Calling out to Weezard for LED advice

Weezard, I don't know much about electronics, but I can solder WAY better than your average bear. ;) I've got a Weller WESD51 digital station and Cardas Audio Quad Eutectic solder. Cardas advises a small wattage pencil @ 700 deg F. for small connections. There's not that much total heat to dissipate but it gets the connection done quickly. It's worked well for me in the past. Looks like a piece of cake to me. I didn't want to use bigger supply wire than necessary 'cos to avoid dissipating excess heat into the the device (?)
I've got a big-ass gun too, but I wouldn't put that many watts on such a small package unless necessary. What say you? :confused:

:o

Quote:

---

Originally Posted by DreadedHermie

The PCB is so flexible, can't I just lift up the solder pad end and slip something between the pad and the heatsink while I solder? I've only just now attached one LED and only cemented pad behind the emitters, not the entire body of the device.

Seemed easier than having the thing squirm around while I try to attach the wires, then fighting the wires while I try to glue the LEDs down(?)

---

Like the man said. "typed before I thought"
It's the ledengine beeg boys, ya?
Glue away .

Ignore the doddering stoner that was obviously thinking 5 Watt MCBs.

I think it was the washers trick that threw me.
I just used a fat rubberband for mine.

I'll try to pay mo' betta attention, but :stoned:...

Lolo Weeze

Quote:

---

Originally Posted by DreadedHermie

Weezard, I don't know much about electronics, but I can solder WAY better than your average bear. ;) I've got a Weller WESD51 digital station and Cardas Audio Quad Eutectic solder. Cardas advises a small wattage pencil @ 700 deg F. for small connections. There's not that much total heat to dissipate but it gets the connection done quickly. It's worked well for me in the past. Looks like a piece of cake to me. I didn't want to use bigger supply wire than necessary 'cos to avoid dissipating excess heat into the the device (?)
I've got a big-ass gun too, but I wouldn't put that many watts on such a small package unless necessary. What say you? :confused:

---

Again, disregard my soldering mis-adventures.
I glued a batch of 5 Watt MPCBs to a heatsink before soldering on my first array and am still kickin' myself over it.
:weedpoke::jointsmile: :rastasmoke: :smokin: :rasta: :stoned: :S5: :bigsmoke: :error:
The 20 guage wire between leds is jus' peachy.
It's the long run, (from supply to the lamp) that I would use 16 g. for.
Because it's cheap, readily available and overkill.

In a fog
Weezard

Not too happy with my first glue joint. A little thicker than I would have liked. :mad:

Gonna dash off to the hardware and get some wire, I need one more color so I can keep Blue LED + and - and Red LED + and - easily identifiable. If you have time to check back in later, I'd feel a bit more confident. It'll be a few hours but I'd like to at least test fire this baby tonight! :yippee:

Quote:

---

It's the long run, (from supply to the lamp) that I would use 16 g. for.

---

Actually, I found some 2 conductor 14 ga with a nice flexible jacket called "low voltage wire" which I think is intended for decorative lighting. Not sure what my eventual driver situation will be but for running 6 LEDs off my bench supply I think I'll use that. It's such a short run, I can be extravagant for 6 feet! :D

I may run a separate 16 g. to each pair of LEDs, that'll be easy to work out once I've got parts in hand.

It's been an expensive night so far. :sadcrying I got everything glued onto the heatsink. The first joint which I thought was too thick was actually OK, but I somehow killed that LED anyway.

First, I set the Mastech to full volts, no amps. I just touched the probes to a red LED. It lit briefly, not super bright, but when I tried it a second time, nothing. I could see one of the 4 emitters was darkened--it was fried. It was almost like the power supply gave it a capacitive discharge.

I fired up the other reds, one a time, with no problems. Let them burn in for awhile; they were fairly consistent 10.8V giving 1.2A and 11.2-3V giving 1.5A. Then, on one of many go-rounds, that first one I glued failed to light. On examination, that one also had one cooked quadrant.

The wire I was using was so stiff it was really manhandling the LEDs. I tried to hold off on attaching the wires to the sink cause I hadn't had a chance too really think about they'd be routed: through a hole, around the side, etc. I managed to rip a solder pad each off two of them. Fortunately, I was able to scrale down to the trace and get a lead soldered to them. That's when I decided to go ahead and just use some thermal epoxy to secure the wires near the LEDs for some strain relief.

Gets worse. Still online?

