Addj said:

Curious as to where you're at now with your DIY lights

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I think we all are lol,he hasn't been active on the forums for a while now.

sixstring said:

I think we all are lol,he hasn't been active on the forums for a while now.

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Dang I really enjoyed how open and honest he was with all of his work. I'm an electrician and I'm just starting to get into building my own lifts. Trying to get my hands on some Quantum boards here soon

Yeah the quantum boards are good.supposed to be some back in stock real soon or maybe they are already doing preorders.

Addj said:

Dang I really enjoyed how open and honest he was with all of his work. I'm an electrician and I'm just starting to get into building my own lifts. Trying to get my hands on some Quantum boards here soon

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Just when ya think its over,he popped up @ riu so maybe he will make an appearance here as well soon.

Hello Farmers,

I am ready to make my DIY Cree cob grow light(s). I have read through most of 24 pages of this awesome thread.

I have two 4' by 4' grow tents and a small clone tent.

I would like to use 12 CXB3590 3500k 32v cobs for each tent. I would like to use about 600 watts at the wall.
Running 12 cobs at around 50 watts each puts more at 600 watts per tent. That equates to about 37.5 watts per square foot. That is on the lower end but I can live with that. I may add more cobs later. I am going with the passive pin heat sinks.

Here is where I get a little confused. I kind of understand the Meanwell Drivers but I am still a little confused about the efficiency. I want my light usage to be very efficient.

Is there a driver that can power 6 cobs at 50 watts each that is very efficient? Or should I get 3 drivers that can power 4 cobs @ 50 watts each?

I just can't wrap my mind around the efficiency part of driver/cob selection. I looked at the Meanwell data sheet and all I glean from it is that they sell a dimmable 300 watt driver and 300 divided by 6 is 50 watts. Can someone break down the efficiency/mA part of the equation to me? I have read through most all of the posts and I get that 32v times 1.4a = 44.8 but what does that mean efficiency wise?

I would even be okay with running 12 cobs at 44.8 watts which would give me 537.6 watts per tent which should be 33.6 watts per square foot.

So I have a quote list from Kingbrite which includes.

24 Cree 3590 (cd/db) 3500k 32v cobs
4 Cree 3590 (cd/db) 6500k 32v cobs
28 Passive pin heatsinks
28 Graphite thermal pads
28 Ideal holders
28 Ideal adapters
28 Ledil Angelina 90 degree reflectors
Some Wagu connectors, wire, and nuts/bolts.

Kingbrite is suggesting the MW HLG-320H-C1400B. Is that the best choice, or should I go with a more efficient driver? Can that driver power 6 cobs or less?

The remaining 4 6500k cobs are going into my small cloning area. What driver would work best for those 4 cobs? I want to be able to dim it way down or up to 50 watts.

My last noob question is: If I dim my lights down to 50% does that mean that my light would pull 50% less watts from the wall?

So again I want to get the best driver that will be very efficient.

Thanks for the help.

Gherb

Well you have alot of questions there lol.first off the cree cxb3590 is a 36v cob not 32v so @50w you need to use at least 35v per cob in your driver selections.yes if you dim your driver it will pull less wattage from the wall.i would not use 6500k for your clones.if anything drop that to 5000k but if it was me i would use 4000k.theres plenty of blue spectrum in a 4000k cree for cloning and vegging.i will have to look at the data sheet on that driver to answer your other questions. Be back later :)

ok looks like that driver works fine for 6 x 3590 cree.so 35v x 1.4 amp is damn near 50w per cob so pretty much 300w per driver.meanwell is as good as it gets on eff.as far as this setup its good,you will be around 50 to 55% eff.you can do better using 1050ma drivers but your power per cob will drop to about 35w per cob.even so this type of setup will grow awesome plants. if you plan to grow taller plants like 3 foot plus then maybe go with the 50w per cob setup.in you grow scrog style with a 1 to 2 foot tall canopy then the 35w setup will be awesome.you'd be surprised what the 35w setups can do ;)

sixstring said:

Well you have alot of questions there lol.first off the cree cxb3590 is a 36v cob not 32v so @50w you need to use at least 35v per cob in your driver selections.yes if you dim your driver it will pull less wattage from the wall.i would not use 6500k for your clones.if anything drop that to 5000k but if it was me i would use 4000k.theres plenty of blue spectrum in a 4000k cree for cloning and vegging.i will have to look at the data sheet on that driver to answer your other questions. Be back later :)

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Thanks Sixstring. I was wondering why my math wasn't coming out right. 36 * 1.4 = 50.4 watts a cob. The 32v was a typo and it was confusing me.

