Calling out to Weezard for LED advice

If this is just a flowering light, a 1:4 or even 1:5 blue:red ratio is plenty blue. Your 2:6 design's got a 1:3 ratio goin' on. I found that bluer than I needed for flower; I jes' built it that way cause 'Zard said, "My next light will have 2 blues" (talkin' 'bout his 4+1 cake pan lamp). I didn't realize he was gonna run 'em with 10 reds! I later added a couple more reds to that lamp; it's an 8 + 2 now.

But it's nice to have that blue power available to stop stretch so it's hardly wasted. If you were cutting corners you could get by with a single blue , a 30-watt driver, and 4 reds. (Or up to 7 reds with a mastech 3010) In reality, the 30 watt drivers cost almost what the 60 watters cost, and running 2 blues would be pushing it. They'll actually take up to 18 watts or so...

Really, how you power the reds most efficiently depends on which ones match the closest in Vf.

If you are trying to flower a 3' sq area, that's the rough footprint of a 400HPS. I'd shoot for 200 watts of quality led power to match that. A 6+2 ledengin light will edge out a Procyon (also bluer than it needs to be for flower, IMO) but a 6+2's only 120 watts running flat out. Think I used to run one with 107 watts from the leds, not counting driver consumption. Compares more to a 250HPS, I guess.

I like to keep my light < 6" from the plant tops so it doesn't spread too far. Is that the shape you're trying to light-- 3 x 3? You can build the light to closely match your space. I'd probably use 2 lamps side-by-side for a 3 x 3 space, especially if you're looking for much penetration.

You might check your heatsink supplier. Sometimes 2 ship as cheap as one. You can power the blues from a single driver even if they're on different heatsinks. And you get a price break at 10 reds... Just thinkin' out loud, here...

Lessee, you could get 11 reds. Put 'em on 2 heatsinks, 6 on one, 5 on the other.

Power the closest-matched 7 with a mastech, the closest-matched 4 with a 60-12. (Notice I am using all my driver power). Run a blue on each light. If you want to add more blues, the 60-15 will accomodate you.

That's 195 watts of well-driven leds. Yowsa! (I'd prolly add a 3rd blue later, jes' cause there's enough 15V driver to do it.)

You could also cram 10 reds and 2 blues onto a single heatsink.


It ain't cheap to do this right. That's how come you hear some kids saying leds won't grow. All they've tried used shitty components, shitty matching, shitty drivers. Also how come the only lights that really perform are pricey. Top quality emitters and drivers aren't cheap. They shouldn't be. :thumbsup:

I'll keep an eye on ya. You can always add more emitters to your sink and run some more wire...

DH,

That all made perfect sense! I've been following this thread from the beginning. Right now I'm using a 120W lamp made out of 1W LED. It's doing the job, but not as good as I would like.

The way I see it is that if I'm going to run at least 120W it should be using LED's that I feel give me the most bank per watt. The 1W don't do that. I have supplemented with eight 23W CFL's. And the heat gets up there!

So right now I'm using 304 watts. I'll do 200 all day long!!!!!

I may entertain getting two heat sinks and making a monster! That actually sounds fun!

I have attached a quick "sketch" of the top of the light. I figured it would make sense if I did use two heatsinks, to connect them using a piece of aluminum with a slot down the center of it. That way I could adjust how far apart I want the light to be at any time easily.

Limited by the placement of the fan of course....

After laying it out thoroughly in CAD, I will not be able to cover enough space left to right. I would have to really make a light consisting of 5 pieces. A center piece and four "islands". One in each corner.

I figured a 90 degree beam spread at 6" above the plants. Making it a 1' diameter footprint per LED. It would take 13 red LED's to cover a 3'x3' space leaving little room to waste. There would be three reds on each island and one red and two blues on the center piece.

I'd need to use 5 fans, one for each sink, but they are cheap. In my head it's kind of like a chandelier.....

Anyone have any feedback on my idea? Is there an easier/better way to accomplish lighting a 3'sq. area?

"In my head it's kind of like a chandelier"

I see it!
Darn good idea!

Weeze.

