Cheap and Cheerful DIY using Citizen cobs

Nutria

Well-Known Member
I have built a 1212 setup and I was looking for a grow journal to get some info like gpw, canopy distance, anything else
 

CobKits

Well-Known Member
I have built a 1212 setup and I was looking for a grow journal to get some info like gpw, canopy distance, anything else
those really wont translate from one garden to another. for all intents and purposes any 50W cob built in last 2 years will perform +/- 5% of any other. and theres too many factors with current, # of cobs per square foot, canopy depth, etc, to make any hard and fast rules about what is 'right' or 'wrong'

cobs do seem to be a lot more forgiving than blurple or hps when kept in the right intensity ranges, just my observation. i think the full spectrum aids in plant vigor
 

Nutria

Well-Known Member
those really wont translate from one garden to another. for all intents and purposes any 50W cob built in last 2 years will perform +/- 5% of any other. and theres too many factors with current, # of cobs per square foot, canopy depth, etc, to make any hard and fast rules about what is 'right' or 'wrong'

cobs do seem to be a lot more forgiving than blurple or hps when kept in the right intensity ranges, just my observation. i think the full spectrum aids in plant vigor
Y you are right.. I can drive a cobs at different mA.
If you can help me: I have one 1212@1.4A and a bigger setup with 4x1212@1A, suggested height?
Btw I am concerned about the final yield since I can grow only in a small 2x2ft (60x60cm) tent and not even for a whole year due to high temps. Let's see how does it go!
 

rocho

Well-Known Member
hello I did something of very stupid. I tested my 1212 cob before applying them on the heat sink. after about 10 seconds backlighting i saw some smoke from COBS...of course i ready unplugged the power, the cobs were quite hot to the touch. Do i irreparabily damaged their efficiency and factory performances in your opinion, with just a few seconds without heatsink?:wall:
 

Ninedolla

New 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.
Is that the hlg 185 700 or 1400?
 

klx

Well-Known Member
hello I did something of very stupid. I tested my 1212 cob before applying them on the heat sink. after about 10 seconds backlighting i saw some smoke from COBS...of course i ready unplugged the power, the cobs were quite hot to the touch. Do i irreparabily damaged their efficiency and factory performances in your opinion, with just a few seconds without heatsink?:wall:
Lesson learned. Lucky it was a $12 chip eh!

Jorge's been MIA for a long time i hope he's OK
Yet, it's almost like has never left ;)
 

CobKits

Well-Known Member
hello I did something of very stupid. I tested my 1212 cob before applying them on the heat sink. after about 10 seconds backlighting i saw some smoke from COBS...of course i ready unplugged the power, the cobs were quite hot to the touch. Do i irreparabily damaged their efficiency and factory performances in your opinion, with just a few seconds without heatsink?:wall:
any old light meter or phone app will tell you if the cob is any less bright than its neighbors
 

Redoctober

Well-Known Member
1818 is a little more efficient than a cxb
cxm22 is a little more effcient than that

CV drivers generally have higher wattage output than CC, since the drivers get filled better. a lot of that depends on which driver you select and how it matches cob voltage. the 48As match the 50V citi and luminus chips the best, you can generally get 215-225W out of them on the cob side
Hey @CobKits, love your posts! This is the first I've heard of Luminous Devices, thanks for the heads up! There are so many good COBs coming on the market now, it's awesome to see.

So the CXM is their flagship series I'm guessing, with the Gen 3 being the latest and greatest. You would say it's actually the most efficient when compared to CXB3590 and the new Citizen Gen 6 1818(which I don't see being sold anywhere yet) even though it's significantly cheaper than both? Because that would be amazing!

Also quick question about comparing chips because I have gotten lost in the weeds here (no pun intended). Luminous flux seems to be a number that is on every companies' data sheet, but everyone always uses a different current to measure it, so that number seems either useless or I don't know a way to convert it to a standard current (if that's even possible). My primitive, totally uninformed reasoning on the subject would go something like this:

We'll take 2 different sized chips from different manufacturers as an example, and make up the numbers for ease - Let's just say for arguments sake that the new Gen6 CLU-058 1825 has a luminous flux of 15,000 @ 2amps, and a CXM-22 has a luminous flux of 7,500 @ 1 amp, are those equivalent? Can you divide the 2 amp flux by 2 to match the 1 amp and wind up with an accurate flux measurement? I suspect you're going to tell me it doesn't work that way...

Is luminous flux even a useful number to use as a comparison at all?

