Stealthy LED Project - help wanted

[giblets]

Hello Jopedijoo,
Be carefull what adhesive you use to mount the diodes, sticky metal tape works good and can be "reworked" if you need to change location or change a diode.

Mac, what kinda stuff you talking about? Kapton, or something else?

JJ, that certainly is a consideration. The LEDengin 15W flex-pcbs are designed to be mounted with adhesive-- there's no screw-mounting provision like there is on most "stars."

I use thermal epoxy (arctic silver) and mix it in unequal proportions to deliberately weaken the bond. I've also read of folks mixing thermal grease into the epoxy to accomplish the same thing, but haven't tried that myself. Sounds a little "iffy" to me.

The recommended emergency removal procedure for correctly bonded thermal epoxy involves fracturing the bond following cryogenic freezing. Not sure the leds would survive that.

But, if you destroy an led, the flex-pcb part easily strips away from the emitter, leaving you with just the thermal pad/emitter still attached to the heatsink. That's just a few square millimeters. Easy to work around; just stick the replacement right next to it. The plants won't see it...

Unfortunately, I have a lot of experience in this area...($$$)

 

[giblets]

Is it fair to say that if you're using thermal grease/paste you would have to mount the LEDs mechanically whitch is not possible with Ledengin 15ws?

Yes, that is correct.

I'd rather be able to get them off with acetone

Ain't gonna happen. My epoxy laughs with contempt at your acetone.

 

[giblets]

Could I drive lets say four blue/white 15Ws drawing almost 60Ws from a Mean Well PLN-60-15?

Yes, especially with proper thermal management, unless you really wanna crank those blues. Then, go with the PLN100-15 (75 watts, for a little extra headroom).

(Or maybe two PLN-30s to seperate blues and whites...)

That would be very slick. However, since the PLN 30 series costs almost as much as the PLN 60 series, I prefer the PLN60's. The downside is that a load of only 2 blues (or whites) on a PLN60-15 has so much headroom that the current limiter won't kick in--you can't turn it down low enough. Adding a third emitter puts it in perfect range. However, I've run 2 blues (hard! yee-haw!) on a PLN60-15 without problems.

Same for the reds, is PLN-100-15 (or even PLN-100-12) good enough for 6 reds or would a PLN-150-15 be better?

The mean Well 15 volt drivers only adjust downward to about 13 volts, which is far too much for the reds. (They top out at around 11 Volts.) You need 12 volt Mean Wells for driving your reds.

But, (as I've complained about already) the PLN100's at 12 volts are only rated at 60 watts, so again, I'm liking the PLN60 series. It's just underpriced compared to everything else.

Okay, I think that brings me up to the present in this thread.

 

[Jopedijoo]

Hello, Jopedijoo.

That's a unique name. A google search will round up all your conversations. So I will call you JJ. This is DH, from the other board.

Hi Giblets! Good to have you onboard! Weezard's bat signal seems to be working Yep, not too many Jopes around I see No big secrets behind the name, just the first thing that came to my mind, don't mean a thing.

I'd like to help here, but I don't understand the project. There are two spaces, I got that. But are you building a light for just the flower section, or a multipurpose light for veg and flower (by adjusting red:blue ratio)? Or two separate lights?

Well, I have a two part wardrobe that I was planning on using. I want to make a multipurpose light for both veg and flower for both compartmets and do the cloning business elsewhere. I've got two heat sinks waiting but now I just want to start with building one light and see how that goes.

You have a lot of blue there. To build a flowering lamp, a single 15W. blue will easily keep up with 6 x 660nm reds. (I'll use 7 or 8 reds for each blue on a flowering lamp.)

(IMO) For a flowering lamp you need so little blue that it almost doesn't matter what you use- a CFL - a small T5... unless you're also trying to control the "stretch" immediately following your 12/12 flip. Then, I'd hit them hard with blues (and whites?), and back off the reds for a week or two. That has worked well with some strains if I caught them small enough.

