As always, there's gonna be questions!

FrozenChozen

FrozenChozen

Well-Known Member
I'm in the market for some inexpensive cobs.... Are Cree Cxa2520's worth a damn? I found some inexpensive ones (relatively... $15 a piece) and some 35w watt mean well 700ma drivers for $20.... Roughly $40-$50 a unit after they're built into a "panel" (DIY)... How do I tell what bin/quality they are?

What's the better choice for a 2'l X 3'w X 4'H strictly flowering space, 4-5 of these builds (roughly $200-$250) or ONE 3590 from the "BD" bin (roughly $150-$200)?
 
SupraSPL

SupraSPL

Well-Known Member
Hey FC, for a flowering lamp I recommend the Cree CXA3070 3000K AB bin (may be tricky to find right now though). It can be driven at 1.4A with these $13 drivers for a good up front cost and efficiency compromise. Another option is the Bridgelux Vero 29 3000K available at Digikey and can be driven with the same 1.4A drivers. It is slightly lower efficiency but cheaper up front cost.

Those are the simplest and cheapest parts for DIY LED that I am aware of and will serve you well :leaf:
 
FrozenChozen

FrozenChozen

Well-Known Member
That Vero looks killer! it ships to AK for $3 I can't be upset.... How hard should I drive it? 2 amps? Do you have a driver recommendation, maybe on the low end of the cost spectrum? Or is 1.4 amps better? At $30 a piece per chip and $15 for the drivers, this looks like it may be just what I'm looking for! How many should go with for my 2x3 area? 4?

You da man @SupraSPL!
 
AquariusPanta

AquariusPanta

Well-Known Member
If my memory serves me correctly, the new Vero 29 3000K outperforms the CXA 3070 *Z2* 3000K at currents at and above 700mA. I based the efficiency values for the new Vero 29 from Supra's efficiency sheets, found on my All Things Vero link in my signature box. I printed a different sheet, also created by the indispensable SupraSPL, highlighting the previous Vero 29 make with the current (unless they changed it within the last week) CXA 3070 *Z2*.

The CXA 3070 AB (if found) remains supreme at currents 1400mA and below (more efficient).
 
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FrozenChozen

FrozenChozen

Well-Known Member
AquariusPanta said:
If my memory serves me correctly, the new Vero 29 3000K outperforms the CXA 3070 AB 3000K at currents at and above 700mA. I based the efficiency values for the new Vero 29 from Supra's efficiency sheets, found on my All Things Vero link in my signature box. I printed a different sheet, also created by the indispensable SupraSPL, highlighting the previous Vero 29 make with the current (unless they changed it within the last week) CXA 3070 AB.
Click to expand...
at $30 you can't beat that with a stick!
 
AquariusPanta

AquariusPanta

Well-Known Member
FrozenChozen said:
at $30 you can't beat that with a stick!
Click to expand...
I misspoke too soon and made a visual error and goofed up by assuming the CXA 3070 as an AB bin on the sheet, while it's really a *Z2*. Still though, the Vero 29 shows impressive numbers; it's made quite a comeback since the last model, just ask Supra! (:
 
SupraSPL

SupraSPL

Well-Known Member
Yes AP they sure have :) If you really want to maximize up front cost you can run at 2.1-2.2A. The cheapest 2.1A driver is $34 and temporarily sold out. Each driver is slightly different, some put out 2.2-2.3A. SDS uses a nice dimmable MeanWell the HLN-80H-42 that puts out as much as 2.1A, although if you run it dimmed below 1400mA often, the CXA gets the upper hand.

Here is the math on 1.4A vs 2.1A:
Vero29 @ 1.4A = $32+$13+10=$55 = 51W @ 41%= 21 PAR W = $2.62/PAR W
Vero29 @ 2.1A = $32+$34+10=$76 = 79W @ 38.1% = 30 PAR W = $2.53/PAR W

Another consideration, the 1.4A setup will give you a better spread. 30 PAR W from a single COB is high intensity. If it were too close to the canopy it will bleach the ladies, so it would require more vertical height and a reflector.
 
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SupraSPL

SupraSPL

Well-Known Member
If you really want to turn night into day with a single Vero29, you could use one of these monsters
http://www.ebay.com/itm/150W-LED-Driver-Dimmable-DC30-42V-3-5A-Power-Supply-IP67-Waterproof-with-Dimmer-/161332500561?pt=PCA_UPS&hash=item25902a9851

At 3.6A the 3000K Vero 29 dissipates 142.5W (@ 33.2% for the 3000K). That is 15000 lumens from a single LED. I might have to get one of those drivers to see how much they really put out and if they have decent efficiency. Cost = $32+73+10=$115 = [email protected]%=47.3 PAR W = $2.43/PAR W. Not enough of a cost savings to justify the loss of efficiency and it would likely overpower the Alpine Arctic 11, but it is a very simple lamp design that is for sure.
 
FrozenChozen

FrozenChozen

Well-Known Member
SupraSPL said:
Another consideration, the 1.4A setup will give you a better spread. 30 PAR W from a single COB is high intensity. If it were too close to the canopy it will bleach the ladies, so it would require more vertical height and a reflector.
Click to expand...
What height does this start to happen?
 
SupraSPL

SupraSPL

Well-Known Member
I run my CXAs at 800mA so I get them very close 6-8" without bleaching. But we have had reports from some who run at 1.4A of bleaching troubles but unfortunately I cannot recall the distance.
 
C

churchhaze

Well-Known Member
The spread of a 120 degree cone is going the right direction, but the central axis will get twice as much light intensity as the sides if you don't have overlapping light. This means if you want the outsides medium rare, the middle will be well done, unless you have cobs everywhere.
 
