DIY LEDs - The write-up

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<a href=showthread.php?s=&postid=14881576#post14881576 target=_blank>Originally posted</a> by DheereCrossing
That project I mentioned earlier about a hot wall wart is fixed. The p/s was 300ma and he got a 700ma and if fixed the issue and made the LEDs much brighter. Would going with an even larger supply, like 1000ma cause a problem? Where does any extra power go?
Click to expand...

DheereCrossing - the mA rating on a power supply is the maximum the supply is capable of providing. It's always best to have a LARGER one than your circuit actually needs, to provide some safety margin and improve efficiency.

The amount of current supplied in a circuit is dependent on the voltage, and the load of the circuit. If the circuit isn't much of a load, it doesn't draw as much current. So it's not that there's any 'unused'.

You can do a simple check if you have a multimeter, to make sure you're still not overloading things. Use the ammeter mode, and place the leads from the multimeter between the positive lead of the power supply and the positive lead going to the circuit (i.e. put the meter in SERIES with the circuit on the positive side, putting the positive lead on the positive terminal of the power supply.

Make sure your meter is set to an appropriate range and the leads are installed correctly! Refer to the manual that came with the meter if you're unsure.

Then power on the circuit and read how much current is being drawn. If it is at or over the maximum rating on your power supply, you need to find a larger one. If you're 10% or less than the maximum rating, you'll be OK.

I hope that makes sense. I must stress again that if you don't know how to use a multimeter properly, read the instructions before attempting this. You can blow your meter, or wreck your circuit if things aren't connected correctly! I take no responsibility, etc etc :)

Also, keep in mind that an overloaded power supply is dangerous. It may seem like it's running fine - and may run for quite a while. But it may eventually go, and that can be a fire hazard.
 
<a href=showthread.php?s=&postid=14881756#post14881756 target=_blank>Originally posted</a> by shikhyung
NOTE* - I used 700mA drivers on the BLUE and 1000mA drivers on the WHITE.
I refered to sounwave note.
what is the spacing between the LEDs, I plan to do on my 24x18x20? should a 3 rows x 6 leds with 2" apart from center to center is applicable?
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I used 1.5" spacing between my LEDs. Only my arrangement is all white. It works pretty good without any additional optics. I have ordered some 60 degree lenses, and I think I'll get good overlap with those, as well.

You're 2" suggestion will probably work well, too. I'd bet you could go even wider, but it depends on your desired result. Myself, I wanted to cram as much light density as I could into the space I had to work with.
 
<a href=showthread.php?s=&postid=14882139#post14882139 target=_blank>Originally posted</a> by ReefEnabler
Found 5 of these 32v 12a CNC router supplies, similar to what soundwave used only beefier.

http://cgi.ebay.com/ws/eBayISAPI.dl...Category=71394&_trkparms=algo=LVI&its=I&otn=2

99 bucks... at that price I'd have to use the single supply to power all 6 of my pucks, which means I'd lose the ability to control blue/whites independently with my profilux power bar. But I could use a separate high voltage relay.
Click to expand...

Wow, good deal. Wish I found that before overpaying for my 24V supply!

I see what you mean about no independent control, though. That wasn't an issue for me, so I went with a single supply.

Re: your question about the supply voltage for the buckpucks - don't overdrive them. They may work at first, but at best you'll shorten their life, at worst you'll blow one entirely (I blew the two spares I ordered - one because of a wiring mistake on my prototype and another mysteriously after I finished the build. You do NOT want to smell the smoke they release when they go! It took 3 days to clear the house of the smell!
 
i went ahead and ordered one of the 32v 12a supplies :D

its a bit overkill for now, but the good news is if I ever decide to go LED only or double the amount of LEDs I can probably still use this :)
 
here's a quick video of my moonlights/t5 shimmer bar mocked up. i had some problems again LOL....putting everything in the project box, i broke one of the power wires on the whites & managed to break one of the wires going to the pot for the dimable blues :mad2:

i had to get a new pot & then try & figure out which wire to hook to which pin. while i was resoldering, i decided to do some molex quick-connects to facilitate taking it apart in sections in case i need to work on a component later on.

anywhoooo, here is the vid. the whites are like WOAH bright & the blues i think i can dim them down good for moonlights w/out being too bright. it is kinda hard to tell the dimming part of the blues cause as they got dimmer, the auto-focus on the camera brightened the background LOL

http://www.youtube.com/watch?v=1Bb7zon3lXQ
 
ReefEnabler, can you link to the one you purchased? I can't seem to find it.

How many LED/BuckPucks do you think you can run off of it?
 