Yeah, you're propably right, it seems to be a lot of blue indeed. I thought I'll just make sure to have enough blue to keep the plants short in SOG and so they wouldn't spead so much to the sides either as the space is limited. For SGROG vegging is needed of course but for SOG I'll probably be skipping vegging pretty much altogether. So you think that controlling strech could be done with just one blue and two whites? I could save the other blue emitter for the other light..

Old mac has much experience with white leds, and his T1 Smartlamps are very effective. So, if he thinks white leds help, they probably do. If you mount your whites judiciously you might later be able to conduct some experiments with, and without them.

Are you suggesting to sepparate the blues and the whites to be able to see their individual effect?

For example, a Procyon is (sort of) 2:5 blue to red. That's too blue for flowering (I have one), and if you mount up all your emitters on a single light the result will probably be similar. If you study how white LEDs are made, you might consider them a modified blue (and not for the better as far as plant growth is concerned, IMO).

If you take a look at the typical relative spectral distribution curve of the warm whites http://www.ledengin.com/products/15wLZ/LZ4-00WW15.pdf it seems that they emit more red than blue. It might be that I'm not interpreting it correctly though. But even so the whites shouldn't affect the red:blue ratio too much in my opinion as they have both but could add a couple of ingredients to the soup.

For good news, the whites want the same voltage as the blues, so you could run the 2 blues and 2 whites all off one PLN60-15; just not very hard. I've put 18 watts into a blue before (20 watts killed it) so if you're really going to run them hard, 3 blues (or whites) is the max for a 60 watt driver.

If I drop the other blue I suppose the 60-15 driver would be perfect for one blue and two whites.

About the Mean Wells: that PLN 100 series doesn't start putting out 100 watts until you get into the 20V and higher output configuration. A PLN100-12 is rated at only 60 watts , and the PLN100-15 at 75 watts. (For running 4 blues or whites more vigorously, that's a nice driver, but it's $90 USD, plus shipping.) At $55, the PLN60-12 will drive 4 15W. reds very nicely, and that's the building block I use with the Mean Wells.

I didn't realise that the PLN-100s are rated at only 60 and 75 watts, thanks for pointing that out! I took a quick look and the PLN-60s seem to be rated at 60 watts though, that's kinda wierd. I might have to take another look..

I have a better tip. (Big tipper )

Last time I ran 14 guage to my emitters. But, the 15W LEDengins are quite delicate at the soldering pads for such huge wire. It retains too much heat energy and will act like a too-big soldering gun, and can melt the solder pads and the copper traces loose on the flex-PCB. (That repair can be tricky.)

So, I finally got smart and ran a short "leader" wire of a smaller gauge (3-4" of 20 ga. or so) between the led and the 14 ga. supply wires. Much easier to work with in terms of twisting and turning, too.

Good advice, thanks! S'il vous plait..


JJ, you're not gonna need these dimmers if you use Meanwells or Mastechs. 'Zard used these as regulators for a homemade driver, and to bring down the voltage, if I remember right. (W., please correct me if you've got a different plan, here.) Meanwells have PWM dimming built-in (very nice), and the leds hook up directly to them. Very slick and easy.

Oh so no dimmers ay? That's good news! The less parts there is to the puzzle the better this will do.

Mac, what kinda stuff you talking about? Kapton, or something else?

JJ, that certainly is a consideration. The LEDengin 15W flex-pcbs are designed to be mounted with adhesive-- there's no screw-mounting provision like there is on most "stars."

I thought I read someplace that using metal tape for high power LEDs wouldn't be suggested but not really sure why. I've seen tape used with one watters but with 15Ws, dunno. Using just tape would indeed be chimp proof if it's possible! LedEngin suggest using thermal epoxy or thermally thermoplastic elomer (?) supplied only in pellet form which don't seem to handy to me.. http://www.ledengin.com/products/appnotes/15W_thermgmt-note.pdf

I use thermal epoxy (arctic silver) and mix it in unequal proportions to deliberately weaken the bond. I've also read of folks mixing thermal grease into the epoxy to accomplish the same thing, but haven't tried that myself. Sounds a little "iffy" to me.

