DIY LED setup, help needed with amperage?

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CannaBare

Well-Known Member
Hi everyone!

I have been stuck on my computer for weeks looking at the possibilities of LED's and I've decided to go with Cree X-TE white at different temperatures. The Led itself can be run at a max amperage of 1.5A at 2.85V. My question is what to run the LED at? I can find 60w drivers that run at 700mA, 1050mA, and 1400mA. At first I was thinking of getting the driver that ran at 1050mA but a friend of mine told me to get 1400mA because it's still less than max and life of LED is maintained if heat is maintained. What does Everyone think? What should I run the LED's at?


ALSO I am having trouble finding a heatsink 16in x 16in square extruded aluminum. If anyone can do any better please help me!

Thank you in advance!
cannabare
 
Abiqua

Abiqua

Well-Known Member
Did you consult the datasheet?


Most LED's are more efficient when under driven. You will not be able to run @1.5Amps unless you have a major heatsink source and even then......the LED diode still won't be as efficient as being driven @ 700mA.


HeatSinkUSA I believe does a custom size for 16x16 if you call, otherwise I have seen a few on the Eslay.
 
C

CannaBare

Well-Known Member
How do you determine which is more efficient? I have looked over datasheets millions of times and I am again. I'm still learning everything
 
C

CannaBare

Well-Known Member
I think I got it. Cree has a product compare that shows performance at a certain amperage.

ANOTHER question: I am planning to buy the LEDs in 1000 strands. How exactly do those come? I will also ask over the phone but I can't find any information on it.
 
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CannaBare

Well-Known Member
Is it necessary to run the LED at such a low Amperage? I think I might still go with 1050mA because for my setup I will have 16 2700k to 4 5000k. I want to keep PAR high and I assume it is higher at higher Amperage. It may be true the efficiency goes down but wouldn't it be the same as adding enough low power LED to equal one high power LED?
 
SupraSPL

SupraSPL

Well-Known Member
Here is an example of how the efficiency drops as the current increases (current droop). These numbers assume that you will be running the LEDs very cool (Tj 50C) by using large heatsinks and or active cooling.

Cree XTE 3200K R3 bin $3
.35A 38.2%
.5A 35.3%
.6A 33.8%
.7A 32%
1.05A 26.3%
1.5A 24.5%

Keep in mind that 400 HPS is about 35% when brand new and is about 2000K so that is pretty hard to beat. You might also consider the Cree XML2. It cost more per watt but you will be using less heatsink, less driver, less cooling and less electricity to get the same job done.

Cree XML2 3000K T5 bin $6
.35A 44.3%
.7A 40.6%
1A 38%
1.5A 34.3%
1.75A 33%
2A 31.5%

The Cree XML2 4200K T5 bin has similar numbers and is much cheaper ~$4 on 20mm star from fasttech
 
C

CannaBare

Well-Known Member
SupraSPL said:
Here is an example of how the efficiency drops as the current increases (current droop). These numbers assume that you will be running the LEDs very cool (Tj 50C) by using large heatsinks and or active cooling.

Cree XTE 3200K R3 bin $3
.35A 38.2%
.5A 35.3%
.6A 33.8%
.7A 32%
1.05A 26.3%
1.5A 24.5%

Keep in mind that 400 HPS is about 35% when brand new and is about 2000K so that is pretty hard to beat. You might also consider the Cree XML2. It cost more per watt but you will be using less heatsink, less driver, less cooling and less electricity to get the same job done.

Cree XML2 3000K T5 bin $6
.35A 44.3%
.7A 40.6%
1A 38%
1.5A 34.3%
1.75A 33%
2A 31.5%

The Cree XML2 4200K T5 bin has similar numbers and is much cheaper ~$4 on 20mm star from fasttech
Click to expand...
Initially For Each array I was planning to have up to 20 XT-E bulbs at 1050mA in a custom design on a 12in square forced air heatsink over a scrog net. What kind of amperage would you run over 1 sq ft? I am planning to place the array's close to the canopy and raising with the buds as they grow.

Thanks those numbers put things to perspective!
 
smokey the cat

smokey the cat

Well-Known Member
Have you found a suitable heatisnk yet? This will be the limiting factor. If you can find something with enough surface area it'll be fine. More efficient chips help here again - less heat produced at a given light level.

Running 100W on a much smaller active heatsink I can assure you that your aim of 20 XTE will be fine with a fan on top. How much further you can push it depends on cooling, size of sink and your propensity to heatglue giant computer fans all over things.


How much wattage do you want? Running 20 XTE @ 1050mA is close to 60W, running them at 1400mA close to 100W. Again though I'd recommend you get the most efficient chips you can afford - rather than the same wattage of less efficient chips.
 
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CannaBare

Well-Known Member
I found a Heatsink from heatsinkusa 16x16in with .80 C/W that I thought could do the job with a fan.

Wattage does not matter as long as the plants get light where they need it. What would be the best amperage for a scrog set-up?
I was planning for each panel to cover the size of the panel. My LED design is more spaced out maybe .75-1.5in between each led.
 
C

CannaBare

Well-Known Member
I have recently thought to shrink my design down to 6 x 6in and run all of the LEDs at 350mA?

Again I am worried about light getting to the plants.

Thanks!
 
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