D.i.y. Cxb-3590 Cob Panel Vs. Hps

[HughJassBud]

I think you have to careful be saying things like NEVER or NOT EVER. You may be right that the CXB 3590 won't perform to those levels, but COB's are a still evolving technology where HPS is pretty well developed at this point. I'm not sure what your background in electronics or microprocessors are, but I believe we will see similar gains as what were found in that industry. The limiting factors in these COB's are diode size, material science, and tooling to produce new designs efficiently. All of these things will improve in the years to come and I have no doubt someone will eventually develop a purpose built COB especially for horticultural applications.....if it hasn't been done already.

As far as penetration goes, I tend to agree with you but am not totally convinced that these COB's won't be able to stand the test. Especially when placed close enough together, where wave theory tells us they will amplify each other. The other thing that I think you may be overlooking is the size of the element. A 1000 watt bulb element is several inches long and projects light in 360 degrees. So when doing a point source calculation you have to consider the density of photons at their origin. Like spokes on a tire, they get further and further away from each other the further you go from the center. The light emitting part of a COB is something like 32 x 32mm and only projects light in 110 degree pattern. That's pretty damn small. So the light being emitted from that small area should be very dense considering the high lumen efficacy. This should translate to relatively good penetration DIRECTLY UNDER the COB. This is where getting them close enough together becomes key.

Anyhow, we will see. I already have all the HPS technology I need. If in fact you are right and there isn't a significant advantage to running these then I may go back to HPS and use the COB's in Veg where I am sure they will perform at least as well as a T5. I will continue forward though in the interest of embracing new technology and doing my part, from a consumer standpoint, to further develop it. Take a looke at what @sixstring is doing. The way he is set up I think he is more likely to produce "Trees" or at least big ass bushes on his ladies, like 80's porn.

Maybe like someone else said, I should just run 20 of these fuckers in a Raptor hood for a 1000watt COB to 1000watt HPS comparison......I have enough to do it but that seems like overkill to me.

Dynamite looking ladies, great looking Nugz! You've obviously honed in your skills under HPS. I wouldn't advocate anyone change if they are growing like you, unless of course they just get bored and want to do something different like me. Thanks for taking the time to check back in!

 

[HughJassBud]

Finally, my heat sinks arrived! To be different I went with a green heat sink......who doesn't like green after all!

Here is a shot of the bottom with the mounting holes for the holders and to affix it to a sheet of aluminum.

Overall, I am pleased with the product I received. These were built to my specifications, so I only have myself to blame if the design doesn't work out for some reason.

 

[Toaster79]

Black color radiates heat much better ;

I'd sand and polish the mounting surface. You know the drill, just like in the old times of overlocking CPUs

 

[HughJassBud]

Black color radiates heat much better ;

I'd sand and polish the mounting surface. You know the drill, just like in the old times of overlocking CPUs

I think the difference between green and black anodized for this application will be minimal for heat transfer. The three primary methods of heat transfer are Conduction, Convection, and Radiation. Conduction is effected by the material, which in this case is aluminum and the anodized bit shouldn't make a difference really. The convection efficiency is its ability to transfer heat to air, this is why the pin design is so effective but in general the design and ambient air temperature/speed will effect this the most. Lastly is radiation, which is relatively negligible in this case compared to the other methods of heat dissipation. However, you are right, black is better at radiating heat.

I will polish a couple and see what the difference is. I don't think these are going to put off quite as much heat as some of the processors I've overclocked in the past, but I could be wrong. The bottom surface is already pretty flat, which makes me happy. I'm not sure if the anodized finish will make much of a difference or if it's better to polish through it. Anyone with an idea of how this will effect things, please chime in.

 

[HughJassBud]

http://www.aavid.com/product-group/extrusions-na/anodize

this article basically asserts that the color doesn't matter so much as the finish. Radiated heat is all well outside the visible spectrum, so the visible color is negligible. However, the anodized surface alone apparently helps the heat sink radiate heat. Interesting....I had never strongly considered this before.

 

[jdb420]

FedEx says the heatsinks will be here today. So, I will be building things this week! Stay tuned for a parts list and complete step-by-step explanation of building these lights!

I'm really looking forward to this! I expect they will far outperform a 1000w HPS.

Also, I'm really struggling to decide whether to do 12 or 16 COB's per Raptor hood. There is a lot of stuff on youtube from growmau5 and @REALSTYLES that suggest its completely adequate to space the COBS 1 ft apart. 16 would be like 11 inches off center 1 way and 8 inches off center the other. 12 COBS would be 11" and 12" respectively; so a little closer to the spacing used by others.

