DIY COB led light build

dedragon

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I love the look of shimmer a dense led cluster gives but i want to go cheap this time. My thoughts were using a cheaper 100W 3000mah cob like this ()
but not sure if i should go with 440 or 460nm, this will mostly be for actinic pop and shimmer.
Also can i run the light at a lower wattage like 60W and 1400mah to lower the intensity and increase the lifespan of the led or will it cause more harm to it. these will not be a main source of light so par loss isnt an issue
 

jhuntstl

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I am using some 50w cob fixtures, but I did not DIY. I'm a huge fan of the shimmer. I've been poking around looking into sourcing the parts for a DIY, so I'll be following along.
 

oreo54

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See #17....

Any current decrease should extend lifespan and run the cobs more efficiently.
10 x 10 array is running each series row at 300mA w/ a 3A driver.

Depending how you want to dim it an ldd hw@ 1500mA. 36v dc power supply w/ some upward adjustment.
You actually need like 37v for 34v cob + LDD.
Buying ldds means you don't have to " buy" a new ac/ dc converter for each cob.
34 * 1.5 = 51watts/ cob.

(51 * x # of cobs) x 1.1 = power supply wattage. Roughly.
 
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dedragon

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awesome thank you for the info, i think im gonna test one out with a meanwell lpc 1400 and a pin heatsink from rapid led
 
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dedragon

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need to see if i need a lens or how it would even mount
 

oreo54

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need to see if i need a lens or how it would even mount
If you don't want to drill and tap there are thermal glues.
"Heatsink Plaster" us a common brand or 2 part epoxies.

Using square pin heatsinks you can rail mount them.
 
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dedragon

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That would be great next to my soon to be incoming orphek icon. Im gonna test this just to see what it will do in the meantime as amazon has free returns, interested to see what the blue setting looks like shimmer wise, the wide angle may be a problem but I am also thinking about adding a canopy
 
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dedragon

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dedicated RGB (no whites to take power away) light so hopefully the blues are in the usual realm of 420-480 and get a little more juice, we will see
 
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dedragon

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kessil a160s are just too expensive for me given what a 100W cob led light can be built for IMO
 
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dedragon

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knowing me i will probably build these anyway just as a comparison because it will be a very cheap diy cob,
Im thinking $40 per 100w cob fixture + cost of mounting(powered at 60W and 1400mah, between 35-41 v)
 
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dedragon

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bit confused by that but seems that the consensus was 440-450 for added pop over the 460-470 range, i am using an illumagic vitamini super actinic as well with its spectrum linked below if it matters

 

SteveMM62Reef

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I’m also looking at the Chanzon 30 watt COB LED’s. Want these for a Midday Sun, with running these a couple hours a day, center of the Aquarium was going to run 10000 to 15000K to each side of center either the Blue 460-470nm or the Royal Blue 440-445nm. Don’t know which color would be better? Also can I run Three COB’s off of one Driver, by selecting a Higher Wattage Driver? Found the Fan less Heat Sinks on eBay for a decent Price.
 

oreo54

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900mA, 30-34v Chazon specs for 30 w cob.

"Technically" one can run a bunch off say a constant current current driver with the required 34 or greater voltage.
They would be wired in parallel.
Current will divide by # of cobs

So a 900mA driver will provide 300mA for 3 parallel cobs .
Soo normally one would go with like a 1500mA driver so each of 3 cobs sees 500mA.

"Practically" there are some issues.
One cobs can be electrically unbalanced and not light uniformly.
Two if one fails open the remaining cobs will share the full current.
1500/2.
There are ways to deal with this. Some more complicated than others.
A simple fuse on each cob would prevent too much current going through the remaining ones
.Current balancing circuits and even dedicated to this task ic's are available.

Bottom line is if you use a 2100 mA driver, 3 fuses at 1A and a driver capable of outputting 34 or greater volts you can run 3 parallel cobs at 700mA each " relatively" safely

Last if one went constant voltage you could use the same parallel cobs, A 36 v power supply with some voltage adjustment to tailor the output to the cob v(f) and a proper resistor with the correct ohms and wattage and run as many cobs as mA are available on the power supply.
Example for 3cibs run at 36v constant and 500mA each.
  • each 4.7 ohm resistor dissipates 1175 mW
  • the wizard thinks the power dissipated in your resistor is a concern
  • together, all resistors dissipate 3525 mW
  • together, the diodes dissipate 51000 mW
  • total power dissipated by the array is 54525 mW
  • the array draws current of 1500 mA from the source
The greater the difference between the power supply and cob v[ f] the worse the efficiency and the more heat on the resistor. Thus the voltage adjustment.
Cob v(f)'s at a specific voltage should be uniform.
Never seen anyone do this though.

There are probably 1/2 doz. real or imagined differences people believe regarding which " blue" to use.
 
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