Cause I cooked them, too. Both of 'em. :sadcrying

They were working fine, although they wern't too close electrically.
Blue#1: 15.2V gave 1.5A, 14.7V gave 1.2A
Blue #2: 15.6v gave 1.5A, 15.1V gave 1.2A

I ran them singly, and together, and let 'em burn in for awhile. Here's where I must have made a mistake, but then I'm still not sure how these CC / CV supplies are "bending" the "law." It seemed like the pair should be able to handle 3A between them. 14.8V gave 2.2A when I dialed it in. I played around near those parametersfor awhile, disconnected them (spike there somehow?) and when I tried to reignite them, they too had one "corner" out.
So the blues are history, too. :i feel stupid:

Not really sure why I've had such a destructive night. I've still got 3 working reds, but now I don't want to hook them up as a group without some advice. Should 3 of them be able to take 3.6A at 10.8V, or will this PS somehow feed 3.6A to each of them? :confused:

Wow! you are having one expensive night.
The 1.5A rating is the absolute max and is not usually do-able in real life.
So, in order to push an emitter to abs max current one might have to exceed Vf max.
That will show no mercy. a millisecond is too long
Ouch, brah!

Quote:

---

Originally Posted by DreadedHermie

Cause I cooked them, too. Both of 'em. :sadcrying

They were working fine, although they wern't too close electrically.
Blue#1: 15.2V gave 1.5A, 14.7V gave 1.2A
Blue #2: 15.6v gave 1.5A, 15.1V gave 1.2A

A .48 ohm resistor in series with Blue #1 would have balanced the two emitters in parallel at 15.1 V.

I ran them singly, and together, and let 'em burn in for awhile. Here's where I must have made a mistake, but then I'm still not sure how these CC / CV supplies are "bending" the "law." It seemed like the pair should be able to handle 3A between them. 14.8V gave 2.2A when I dialed it in. I played around near those parametersfor awhile, disconnected them (spike there somehow?) and when I tried to reignite them, they too had one "corner" out.
So the blues are history, too. :i feel stupid:

Not really sure why I've had such a destructive night. I've still got 3 working reds, but now I don't want to hook them up as a group without some advice. Should 3 of them be able to take 3.6A at 10.8V, or will this PS somehow feed 3.6A to each of them? :confused:

---

If they draw 1.2A at 10.8V within .1 V. each, then 3 in parallel should divide the 3.6 A. draw almost equally.
I'm wondering if you are getting zapped by static electricity.
These pups will not tolerated much reverse bias. and should be treated like cmos when handled.
That means no shoes and/or a wrist strap.
Never did ask where you are from.
Most of the mainland is cold and low humidity in February.
Perfect conditions for zapping LEDs.

Don't think it's static. Hot and humid here, all year long. (That's why I need the LEDs.) Dirty power's probably at least as likely, and I don't think that's it either. The problems occur when I hook up multiple LEDs. And they never seem to "blow" while they're operating.

When I got started, I deliberated toasted a whole grab bag of Radio Shack cheapies just so I'd get a feel for how it happens. This is strange. They seem to be working okay, and when I go to start 'em up again, nothing happens. :confused: On exam, they're cooked. I 4 x color-coded the wires so I'd be able to easily tell 'em apart--pretty certain I didn't reverse-bias 'em, too.

Maybe I "milliseconded" them by accident. In that case do they keep working but refuse to fire up next time?

Quote:

---

Originally Posted by DreadedHermie

Don't think it's static. Hot and humid here, all year long. (That's why I need the LEDs.) Dirty power's probably at least as likely, and I don't think that's it either. The problems occur when I hook up multiple LEDs. And they never seem to "blow" while they're operating.

When I got started, I deliberated toasted a whole grab bag of Radio Shack cheapies just so I'd get a feel for how it happens. This is strange. They seem to be working okay, and when I go to start 'em up again, nothing happens. :confused: On exam, they're cooked. I 4 x color-coded the wires so I'd be able to easily tell 'em apart--pretty certain I didn't reverse-bias 'em, too.

Maybe I "milliseconded" them by accident. In that case do they keep working but refuse to fire up next time?

---

Let's think about this.

If you apply input power to a constant current regulator with no load.
It will "see" almost no resistance at it's output.
Whatever your pre-set current is, the supply will raise it's voltage as high as it can to try to hit that preset.
So a supply with no load will sit at whatever voltage you have preset.
That means you must have a load connected when you turn on the supply.
If you power-up the supply and then try to connect or disconnect a load, the supply may get confused and voltage spike your load.
It's a very short spike, but more than enough to punch a hole in a led junction.
When testing I start with everything tightly connected, use variable voltage setting and bring it up slowly until I hit my target current. Then record the voltage reading.
I turn off the supply and wait a few seconds for the supply to drain before disconnecting anything.
Have not fried a big led yet.
Did eat a couple 3 Watt mpcb when I was learning, though.

