver, wired in parallel

each cob will get 750mA

bet depending of the cob you get there are better options


if u just wanna play order a 10 pack of those chinese cobs or just buy a siingle cxb3590 and run that driver direct to it on a pc sink and u r good to go



@jikko77

http://spectra.1023world.net/


i like this site for dreaming of lights

 

[jikko77]

@jikko77
http://spectra.1023world.net/
i like this site for dreaming of lights

thanks man, i'll try to play as well

 

[Dion]

thanks man, i'll try to play as well

this is my current spectrum

likely off but thats what i have now

100w of 3000K plus 15w of 420,440, 450nm and 30w of 620-660nm

notice the spill over still gives a bit of far red


I want to see what you think would be the perfect spectrum?

 

[Mr Celsius]

First off, thank you for the good write up and all your time/effort.

I am looking to create an array that has a coverage of 4' x 8'. I'm looking for some clarification about what COB's I should buy and how many of them.

If I understand this correctly, 1 COB per sq ft is the recommended amount? If so, I would need 32 COB? Which COB is preferred at this point? CXB3070 or CXB3590? Lens, reflector, nothing? Also, if I understand correctly, for flower the 3500k is ideal?

I understand the technicals of wiring them all up, cooling them and how to drive them. I just need the guidance on how many and which.

Thank you

 

[Dion]

First off, thank you for the good write up and all your time/effort.

I am looking to create an array that has a coverage of 4' x 8'. I'm looking for some clarification about what COB's I should buy and how many of them.

If I understand this correctly, 1 COB per sq ft is the recommended amount? If so, I would need 32 COB? Which COB is preferred at this point? CXB3070 or CXB3590? Lens, reflector, nothing? Also, if I understand correctly, for flower the 3500k is ideal?

I understand the technicals of wiring them all up, cooling them and how to drive them. I just need the guidance on how many and which.

Thank you

CXB3590 3500K CD bin is what you want

drive them at 1400mA and 500w(10 c0bs) per 4x4 so 1000w for you


so take 20 cobs for your 4x8 ppfd 900

if u can afford more cobs you can drive them softer( still 1000w total just more cobs)

 

[Mr Celsius]

CXB3590 3500K CD bin is what you want

drive them at 1400mA and 500w(10 c0bs) per 4x4 so 1000w for you


so take 20 cobs for your 4x8 ppfd 900

if u can afford more cobs you can drive them softer( still 1000w total just more cobs)

Just to clarify, we are talking about the 37V version? If I got the 72V I assume I would drive them at 700mA, right?

What is the advantage of driving them softer? Longer life?

 

[Dion]

Just to clarify, we are talking about the 37V version? If I got the 72V I assume I would drive them at 700mA, right?

What is the advantage of driving them softer? Longer life?

yes 36v version(if 72 then 700mA= circa 50w, correct)

the advantage of driving cobs softer is more efficiency/better lumen per watt


e.g. using a single cxb3590 3500K CD bin(for reference a 600w hps is about 36% eff)


at 2100mA= 75.5w total x 49.7% eff=
37.5w of light and 38watts of heat/waste

at 1750A=60w= total x 52% eff=
31w of light and 29w of heat/waste

at 1400mA=48.85w x 56.34% eff=
27.5w of light and 21.4 w of heat/waste

at 1150=35.54w x 61.2% eff=
21.7w of light and 13.8w of heat/waste

at 700mA=22.9w x 64% eff=
14.6w of light and 8.2w of heat/watse


numbers are rounded but it give you a general idea


so to achive the same amount of light as 2x the first set up(75w @2100mA/ 37.5w of light x2)
we would have to use 5 of the 700mA set up(so 5 cobs at 700mA produces the same amount of light as 2 cobs at 2100mA)

the difference is that we would only consume 114.5 watts running soft vs the 151w if running only 2 cobs


so you spend more upfront to have a more efficient system

the cxb3590 is pretty good at 1400mA-1750 is ok too
but if you can afford it you could go for 1050, its a good compromise between cost and efficiency coming in at over 61%

the HLG-240H-C1050 can run 7 cobs
the HLG-240H-C1400 can run 5 cobs
the HLG-240H-C1750 runs 4
theHLG-185H-C1400 runs 4






EDIT: you should go bare cobs or reflectors
in a tent or if you have reflective surfaces directly around the grow area you dont really need optics

 

[jikko77]

@Dion: nice tool! very nice tool!
by any chance do you have the cxb reading?
what would you use to simulate a cxb?

 

[Dion]

@Dion: nice tool! very nice tool!
by any chance do you have the cxb reading?
what would you use to simulate a cxb?

do u mean the cxb 5000k?

im not as tech savvy as u , was hoping u might be able to figure that out

for now im using the LED tab in items and the generic 3000k temp for my 3000k cxa2540s hence i said its probably off

you could he cree xr warm white and beef it up with monos based off the info and graphs at cutter?

