My friend, I've read your stuff here and at Steve F.'s site. I want to build a dedicated flowering lamp using Ledengin 15 watters. (4 reds, 1 blue, and possibly 1 warm white; LM 317's so I can tweak the ratios.) Essentially, a copy of your 4+1 cake pan lamp but built on a 4 x 18" finned heatsink so I can see what's going on under it.)

If I were to post my picks for power supply, resistor ratings / values, etc., would you critique and perhaps offer some guidance? I have already purchased the Mastech 3010 you've talked about.

Hoping you'll see this,
Crunchypants

Aloha, CP
Saw your post in KNNA's thread.
Answered it, sort of.
This is prolly a way mo' betta place for it though.
No wanna hi-jack da "bean counters" thread,ya

Happy to help, brah.
Dunno 'bout critique n guidance.
But, I'll kibbitz gleefully.

Let 'er rip.
Weezard

Oh, went and got the post from KNNA's thread.
Here, 'tis
"
The Herding instinct in Photons and micro-einsteins.
Quote:
Originally Posted by Crunchypants http://boards.cannabis.com/images/buttons/viewpost.gif
Weezard, I'm planning to homebrew a version of your 4+1 x 15w. light. Looks like the Ledengin LED's have a 90-110 degree beam, though. Would you recommend additional optics or did the 15's work okay for you unmodified?

Mine are mounted in a deep aluminum cake pan which serves as a reflector.
Didn't find lenses for the ledengins but the 5Watt leds that I lensed are clearly better than the same configuration without the lenses.
Would call it proof if the red leds were identical.
The lensed set is 660nm., the un-lensed are 625nm.
Perhaps the difference in efficiency compensates.
Ah dunno.
I just ordered more lenses.
Will install them on the 625nm lamp and start taking pictures
of the progress.
If you find, say, 40 degree lenses that fit the 15W ledengin lens, please drop me a line.

Also, MPJA has a 28v. / 5.5A power supply (the 24v. is out of stock for awhile). I was thinking getting one to power 2 parallel legs of (2) 15w. 660's, with an LM317 on each leg. Am I just making extra work for myself by not running a 24v. supply into a single LM317 and parallelling (4) 660's off the 317? Seemed like a bit of current to push through a single 317, but I don't really know.

LM317 has a absolute maximum of 1.5A!
You might want to use an LM138 - 338 instead.

Driving an approximately. 12V led from a 28V supply will work well if you run the 2 parallel sets in series.
That will give you 4V headroom but would have to pass 2.1A.
That would require a pass transistor, etc.

So the LM138 series with a max of 5A. would probably serve better for ease of design.
Google the LM138 series for a quick and easy schematic.

The problem then is the blue led which uses closer to 15V, for peak efficiency.
I use 2 separate supplies because dissapating "excess" energy just rubs me the wrong way
My next ledengin lamp will have 2 Blues.
The goal here is to waste as little power as possible in the regulator.

I would like to underdrive the LED's slightly, and have some extra headroom in the build. Thanks!

Good idea!
I limit mine and use a thermal switch in series with the fan to keep everything under 50C.
Better Photons:Watts = less waste heat to deal with as well.

Easy lamp to build and it will work for flowering.
Mine covers app. 2 sq ft. and takes 2 or 3 weeks longer, start to finish, than HPS.
But the quality?
Wicked good!

Let me know if I can help.

Aloha,
Weezard "

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Point taken--I'll move my ignorance-fest back here.

I could have asked Knna, but then I'd have had to have someone explain his answer to me.

I had begun to think you weren't going to see this post, and at some point my eagerness overcame my sense of etiquette. Hope not to have offended anyone, and thanks again for your willingness to help.

Dang! I had just found some little finned heatsinks at Radio Shack for the 317 in the TO-220 package. Going to have to think about mounting strategies for the LM 138 after I read up on it more. Looks like a big power transistor with the case electrically hot. Gotta figure out how to deal with that. CP.

We're dealing with low voltage here so an electrically "hot" heatsink need not be a problem.
The Ledengin die appears to be well insulated.


Looks like you are serious about this.
Sorry, but I'm not used to someone who reads and retains everything they can find before they start asking questions.
I'm impressed! And flattered.