The other part of this argument is that I am seeing an average of about 1.3-1.5 gpw with CXB3590's. So I am thinking if I want 2 lbs, 904 grams, it would be easier with a 16 COB, 800 watt panels than 600 watt panels. As stated above, this isn't really the heart of the issue, but it is a consistent standard that people look at. After all, it roughly translates to operating cost per gram produced.

I'm tempted to do both and see what is to be gained from additional COB's in the same footprint. At some point there has to be a diminishing return, so finding that is the key to maximizing efficiency......I think.

Anyhow, a few pics to show things currently in flower.......14 days in to bud....

Watussi (plants on left of pic)


Hey Hugh, just wanted to give you an idea. Go for the 16 instead of 12 if you can afford it. If it is too intense, you can dim them, and then you gain efficiency and create less heat. I'll be curious to see if it makes a difference. Maybe do 1 hood with 12 and the other at 16. Then you can compare the two and let us know the results. I'm gonna space 30 over a
4 x 8 area and I'll let you know how mine turns out. I'm gonna get them up and going again in the next 2 weeks. I broke apart my other 2 lights with heatsink usa heatsinks to replace them with the pin fin. I also am adding 4 more lights. I'm using the meanwell 240 to power 5 cobs per bar. 3 lights per 4x4. I ordered the other 4 off of timbergrowlights.com and I will report back on them versus the ones I built. Please let us know your thoughts on thermal management of these cobs and anything else you can teach us. I appreciate your efforts and all your information you have shared with us. Also, keep your rh at 40 the whole grow and down to 35 or 30 at the end of bloom. This will increase nutirent uptake and growth. I think once people use this information to their advantage. They will see returns of watts per gram really beat out the hps. The haters can keep on hating, but they need to face the facts. Cob led is the future of growing, and the days of hps being king are slowly fading away. The end product is better when grown with led. That part is hardest to ignore. Who wants quantity without quality ? So, for all of you doubting the technology, try it for yourself and you will see why people are using led for grows. They saw quality brings more value to your crop, so less is more. I'd rather have a little less and it be fire than to say I yielded more, but it isn't as tasty. The proof is always in the pudding. And I'd rather have less pudding that tastes better than to have more pudding that doesn't taste as great. To each his own, but that's why you see the connoisseur going the cob route. Once the price drops a little, the big operations will follow our lead. A little less product that is superior in quality will still be worth as much, if not more.

 

[REALSTYLES]

Cree CXB3590 72v being ran @500ma is 70% efficient and here's a 2x4 tent with only 60w total power

 

[HughJassBud]

Hey Hugh, just wanted to give you an idea. Go for the 16 instead of 12 if you can afford it. If it is too intense, you can dim them, and then you gain efficiency and create less heat. I'll be curious to see if it makes a difference. Maybe do 1 hood with 12 and the other at 16. Then you can compare the two and let us know the results. I'm gonna space 30 over a
4 x 8 area and I'll let you know how mine turns out. I'm gonna get them up and going again in the next 2 weeks. I broke apart my other 2 lights with heatsink usa heatsinks to replace them with the pin fin. I also am adding 4 more lights. I'm using the meanwell 240 to power 5 cobs per bar. 3 lights per 4x4. I ordered the other 4 off of timbergrowlights.com and I will report back on them versus the ones I built. Please let us know your thoughts on thermal management of these cobs and anything else you can teach us. I appreciate your efforts and all your information you have shared with us. Also, keep your rh at 40 the whole grow and down to 35 or 30 at the end of bloom. This will increase nutirent uptake and growth. I think once people use this information to their advantage. They will see returns of watts per gram really beat out the hps. The haters can keep on hating, but they need to face the facts. Cob led is the future of growing, and the days of hps being king are slowly fading away. The end product is better when grown with led. That part is hardest to ignore. Who wants quantity without quality ? So, for all of you doubting the technology, try it for yourself and you will see why people are using led for grows. They saw quality brings more value to your crop, so less is more. I'd rather have a little less and it be fire than to say I yielded more, but it isn't as tasty. The proof is always in the pudding. And I'd rather have less pudding that tastes better than to have more pudding that doesn't taste as great. To each his own, but that's why you see the connoisseur going the cob route. Once the price drops a little, the big operations will follow our lead. A little less product that is superior in quality will still be worth as much, if not more.