Keep in mind, that it's before 11 am my time. So take anything I write before noon with a boxcar of salt.

Not a morning person.

Breakfast is up, I'll be back later.

Weeze

Thanks for the continued support. The LED's may have won the first round (a Pyrrhic victory, for sure) but I am not giving up (yet). Taking the mutts for a walk to clear my head, and prolly reorder parts tonight.

Your analyses of the potential causes for the problems seem valid to me. All I know of operating this Mastech is the little pamphlet it shipped with. Doesn't cover much; includes a couple of recipes for LED disaster, apparently. I definitely was disconnecting the LEDs abruptly and this possibly resulted in some of my catastrophies, since the LEDs appeared to be working fine when I disconnected them. I think I was subconsciously (rather, consciously and ignorantly) trying to avoid a turn-off spike from the PS and in the process spiked them even more effectively.

Anything you can think of to help keep the next batch of LEDs alive will be appreciated.

Quote:

---

Originally Posted by Weezard

No worries, brah. I thought it was droll.

And your avatar is great!
Reminded me of my first stab at being the electrician, (or somebody like him), at about that age..
('cept I used a small, stainless steel, turbine blade that I held with a boxing glove.)
Jammed it in a broken socket 'cause I wanted to "magnetize" it.
Parental units were not amused.:D

So, it's time to outshine the Procyon.
Been saving my pennies and it's need to build some more Ledengin 15W arrays.

Been playing with an idea that involves 3/4" soft copper water pipe.
Want to coil it in a flat spiral, squish the spiral disk almost flat, sand and polish one side and attach the LEDs with thermal cement.
Then, if I hang it from the center I end up with a "cone-o-light"
Pumping water through the pipe and back into a res. will cool the leds and keep res. temps up in the winter for mainland folks.
I'll probably have to feed it from the tap and tie the output into my drip irrigation for the yard.
That will transport the heat out of the grow room.
Still a pipe dream, until I get to the plumbing supply store.

Howz your design coming?

Aloha,
Weezard

---

This is a very good idea, congratulations :D Water cooled led set, I was thinking of doing the same with my HID HPS 400w grolux but I decided to go CFL, possibly 20x50W or something heh.. who knows i might need this for the 50 20watters heh.

Peace,
Denial

Mahalo!

Weeze

Quote:

---

Originally Posted by DreadedHermie

Thanks for the continued support. The LED's may have won the first round (a Pyrrhic victory, for sure) but I am not giving up (yet). Taking the mutts for a walk to clear my head, and prolly reorder parts tonight.

Your analyses of the potential causes for the problems seem valid to me. All I know of operating this Mastech is the little pamphlet it shipped with. Doesn't cover much; includes a couple of recipes for LED disaster, apparently. I definitely was disconnecting the LEDs abruptly and this possibly resulted in some of my catastrophies, since the LEDs appeared to be working fine when I disconnected them. I think I was subconsciously (rather, consciously and ignorantly) trying to avoid a turn-off spike from the PS and in the process spiked them even more effectively.

Good analysis!

Disconnecting an alligator clip sounds "clean" until you see it on a 'scope.
Literally, thousands of "off n onnies" in a fraction of a second. Looks like a burst of rf.
If there's any inductance at all in the circuit, at these currents, the spikes will be higher than the dc level and will be in the wrong direction!
Once you get over a few amps, coiling a lead for strain relief is enough inductance to make trouble.
Then there are small, distributed capacitances...

Anything you can think of to help keep the next batch of LEDs alive will be appreciated.

---

So, next time, hard wire the leds and use the power switch on the supply to power down and we should be OK.
I've been running 13. 5 Watt leds from my Mastech for months with the supply on a timer.
Keep it set at 12.6V 3.4A.
So I bang the AC on and off with few problems.
(it did occasionally cause my UPS to "freak out" and beeeep at me.)

Had to plug the timer into a plain old socket and eschew the UPS for those leds because when it siezed-up like that it shut down the airpumps.
Not acceptable!

I feel your pain, brah.
Fried my first home-made geiger counter in the '60s.
Almost cried when the magic smoke got out.

Aloha,
Weezard.