To me, this is a way of obtaining meds that I can not obtain through legal channels or afford on the street.
I don't worry myself about a nanometer here or a uE there.
I just want maximum yield for minimum cost.

You may be dissapointed with the single warm white led.
At least as far as "seeing what you are doing" goes
As you say the white led is a crippled blue led and will be swamped by the red and blue.
I am using a 120W CFL to supply any odd color that my girls may be "pining" for.
(Does it do any good?
Jury is still out on that. )
And still, even with a flash, getting a true color picture is accomplished only with the LEDs powered off.
Fer instance:
frosty.JPG

Here's a shot of the top of my light if you haven't already seen it;
smoke test.JPG
Shouldn't be hard to improve on this mess.
It works, but it's far from elegant.

Am still running the last light array I built on my bench supply.
I plan on using an Laptop switching supply for it and getting my bench supply back to develop my next light any day now

I gotta ask, why "crunchypants"?

Aloha,
Wee Zard

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

About the time WhiskeyTango started adding supplements to his Procyons I began wondering if I could close that 2-3 week gap in finishing that everyone seems to have noticed with LED's. I added 2 x 13 watt cfl's and/or 1 x 24 watt T5HO (nominal 2 footer) to sweeten the mix. I tried both 3K warm and 6500 cool at alternate times, in a not-very-scientific way. Improvement didn't seem worth the added heat, and strangely, I thought the 6500 degree provided slightly better (still minimally better) results. So I guess I've proved to myself I don't need to fuss with adding white LED's to my lamp.

120 watts of CFL is another story; be interested to see the results of this experiment. What color temp are you using?

Well, I was just trying to blend in by looking like a 19-year-old male with a chip on his shoulder. Before I registered at CannCom I lurked around the other boards for awhile, and a vaguely suggestive username seemed to be the norm. After I settled in at CannCom and read some posts and stickies by Stinky and Rhizome, I realized this community was much different than the recreational doper sites. (This impression was reaffirmed in the recent weeks when CannCom was down, and I revisited some of those "other" sites.)

At that point, I thought about picking a different username, but thought maybe the mods would see a "wise-ass" change his name without a single post and assume I was just a troll. I didn't want to get banned before I even started, so I just left it.

I never really planned on posting much, because the site elders were effectively advising all the noobs without my help, and I could answer my own questions by simply reading what's already been posted. But then SnS took the plunge with their LED grow, and heavyweights like Knna, you, and others started weighing in. CannCom became the unofficial clearinghouse for LED grow info, even more so than the GPL site.

If I had to do again, I would observe the CannCom convention of whimsical, grow-related handles and be "Foley R. Feading" or "The Dreaded Hermie."

Guess I should probably change it; no sense coming off like an adolescent in an adult community.

I feel more mature already, except I liked my Jan 2008 registration date. Color me noob! CP, now DH!

This is the stuff I wanted to mount my components on. I don't look forward to drilling it, though. The cake pan is looking better and better.b44e_1.jpg

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.

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

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

That's Aluminum.
Piece of cake to drill and tap.

Keep in mind, the current regulator/power supply does not have to share the 'sink with the leds if you use "fat" wire to feed the array.
I try to keep as much heat as I can outside the G.R..

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

I get it. I was about to suggest you call that setup a CFL-assisted-by-LED grow, though.

Yep, have thought along those lines but am obviously working my way through some other details first. (Like building a basic, working light!) Rectangular aluminum stock with forced air cooling through the center seemed more realistic for me to attempt; my plumbing seems to cause flooding.

Well, I think you just opened up some new possibilities. For some reason I was thinking the current regulators needed to be close to the load; I'd planned to mount 'em on the 'sink near the LED's. I prolly misinterpreted the data about filter caps needing to be close to the current regulator(s).

I had planned on keeping the power supply out of the grow area, but are you telling me I can keep the current regulators adjacent to the power supply? I could mount them in a separate case and keep the light nice and neat. This would also let me use the 338's in a TO-3 package, which seem much more popular, and look like they'd dissipate heat much better.

BTW, I don't see any "proper operation assumes adequate heatsinking" type disclaimers on any of the 338 family, unlike the LM317's. I also can't figure out what the voltage drop across the 338's is-- in one graph it looks like they'll want 1.5-2 volts at around 4 Amps. Help??