Is there a reason to weaken the bond deliberately? The emitters (thermal pads atleast) won't come off anyway if mounted with epoxy, ay?

The recommended emergency removal procedure for correctly bonded thermal epoxy involves fracturing the bond following cryogenic freezing. Not sure the leds would survive that.

But, if you destroy an led, the flex-pcb part easily strips away from the emitter, leaving you with just the thermal pad/emitter still attached to the heatsink. That's just a few square millimeters. Easy to work around; just stick the replacement right next to it. The plants won't see it...

Unfortunately, I have a lot of experience in this area...($$$)

Your experience with these things is valued and might save me from repeating the same.. um, lessons !

However, since the PLN 30 series costs almost as much as the PLN 60 series, I prefer the PLN60's. The downside is that a load of only 2 blues (or whites) on a PLN60-15 has so much headroom that the current limiter won't kick in--you can't turn it down low enough. Adding a third emitter puts it in perfect range. However, I've run 2 blues (hard! yee-haw!) on a PLN60-15 without problems.

The mean Well 15 volt drivers only adjust downward to about 13 volts, which is far too much for the reds. (They top out at around 11 Volts.) You need 12 volt Mean Wells for driving your reds.

But, (as I've complained about already) the PLN100's at 12 volts are only rated at 60 watts, so again, I'm liking the PLN60 series. It's just underpriced compared to everything else.

Real good This makes it easy for me. It seems that if I drop the other blue I could power it and the two whites with a PLN-60-15. Driving the blues and the whites from separate MeanWells (1B:2WW or 2B:2WW) would be trickier. Maybe with the PLN-30s, would cost a few more though. Then I would have a choise of either having two PLN-60-12s or a Mastech 3010 (or similar) to drive the six reds. I like the MeanWells for being small, tidy and mute. Mastech would be handy and has them digital panels for voltage and amps but is somewhat bulky and has a fan making eerie noises, right? Tough decisions

Okay, I think that brings me up to the present in this thread.

Good luck with your project,

DH / giblets

so much!

 

[Jopedijoo]

Ahoy!

Ahoy!

I'd go with Weezard on this one, he's used the 15w LedEngin's and I have not. I'm just gun shy of thermal epoxy after the first LED light I built, I got screwed on some white LEDs that did not have the wavelength I wanted or needed. I could not remove them without destroying them, which was not so bad since they were cheap, shitty, 1w chinese diodes, but the damn work involved like to have killed me.

BTW SupraSPL had a great idea (I thought) of using a thermal paste and a little silicone on the outer edges to give a mechanical grip. Weez could say if that is workable for the LedEgin's, tho it sounded like it might not.

Yeap, I think I'm starting to lean towards using the epoxy. It seems to have its pros and other than money wise it ain't too big of a disaster if some of the LEDs need to be replaces.

Speaking of whites, I really like the idea of adding some since the best off the shelf LED light I know of uses some whites. It certianly can't hurt and might help something.

No pain, no gain, eh? We'll see about that.. Cheers!

 

[guest1ab]

Someone tried growing with just warms whites and ended up killing the plants quite fast. Weezard might be able to link you to that grow, I have a hole in my head and no remember :

I don't think you can tune the whites. They have a fixed spectrum so you can "alter" that only by choosing different whites, warm white, neutral white, cool white... I'm not sure if you could pull a grow by using just reds added to the whites, but you'd be better off by using blues and reds.. and yea well, maybe the whites

Well....I've got the warm whites and the "bluish" whites too.
Can anyone verify whether you can tune the spectrum of white LEDs?

 

[giblets]

So you think that controlling strech could be done with just one blue and two whites?

Never said that. Said this:

(IMO) For a flowering lamp you need so little blue that it almost doesn't matter what you use- a CFL - a small T5... unless you're also trying to control the "stretch" immediately following your 12/12 flip. Then, I'd hit them hard with blues (and whites?), and back off the reds for a week or two.

