Heatsink help needed.
- Thread starter k dog
- Start date
Kinkz
Active Member
http://www.heatsinkusa.com/5-886-wide-extruded-aluminum-heatsink/
Is a great site for sourcing heatsinks, can choose your desired length to suite your needs.
I rarely see people individually setup CPU heatsinks for cobs unless its just a couple or a few, would be better to run something like I linked above for 5 cobs and simply wire some PC fans to an adapter on the aluminum heatsink IMO.
Here's a great step by step tutorial on installing a setup using a similar style heatsink:
https://www.reddit.com/r/microgrowery/comments/2lvpto/guide_ledwizards_diy_1000_true_watt_led_light/
Is a great site for sourcing heatsinks, can choose your desired length to suite your needs.
I rarely see people individually setup CPU heatsinks for cobs unless its just a couple or a few, would be better to run something like I linked above for 5 cobs and simply wire some PC fans to an adapter on the aluminum heatsink IMO.
Here's a great step by step tutorial on installing a setup using a similar style heatsink:
https://www.reddit.com/r/microgrowery/comments/2lvpto/guide_ledwizards_diy_1000_true_watt_led_light/
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qballizhere
Well-Known Member
You can go to https://kingbriteled.en.alibaba.com/featureproductlist.html or http://cobkits.com/shop/page/2/ 5 cree will not do a 4x4 that well you will need like 8 3590 for a 4x4 @1.4A
k dog
New Member
Thanks qballizhere. I just looked at the numbers again and you're right. I will probably drop down to a 3X3. That will push it up to about 80 per sq. ft. Also after researching the passive heatsinks the cost is about $100 for the 5 cobs. Any info on fan cooled heatsinks would be greatly appreciated.
qballizhere
Well-Known Member
Still low for a 3x3 here is the calculator numbers
CXB3590CD36V3500K 5 COBS @1.4A ON 5.88 PROFILE HEATSINK
9 SQ.FT. CANOPY 93% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 262.37
Cobs power watts: 244
Total voltage forward: 174
Total lumens: 44540
Total PAR watts assuming 10% loss: 124
Total PPF: 576.6
PPFD based on canopy area: 689.61 <<<<<you want it to be 800-1000
PAR watts per sq.ft.: 13.78
Cob efficiency: 56.34%
Power watts per sq.ft.: 27.11
Voltage forward per cob: 34.89
Lumens per watt: 182.54
Heatsink riser thickness / number of fins / fin's length: 0.27in/14/1.0in
Heatsink area per inch: 260.01 cm^2
Total heat watts: 107
umol/s/W / CRI: 4.65 / Estimated
Heatsink length passive cooling @120cm^2/heatwatt: 49 inches
Heatsink length active cooling @40cm^2/heatwatt: 16 inches
COB cost dollar per PAR watt: $1.92
Electric cost @12/12 in 30 days: $9.95
Electric cost @18/6 in 30 days: $14.67
Cost per cob: $47.62
Heatsink cost per inch cut: $1.74
Total cobs cost: $238
Total heatsink passive cooling cost: $85
Total heatsink active cooling cost: $27
What info are you looking for for air cooled heatsinks?
CXB3590CD36V3500K 5 COBS @1.4A ON 5.88 PROFILE HEATSINK
9 SQ.FT. CANOPY 93% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 262.37
Cobs power watts: 244
Total voltage forward: 174
Total lumens: 44540
Total PAR watts assuming 10% loss: 124
Total PPF: 576.6
PPFD based on canopy area: 689.61 <<<<<you want it to be 800-1000
PAR watts per sq.ft.: 13.78
Cob efficiency: 56.34%
Power watts per sq.ft.: 27.11
Voltage forward per cob: 34.89
Lumens per watt: 182.54
Heatsink riser thickness / number of fins / fin's length: 0.27in/14/1.0in
Heatsink area per inch: 260.01 cm^2
Total heat watts: 107
umol/s/W / CRI: 4.65 / Estimated
Heatsink length passive cooling @120cm^2/heatwatt: 49 inches
Heatsink length active cooling @40cm^2/heatwatt: 16 inches
COB cost dollar per PAR watt: $1.92
Electric cost @12/12 in 30 days: $9.95
Electric cost @18/6 in 30 days: $14.67
Cost per cob: $47.62
Heatsink cost per inch cut: $1.74
Total cobs cost: $238
Total heatsink passive cooling cost: $85
Total heatsink active cooling cost: $27
What info are you looking for for air cooled heatsinks?
k dog
New Member
I was looking at some arctic alpine 64 plus cpu coolers. I was thinking of using cree cxb3590 -0000-000N0BCD40E 4000k neutral white 12000 lumen.
qballizhere
Well-Known Member
To me the cpu coolers are just that for cpu and not active cooling for leds now im not saying they will not work but when you can get a heatsink that was designed for leds for less than $11 from china the price difference is only $1 maybe $2 say $3 at the most. Then you need a different driver to run the fans so what you saved for using the cpu coolers you just spent on a driver for the fans plus more. If you want to run active cooling that is fine you can use a smaller heatsink since you have the fan.