I want the best kelvin for my clones. If that is 4000k then that is what I will go with. Or should I just go with more 3500k for the clone booth?

The driver is the main thing I need help with. I need to know which ones to get that will be the most efficient. I also would like the "drivers for dummies" explanation on efficiency in relation to drivers and cobs.

Thanks,

Gherb

lots of people use 3500k cree for full term growing,seed to harvest.i have some 3000k vero in my veg room that absolutely blow away my t5 lamps with 6500k bulbs.its just a much defferent,broader spectrum with cobs.i would say 3500k 80cri or 4000k 90cri for your veg setup,up to you.as far as efficiency goes,the softer you drive the cob the better they look on paper.the guy who started this thread @SupraSPL was big on driving the cobs lower like 700 ma and using more cobs.up front cost is a bit more but you can reach close to 70% eff running like this.with that said i have done my share of reading and from what i seen with growmau5 and greengenes plants i decided to use 1050ma and 1400ma drivers and decide what works best for my garden.im happy with both setups but if i could do it all over i would of built all my setups with 1050ma and used 10in spacing on everything.

sixstring said:

ok looks like that driver works fine for 6 x 3590 cree.so 35v x 1.4 amp is damn near 50w per cob so pretty much 300w per driver.meanwell is as good as it gets on eff.as far as this setup its good,you will be around 50 to 55% eff.you can do better using 1050ma drivers but your power per cob will drop to about 35w per cob.even so this type of setup will grow awesome plants. if you plan to grow taller plants like 3 foot plus then maybe go with the 50w per cob setup.in you grow scrog style with a 1 to 2 foot tall canopy then the 35w setup will be awesome.you'd be surprised what the 35w setups can do ;)

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So if I went with the 1050 ma driver that would be 36v * 1.05 amps = around 35 watts per cob. Does the first number on the M W driver indicate the watts that it can push? What would the efficiency change to?

You respond quicker than I can ask stuff. I'm a slow typer.

I am definitely a scrogger so the 1050 ma might be the way to go for me. I might want to go with 16 cobs a tent. Spaced at 10" on center seems like it would equate to more watts per square foot than 35.

Here is the real question, can the MW HLG-320H-C1400B run 8 cobs at 35 watts each? Why do people choose drivers that only run 4 cobs? Is it cost or efficiency or both?

Thanks for answering all my questions. I have read lots of posts where you answer these same questions over and over again.

Is there a calculator somewhere? Before I got interested in cobs it seems like there was a calculator that you could punch in cobs, drivers, and other variables to get efficiency, watts per square foot, and other good stuff.

haha, I've just been through all this with Sixstring trying to figure out what I want for a bloom tent };-)

For the HLG-320H-C1400B the constant current range (where you want to stay for your constant current output) is 114 ~ 229V. if you use the maximum voltage number and divide by the voltage of a COB, you will get the number of COBs for that supply. In this case, 229V/36V per COB = 6.3 COBs. Basically 6 - 36v COBs.

The efficiency of the drivers are all pretty much 94% which is pretty good. Ideally you would want to have 100% where all the wall AC power is converted 100% into of the DC power. In this case it's 94% which means 6% of the power is lost in the conversion and its result is heat dissipated by the driver.

The other efficiency, is the amount of lumins per watt for the COBs, this is where I still get kind of lost, but as Sixstring has said is you get better efficiency running these things with lower currents. The harder you drive these COBs, the more wattage they use, the brighter(more lumins) they get, but it's not a linear curve, so you start losing the lumins per watt which turns into heat into the heatsink....