If those WW leds act like a conventional 3000K light source you'd have to cut them back along with the reds. But I don't know what they'll do; that's why I'd include provisions to operate them separately, although that can be as simple as moving the DC supply wire from a WW led to a blue...

A single blue might control stretch in a 12" square. If you are going to attempt this kind of control in a larger area you probably want both blues available. But for general cannabis flowering that much blue is overkill.

Are you suggesting to sepparate the blues and the whites to be able to see their individual effect?

Absolutely. We know we have good results with just red and blue. That news is 50 years old. Adding white has not produced definitive results for me, nor for Zard, that I'm aware of. (The effect of the reds and blues is so pronounced it's like the plants can't "see" the white light.) To me, white leds represent an unknown quantity, while the effect of blues seems well understood. Without being able to control colors individually, you won't know "what caused what," be your results favorable, or otherwise.

Is there a reason to weaken the bond deliberately?

Yes, to be able "attempt" to remove the leds later without destroying them. I also used this trick to temporarily attach supplemental finned heatsinks to the Meanwells.

If you take a look at the typical relative spectral distribution curve of the warm whites

There's the rub -- it's relative, not absolute. That emitter started its life as a blue, and that graph depicts the relative proportion of what's left. That emitter was engineered to produce a light pleasing to the human eye --not as an effective horticultural light. FWIW, that curve *looks* predominantly amber to orangeish-red, with a spike at shorter-wave blue. I've had better horticultural results with deep red and ~460 blue.

Mastech... has a fan making eerie noises, right?

Don't know where you got that impression. The fan is "on demand" and is so quiet that at first I didn't notice it was kicking on. My desktop computer's quite a bit louder. If you're planning to adequately ventilate your grow area the Mastech's fan noise would be negligible.

 

[Jopedijoo]

If those WW leds act like a conventional 3000K light source you'd have to cut them back along with the reds. But I don't know what they'll do; that's why I'd include provisions to operate them separately, although that can be as simple as moving the DC supply wire from a WW led to a blue...

Yes, it seems reasonable to power all the colors separate. As I already have the reds, blues and the whites we might as well see what they do. Powering them is still a little question mark for me. For some reason I want to use just the Meanwells for this project. Call me stubborn if you will So it will be the two 60-12s for the reds, but for the blues and the whites I'm not sure if I should use the 30-15s or the 45-15s which seem to give out 30 and 45 watts respectively. A few posts back I was suggesting on using the PLN-30s and you agreed that it would be all sprite, but now that I give it a second thought I see that doing that doesn't really leave any headroom there. Using 45-15s for powering would leave a 15W, 30% headroom. Is that too much already? I while back you were saying that a 60-15 with just two emitters has so much headrooms that the current limiter won't kick in. Is this similar with a 45-15 running 30 watts of LEDs? So shortly, 30-15 or 45-15 for the blues and the whites? Or neither..?

Also, if I would drop the other blue and drive it and the two whites from separate drivers, I'm not sure how that would be done. PLNs go down just to 30 watts and that's seems too much for just one blue...

A single blue might control stretch in a 12" square. If you are going to attempt this kind of control in a larger area you probably want both blues available. But for general cannabis flowering that much blue is overkill.

Got that, thanks! I'm still not sure if I understand the PWM dimming feature on the Meanwells. There seem to be the screws for adjusting voltage and amp, but is there another switch for dimming like Weezard has or is dimming done by turning these screws? If so, how exactly is that done, leaving the voltage stay put and turning the amps down, or..? And probably having a meter inbetween to see what's happening? If it's possible to dim 0-100% I could turn down the blues when not needed and still have the option of heavy blue if using both emitters, right?

