Calling out to Weezard for LED advice

[Crunchypants]

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

Crunchypants Reviewed by Crunchypants on 02-11-2009. Calling out to Weezard for LED advice 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 Rating: 5

[Weezard]

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
Weezard, I'm planning to homebrew a version of your 4+1 x 15w. light. :thumbsup: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!:stoned:

Let me know if I can help.

Aloha,
Weezard "

[Crunchypants]

This is prolly a way mo' betta place for it though.
No wanna hi-jack da "bean counters" thread,ya

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.

[Weezard]

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.

Tell me about it!

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.

Not at all. Best way to do it.

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:
[attachment=o213252]

Here's a shot of the top of my light if you haven't already seen it;
[attachment=o213253]
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

[Crunchypants]

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. )

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?

I gotta ask, why "crunchypants"?

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.

[DreadedHermie]

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

[DreadedHermie]

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.[attachment=o213335]

[Weezard]

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?

It's actually 42W. CFL
The package hype claimed 120W. equivalent.
Was meant to be a tiny joke, but I forgot da li'l smiley on da end.

They list no color temp.:wtf:
It looks half way between warm and cool. I'd call it daylight.
I'm still at least 2 weeks from a bud density comparison.
but it did not "speed 'em up".

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.

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

[Weezard]

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.[attachment=o213335]

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..

[DreadedHermie]

It's actually 42W. CFL
The package hype claimed 120W. equivalent.
Was meant to be a tiny joke, but I forgot da li'l smiley on da end.

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

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.

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.

Howz your design coming?

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??