I think I am going to run 16 and see how it goes. I would like to buy some more to put into the bud room right away, but I think I may focus on filling in my veg room with COB's first. Bars of 4; something like what @sixstring did in his room....or maybe in 5's like what @REALSTYLES did above. My T5's are 5 or 6 years old now, some of the ballast have burned out and the replacements seem a lot hotter. I suspect the growth in veg under these will be closer to what is seen under a metal halide. Especially if I am running the 500ok CXB's, which I have 5 of already. I just emailed Jerry yesterday though and I'm already thinking about taking the plunge.

@REALSTYLES
I'm happy to see I've caught your attention. You're DIY build is what started me on this journey. From it I learned of a bunch of other people and so on, but your work is what inspired me to try this myself. Thanks for everything you've done so far!

About that light, is that 60 watts including the heat sink fan or is that based on just those 5 cobs running at like 167mA @ 72v? For veg, what color have you settled on or do you run a mix (ie. 5000k, 3500k, etc.)?

I should probably go see what your latest posting on the matter are, I think I have read you saying the 3500k work well all the way through, but I don't remember.

 

[HughJassBud]

@REALSTYLES
Well, I went back and read to answer my own question. 6500k is what you look to be using. I should have known, I think I'm starting to get all these different grows confused LOL. I wish I had some DD bin CXB's. Jerry hasn't listed any 6500k variety ones in his stock when I have asked him so far, but I will email him and ask specifically to see what he says.

Thanks again for everything, really awesome guide you put together.

 

[HughJassBud]

Well I asked Jerry again and it turns out he has stock of DD bin, but in the 36v variety. So, I ordered 5 more 6500k COB's in the DD bin. They are 36v variety though so I won't be able to run them in series with the 72v ones I already have. So, I think I will run 2 panels/bars with 5 COB's each to space out over m 3' x 6' Active Aqua table in the Veg room. I need a good light meter to test out these lights with. Does anyone have a suggestion?

 

[REALSTYLES]

@REALSTYLES
Well, I went back and read to answer my own question. 6500k is what you look to be using. I should have known, I think I'm starting to get all these different grows confused LOL. I wish I had some DD bin CXB's. Jerry hasn't listed any 6500k variety ones in his stock when I have asked him so far, but I will email him and ask specifically to see what he says.

Thanks again for everything, really awesome guide you put together.

I use 3500k CD bin as well here's my current grow

 

[HughJassBud]

I use 3500k CD bin as well here's my current grow

GORILLA!!!

Those are some fine looking ladies. They are going to be huge by the time they're done stretching if that's the first day!

Why the switch to passive pin over your current design? I'm just wondering because I was considering using your desing in my Veg room. Or something like it at least with heat sinks USA.

I like Jerry, he is a great guy I think, but perhaps you can get those passive heat sinks for less elsewhere. He had quoted me $12 for the ones you are talking about, I think.

[email protected] <---They made me the ones I show in the pic above for $6.50 a piece. With shipping they came out to $12 a piece for 50 total. 99lbs shipping weight. Shipping was $275 - the less expensive, slower option. It did take a while, but I think there is a 30 day lead time or something. Also, I provided her some solid works sketches for my design and they built them according to that. You can have them anodized any color you like.

My only complaints:
I've opened one box so far and there are some that are bent kind of badly on the outside corners of the box. I have been using a pair of vice grips to grab them and slowly straighten them. So far none have broke.

Joyce is very nice, but I don't think she had been dealing with Western customers very much yet. However, she was able to accommodate me through paypal and eventually we got everything settled.

I'm going to add a couple of Jerry's Heatsinks to my order just for the sake of comparison. Maybe the pins are smaller or more numerous? Perhaps I was sold a lead/aluminum blend :) I should do some more testing before I advocate one over the other.

 

[sixstring]

I think I am going to run 16 and see how it goes. I would like to buy some more to put into the bud room right away, but I think I may focus on filling in my veg room with COB's first. Bars of 4; something like what @sixstring did in his room....or maybe in 5's like what @REALSTYLES did above. My T5's are 5 or 6 years old now, some of the ballast have burned out and the replacements seem a lot hotter. I suspect the growth in veg under these will be closer to what is seen under a metal halide. Especially if I am running the 500ok CXB's, which I have 5 of already. I just emailed Jerry yesterday though and I'm already thinking about taking the plunge.

@REALSTYLES
I'm happy to see I've caught your attention. You're DIY build is what started me on this journey. From it I learned of a bunch of other people and so on, but your work is what inspired me to try this myself. Thanks for everything you've done so far!