 

[jikko77]

do u mean the cxb 5000k?

im not as tech savvy as u , was hoping u might be able to figure that out

for now im using the LED tab in items and the generic 3000k temp for my 3000k cxa2540s hence i said its probably off

you could he cree xr warm white and beef it up with monos based off the info and graphs at cutter?

hahaha, to me you're way more techy than me .

the thing is i don't have a photospectrometer to read the "light", and doing it by hand would be an innacurate work, even becase we lack the precise number of the pick it has.



well let me see what i can do

thanks again

edit: more crap from cutter.au.




cxb3590 3000°k (no idea if 80 or 90 cri):


edit2: looks like there is no way you can import any custom spectrum if not done by a spectrometer. it has to be converted in cvs as well. i don't have any. if someone has one and can provide a read of any cxb led would be very nice.

edit3: found on reddit, someone did this on a cxb3590. (i were doing the same for the 3070, before this appeared to me)

 

[Mr Celsius]

How many BTUs of heat does one CXB3590 put out? I'm trying to gauge the cooling required for a sealed room. Planning on putting 24 cobs over a 4'x8' space.

Thank you

Edit:

After a little bit of digging and some assumptions, am I right in the following?:

CXB3590 have ~55% efficiency, so the remaining 45% would be heat? If driving each cob at ~50w x 24 cobs = ~1200w and 45% of that is heat wasted, we would be left with 540w of wasted heat? Each watt is equal to 3.41btu's, so 3.41 x 540w = 1841.4btu/h? If correct, the actual heat dissipation is negligible and easily handled by a very small and basic AC unit. I believe my dehumidifier would be the greatest source of BTU generation, along with weather fluctuations.

 

[Dion]

How many BTUs of heat does one CXB3590 put out? I'm trying to gauge the cooling required for a sealed room. Planning on putting 24 cobs over a 4'x8' space.

Thank you

Edit:

After a little bit of digging and some assumptions, am I right in the following?:

CXB3590 have ~55% efficiency, so the remaining 45% would be heat? If driving each cob at ~50w x 24 cobs = ~1200w and 45% of that is heat wasted, we would be left with 540w of wasted heat? Each watt is equal to 3.41btu's, so 3.41 x 540w = 1841.4btu/h? If correct, the actual heat dissipation is negligible and easily handled by a very small and basic AC unit. I believe my dehumidifier would be the greatest source of BTU generation, along with weather fluctuations.

yeah
only the eff % is a bit off
refer to this post and adjust according to your drive current


https://www.icmag.com/ic/showpost.php?p=7512858&postcount=970

 

[Mr Celsius]

yeah
only the eff % is a bit off
refer to this post and adjust according to your drive current


https://www.icmag.com/ic/showpost.php?p=7512858&postcount=970

Thank you for all your help!

 

[Dion]

Thank you for all your help!

sure no worries

note that under LED you should keep ur room a bit warmer too because there is less heat projected off the light source

if u want to avoid cal mag issues common with LED grows and keep ur ladies drinking lots aim for high 20s degrees Celsius

 

[jikko77]

heya.
starting a v2 diy pannel.
driver and cable arrived, now i've to order the cob.
this time i've space for a 5 cob string.

what to order?

i think i'll order the 3070 again.

i do have, already, a sting of 3x cxb3070 3000°k
my idea is 2x 5000°k and 3x 3000°k, or 3x 5000°k snd 2x 3000°K, then add some mono, once i've a better understanding on what i need to modify the spectrum and how many mono to use, for sure i'll go for the far red (730-ish nm).

adding the recent finding here as well:

https://www.icmag.com/ic/showpost.php?p=7515278&postcount=22

 

[Dion]

heya.
starting a v2 diy pannel.
driver and cable arrived, now i've to order the cob.
this time i've space for a 5 cob string.

what to order?

i think i'll order the 3070 again.

i do have, already, a sting of 3x cxb3070 3000°k
my idea is 2x 5000°k and 3x 3000°k, or 3x 5000°k snd 2x 3000°K, then add some mono, once i've a better understanding on what i need to modify the spectrum and how many mono to use, for sure i'll go for the far red (730-ish nm).

adding the recent finding here as well:

https://www.icmag.com/ic/showpost.php?p=7515278&postcount=22

if u r going to run the far red after lights out for the emersion effect or whatever than id just use the cheapest legit cree reds i can get for that you only need a watt or 2 max per sq foot

you have a 3x3 right? so 2 doides at like 2 watt each woudl be fine


if u want to have deep reds all day consider the high CRI cobs

 

[Dion]

ive always wondered if we would be better off running a CXB3590s worth of dollars in these at the same watts

eg a cxb3590 costa bout $50 and we would run it at 50w


how about 25 of these 100w cobs each run at 2w? what woudl the efficency be like?


http://www.aliexpress.com/item/High...10&btsid=132d6312-72fe-4466-8aa3-d46b7c823958