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Diy Cob Light Build Help!! Input Needed Please!

Alright so here we go first diy cob build...

So im going to hook up 5 parallel strings of 2 parallel cobs each on a cpu heatsink+fan using a single power supply(36v 11A) 5step up buck converters(one on each string for the leds) and one step down to run the 10 fans.

List of equipment
10 CXA2530 5000k 3800lm ( 37v 800ma but will be run at 750ma)
10 heatsinks + fans
5 step-up ( 250w 10a (8.5 to 48v in) (12 to 50v out))
1 step-down (36v to 12v)
6 electrical boxes (for buck converters)
1 36v 0-11A power supply(400w)
power distribution block
Thermal paste
25ft 14gauge solid wire
Small metal bars to screw heatsink to

So the cobs can take 1600ma max and need 37v at 800ma so i will run 5 strings of 2 at 1500ma using a stepup so if a cob goes out the other one wont burn.
So if my math is right 10x750ma is 7.5a X 36v(270w) + 10 x (12v x ~120ma) (15w) my overall power would be about 285W.

So power supply to distribution block will give me 6x 36v (5 with step up cc/cv and one with step down cc/cv)
Then i will have 6 matching negatives paralleled to the same block going back to power supply.

But for some reason this all sounds way too simple... am I missing something? Do I need some sort of a resistor or would the step-up unit include that? Do I need something between my -36v and -12v before they all go back to the power supply?
 
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Actually you're making it more complicated than it can be!
Lose the fans, change power supply, lose the step up, the step down, electrical boxes, power distribution block
 
Yea but the goal here was to make it under 200$ this setup will give me 36000-39500lm @ ~300w for 165$ canadian. Led drivers are priced out of this world...these suckers at 50% need 800ma @ 37v(30w) each ... wouldn't the fans on cpu heatsinks be a must?

Edit. Boxes are plastic electronic boxes for step-up so its not loose...
 
Last edited:
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263
Yea but the goal here was to make it under 200$ this setup will give me 36000-39500lm @ ~300w for 165$ canadian. Led drivers are priced out of this world...these suckers at 50% need 800ma @ 37v(30w) each ... wouldn't the fans on cpu heatsinks be a must?

Edit. Boxes are plastic electronic boxes for step-up so its not loose...
I wouldn't say they're priced high, they're priced for the quality you get. I'd say the cheaper ones are priced high for the lack of quality you get. That being said you can use whatever you want, if I had limited funds I wouldn't not build an LED cause I couldn't afford Top quality component.

Probably better to call them power supplies versus LED drivers.

LED put off so little heat that a proper heat sink would dissipate it.
I don't know what heat sink you're using, But if it's not adequate then you'd need a fan.

Ok on the electrical boxes.
Ok on everything else.
 
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263
Yea but the goal here was to make it under 200$ this setup will give me 36000-39500lm @ ~300w for 165$ canadian. Led drivers are priced out of this world...these suckers at 50% need 800ma @ 37v(30w) each ... wouldn't the fans on cpu heatsinks be a must?
Why did you choose those CXA

Edit. Boxes are plastic electronic boxes for step-up so its not loose...
Can you post links to what you're using?
165 dollars for 10 yolks @ 300w
Why did you choose CXA2530?
Why 5000k?
 
Yea these suckers are going to be paired with a 600w HPS dimmed at 50%. I will have the hps top center and the leds angled around the walls to blast from all directions. The 600w is too hot for my 4x3 space i need a 6" 660cfm fan full blast to keep it under 30... I will be running 2 paralleled strings of 5 instead of 5x2 and run them at 1A each so power supply step up run 5 parallels they will all be mounted to cpu heatsinks since they aren't very big I'll use fans.
 
I got 10 cree CXA2530-11A 5000k 3600 to 3900lm at 800ma for 75$, 36v 0-11a power supply 35$, wire 10$, 6 electronic plastic boxes 8$, 5 step-up 15$, 1 step-down 2$, distribution block 10$, heat sinks and fans salvaged, 5$ paste and 3.50$ coloured heat shrink wrap. So 165 canadian for 36 000 to 39 000 lumens and ~300w of power to crank these suckers
 
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Do I need some sort of a resistor or would the step-up unit include that? Do I need something between my -36v and -12v before they all go back to the power supply?
Ok so these are your only questions...
Do I need a resistor? No
Potentiometer would be nice.
Do I need something between my -36v and -12v before they all go back to the power supply? What are you referencing?
 
The stepup has a potentiometer on it and the 12v is for my fans id make a 3rd parallel with a stepdown 36v to 12v and wire the 10fans
 
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Okay regardless of which version of cree's you're going with.

You still haven't answered why you got 5000K?
 
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You do realize the 5000K spectrum is for veg and not flower though right?

Would never use anything higher than 3500K if I intended on using it for flowering...
 
Yea my main issue is in summer mh/hps gets too hot so this way i can vedge when its hot as hell out but wouldn't it still be usefull in flowering?
 

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