About that light, is that 60 watts including the heat sink fan or is that based on just those 5 cobs running at like 167mA @ 72v? For veg, what color have you settled on or do you run a mix (ie. 5000k, 3500k, etc.)?

I should probably go see what your latest posting on the matter are, I think I have read you saying the 3500k work well all the way through, but I don't remember.

im using 5 cob per bar in my setup with 4 x 3500k and 1 x 3000k cob per bar.i think my next set of bars will have some 2700k cobs in em like 2x 3500 2x 2700 1 x 3000,or i may just build a bar with mostly 2700k to see how it flowers.dont believe a word the non cob growers say about plant size and led.light intensity is just as high or higher with cob led if you have the right amount per sq ft.
these under driven cobs seem to completely suck ass @ 38 w a piece lol

@HughJassBud those green sinks look pretty sweet and it sounds like ya cant beat the price.you can use a thick string or small rope to bend the pins back also.what are you using for t.i.m. material bewteen the cob and heatsink,thermal grease? i used the thermal pads from plc and they seem to be the whip for installation,plus my thinking was i wont have to worry about sanding/grinding sinks flat as these pads are thick enough to correct any gaps you might have with grease.

 

[HughJassBud]

im using 5 cob per bar in my setup with 4 x 3500k and 1 x 3000k cob per bar.i think my next set of bars will have some 2700k cobs in em like 2x 3500 2x 2700 1 x 3000,or i may just build a bar with mostly 2700k to see how it flowers.dont believe a word the non cob growers say about plant size and led.light intensity is just as high or higher with cob led if you have the right amount per sq ft.
these under driven cobs seem to completely suck ass @ 38 w a piece lol
View attachment 614208


@HughJassBud those green sinks look pretty sweet and it sounds like ya cant beat the price.you can use a thick string or small rope to bend the pins back also.what are you using for t.i.m. material bewteen the cob and heatsink,thermal grease? i used the thermal pads from plc and they seem to be the whip for installation,plus my thinking was i wont have to worry about sanding/grinding sinks flat as these pads are thick enough to correct any gaps you might have with grease.

Gosh @sixstring ......with discouraging results like that, why should I even go on?

Yeah, I had a feeling you would blow those up....for 38w a piece that is incredible. I've been trying to use your "top every 6th node" method. So far it seems to be working really well.

I'm not really too worried about nay-sayers. I have a healthy dose of math and science to back up my theory in relation to these COB's, but I am really glad you can show some results that prove the concept. I actually appreciate the non-believers because it gives me an opportunity to look at things from both sides of the table as opposed to a biased approach. It's always hard for a new technology to come in and dethrone the existing status quo too, so I imagine it will take a time for some people to drink the kool-aid.

 

[sixstring]

If that plant ever finishes up im planning to put a few of my trusty mk in that spot and then i will have a much better idea of what these bars are yielding. But i did use my light meter in there to see what kind of output im getting.the cobs are brighter by quite a bit @36 inches from the lamp compared to a brand new 600hps and even a tad brighter than my gavita set at 800w but those lamps are about 6 months old.the thing is those measurements dont change much over the whole 4 x 6ft area under the cobs.but under the hps they drop like a rock as soon as you move away from directly under the lamp.for me its a no brainer,the cobs put out more light and over a much larger area with less power and heat

 

[HughJassBud]

@sixstring

Also, I asked Jerry today what he had in terms of deep reds.....

Me: "Do you ever get anything higher than CD bin for the 3500k? What about 3000k or lower even? Does such a thing exist, a COB with very deep reds?"

Jerry: "For 3500K, CD is the top bin available now, for Cree cob, only white leds.
But I will talk with Cree if it is possible to make red leds."

So, I'm not sure if he understood me. I am also interested in running some more reds in bloom though.

 

[HughJassBud]

If that plant ever finishes up im planning to put a few of my trusty mk in that spot and then i will have a much better idea of what these bars are yielding. But i did use my light meter in there to see what kind of output im getting.the cobs are brighter by quite a bit @36 inches from the lamp compared to a brand new 600hps and even a tad brighter than my gavita set at 800w but those lamps are about 6 months old.the thing is those measurements dont change much over the whole 4 x 6ft area under the cobs.but under the hps they drop like a rock as soon as you move away from directly under the lamp.for me its a no brainer,the cobs put out more light and over a much larger area with less power and heat

No shit. I wouldn't have expected that. I thought there would be far greater diminishing returns as you moved away from directly under the COB, more so than HPS. I am very surprised by that. Also, that is very exciting! 16 is probably going to be overkill based on what you are saying.....