LED wives and mothers are waving tearfully goodbye to their loved ones: the unfortunate few who have been selected to do glorious battle with the now-infamous Dreaded Hermie. No one speaks of it, but they all know: we might not survive this....

[attachment=o213864]

Quote:

---

Disconnecting an alligator clip sounds "clean" until you see it on a 'scope.
Literally, thousands of "off n onnies" in a fraction of a second. Looks like a burst of rf.
If there's any inductance at all in the circuit, at these currents, the spikes will be higher than the dc level and will be in the wrong direction!
Once you get over a few amps, coiling a lead for strain relief is enough inductance to make trouble.
Then there are small, distributed capacitances...

So, next time, hard wire the leds and use the power switch on the supply to power down and we should be OK.
I've been running 13. 5 Watt leds from my Mastech for months with the supply on a timer.
Keep it set at 12.6V 3.4A.
So I bang the AC on and off with few problems.
(it did occasionally cause my UPS to "freak out" and beeeep at me.)

---

Weezard, thanks. These details/specifics are what I'm needing. I reordered my supplies and should be back blowing stuff up by the end of the week, although responsibilities in the "real" world may cut into my mad scientist time over the coming weeks. Getting older ain't so bad, but having to act like an actual adult does get tiresome. ;)

I started looking at thermal switches. Most that are referred to that way on the 'Bay open the circuit at a given (rising) temp. The ones that close the circuit seem to be called "thermostats" or fan switches. From your brief description of operation I'm gonna assume the latter is what you're using.

Looking at a pic of your light, looks like you have 3 of them, all mounted in places you'd expect the sink to be the hottest--right near the leds. It also looks like you've got it wired so any one of the switches can complete the circuit by itself. Close? :detective1:

I found some switches that close when temps rise to 50 deg. C. Looks like the right range for me, although certainly I'll hard wire both fans at first.

[attachment=o213907]

DH

[attachment=o213910]

The attachment's just the pdf datasheet from Mouser. Couldn't get it to work, trying again. :wtf:

Quote:

---

Originally Posted by DreadedHermie

[attachment=o213910]

The attachment's just the pdf datasheet from Mouser. Couldn't get it to work, trying again. :wtf:

---

STC 120 looks about right.

And you are spot on about;

"It also looks like you've got it wired so any one of the switches can complete the circuit by itself. Close? :detective1: "

Give that man a ceegar!:jointsmile::D

Duty cycle depends on ambient.
Generally, the fan runs for 30 minutes and then shuts off for 10 minutes.
Found 'em cheap, so I bought a dozen.
Figure I can use them to ride herd on my peltier devices.:cool:(Long story.)

Aloha,
Weeze.

So I looked at 'em. Looks like a miniature heat pump. Great idea, if you have a place to exhaust the heat. :( The ones I saw drew like 2A, though. Is this the kinda thing you're talking about?

Quote:

---

Originally Posted by DreadedHermie

So I looked at 'em. Looks like a miniature heat pump. Great idea, if you have a place to exhaust the heat. :( The ones I saw drew like 2A, though. Is this the kinda thing you're talking about?

---

Bought them to cool leds but the power draw was not acceptable.

So, designed a shake table with a shroud to pull the heat from their hot sides.
The cold sides form a chamber that is held well below freezing.
The bottom of the chamber is a set of drawers with silkscreen stretched across them.
Trying to automate bubblehash production without all the ice-water and work.

Put the sugar-leaf in the chamber, turn on the shaker, wait a bit, scrape chilly kif , (Bubba Hash),:D off of the screens.

Just another pipe dream that may or may not work well.
It's not like I'm too busy to play, ya?
Zippy would be proud. Yow!

Weezard

:clap: Dang, Weezard! You are like the Thomas Edison of reefer! (Or Rube Goldberg, maybe.) :D

I think I would try to mount such a machine in a semi-functional clothes dryer. The rotating drum (esp. if it's off-balance) could give you the shaking, and if you could get the waste heat to the drum you could at least dry your delicates with it.

Supporting a local economy is admirable, so shaking the table via hula-power is an inviting possiblity, and so socially responsible. ;)

I half expect you to come up with a machine that you just put a seed in, and 5 months later it spits out a nicely rolled doob. :jointsmile:

Received leds and fans already (also a PLN 60-15 and a 60-12). :dance: Hopefully I can find time to play this weekend, and go slow enough not to destroy anything else. :(

Any more helpful hints along those lines? :hippy:

Quote:

---

When testing I start with everything tightly connected, use variable voltage setting and bring it up slowly until I hit my target current. Then record the voltage reading.