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FrozenChozen

FrozenChozen

Well-Known Member
churchhaze said:
The spread of a 120 degree cone is going the right direction, but the central axis will get twice as much light intensity as the sides if you don't have overlapping light. This means if you want the outsides medium rare, the middle will be well done, unless you have cobs everywhere.
Click to expand...
in 2'x3' is that about 4 cobs or is it more?(to get nice overlap)
 
FrozenChozen

FrozenChozen

Well-Known Member
@SupraSPL
Whats the math like @ 3 amps for the vero 29?
I found some $20 drivers ($80 for 4 units) and I'm thinking that 3 Vero 29s (~$90) @ 100 watts might be the way to go... Which from my understanding is close to about "600+ watts" of HPS.... Then run 'em at about 18 inches away from the canopy (is that far enough away?)....

Will these heat sinks be enough to dissipate that much amperage? They're about 5" in diameter and 2" thick, with a copper core (about 1" in diameter)
IMG_9277.JPG IMG_9278.JPG

Should I go with a larger heat sink or blast the fan on the back at nearly 1 amp (almost 45 cfm)?
What's the math on passive heat dissipation versus amperage and the amount (total volume) of heat sink needed? Does that make sense?
What is better, more copper or aluminum?

And what about active cooling,
How much heat sink is needed versus the amount of cfm being blasted through it?
I'm kinda all over the place but, if that heat sink won't cut it, how much amperage can I run with something like that?
 

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SupraSPL

SupraSPL

Well-Known Member
Hey FC, there are few things regarding the drivers. First of all $20 is a good price for those, so this could work. The Vero 29 at 3A should be about 39vF, so it would be important that the driver can handle up to about 40vF. Also, many drivers make bold claims about their output but actual output can be much much less. And finally, the output will fall as the driver warms up.

Anyway, at 2.8A, the 3000K 80cri Vero 29 puts out about 12000 lumens, dissipates 110W, runs at about 35.7% efficiency and cost $0.83/PAR W. Those are actually not that bad of numbers and if you use a simple reflector, could be a viable grow lamp for sure. The COB would be creating about 70W of heat. I have done tests with COB creating as much as 60W of heat and the standard CPU heatsink like the one you linked had no trouble handling it (fan running at 12V)

Do you have a link to the driver, I might be familiar with it. I have come across some "3A" drivers that only put out 2.1-2.3A. These $34 drivers for example(currently sold out):
http://www.ebay.com/itm/100W-Watt-High-Power-LED-Driver-AC90V-265V-50-60HZ-Waterproof-/181302171749?pt=LH_DefaultDomain_0&hash=item2a36739865

I am considering buying one of these to put to the test:
http://www.ebay.com/itm/IP67-Waterproof-150W-Dimmable-Electronic-LED-Driver-DC30-42V-3-5A-Power-Supply-/221610886880?pt=US_Lighting_Parts_and_Accessories&hash=item339909c6e0

At 3.6A the Vero makes about 15000lm, dissipates about 142W, runs at about 33.2% efficiency, cost $0.68/PAR W and creates about 95W of heat.
 
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SupraSPL

SupraSPL

Well-Known Member
FrozenChozen

FrozenChozen

Well-Known Member
SupraSPL said:
I also ordered some monster 150W heatsinks for the test. Might as well go big with these and keep it as cool as possible, you can usually find them cheap on eBay

http://www.newegg.com/Product/Product.aspx?Item=N82E16835186092&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-CPU Fans & Heatsinks-_-N82E16835186092&gclid=CI-PiP_5ksICFeVj7AodHR4AOQ

http://www.amazon.com/ARCTIC-Freezer-i11-Heatpipes-Vibration-Dampened/dp/B00HO9P05A
Click to expand...
I have a local computer repair store and can get heat sinks and fans a dime a dozen (well $1 a piece)
 
FrozenChozen

FrozenChozen

Well-Known Member
SupraSPL said:
Hey FC, there are few things regarding the drivers. First of all $20 is a good price for those, so this could work. The Vero 29 at 3A should be about 39vF, so it would be important that the driver can handle up to about 40vF. Also, many drivers make bold claims about their output but actual output can be much much less. And finally, the output will fall as the driver warms up.

Anyway, at 2.8A, the 3000K 80cri Vero 29 puts out about 12000 lumens, dissipates 110W, runs at about 35.7% efficiency and cost $0.83/PAR W. Those are actually not that bad of numbers and if you use a simple reflector, could be a viable grow lamp for sure. The COB would be creating about 70W of heat. I have done tests with COB creating as much as 60W of heat and the standard CPU heatsink like the one you linked had no trouble handling it (fan running at 12V)

Do you have a link to the driver, I might be familiar with it. I have come across some "3A" drivers that only put out 2.1-2.3A. These $34 drivers for example(currently sold out):
http://www.ebay.com/itm/100W-Watt-High-Power-LED-Driver-AC90V-265V-50-60HZ-Waterproof-/181302171749?pt=LH_DefaultDomain_0&hash=item2a36739865

I am considering buying one of these to put to the test:
http://www.ebay.com/itm/IP67-Waterproof-150W-Dimmable-Electronic-LED-Driver-DC30-42V-3-5A-Power-Supply-/221610886880?pt=US_Lighting_Parts_and_Accessories&hash=item339909c6e0

At 3.6A the Vero makes about 15000lm, dissipates about 142W, runs at about 33.2% efficiency, cost $0.68/PAR W and creates about 95W of heat.
Click to expand...
this is what I was checking out.... only goes up to 36 v though.... this a problem hunh?
http://www.ebay.com/itm/New-LED-Power-Supply-Driver-4-100Watt-High-power-LED-Lamp-Bulb-Light-85-265V-2-/301364405189?pt=US_Car_Lighting&hash=item462ab7e3c5
 
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