I think I have this all right, @sixstring can verify it };-)

I hope this helped a little };-)

Hi guys,

I had to post here just to say a big thank you to everyone providing the information in this thread, it's really helped me to make the decision to go DIY.

I've just ordered most of the parts I'm gonna need, I'm gonna post what I've bought and if any of you guys spot any problems let me know. This is just a test run for me really, if I like the results I'll upgrade to better COB's in a couple of years.

I was planning to use 4 x CXB5390's but I was having trouble finding anywhere to buy them from, so after reading around for alternatives I've bought 10 x Citizen CLU048-1212C4-353M2M2-F1 Version 6 (3500K). These are not as bright but I'm going to use twice as many.

Heatsinks I have got 2 x 600mm (24") x 146mm (5.75") x 22mm (0.9") I'm planning on using 4 cobs per heat sink. I have 6 x 140mm PC case fans (82 CFM) for cooling, hoping I don't need that many, but they were cheap, I'll start with one per heatsink and add more if needed.

Drivers are these -

The spec sheet on the cobs http://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/COB_5/CLU048-1212C4_P3392_1115.pdf gives the typical flux as 4448lm @ 1050mA. I'm going to be running them a 1400mA so I'm expecting more lumens, anyone know how many there should be running @50w? Infact any experiences with Citizen cobs would be great.

Grow space is 3'3 x 4'4 (14.5'sq). I'm planning to have 8 of these 1212's cover half of the room (I can dim them if needed), with my blurple Mars 2 900 (274w draw) covering the other half as a comparison.

ChunkySkunky said:

Hi guys,

I had to post here just to say a big thank you to everyone providing the information in this thread, it's really helped me to make the decision to go DIY.

I've just ordered most of the parts I'm gonna need, I'm gonna post what I've bought and if any of you guys spot any problems let me know. This is just a test run for me really, if I like the results I'll upgrade to better COB's in a couple of years.

I was planning to use 4 x CXB5390's but I was having trouble finding anywhere to buy them from, so after reading around for alternatives I've bought 10 x Citizen CLU048-1212C4-353M2M2-F1 Version 6 (3500K). These are not as bright but I'm going to use twice as many.

Heatsinks I have got 2 x 600mm (24") x 146mm (5.75") x 22mm (0.9") I'm planning on using 4 cobs per heat sink. I have 6 x 140mm PC case fans (82 CFM) for cooling, hoping I don't need that many, but they were cheap, I'll start with one per heatsink and add more if needed.

Drivers are these -

The spec sheet on the cobs http://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/COB_5/CLU048-1212C4_P3392_1115.pdf gives the typical flux as 4448lm @ 1050mA. I'm going to be running them a 1400mA so I'm expecting more lumens, anyone know how many there should be running @50w? Infact any experiences with Citizen cobs would be great.

Grow space is 3'3 x 4'4 (14.5'sq). I'm planning to have 8 of these 1212's cover have of the room (I can dim them if needed), with my blurple Mars 2 900 (274w draw) covering the other half as a comparison.

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i have a build just like this except i went with round heatsinks,passive cooling.the 1212 @1400ma is bright as hell.you will be happy with the light.gl on the build and let us know if ya have any questions.peace

That's just what I was hoping someone would say, thanks man :)

I really like the efficiency/low heat aspect so I'm hoping I can dim them a little.

Plans are to make another one of these to replace the Mars, so that would be 16 cobs @ 50w each covering 14.5 sq ft, 55w/sqft. I think that's a little more than I'll need. Better to have too much and dim them than..........

I was looking at the passive cob heatsinks, they are quite cheap too, I might try them for the next one.

Can someone clarify the best way to select the driver for the cob application?

I am still trying to wrap my mind around that part.

I thought you took the cob volts that you want to use and multiply that by the driver ma to figure out what watts you can run your cobs at. Then you divide the total watts of the driver by the watts that you are going to run your cobs at.

So I want to use 16 cxb3590 36v.
I want to run them soft because that's what the cool kids are doing.

So 36v * 1050ma = 37.8 watts per cob.
I would like to use as few drivers as possible so it looks like the MW HLG-320H-C1400B is 320 watt driver (this is where I get confused). I thought I could divide 320 watts by the 37.8 watts I plan on running my cobs at which would 320/37.8 = 8.4 (8 cobs per driver).