---

Weezard, I don't want to have a semantic-induced disaster here, so: The instructions I got with my Mastech are worded this way:

2.2 Operating Procedure

2.2.1 For constant voltage mode adjust controls 3 & 4 clockwise....
2.2.2 For constant current mode adjust controls 5 & 6 clockwise....
2.2.3 For restricted current protection mode switch on the power...

I can type the whole sections out (they're short) if this is different than the instruction book you got with your Mastech. They don't discuss a "variable voltage" setting per se, and following their procedures outlined above has been costly. Sorry to be such a dolt, but could you outline your start-up procedure to include "knob positions" before power-up, or otherwise reconcile your expression "variable voltage" to Mastech's "constant" or "restricted" modes?

I know following their instructions exactly will spike the leds. My electronics training consists entirely of having worked as a janitor at an audio shop in the early 70's (after I ran out of $ for school) and looking over the tech's shoulders as they worked and eavesdropping on their techie conversations. These guys were not too keen to share any info, and trying to read books (pre-internet) to figure out what they were talking about was really frustrating. I understand what pots and resistors do, and have been zapped by a few caps that were storing up a present for me. :eek: I have used tiny leds for years as indicator lights (with a drop-down resistor) but these high-power emitters are a different beast for sure.

I can do the simple math involved with calculations involving Ohm's law, but sometimes I'm baffled about which terms to plug into the equation, like when there are multiple values (2.2V here, 1.2V on the other side of a resistor, etc.)--which one gets plugged into the equation? :i feel stupid: (if that makes any sense?)

Thanks in advance. I think if you can explain this so I can understand it, I can eventually do a tutorial / build log so anybody that can solder can also do it. There's quite a few folks following this thread, unproductive as it has been to this point, so I think the interest is out there.

Seems like commercially produced led grow lamps are not getting any cheaper (contrary to what usually happens with tech stuff), and the Procyon was the only one that was honest about what components were used. Unfortunately, you risk paying high dollars for glorified china panels if you don't assemble the components yourself. There are a lot of profiteers out there jumping on the led bandwagon, but the fact that they're overstating their products' capabilities is causing lots of folks to discount led growing altogether.

Quote:

---

I think if you can explain this so I can understand it

---

Sorry, Weezard. The power supply operation. That's what I'm talking about. Not the Ohm's Law stuff. If the need arises I'll make a calculation and ask for feedback.

I've been typing in a hurry, sorry if my posts have been jumping around a bit. Hermie

Quote:

---

Originally Posted by DreadedHermie

Sorry, Weezard. The power supply operation. That's what I'm talking about. Not the Ohm's Law stuff. If the need arises I'll make a calculation and ask for feedback.

I've been typing in a hurry, sorry if my posts have been jumping around a bit. Hermie

---

No worries, been jumping around a bit meself of late.
Social obligations and all.
Will get back to you on the rest.

That "manual" was worse than worthless.
I tossed it and played it by ear.
Variable voltage is prolly what they call constant voltage.
I'll see about knobs 3, 4, 5, & 6 setting tomorrow.
The girls are asleep right now.

Basically, it's safe to turn the current adjust clockwise, (all the way up), and bring the voltage adjust up slowly until the current meter reads, say 1.25A.
the voltmeter will then show the actual Vf for that led.
Magic marker each LED, then plan on how to feed them.

What kine. manual did you get with the PLXXs?

l8r
Weeze

This thread has been very helpful and too much of a coincidence for me not to post. Before I get into it, Weezard thanks for keeping your name the same across multiple forums, googling your name was what made me find and join this forum.

Crunchy - Completely independently, I swear :-), we ended up with almost the same LED set. I purchased 4 660, 1 Dental, and 2 WW 15watts from LEDEngin.

I'm in the process of getting all my materials together and am trying to figure out how to power these beasts, circuit theory 1 was entirely too long ago and I'm struggling. I'm thinking about going the easy route since I don't the appropriate equipment to create my own driver, so... I'm thinking of going the route of Mean Well PLN-60-48 to power the blue and the ww in series since their Vf is similar and possibly getting another one to power the 4 reds. First, is that the right choice? Secondly, I have a email out to LEDEngine for a data sheet on the 660, but if the numbers match the regular red data sheet I think I would be ok using the same power supply for my 660's. I've read this entire thread about 3 times now and I don't think the Vf for the 660's was measured, is it around 11V?

