DIY LEDs - The write-up

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Thread of the Month !!

Thanks for the write up. Fantastic job.

Put me in the club who would like to do this to their nano.
 
It'd be well deserved.

You and evilc are doing us all a great service by laying out this info.

By far the most aesthetically pleasing setup I've seen
 
Small update. I figured I'd share a picture of the power supply enclosure.

powersupply.jpg
 
Thread of the month for sure. you just changed the world. im going to do this next time i got to change my 4 pc's on one of my nano's
 
<a href=showthread.php?s=&postid=14503776#post14503776 target=_blank>Originally posted</a> by stugray
...
One thing I would ask, is have you tried to remove a star from the heatsink after using that epoxy? Do they Pop right off with a screwdriver? ... My plan was to use heat sink 'compound' and screw ( instead of glue ) the stars to the heat sink. It would make future replacements much quicker & easier. ...
I don't know how Reef-Safe the thermal compound/paste would be. Some even have copper or silver. And paste has problems with degraded performance due to air voids forming with thermal cycling. Twelve hours full on, twelve hours of "moon"? If you had the stars held on with springs of some sort (instead of fixed fasteners, like screws or bolts) the springs can take up the slack when the paste expands/contracts with thermal cycling, so air voids within the paste are somewhat minimized.

There is an alternative. It transfers heat better than thermal epoxy, doesn't have the mess or thermal cycling problems of paste, easier to use and can't leak into the tank.

TIM (Thermal Interface Material) is available as sheets similar to double sided tape. Sissors or an exacto knife cuts it to size and shape, then peel one side and sitck it to the LED star, then stick the star in place and secure it with your screws.
 
Hey Soundwave, fantastic writeup!!

Any chance you could get a kill-a-watt meter hooked up on the power supplies? I'd love to know the watt draw of this :)

Thanks!
Mark
 
<a href=showthread.php?s=&postid=14525923#post14525923 target=_blank>Originally posted</a> by EBOLII
or the mathematics to calculate......

well, we can try

the buckpacks are 85% efficient at 24V input, so:

each white @ 1.000 amp = 1.18 amps
each blue @ 0.700 amp = 0.83 amps

The power supply is rated at 80% efficiency, but I'm not sure how to translate an amp draw of 1.18 amps @ 24VDC on the output side of the transformer into the 120VAC amp / watt draw on the input side, which is what (watt?) we need ;)
 
Ohms Law
Power(Watts) = I (current) X V (Voltage)
so
1.18 A X 24 V = 28.32 Watts
so
I = Power/Voltage
28.32/120 = .236 A Draw on AC side
 
<a href=showthread.php?s=&postid=14526486#post14526486 target=_blank>Originally posted</a> by lynxvs
Ohms Law
Power(Watts) = I (current) X V (Voltage)
so
1.18 A X 24 V = 28.32 Watts
so
I = Power/Voltage
28.32/120 = .236 A Draw on AC side


thx lynxvs! watts is actually a better way to go, so 28.32 watts at 80% efficiency would be a 35.4 watt draw for each white string of 6 led's. The blue led's are 19.76 watts at 24V, so they are 24.7 watts for each string of 6 led's.

So, each block of 24 LEDS has 2 strings of blue, and 2 strings of white.

That totals to (35.4 * 2) + (24.7 * 2) = 120 watts

So the full fixture made by soundwave should if hooked up to a kill-a-watt meter come in around 240 watts.

That is pretty awesome :)
 
Reef55,

6 LEDs in series at 3.7 Volts each is 22.2 Volts output from the Buckpucks.
That is 22.2 Watts output from the supplies.

At 80% eff., that is 27.75 Watts each string for the whites.

Close, but you didnt account for the fact that the supplies are constant current, so for 6 LEDs in series, the voltage is 22.2.

Stu
 
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