ReefEnabler,

"I'd have to use the single supply to power all 6 of my pucks, which means I'd lose the ability to control blue/whites independently with my profilux power bar"

I dont believe that is the case.

Each buckpuck ( or group of them ) is controllable by a different potentiometer, right? ( you got the adjustable pucks? )

Then you would still be able to adjust each string individually.
The current through the driver is independent of the supply voltage as long as the main supply can provide enough current for all the buckpucks.

Stu
 
But, if you wanted to be able to turn white on/off independently of blue, say with a reef controller for sunrise effects, you would need two power sources; one for each color. Otherwise you'd need something like an arduino to control the potentiometer on all six to off/on. (That would be very very cool of course.)
 
if you watch my vid posted above, the whites aren't dimable...they are on or off (by unplugging the power supply) but when the blues dim & then go out, it is cause the pot was turned all the way down.....in fact, they don't come on till it is at about 10-20% of a turn

so if you can figure out some way for the profilux to regulate the voltage to them, you should be able to do sunrise/sunset that way
 
stugray, fernandokng; Nice switcher finds! Wow! Those are some inexpensive supplies!


ejmitch: Hold up on the Enabler repeat!

ReefE;
The 32V supply... CNC supplies are often linear supplies NOT switching supplies! Speed controlled motors use power in a pulsing way that can confuse and cause switching supplies to go unstable. If I see a supply listed as "CNC", or "for servo motors", or "for stepping motors", that clarification is often for linears or less! Less being completely unregulated supplies that have outputs 'around' the listed voltage.

Looking at the Ebay listing I see no sign of "switching" and the physical size looks way too big for that power level to be a switching supply.

Why do we want a switching supply? Because they are much, MUCH more efficient. That linear supply will probably be about 60% efficient. Whereas a switcher will be about 90% efficient. The switcher will also be about 1/3 the weight and about 1/2 the size.

With a linear supply look at your resulting setup and realize that you could be running 40% more LEDs on the same power consumption if instead you'd used a switcher. Also more heat, 40%, will be dumped in the room.

Often we are running LEDs to save energy. Using a linear supply is very counter productive to that goal.
 
<a href=showthread.php?s=&postid=14883935#post14883935 target=_blank>Originally posted</a> by stugray
ReefEnabler,

"I'd have to use the single supply to power all 6 of my pucks, which means I'd lose the ability to control blue/whites independently with my profilux power bar"

I dont believe that is the case.

Each buckpuck ( or group of them ) is controllable by a different potentiometer, right? ( you got the adjustable pucks? )

Then you would still be able to adjust each string individually.
The current through the driver is independent of the supply voltage as long as the main supply can provide enough current for all the buckpucks.

Stu
Click to expand...

Stu I know I could use the electronics to dim them, but I was more talking about using my profilux powerbar to switch on/off channels on a timer. With two supplies I just hook two powercords into the Profilux powerbar and can automate them without any extra work or wiring.

If I wanted to use the profilux to control two channels then I'd need a 120v relay, not a big deal.

I still have the rabbit 4010 which I still plan to sink my teeth into, but I'm not counting on it for now.


Kcress, thanks for the clarification.
 
Last edited:
<a href=showthread.php?s=&postid=14884471#post14884471 target=_blank>Originally posted</a> by ReefEnabler
Kcress, thanks for the clarification.
Click to expand...



Not that you wanted to hear it... :p
 
Kcress, Thanks for the notice about the linear driver vs. a regulated switching supply.

Actually, that 24V @ 6.5A could run six strings of six lights = 36 LEDs. Each string maxes at 1000mA making a total of 6A, still under the 6.5A max. If instead they are dimmed to around 700mA (reduces brightness only a little and extends LED life) that is a total of 4.2A, well under the 6.5A max.

Am I calculating things correctly? If so, these are looking like great power supplies!
 
<a href=showthread.php?s=&postid=14886570#post14886570 target=_blank>Originally posted</a> by ejmitch
Kcress, Thanks for the notice about the linear driver vs. a regulated switching supply.
Click to expand...

Careful... linear power supply not linear driver.


Am I calculating things correctly?
Click to expand...

Maybe.. It depends on the Vf of the LEDs. If you're using Buck Pucks you would need:

24V - 2V - [6 x Vf] = positive number of at least 0.5V or a little more.
 
Great thread! Demystifies LEDs. I would like to consider using LEDs for my 6 foot wide tank. PFO and others at $3300 is insane. Maybe now I can afford finding someone to build me a setup, as I am dangerous with a soldering iron :)
 
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