I also bought 7 cheap cpu heat sinks w/ fans to cool the LED's. Is there an easy way for me to power the cpu fans with the power supplies above or am I going to have to power them some other way?

Weezard - you have no idea how much research I have done in the past month, it's almost embarrassing. Finding and reading your posts was quite exciting and convinced me to spend my cash. Thanks.

Welcome, Neural! Now Weezard class has two students enrolled.

I will give you my opinions happily, but until my ramblings are approved or condemned by Weezard, please take them for just that: the ramblings of a convicted LED killer. :pimp: I can you tell things that I did that probably cost $35 per boo-boo; knowing to avoid them should help... :hippy:

Quote:

---

I fired up the other reds, one a time, with no problems. Let them burn in for awhile; they were fairly consistent

10.8V giving 1.2A and
11.2-3V giving 1.5A.

Then, on one of many go-rounds, that first one I glued failed to light.

---

The higher you set the voltage on your power supply the more current the leds will draw. So, the group of 660's I got was very consistent and 10.8V would have been good for all of them. If you got 1 oddball that drew 1.2 amps at only 9V you'd need use a series resistor to prevent it from receiving more than 9V as you turn the shared supply up to 10.8V to power the "normal" leds. This is the problem with running the leds in series string. Putting that resistor on the 9V led puts it in series with all the other leds. too. So you get nowhere in terms of balancing the circuit.


DO NOT go all the way to 1.5A. This is a theoretical max and you can't run 'em that hard in the working light because, for example, if they get hotter they'll pull MORE juice, which will make them HOTTER, and so on.

1.2A is where Weezard likes to run the reds. There's a procedure for measuring Vf that employs a CC / CV bench power supply. You got wunna dem? (you can run the leds off 'em too, hint, hint).

The conventional wisdom (which I totally IGNORED when I ordered my drivers) is to mount the leds to a heatsink and see what voltage it takes to drive the led with your desired current. (using the bench suppply trick). Then you order a driver to fill that need. The Mean Well's are adjustable, so we should be able to get them dialed right in.

IF (big if) your WW and DB have almost identical Vf, and you put them in a series string, they would want ~45V to pull 1.2A each. The Mean Well claims to adjust down to 43.6V, so that should certainly work. But, you've got no simple way that I know of to balance the individual Vf's. (You know these 15Watt leds are really 4 x 5 watters in a series package, right?) They function like a "series string" of the older, individual emitters, so that's how I'm approaching putting them into the circuit. I plan on using the PLN 60-15 for my blues and wiring them in parallel so I can use balancing resistors if necessary.

You might check out the PWM controllers at Quikar.com. They look useful for balancing things out, you might be able to employ one for your fans. If you were running your reds at 11VC or so 12V case fans would work, but I'd get a second opinion on combining leds and fans on the same run.

Watt for watt, led drivers are so expensive and crap-ola wall-warts at 9-12V are sooo cheap, I plan on running the fans off their own circuit, mebbe 2, for backup.

The idea, as Weezard has said, is to waste as little energy as possible in resistors, etc. My problem is heat, so I especially don't need to be creating excess current only to dispose of it as heat.

Yes, Weezard--No manual with the Mean Well's. They prolly figure anybody who'd order one would know what to do with it. I planned to set them to the desired voltage with a meter.

I would like to do an in-circuit measurement (hooked up before power-up:thumbsup:) to confirm "no-sag" or "CV compensation for sag" at some point. Sound expensive yet?

"You might check out the PWM controllers at Quikar.com. They look useful for balancing things out, you might be able to employ one for your fans."

Not a bad idea.:thumbsup:

"If you were running your reds at 11VC or so 12V case fans would work, but I'd get a second opinion on combining leds and fans on the same run."

Fans and leds on a CC supply?
Not a good idea.

"Watt for watt, led drivers are so expensive and crap-ola wall-warts at 9-12V are sooo cheap, I plan on running the fans off their own circuit, mebbe 2, for backup."

Much better idea.:cool:

Ideally, we would not need fans at all.
But, that's another pipe dream.:hippy:

Park and lock it.
Not responsible.;)

Weezard

Quote:

---

Originally Posted by Neural

This thread has been very helpful and too much of a coincidence for me not to post. Before I get into it, Weezard thanks for keeping your name the same across multiple forums, googling your name was what made me find and join this forum.

Aloha, Neural.
Mahalo and E como mai!
I'm just a simple, country 'zard, but you are welcome to whatever assistance we can provide.
..
Weezard - you have no idea how much research I have done in the past month, it's almost embarrassing.