Hey, (duh) doesn't a power supply + current regulator = "LED driver?" Dang, I'm dense sometimes. Jes' call me "Pb."

If you allow for a 3 volt drop across the regulator and the 1.25V. drop across the sense resistor in your design, you should have enough headroom to keep the 338s happy.

Now, I'm havin' fun.
Weezard

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Okay, now I'm excited because I actually understand all that.

What I'm not sure about (among many other things) is what the 15w. 660's are actually going to be pulling current-wise. They're rated at 1500mA, so if I'm running them conservatively are they pulling a bit over an amp or so each, or are these things actually meant to be run at 750mA? (I'm cautious of power ratings, I remember audio amps that were in reality about 30 watts RMS being rated at 600 watts "intermitent peak-to-peak" or some other hogwash.)

If the reds are indeed capable of pulling an amp and a half each, my 5.5 amp power supply isn't as overkill as I'd thought.

Dang! I hate to waste 16W., especially by turning it into heat! Can I improve my design? Maybe find a 24v. supply instead?

And I can think so much more clearly.

This is why I have that bench supply! I can use it to see what my LED's want to be fed, and buy a power supply that fills that need.

The LM138 is good for higher temps than the 338 (150 C. vs, 125 C.) so I'll use those. Found some real sporty dedicated heatsinks for the TO-3 package. My driver will look like the Batmobile, or perhaps the Nautilus (esp. if I do any plumbing! )

So, Weezard, my last question, hopefully, before I start buying components for the red circuit, is:

What watt rating to I need for R1 and R2? It seems like folks are using a 5K ohm Radio Shack pot for R2. These are only rated at a half watt. However, I see some devices on your light that look like 7W resistors. How much juice is going through the R1-R2 resistor combo?

Mouser has a 5 watt wirewound pot-style variable resistor for only $4, but only up to 2K ohm. Would you recommend recalculating R1 value and using resistors/pots rated at 5 watts, or are half-watt parts sufficient here? I know the LM138 is going to have to handle some heat, but what about R1 and R2? Are they putting the brakes on any significant current flow, or are they just reference / sense components? And what the heck is a sense resistor, anyway? (Well, that was more than one question, I guess.)

A sense resisror is so called because it hooks to the sense input of a regulator.

Here's how the LM317 CCR circuit works;

The lm317 is designed to be a variable voltage regulator
and it "wants to see" 1.25Vdc between the output pin and the ADJ/Sense pin. before it will begin regulating anything.
We take advantage of those facts for our current regulator.
We tie a restor to the output pin and draw the current to our load through that resistor.
If we run a wire from the load side of the resistor to the adjust pin, that pin will sense the voltage drop across the resistor.
So, ohm's law.
If we want a 1 ampere current limit, we use a resistor value that will drop 1.25V at 1 amp.
Once the adjust pin senses 1.25v.it regulates voltage to keep that voltage drop, and thus the current, constant.
1 A. X 1.25 V. = 1.25 W.
While a 2 watt resistor would suffice, a 5 or 10 watt resistor will run cooler and thus regulate tighter.
I had some 10 Watt, 1 ohm power resistors laying around so I thermal glued them to the heatsink.
Overkill? Perhaps,. But overkill is a good thing in this case .
Gives me about 1.2A. which is exactly what I wanted.
Seems to be the sweet spot in photons per watt.

What is this R2 you speak of?
The current limit configuration only requires one resistor.
schemo1.jpg
And, I think this all applies to the 138 series as well.

It's very simple.

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Here's where I'm getting that R2 stuff:IMG_0832.JPG

IMG_0829.JPG


Here's the TO-3 heatsinks:hs9.jpg

Looks like R2 is like a trimmer to make the voltage variable(?). Of course, once it's dialed in you can measure the resistance the pot's providing and replace the pot with a fixed resistor, unless you want to be able to change how much your blues are putting out, for example. Somehow I think PWM might be more efficient at doing this, but I'm not that far along yet.

PLN-100-spec.pdf

What about this bad boy? (The 12v. version.) Looks like all the goodies are built-in. A little pricey, and maybe marginal headroon for 4 660's. Would you still need CCR's on top of this?