Here is the numbers for a 4k 3590
CXB3590DB36V4000K 5 COBS @1.4A ON 5.88 PROFILE HEATSINK
9 SQ.FT. CANOPY 93% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 262.37
Cobs power watts: 244
Total voltage forward: 174
Total lumens: 48102
Total PAR watts assuming 10% loss: 134
Total PPF: 607.02
PPFD based on canopy area: 725.99
PAR watts per sq.ft.: 14.89
Cob efficiency: 61.03%
Power watts per sq.ft.: 27.11
Voltage forward per cob: 34.89
Lumens per watt: 197.14
Heatsink riser thickness / number of fins / fin's length: 0.27in/14/1.0in
Heatsink area per inch: 260.01 cm^2
Total heat watts: 95
umol/s/W / CRI: 4.53 / 70CRI
Heatsink length passive cooling @120cm^2/heatwatt: 44 inches
Heatsink length active cooling @40cm^2/heatwatt: 15 inches
COB cost dollar per PAR watt: $1.87
Electric cost @12/12 in 30 days: $9.95
Electric cost @18/6 in 30 days: $14.67
Cost per cob: $50.17
Heatsink cost per inch cut: $1.74
Total cobs cost: $251
Total heatsink passive cooling cost: $77
Total heatsink active cooling cost: $26
An idea for you is you can run 5 citizen or Luminus cxm22 @1.4a and would give you good coverage.
Here is what the citi output would be
Citizen.1818C4.3000K 5 COBS @1.4A ON 5.88 PROFILE HEATSINK
9 SQ.FT. CANOPY 93% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 391.4
Cobs power watts: 364
Total voltage forward: 260
Total lumens: 54236
Total PAR watts assuming 10% loss: 149
Total PPF: 724.14
PPFD based on canopy area: 866.06
PAR watts per sq.ft.: 16.56
Cob efficiency: 45.48%
Power watts per sq.ft.: 40.44
Voltage forward per cob: 52.0
Lumens per watt: 149.0
Heatsink riser thickness / number of fins / fin's length: 0.27in/14/1.0in
Heatsink area per inch: 260.01 cm^2
Total heat watts: 198
umol/s/W / CRI: 4.86 / 80CRI
Heatsink length passive cooling @120cm^2/heatwatt: 91 inches
Heatsink length active cooling @40cm^2/heatwatt: 30 inches
COB cost dollar per PAR watt: $1.08
Electric cost @12/12 in 30 days: $14.59
Electric cost @18/6 in 30 days: $21.64
Cost per cob: $32.08
Heatsink cost per inch cut: $1.74
Total cobs cost: $160
Total heatsink passive cooling cost: $158
Total heatsink active cooling cost: $52
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k dog
New Member
I found the cree cxb3590-0000-000N0BCD40E cobs for 31.99 each plus 8.99 for shipping so I think that I'll probably go with them. As far as the heatsink goes that works out to be around 15.66 for each cob. That's less than what I figured it at. I rounded up a bit just to be on the safe side. The Arctic Alpine 64's go for around $12, so with the driver to run them it's just about the same cost per cob. That being said, I'll probably go with the passive heatsink just to save a little on the electric bill although the 64's only require .22 amps @ 12 VDC. One thing that I'm confused about is that you gave a total lumens at 48,102 and the Cree data sheet says that 5 of these cobs should total about 62,500 lumens. What is the reason for this difference? I really appreciate your info as it has helped me a lot.
qballizhere
Well-Known Member
I didnt look at the spec sheet I cheated and used the cob calculator and copied the info over.
Any idea what the cxm22 would be
qballizhere
Well-Known Member
A little better than the citizen 1818
mauricem00
Well-Known Member
5000lumens per square foot is a little low?that seems suprising
qballizhere
Well-Known Member
like to run flower about 800-1000 ppfd
mauricem00
Well-Known Member
how much improvement does that provide over 450- 500ppfd? what does using twice as much power get you?
k dog
New Member
The cob that I'll be using will actually be a minimum of about 6900 lumens per sq. ft. I'm hoping that will enough.
mauricem00
Well-Known Member
dang I run between 3200 and 3700 lumens per sq foot with my T5s and 55 watt 2G11 cfls and am getting 0.75 gpw of high quality flower from my plant. if you need to run 7000-1000 lpw with LEDs than where is the energy savings?
k dog
New Member
That's 6900 lumens per sq. foot not per watt. This setup should pull about 260 watts at the wall. I patterned this setup after one that produced about 1.5 gpw yield. I'll see for sure later when all is said and done.
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qballizhere
Well-Known Member
ppfd is not just power its ppf and other variables each cob will output only so much how hard you drive them helps....... yes you get better efficiency running them softer but then you are adding more cobs to make up the difference. There has to be a point where it is costing you more than it is worth. Whatever your gpw is @500 ppfd you could add 20-30% more at 1000 ppfd. I have seen people say its more.
Dont forget the numbers you read in the data sheets are at max power and we are not running them maxed out. They will work and grow..... the suggestions I make are to get in the top 90% of light and output for maximum yield and photosynthesis. I think of it like your putting a governor on your car to help save on gas and you cant go over 50
qballizhere
Well-Known Member
There are cobs that will put out 17000 to almost 20000 lumen each. That is why there is not one cob that is the best for everyone. It depends on your grow and situation the reasons you are growing. For me going from 4k hps room to cob leds made sense for several different reasons. When the flower room is done I will have over 735000 lumen hitting the canopy in a 13'x16' room using 30a less power than hps.
k dog
New Member
Agreed. Every situation is different. I'm new at this and as I go along I'll refine my system and method. I think that this setup is a good starting point.