Absolutely. We know we have good results with just red and blue. That news is 50 years old. Adding white has not produced definitive results for me, nor for Zard, that I'm aware of. (The effect of the reds and blues is so pronounced it's like the plants can't "see" the white light.) To me, white leds represent an unknown quantity, while the effect of blues seems well understood. Without being able to control colors individually, you won't know "what caused what," be your results favorable, or otherwise.

I see that you and Weezard haven't had much use for white and I respect that! You have a working light and that's great! But there are also people that have had good results with using white. Old Mac was liking them whites and Knna & Co at the spanish forum have had best results with adding some white. By what I've seen on the forums it seems that while red and blue are the main players that there is still something missing, don't you agree?. Be it white, far red or even yellow... I dunno, what do you think?

Don't know where you got that impression. The fan is "on demand" and is so quiet that at first I didn't notice it was kicking on. My desktop computer's quite a bit louder. If you're planning to adequately ventilate your grow area the Mastech's fan noise would be negligible.

Well, there are fans and there are fans. I think my question was badly framed, sorry about that. I guess I was just asking if the Mastech's fan(s) is one of the quieter or the louder ones..

 

[Weezard]

White! Watt waste?

White! Watt waste?

"I see that you and Weezard haven't had much use for white and I respect that! You have a working light and that's great! But there are also people that have had good results with using white. Old Mac was liking them whites

They come with the lights.
The lights work well!
What's not to like?
Also, when you have that much skill and experience, you can grow melons with moonlight.

Now , If I had 2 Theoreme lights, and I disconnect the white leds on one of them and put those Watts into more 660nm. reds instead.
Then grew clones under both lights.
And the extra "red instead" light grew fatter bud?
Well, then I'd say, "no waste time and energy on white leds".
But, since all of the preceeding would be beyond my means, I do not.

and Knna & Co at the spanish forum have had best results with adding some white.

I really would like to see someone in Knna's circle do a with and without white, side by side.

By what I've seen on the forums it seems that while red and blue are the main players that there is still something missing, don't you agree?.

Emphatically not!


I strongly doubt that there's some "lost chord" that will significantly enhance one's grow.
It is much more productive to learn how to use just red and blue led light IMO.
If you apply the habits of a 1Kw HPS grower there will be shortfalls, of course.
But, I suggest, that once you learn the "zen" of led growing, just Red & Blue are sufficient for an enviable result.
That, I can say from experience.
I have grown sunlight sized bud with just two colors.
(Not sunlight sized plants, mind you, but same quality bud on 2' tall clones)

Be it white, far red or even yellow... I dunno, what do you think?"

I know that one can produce white light by mixing red, green, and blue light.
I know that plants are not as responsive to green light.
I know that you can do very well under just deep red and blue.
So I think that not providing green light will save me one third, at least, on the power bill with little, to no impact on yield.

Well, ya did ask.
And it's jus' a strong opinion.
Nothing I'd like more than for someone to prove otherwise.

Aloha
Wee Zard (Braced for slings n arrows)

 

[whatissixbynine]

......

Sure, IF you monitor the voltage as you turn up the current, and stop at less than Vmax.!
Whatever the current actually is at that point, is all you can safely apply.
So, if you get to 14.85V. on an emitter with a Vmax of 15.0V, stop!
If your current is only , say, 950ma. at that point, then your maximum wattage is limited to app. 14.2 Watts.

Is clear?

....

Aloha.
Weeze

[/COLOR][/SIZE]

ok let long term training commence here.

I assume you mean the W / A = V
so 14.85/.950~=14.95

Do you use a UPS power supply in the chain to prevent voltage drops, brownouts, spikes, etc?

 

[Weezard]

Somebody's been tokin' anti-math buds.

Somebody's been tokin' anti-math buds.

ok let long term training commence here.

I assume you mean the W / A = V
so 14.85/.950~=14.95

Well, if 6 X 9 = 42, then yes.

But in my tiny world. it's more like V X A = W.
Or, 14.1075 Watts to be too precise.

W/A would be 14.1075/.95 =14.85 Yah?


