Cree CXA3050 100W Custom LED Grow Journal with Dinafem Blue Widow

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CannaBare

Well-Known Member
SupraSPL said:
If we assume the minimum lumens for the bin and a Tj of 50C, 38-40 watts of heat.
Click to expand...
even when running at 1.5A? Do you have any efficiency numbers for the 3050 chip?

edit:

Do you think my Heatsink with fan will maintain a low temp for longer led life? Like 75 Tj?
 
SupraSPL

SupraSPL

Well-Known Member
I got these numbers from the CXA3050 datasheet. I am assuming an LER of 328 for the 3000K and I am basing off the minimum stated output for the mid level bin (5225 lumens at 1.4A @ Tj85c). These numbers take into account current droop, temp droop and vF shift.

Here are the numbers corrected for a Tj of 50C.
Current/Dissipation/Efficiency
.35A/12W/43%
.7A/25W/40%
1.05A/38W/35%
1.4A/53W/32%
1.8A/70W/30%

So at 1.4A we get 17W of photons and 36W of heat.
 
SupraSPL

SupraSPL

Well-Known Member
The current droop is much worse for blues/whites than for reds. That should be a clue to the nature of the problem. Even if they find a way to further reduce current droop, it may not be physically possible to achieve 300 white lumens per watt at reasonable currents/costs. Currently we are at about 50% efficient or 165 lumens/watt. Every small improvement we make is a significant reduction in heatsink/cooling needs. Amazing improvements in the last few years.
 
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mtnstream

Active Member
Good stuff! Hate to hijack bbs thread with all of this great info.
Can you add the 3590 top bin (BD) for efficacy comp?

bbs, update?
SupraSPL said:
I got these numbers from the CXA3050 datasheet. I am assuming an LER of 328 for the 3000K and I am basing off the minimum stated output for the mid level bin (5225 lumens at 1.4A @ Tj85c). These numbers take into account current droop, temp droop and vF shift.

Here are the numbers corrected for a Tj of 50C.
Current/Dissipation/Efficiency
.35A/12W/43%
.7A/25W/40%
1.05A/38W/35%
1.4A/53W/32%
1.8A/70W/30%

So at 1.4A we get 17W of photons and 36W of heat.
Click to expand...
 
SupraSPL

SupraSPL

Well-Known Member
Mid bin:

CXA3050 3000K Tj 50C bin W4
Current/Dissipation/Efficiency
.4A/13.5W/43%
.7A/25W/40%
1.05A/38W/35%
1.4A/53W/32%
1.8A/70W/30%

CXA3070 3000K Tj 50C bin Z2
Current/Dissipation/Efficiency
.35A/12W/43%
.7A/25W/42.5%
1.05A/38W/39%
1.4A/52W/36%
1.8A/70W/33%

CXA3590 3000K Tj 50C bin BB
Current/Dissipation/Efficiency
.35A/24W/46%
.7A/51W/40%
1.05A/80W/35%
1.4A/112W/31.5%
1.8A/150W/27%

Top bin:
CXA3590 3000K Tj 50C bin BD
Current/Dissipation/Efficiency
.35A/24W/48.3%
.7A/51W/42%
1.05A/80W/37%
1.4A/112W/33.3%
1.8A/150W/28.4%
 
B

bbspills

Well-Known Member
mtnstream said:
Good stuff! Hate to hijack bbs thread with all of this great info.
Can you add the 3590 top bin (BD) for efficacy comp?

bbs, update?
Click to expand...

Sorry I haven't been updating as much, but I did just switch back my lights to 12/12 yesterday, so now that the flowering period has begun I'll begin posting more. Veg updates just aren't nearly as exciting.

I still have 2 plants in my setup with a C99 and a blue widow clone.
 
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CannaBare

Well-Known Member
Here is my new box built specially for the CXA 3050. Each box is a 2ft square with four 1 sq ft holes netted for scrog. Walls will be construction sheeting. Now I just need my 1.5A drivers and we can start the show!


IMG_20140115_094316.jpg

edit: total cost for one box with all the bells... 400. Not bad! :)
 
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bbspills

Well-Known Member
Right on, you might want to look into using fans to cool those heatsinks. These COBs can get pretty hot if not properly cooled.
 
C

CannaBare

Well-Known Member
bbspills said:
Right on, you might want to look into using fans to cool those heatsinks. These COBs can get pretty hot if not properly cooled.
Click to expand...
I am actually getting a 15 CFM fan for each heatsink. Do you think will be enough?

http://www.allelectronics.com/make-a-store/item/CF-398/12-VDC-40MM-SQUARE-X-28MM-FAN/1.html

each heatsink is 1.816 inches square!

edit:

My biggest worry has been the temp but its hard to test until I actually get everything. Each fan will be hot glued to a heatsink and hooked to a 12v 500mA source. As a stand alone heatsink it cools 4.5 C/W/m^3. So based on Supra numbers without a fan heatsink combo I would be in trouble. I hope the fan can handle it.
 
caretak3r

caretak3r

Well-Known Member
general LED/COB question based on some information from PICOGRAV's thread. In one of his early posts he noted that he was driving the 2700K light vero29 @ 35-37V and 1.8A. He was using a cool lab power supply with the ability to dial in both voltage an amperage. I'm wondering whether there would be any problems using a driver rated @ 30-36V for a 3050 that is spec'd @ 37V. Same question for the vero29, which is spec'd @ 39V.
 
C

CannaBare

Well-Known Member
IMG_20140115_130049.jpg

Here it is with the fan on it! These fans really push some air at only half speed! can't wait to get the power supply and see what they can really do!
 
M

mtnstream

Active Member
Hey bbs,
How warm are those drivers running @1500mA? Thxs.

edit: I was surprised how small those HY 50W drivers
are compared to my Meanwell.
 
B

bbspills

Well-Known Member
mtnstream said:
Hey bbs,
How warm are those drivers running @1500mA? Thxs.

edit: I was surprised how small those HY 50W drivers
are compared to my Meanwell.
Click to expand...

Yeah the drivers aren't very big. I initially had them inside my enclosure, but decided to put them outside my cabinet for better airflow and cooling inside the enclosure.

They get warm to the touch, but I actually put a small PC fan blowing across the two drivers so they are never above ambient temperature.

I don't know if keeping them cooler helps with efficiency, but I figure it couldn't hurt.
 
SupraSPL

SupraSPL

Well-Known Member
As far as I can tell there is no significant change in overall efficiency from cool to warm but keeping them cool may increase reliability.

Cooler temps may increase the drive current. Some drivers have circuitry to keep the current output fixed but most decrease their output as driver temp rises.
 
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