@h4ppyf4rmer said above that the calculation is done a little differently:

h4ppyf4rmer said:

For the HLG-320H-C1400B the constant current range (where you want to stay for your constant current output) is 114 ~ 229V. if you use the maximum voltage number and divide by the voltage of a COB, you will get the number of COBs for that supply. In this case, 229V/36V per COB = 6.3 COBs. Basically 6 - 36v COBs.

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That was a good catch because if that is the case, I would not be able to run 8 cobs at 37 watts on the HLG-320H-C1400B driver. So I either need to find a different driver or use 3 drivers and dim them down.

Does that sound right?

Thanks,
Gherb

I did find a good temporary use for the cheesy cob led that was given to me by a friend. I will use it in my 2' by 2' by 3' clone tent until I get my two dimmable cobs in there. I might be able to use one cob in there. The cheapo cob led might be too hot and bright for my little clones. I am going run it for the day to see how high the temp gets when the ambient temp of my houses rises. I think it would make a great cactus tent.

Gherb said:

Can someone clarify the best way to select the driver for the cob application?

I am still trying to wrap my mind around that part.

I thought you took the cob volts that you want to use and multiply that by the driver ma to figure out what watts you can run your cobs at. Then you divide the total watts of the driver by the watts that you are going to run your cobs at.

So I want to use 16 cxb3590 36v.
I want to run them soft because that's what the cool kids are doing.

So 36v * 1050ma = 37.8 watts per cob.
I would like to use as few drivers as possible so it looks like the MW HLG-320H-C1400B is 320 watt driver (this is where I get confused). I thought I could divide 320 watts by the 37.8 watts I plan on running my cobs at which would 320/37.8 = 8.4 (8 cobs per driver).

@h4ppyf4rmer said above that the calculation is done a little differently:



That was a good catch because if that is the case, I would not be able to run 8 cobs at 37 watts on the HLG-320H-C1400B driver. So I either need to find a different driver or use 3 drivers and dim them down.

Does that sound right?

Thanks,
Gherb

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ok a few things.first you need to look at the drivers top rated volatage so with that 320-1050ma driver it is 305v. so take 305/35v per cob( cree cxb3590 run at 1050ma will be around 35v per cob) and you come to 8,7 cobs.but heres the kicker.if you plan to use ideal cob holders they are rated to 250v so if you want to use this driver you must solder the connections to the cobs instead of using the holders.or you can us a dif driver like the 240-1050 will drive 6 cobs at that current.so yeah the 320-1050 meanwell is rated for 320watts and the 240 is rated to 240ish watts.but you will dictate the wattage by how many cobs you can fit on a specific driver.for this style of setup i like the mw hlg 185-1050b because i can get them cheap and safely run 5 cobs per driver.but the 240-1050 with 6 cobs per driver is also an option with cob holders because it puts you around 230v total.

sixstring said:

but heres the kicker.if you plan to use ideal cob holders they are rated to 250v so if you want to use this driver you must solder the connections to the cobs instead of using the holders.

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hmmm, that's interesting because I was going to run 8 36V COBs on the the hlg 480H-C-1400b in COB holders, I'll have to look into this!!

h4ppyf4rmer said:

hmmm, that's interesting because I was going to run 8 36V COBs on the the hlg 480H-C-1400b in COB holders, I'll have to look into this!!

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Yeah the ideal cob holders are rated for 250v max and 4 amps.its not hard to solder the wires if your dead set on the larger drivers.that new 480 is a beast plus you can dim to off where most of the meanwells only dim to like 5 or 10% power.

h4ppyf4rmer said:

hmmm, that's interesting because I was going to run 8 36V COBs on the the hlg 480H-C-1400b in COB holders, I'll have to look into this!!

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Yeah that does change things a bit. I can solder but would prefer not to.

I have question about efficiency. I was looking at that hlg 480H-C-1400b and was wondering if using the 480H to power 8 cobs but dimmed down to 40 watts per cob has a negative or positive impact on the efficiency of the driver and/or cob?