Do you use a UPS power supply in the chain to prevent voltage drops, brownouts, spikes, etc?

I do use a UPS for our frequent power outages.
(Another plus for LEDs' low power consumption.)
But the constant current supplies have enough headroom to handle the other worries.
Also have a UPS on the greenhouse alarm.

LTT has begun.

Aloha Weeze

 

[Jopedijoo]

I really would like to see someone in Knna's circle do a with and without white, side by side.

That I would also like to see too! I was trying to decipher the spanish forum a while back with Google translate, but it got tiresome quite fast. Someone might have already done the experiment, I couldn't say.. It's a pity that the LED talk has died down a bit lately... Everything might have already been said but done, hardly. Would be nice to see more test results, true!

By what I've seen on the forums it seems that while red and blue are the main players that there is still something missing, don't you agree?.

Emphatically not!


I strongly doubt that there's some "lost chord" that will significantly enhance one's grow.
It is much more productive to learn how to use just red and blue led light IMO.
If you apply the habits of a 1Kw HPS grower there will be shortfalls, of course.
But, I suggest, that once you learn the "zen" of led growing, just Red & Blue are sufficient for an enviable result.
That, I can say from experience.
I have grown sunlight sized bud with just two colors.
(Not sunlight sized plants, mind you, but same quality bud on 2' tall clones)

Maybe I'm not up to date but I was thinking that plants growing under just red and blue were not finishing in time, no? And you could maybe aid that with the 730nm, not that it would increase the yield (or make other contributions) though.. You're probably right that it would be wise to start with just red and blue and then see if adding something will make a difference. I'd like to try them 590nm ambers at some point too.. Not that I really want to duplicate HPS but atleast it's a "real" color unlike white and would be nice to see what that does. I think I'm getting ahead of myself here...

Be it white, far red or even yellow... I dunno, what do you think?"

I know that one can produce white light by mixing red, green, and blue light.
I know that plants are not as responsive to green light.
I know that you can do very well under just deep red and blue.
So I think that not providing green light will save me one third, at least, on the power bill with little, to no impact on yield.

Well, ya did ask.
And it's jus' a strong opinion.
Nothing I'd like more than for someone to prove otherwise.

That's cool, we don't have to agree on everything here, all conversation is good And you might be absolutely right..

Aloha
Wee Zard (Braced for slings n arrows)

Well, it's been snowing in Jopeland today...

 

[Jopedijoo]

LTT has begun.

Aloha Weeze

LTT..? Light triggered thyristor? Libya Telecom & Technology?? Leninist–Trotskyist Tendency??? It's getting a bit scary out here, I say...

 

[Weezard]

No overthink.

No overthink.

LTT..? Light triggered thyristor? Libya Telecom & Technology?? Leninist–Trotskyist Tendency??? It's getting a bit scary out here, I say...

"
Originally Posted by whatissixbynine
ok let long term training commence here."

Fear not.
Was a gentle jibe at "6X9? "
He "corrected" my math.

"I calls my mule Algebra,
'cause I cain't figger her out. "- Buh'wheat

Hi Gib, (saw you lurkin' dere.)

Aloha Weeze

 

[Jopedijoo]

"
Originally Posted by whatissixbynine
ok let long term training commence here."

Oops missed that, sorry Got carried away and tried to use Wiki for help, didn't work too good

 

[giblets]

A few posts back I was suggesting on using the PLN-30s....but...that doesn't really leave any headroom there.

It is a moot point unless you check your emitters' current draw at various voltages so you know how high you can set your operating voltages. If you are *guessing*, you'll need to be a bit "conservative." PLN30's will do 2 blues "conservative" all day long. Plenny headroom for dat.


Using 45-15s for powering would leave a 15W, 30% headroom. Is that too much already?

Are these actually out already? I can't even get a real price on one...But, according to the specs, it'll limit current at 75% of rated output (or above)--it won't "dial down" any lower than ~34watts. That's pushing it, but it's another moot point if you can't get these drivers yet.