 

[jdb420]

I use 3500k CD bin as well here's my current grow

Realstyles, I noticed what you said about the pin fin heat sinks. Try northern grow lights. They charged me 20 bucks shipping on 11 of the heatsinks you want. The size you want is 20 bucks. You don't need heatsinks that big unless you plan on running them over 50 watts each. Also, they sent me an email with a link to a free template for spreading your thermal paste if you don't want to use the pads. Their heatsinks are better than what I got from timbergrowlights.com. northern drilled holes in the side so you can use m4 bolts to mount them to L chanel aluminum. That way your outer 4 holes can be used for your lenses. Also, that free template they emailed me works perfectly. Take that email to staples or office Depot and have them print it on a transparency sheet. Then when you cut out your square you will have a coating that's exactly the thickness you want and the sheet prints 3 templates, so there is an extra 2 templates if you need them. Works great. They also gave me the bolts I need to secure everything. They will ask what cobs you plan on using so they can get you the right hardware. They are the best bang for your buck. And shipping is reasonable. Based on what I saw, that should come out to 200 shipping instead of waiting from china and spying 275 for 100 of them to be shipped. Any questions, feel free to ask me. But northern has a heatsink that is only 13 bucks i think for the size that goes up to 50 watts. Larger ones will run cooler I suppose. Hugh, what do you think the temperature difference will be on the 100 mm heat sink versus the 130 mm heatsink ?

 

[HughJassBud]

Realstyles, I noticed what you said about the pin fin heat sinks. Try northern grow lights. They charged me 20 bucks shipping on 11 of the heatsinks you want. The size you want is 20 bucks. You don't need heatsinks that big unless you plan on running them over 50 watts each. Also, they sent me an email with a link to a free template for spreading your thermal paste if you don't want to use the pads. Their heatsinks are better than what I got from timbergrowlights.com. northern drilled holes in the side so you can use m4 bolts to mount them to L chanel aluminum. That way your outer 4 holes can be used for your lenses. Also, that free template they emailed me works perfectly. Take that email to staples or office Depot and have them print it on a transparency sheet. Then when you cut out your square you will have a coating that's exactly the thickness you want and the sheet prints 3 templates, so there is an extra 2 templates if you need them. Works great. They also gave me the bolts I need to secure everything. They will ask what cobs you plan on using so they can get you the right hardware. They are the best bang for your buck. And shipping is reasonable. Based on what I saw, that should come out to 200 shipping instead of waiting from china and spying 275 for 100 of them to be shipped. Any questions, feel free to ask me. But northern has a heatsink that is only 13 bucks i think for the size that goes up to 50 watts. Larger ones will run cooler I suppose. Hugh, what do you think the temperature difference will be on the 100 mm heat sink versus the 130 mm heatsink ?

I did some COMSOL simulations on this a couple weeks ago. I'll have to go back and see if I can find those files at work. I may not have saved them, but I can do it again if I have time.

The difference is probably pretty big. Convection is related to surface area, so just in terms of the "disc" part the surface area is going increase exponentially with the radius. The number of fins and or pins increases too.

So from 100 to 130 is the difference of 50mm vs 65mm radius. In terms of surface area, increasing radius from 50mm to 65mm will net ~60%more surface area! So that alone is pretty substantial in terms of convection. In terms of conduction, there is just a lot more aluminum to move the heat into. That helps as well. Of course, at some point there are diminishing returns here too.

To give you a really good answer though I will need to model both and run a quick simulation at work. I don't have the software at home to do it. I can say that the design I came up with was in order to limit the temperature of the COB to 55 degrees celcius (131F) with a 30 degree celcius (85F) ambient temperature and no air movement. In my mind I thought this would be about worst case scenario if the lights were on but my inline fans weren't for some reason. That required a 10mm base and 60mm pins, but I think I could have kept the radius around 60mm and been OK. I went with 70mm for that engineered safety factor. Oh, and that is all based on 30 watts of heat generation. Which I don't think these will get anywhere close to at the amperage I plan to run....

Also, I need to account for radiated energy if I can. Somehow I need to account for the anodized finish as well. That might take a little research on my part. COMSOL isn't something I use every day. So its probably worth simulating again.

So, yeah, 100mm diameter is probably fine in most cases. Especially if it is a solid 10mm disc with pins. 7mm is the min thickness I would use personally based on my brief research. If you ever want to run at like 75 watts or something, I would definitely go bigger to be safe.

 

[HughJassBud]

@sixstring

you can use a thick string or small rope to bend the pins back also

Genius! This works really well too.