Quite right! PWM is a better choice, but, in a pinch, a high current low resistance trimmer with a limit resistor will work for varying current.

You might be over-thinking the CCR part.

Disclaimer:
This works a treat with the LMx17 series and should work just as well with the LMx38. But, I have yet to try it with the x38s.

See easier that you thunk, ya?

Weezard

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Yes, I am positively devoted to overthinking (everything) now, not after I've smoked $150+ of LED's!

Very elegant in its simplicity. Without your guidance I would be making this way harder than it needs to be. Thanks again!


BTW, read somewhere you're on nursing duty this week. Please give my best to your patient, and I hope you're better at nursing than I am at EE.

I found a CRAZY thick aluminum cake pan last night, 13' x 9", except it's also non-stick. What's your take on grinding the teflon off so I can epoxy to it?

Dude!
You didn't say you had a fat budget.

Hell yes! That will work.
That's exactly what I would use if a had 2 pennies to rub together.
I'd use the 120Vac input unit and be done with it.
It is truely all you need besides leds, wire, and a heatsink

They are PWM based.
Very little power wasted as heat
Just buy, plug, n play.

I only reneck my own supplies because I have to choose between toys and food.
(Sometimes the toys win. Keeps me from gettin fat, ya?)


So rich!!
Must be nice.


Aloha nui.
Weezard

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

I'd be very careful.
When Teflon is heated past 4 or 5 hundred degrees F. it produces a poisonous gas.
Not powdered Teflon, an actual gas, so wearing a grinding mask is not gonna save ya.
It WILL kill birds, so it can't be healthy for people.
If you do this, sand the Teflon off by hand, outdoors, down-wind and very slowly.

We seem to be leapfrogging messages.

Ciao
Weeze

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Thanks. I think that real heatsink stock is the way to go.

Not so much, but the power supply I'd use would be around $75.rs-150-spec.pdf

By the time I get the 338 heatsinks ($10, plus $10 more for shipping, plus $10 ea. for the 338's, the led driver is actually cheaper. Certainly neater, as well. Think I'm ready to start ordering. Do ya think I should do a build log?

Build log?
Why not?

Grow log?
Abso-freakin-lutely!
Be a good way to give back to the boards that gave so much to us.

On that Driver, the 100-12 might not cut it.
I'd vote for the 60-15 or the 100-15 for the 12-13 volts the red leds are going to want.
My blue wanted 13.8 V. if I remember correctly but you won't be able to run it off the same driver.
(Reds n blues have different Vf. for a given current.
That would confuse your driver.)
Of course 2 $80 drivers is an option, but you might be able to use one 100-15 driver on the blue with dropping resistors in series with the red leds to shave the difference.
Something to think about.

Aloha,
Weezard.

__________________
Plants do things for a reason.....they don't just decide one day to get root rot or act funny..... - Weedhound
"Their perception is their reality" - Irydyum

"Gotta keep in mind that people and pot plants are very much alike, how well and when you finish is based on genetics. - O. M.

My attitude? Deliberate Indifference! -Thanks D.H.

http://boards.cannabis.com/plant-pro...anted-one.html

Nope, I want to run separate drivers for the reds and blues. Using resistors and creating waste heat just seems sloppy to me. If it were a real small lamp it'd be different.

Actually, I've been planning to build two lights, 75-90 watts each. So if I overbuy for the blue driver I can power the blues in both lights with a single driver, yes? I just wanted to build one light at a time so I can work out any kinks before I do the second one.

One thing I noticed, the specs for the PLN-60 and PLN-100 are nearly identical in the 12V versions. The higher voltage PLN-100's begin to outrun the PLN-60's, but the 12V PLN-100 is only rated at 60W.

The data sheet for the red 630's (I don't think there's one out for the 660's yet) led me to believe they'll want 11.4 volts MAX if I remember right. But you described a trick somewhere for determining what LED's want by using your bench supply. Might have been just turning the thing up until it kicks over to current limiting. Haveta look around for that. Seems wise to experiment with the bench supply before actually purchasing the driver so I get it right. And, I can use the bench supply to drive the LED's, too.

But your suggestions are right on the money. Keep 'em coming!