I while back you were saying that a 60-15 with just two emitters has so much headrooms that the current limiter won't kick in. Is this similar with a 45-15 running 30 watts of LEDs?

Yep. See above.



So shortly, 30-15 or 45-15 for the blues and the whites? Or neither..?

I don't see an advantage in using PLN45's over 60's as far as current control is concerned (for powering 2 "un-measured" blues).


Also, if I would drop the other blue and drive it and the two whites from separate drivers, I'm not sure how that would be done. PLNs go down just to 30 watts and that's seems too much for just one blue...

Another problem easily solved with a bench supply.

LEDs aren't magic. There's a few tricks to growing with them, and running the system at peak efficiency is one of them. I've seen some pretty good-looking UFO knockoffs for $150, and if you don't tune your system in properly you might as well save yourself some solder fumes and use a few of those.

Being able to independently manipulate the reds and blues opens up a whole new world of control--that's another important "trick" that you just have to work with for a few crops to appreciate. If you neglect the color-control aspect of design, as many folks have, you'll never understand why we say you only need two colors.

And you know these high-powered leds get quite hot, right? Not like an HPS, but hot enough to require fans, proper ventilation, etc. Tying up drivers and generating additional heat by powering emitters that are providing "just in case" kinda wavelengths may keep your results in the "mediocre" category by effectively negating leds' advantages.

lll

 

[Jopedijoo]

I surrender...

I surrender...

lll

I suppose there is no reason for me being this stubborn.. You have good points! Mastech it is! Or something very similar to the 3010. I already found a replica.. or is Mastech a replica of this, don't know. They sure look very similar and have the same specs so hopefully it's all good. I won't be easily able to get myself a Mastech per se..

I found the PLN-45 only from Meanwell's homepage, didn't try to go shopping for it. So I don't know if it's available yet. They seem to be releasing PLN-20 also, that would be good for driving just one emitter..

I got to ask.. I remember you starting out with 6 reds and 2 blues, did you add more reds or dump the other blue or is that still your setup?

Sorry to be a pain in the ass.. Thank you for your patience!

 

[Oldmac]

LED colors or let's hear it for Red, White and Blue...

LED colors or let's hear it for Red, White and Blue...

....I had a few more cents to throw into the color discussion.

As Weezard and Giblets point out, and rightfully so, it only takes red and blue to make a good LED grow light. Best example of that is the Procyon100, which works remarkedly well considering it's use of 635nm Cree diodes. I'm no expert when it comes to white LEDs, but have been interested in using them for awhile. I actually believe with the "right" white LEDs you could use them IN PLACE of blues. If the white's blue spike was right at 435nm you could accomplish the blue you need and MAYBE pick up some lessor needed wavelengths. I'm not sure whites along with blues are going to add anything and Weez's point that the wattage given over to them might be better used on the blue is probably spot on.

I noted you made reference to far red 730nm light. (I like a person who does research) LEDs in this wavelenght are available and you could use them in a grow light if you wanted to stay all LED. But you can get a metric ton of far red from an incandescent for a lot cheaper so why? UVb is also a lessor needed wavelength, but again can be had cheaply with CFL or flourescent supplemental lighting. The TI SmartLamp that I mentioned has a mix of 150 diodes that are all 2w nominal, the mix is 105 red, 18 blue 15 white and 12 "proprietary". I'm really not sure what the whites bring to the party but someone put some time and effort into this light so I guess they are doing something. BTW this is the only LED light I've seen that can turn trichomes amber. This is due to the "proprietary" LEDs; UVb and IR are the "secret".

For a home brewed light, where simple circuts are in order, red and blue are the ticket to success. And keep in mind that having adjustable red intensity is really not just a trick, it's a great idea! Any other wavelenghts of light needed can be added via supplemental lighting very simply.


Added thought @ Giblets: I was referring to Kapton tape, just could not remember name of the stuff at the time.