What is a good metric to compare COB efficiency between manufacturers and also among chips of the same manufacturer?
...sorry for the barrage of questions
 

Metacanna

Well-Known Member
Question: I will be running Citizens 1212-048 at 1.4A, 50W each, on Arctic Alpine 11 Pro CPU coolers, rated for 100W. What happens if a fan/ PSU dies? I suppose it all depends on the time it will take until I notice the failure. But let's assume I would be away 24h, would the Cobs survive? If one failed, I suppose the chain would be interrupted and the others would survive, I hope.

The 1212-048 datasheet has the following info on the "Reliability" section

Continuous Operation Test: IF=1080mA Ta=25C (with Al-fin) ×1000hrs / IF=1080mA Tj=140C (with Al-fin) ×1000hrs

Does it mean the COB that was tested runned for 1000hrs at 140C ?? That would be great.

At 10$ per COB, I wonder if it's worth to think too much about it, it might be wiser to have one or two replacements around than to try to figure out expensives and complicated solutions. Plus, these PC fans rarely fail, the PSU might be the weaker link, maybe I should avoid cellphone chargers... a 12V MeanWell is cheap anyway.

Having this said, I don't know how the chain of happenings would be in case one Cobs died, I guess the chance of fire hazard is low, but I feel insecure about this. If anyone experienced fan failure would be cool to know the story.
 

klx

Well-Known Member
Question: I will be running Citizens 1212-048 at 1.4A, 50W each, on Arctic Alpine 11 Pro CPU coolers, rated for 100W. What happens if a fan/ PSU dies? I suppose it all depends on the time it will take until I notice the failure. But let's assume I would be away 24h, would the Cobs survive? If one failed, I suppose the chain would be interrupted and the others would survive, I hope.

The 1212-048 datasheet has the following info on the "Reliability" section

Continuous Operation Test: IF=1080mA Ta=25C (with Al-fin) ×1000hrs / IF=1080mA Tj=140C (with Al-fin) ×1000hrs

Does it mean the COB that was tested runned for 1000hrs at 140C ?? That would be great.

At 10$ per COB, I wonder if it's worth to think too much about it, it might be wiser to have one or two replacements around than to try to figure out expensives and complicated solutions. Plus, these PC fans rarely fail, the PSU might be the weaker link, maybe I should avoid cellphone chargers... a 12V MeanWell is cheap anyway.

Having this said, I don't know how the chain of happenings would be in case one Cobs died, I guess the chance of fire hazard is low, but I feel insecure about this. If anyone experienced fan failure would be cool to know the story.
Have you already bought the Alpines? If not, why not just 120mm pin fin heat sinks and go passive. All your worries gone...and they are cheap now.
 

Metacanna

Well-Known Member
No I didn't. I thought about it, but it would increase the cost of cooling. How much are you paying for those pin fin? So far in Europe I didn't find them. Good thing about Alpines is they help to move air, which is very beneficial for small and crowded space like mine. (Me saying by intuition.)
 

klx

Well-Known Member
I am not sure about Europe but I am sure someone from EU on here can point you in the right direction. I just think that these days passive is so cheap it is worth the extra few dollars to remove all those fans and points of failure...but each to their own!
 

CobKits

Well-Known Member
So the CXM is their flagship series I'm guessing, with the Gen 3 being the latest and greatest. You would say it's actually the most efficient when compared to CXB3590 and the new Citizen Gen 6 1818(which I don't see being sold anywhere yet) even though it's significantly cheaper than both? Because that would be amazing!
I have gen 6 1818. i havent ran them side b side yet but they should be right there with the cxm22 gen3. both beat cxb

We'll take 2 different sized chips from different manufacturers as an example, and make up the numbers for ease - Let's just say for arguments sake that the new Gen6 CLU-058 1825 has a luminous flux of 15,000 @ 2amps, and a CXM-22 has a luminous flux of 7,500 @ 1 amp, are those equivalent? Can you divide the 2 amp flux by 2 to match the 1 amp and wind up with an accurate flux measurement? I suspect you're going to tell me it doesn't work that way...
you have to look at watts. any comparisons i ever do is on a watt basis since all the chips have different voltage profiles

Is luminous flux even a useful number to use as a comparison at all?
for the same spectrum and same manufacturer, sure. different manufacturers have slightly different test conditions and the data can be biased

but remember lumens are for humans. there are some color temp and CRIs that have less lumens, like a 300k 90 cri, but it has more usable PAR which is what we are after
 
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