Oh, ah dunno 'bout dat.
I just might have an inkling.:D
Did you get to read any of, "The Perfect LED Grow Light",
thread before it pissadeared?
Some brilliant stuff!

Finding and reading your posts was quite exciting and convinced me to spend my cash. Thanks.

---

Rutro!
Set loose the disclaimers!:)
Stack up the boilerplate.
Our liablility is limited to the admission price, or :twocents:, whichever is less.
Ah didn' do nodding!:D
You are welcome!
This is fun.

Wee Zard:jointsmile:

Quote:

---

Blue#1: 15.2V gave 1.5A, 14.7V gave 1.2A
Blue #2: 15.6v gave 1.5A, 15.1V gave 1.2A

A .48 ohm resistor in series with Blue #1 would have balanced the two emitters in parallel at 15.1 V.

---

Weezard, how did you arrive at this? As I said before, I'm not sure which terms to plug into the equation.

Quote:

---

Originally Posted by DreadedHermie

Weezard, how did you arrive at this? As I said before, I'm not sure which terms to plug into the equation.

---

The answer is quite simple.
I screwed up.:o
Must have been too early.:stoned:
Happens alla time. :rolleyes:
Sorry.

So, let's see if I can still figger.
Um.

R = E/I
So, .4/1.2 = .334 Should be .33 ohms. .34 is close enough and can be cobbled from 2 .68 ohm resistors in parallel.

Here's where I got bumfoozled.
P = E x I .4 x 1.2 = .48 W
A couple 1 or 2 Watt .68 ohm should run cool enough.

Let that be a lesson to ya.
If ya want math done right, yer gonna have to DIY.:(
There is no "I" in Weezard.;)

Oddly unabashed,
Wee Zard

It's posted stuff I was just trying to preview a couple times. When I tried to finish the previous post, it got eaten. :wtf:

Anyway, I'm back at it. Got new leds epoxied to the sink. Wired up and measured a couple reds, both of 'em almost "in the crack" between 2 voltages. About 10.6 and almost 10.9 for the other. Maybe not a problem, I may run 3 leds each on separate power supplies. That kinda depends, and I had calculated a question:

1.2A x 10.8V = 13W.
13W x 4 leds = 56 W.

NOW I read somewhere Mean Well likes 30% extra headroom (130W. of driver to push 100W.of leds) So 4 reds on that PLN 60-12 is close to full 5A load, any way you figure it. Trying to run 6 reds per light means a big-ass driver ($) or 2 x 3. My original plan was to run 4 reds per driver, with one driver split lighting the 2 "extra" leds on both lights.

How much headroom do they really need, is I guess what I'm asking.

These Mean Wells are very nicely made, BTW. :thumbsup: The trim pots that adjust voltage and current feel smooth, like a nice full size pot, and the taper is great, real smooth changes; easy to dial in.

The 12V adjusts from 10.61V to 13.27V (exactly, every time, measured with a Fluke 87) and the 15V goes from 13.21V to 16.55V.

Gonna try and post this now so I don't lose it.

Quote:

---

R = E/I
So, .4/1.2 = .334 Should be .33 ohms. .34 is close enough and can be cobbled from 2 .68 ohm resistors in parallel

---

I get it! :clap: I was trying to "run the equation backwards" with .48ohms plugged in. I wasn't seeing any of the niumbers I was expecting....

Sorry, I'm leapfrogging posts.

If I run blues @ 15.1V:

1.2A x 15.1V= 18.12W each blue

3 x 18.12 = 54.36W

54.36W x 1.3 = 70.67W

Is that how you figure it? Is the PLN 60-15 just marginal to drive 3 blues, or are they just being real conservative?

Weezard, the 15.1V scenario is just hypothetical. I fried the leds that measured this way. :( I just wanted to know how to invoke The Law. :D

I've got the replacements glued on but haven't wired 'em yet. Been up all night (common problem) and I'm 6 hours ahead of you. No touchee $$$ leds till later! :stoned:

Anyway, suppose I've got a happy voltage dialed in for my blues, let's suppose these next ones want 14.8V to draw 1.2A. Here's the question: if I want to dim the blues, can I leave the voltage set where it is and just dial down the current limiter? (That way I could just eyeball the changes and not have to measure.) Or is the proper way to do this by dialing down the voltage?? Does it matter? Would one way create any more waste heat, or stress components more than the other way?