 

[giblets]

Hey, Mac...Weez...
Double check me on this rant, willya?
Don't wanna make a typo or procedural error that might cause somebody problems...

I'm still not sure if I understand the PWM dimming feature on the Meanwells. There seem to be the screws for adjusting voltage and amp, but is there another switch for dimming like Weezard has or is dimming done by turning these screws?

Yes--by turning the screws. There's a trim pot to limit how high the output voltage will go. There is another one to limit how much current can be put out. That's important with leds, because sometimes they start drawing more amps at a given voltage, and will burn themselves up if current isn't limited somehow. Such an led is called a "current hog." I just think of it as "softening up"...the led is actually getting easier to drive. This sometimes happens over time; I re-check them after a month's operation or so. Weezard may have a different procedure for this.

If so, how exactly is that done, leaving the voltage stay put and turning the amps down, or..? And probably having a meter inbetween to see what's happening?

Exactly. When I test leds I make a little table, and record how much 'amps' each one draws at each given voltage. (This is where you need the bench supply.) We're actually doing our own "binning" here...

Let's say you've individually tested all your red leds on the bench supply, and determined they'll put out 1200mA when driven at 10.8 volts. (Lucky you if they match that closely.)

To set your Meanwell, just turn the current limiter screw all the way up (disengaged, basically) and turn the voltage limiter screw all the way down. Confirm the voltage with a meter, it should be around 9-10 volts---safe for the leds. What we're doing here is making sure the driver is set low enough not to exceed the MAX forward voltage (Vf) of the leds when we hook everything up.

Next, unplug the Meanwell, wait 10-15 seconds for the driver to bleed off any residual charges, and connect your leds to the driver with the meter still in the circuit. Power back up. The voltage may read a tad lower than before, now that you have the leds loading the circuit. In fact, if the driver is adjusted below the minimum Vf for the leds, they won't light at all.

Now, carefully start bringing the voltage up by turning that screw. When you reach Vf-min the leds will light, and they'll get brighter as you increase the voltage. When the Voltmeter reads 10.8V, your leds will be drawing 1.2 Amps each, and using ~13 watts.

Next, turn the current limiting screw DOWN until it ju-u-u-st starts to cause the voltage to drop. That's it! You've already set the voltage at a max of 10.8V, and now you've also limited the current at "just enough" to provide 1200mA per emitter. (See why it's important that the emitters are matched?)

If it's possible to dim 0-100% I could turn down the blues when not needed and still have the option of heavy blue if using both emitters, right?

Right. I'll generally unplug drivers altogether rather than turning them way down, just to conserve resources and avoid having to "reset" them.

lll

 

[giblets]

I already found a replica.. or is Mastech a replica of this, don't know. They sure look very similar and have the same specs so hopefully it's all good.

Make sure the mains power switch is "mechanical" so it stays "on" when you run it on a timer. Otherwise it will be inconvenient to use as a driver.

I found the PLN-45 only from Meanwell's homepage, didn't try to go shopping for it. So I don't know if it's available yet. They seem to be releasing PLN-20 also, that would be good for driving just one emitter..

Those PLN's are all nice. Just a question of matching your needs. I'd advise 'overbuying' if there's a decision to make (allow for future expansion). Once you know how to DIY it's easy to add emitters here and there. You can go nuts adding colors to experiment with, once you know how to set up a basic system.

I got to ask.. I remember you starting out with 6 reds and 2 blues, did you add more reds or dump the other blue or is that still your setup?

Both. I added 2 more reds to that light, and with both blues and 8 reds the dang thing was so powerful I was bleaching leaves and stopping growth from 6 inches away. To accommodate a slow-finishing sativa I disconnected one blue and turned down the meanwell that was driving 4 of the 8 reds. I'll hook that blue back up next time I flip a new plant into flower, though--to keep stretch under control.

If I had it to do again, I'd only use one blue per light, or at least separate the two blues as far as possible on the lamp, like Weez did. Or use 5W stars for blues. For a flowering lamp, I think they'd be plenty.

lll