Quote:

---

Originally Posted by DreadedHermie

Weezard, the 15.1V scenario is just hypothetical. I fried the leds that measured this way. :( I just wanted to know how to invoke The Law. :D

I've got the replacements glued on but haven't wired 'em yet. Been up all night (common problem) and I'm 6 hours ahead of you. No touchee $$$ leds till later! :stoned:

Gettin a little gun shy?:)

Anyway, suppose I've got a happy voltage dialed in for my blues, let's suppose these next ones want 14.8V to draw 1.2A. Here's the question: if I want to dim the blues, can I leave the voltage set where it is and just dial down the current limiter? (That way I could just eyeball the changes and not have to measure.) Or is the proper way to do this by dialing down the voltage?? Does it matter? Would one way create any more waste heat, or stress components more than the other way?

---

Changing the current WILL change the voltage as long as the load is relatively constant. So 6 of 1...
But with a current limit supply, it's best to vary the voltage because the current limit will keep the voltage "capped".

I'll need more coffee to respond to your earlier posts.

Solar powered 'Zard

Quote:

---

Originally Posted by Weezard

[FONT=Book Antiqua]

Solar powered 'Zard

---

haha no way dude tell me you aren't providing your led electricity via solar panels, because something there would seem 'just outright wrong' lol.

feds, make some do the craziest of things, I guess lol even the smart ones haha


Peace,
Denial

Quote:

---

Originally Posted by DreadedHermie

It's posted stuff I was just trying to preview a couple times. When I tried to finish the previous post, it got eaten. :wtf:

Boards flakin' again.
Good idea to highlight and hit control-C every 5 lines or so.

Anyway, I'm back at it. Got new leds epoxied to the sink. Wired up and measured a couple reds, both of 'em almost "in the crack" between 2 voltages. About 10.6 and almost 10.9 for the other. Maybe not a problem, I may run 3 leds each on separate power supplies. That kinda depends, and I had calculated a question:

1.2A x 10.8V = 13W.
13W x 4 leds = 56 W.

NOW I read somewhere Mean Well likes 30% extra headroom (130W. of driver to push 100W.of leds) So 4 reds on that PLN 60-12 is close to full 5A load, any way you figure it. Trying to run 6 reds per light means a big-ass driver ($) or 2 x 3. My original plan was to run 4 reds per driver, with one driver split lighting the 2 "extra" leds on both lights.

How much headroom do they really need, is I guess what I'm asking.

That would depend on the stability of the input, but 10% should be sufficient because your load is constant.

These Mean Wells are very nicely made, BTW. :thumbsup: The trim pots that adjust voltage and current feel smooth, like a nice full size pot, and the taper is great, real smooth changes; easy to dial in.

The 12V adjusts from 10.61V to 13.27V (exactly, every time, measured with a Fluke 87) and the 15V goes from 13.21V to 16.55V.

With a resistive load?

Gonna try and post this now so I don't lose it.

---

Seems to have worked.

Aloha,
W.

Quote:

---

Originally Posted by DreadedHermie

I get it! :clap: I was trying to "run the equation backwards" with .48ohms plugged in. I wasn't seeing any of the niumbers I was expecting....



Sorry, I'm leapfrogging posts.

If I run blues @ 15.1V:

1.2A x 15.1V= 18.12W each blue

3 x 18.12 = 54.36W

54.36W x 1.3 = 70.67W

Is that how you figure it? Is the PLN 60-15 just marginal to drive 3 blues, or are they just being real conservative?

---

They are more likely to run at 12.6V or so at 1.2A.
You'll be lucky to get close to 15W. ea.
Since you are not going to get more than 45W. into 3 blue leds, the PLN60-15 will be just peachy.

45W. X 1.3 = 58.5W.

Next time I score some surplus cash, I'm gettin' acouple of those Meanwells.

Just beginning to get vertical.
Weezard

Quote:

---

Originally Posted by denialisback

haha no way dude tell me you aren't providing your led electricity via solar panels, because something there would seem 'just outright wrong' lol.

feds, make some do the craziest of things, I guess lol even the smart ones haha


Peace,
Denial

---

Howzit, D.?

Photovoltaics are on my wish list for the whole grass shack, someday.

But, in this case, I was referring to my personal limitations.
Like my li'l green buddies, I'm slow, stiff and creaky until I warm up a bit.
Coffee helps the brain, but the carcass is gettin' old.
Takes me an hour in the hot tub and a medicine pipe to stifle my sniveling in the AM.

Regards,
Wee Ancient 'Zard