Let's talk fans....

The only part of your lamp that's gotta be in the grow chamber is the heatsink with wired leds attached. If you've got enough heatsink, (or wimpy-enough leds) you don't even need a fan. Remember, fans actually create more heat :eek: via motor operation, fan blade interaction with air molecules, etc. We just use fans to move heat where it does less damage. If you've checked out W.'s 10+2 lamp, he's got his sink cooling fan exhausting the heat out attached ductwork. Mine jes' fire in the general direction of my main exhaust, which is not so elegant. :o

There's a school of thought that tries to eliminate fans from led lamp design altogether. From a design perspective, it's a loftier aspiration. If your light's designed to operate without a fan, it can't overheat because of a fan failure. :thumbsup: Plus you save a couple watts on the fan motor, and a tiny bit of heat actually added by the fan's operation, etc.

I prefer to enter the battle planning to use enough concentrated watts to need a fan. This is war, baby! :gunfighter2: Plus, I like my electronics running cool. :cool:

But here's a thought: with the emitters spread out where the junction heat's not so concentrated -- if your heatsink is well-finned where it'll really catch some air -- you might be able to cool it with general circulation fans in the grow area, aimed so they just catch part of the heatsink. I played with this a bit while setting things up, and it seemed like it woulda worked. I'm kinda klutzy, though, and feel more confident with the fan stuck right to the sink.

A flaw in my design that's always griped me; I've got a fan running to cool the heatsink, but the "breeze" coming off the sink fan is firing 180deg away from the plants. :wtf:

Don't get me wrong, it works well. But I've been thinking of cutting a ~3" hole outta the center of a heatsink and mounting the fan so it cools the sink and fires the (slightly) warmed air downward at the plants. The cooling fan would then be functioning also as a circulation fan. It'd need a simple baffle to block the fan from simply pulling air straight through the hole. Just a thought--trying to redirect that wasted exhaust airflow into something beneficial.

Alternatively to the hub-and-spoke design, you could do a criss-cross design, or a square "catwalk" layout, too. Whatever layout you use, if your heatsinks are thermally connected, you don't need a fan behind every set of emitters. This is especially true with beefy, highly conductive heatsink stock.

I decided to think of my lights as "built-in;" after all, it's not like I'm running from room to room with the things--the flower room ain't goin' nowhere. So, rather than approaching the design from a traditional "portable" light paradigm, it became: "Okay, how do I light this specific space?" It's custom-made, baby! :pimp:

Hermie,

You made my head spin with that! I kept up though. Great ideas! No waste, that's the way to go.

I haven't put much thought towards this today or yesterday as work has kept me very busy.

After doing the math it would be easier to rig up some kind of light mover and use an 8+2 light. That should penetrate well. The mover on a 6' rail is like $160-$180. I could cut the rail to fit my space and eliminate the need to make a bigger/wider/crazier light. Just the extra LED's needed to make the big dog light I would like cost as much as the light mover. That's not taking into account the extra heat sink, fans, and LED drivers.

That way I can put the light 6" or so over the plants and they will all get even coverage! Would be a great SCROG experiment......

These CFL's are too hot. Room temps are 82 with the lights on and 73 with them off. Should be able to keep it in the 70's all LED.

Also noticed the other day that the three plants I have are all hermied. No pun intended. That's what you get for using bagseed. :-( Big let down. I need to get some good feminized ones for the new light.

Are you still talking about a 3 x 3 space? That's a pretty short track!

If your emitters are grouped together or lensed so the light is acting like a single point source (capable of throwing "shadows") a mover might make sense in a long enough space. The dispersion (and reflections) you get with the 15W leds is quite even, and a mover would benefit them less than, say, a Procyon (because of its lensing).

I played around with covering a 3 x 3 space a bit. Best way to light it depends on what's in there, to a degree. 1 biggun? 4 @ 18" sq? A mixed bag of strains and ages? I'm liking the flexibility of 1, 2, even 3 lights you can move in close to the plants as opposed to the "hovering mothership" concept. Just able to hit the plants harder, seems like.

And if you're looking at heatsinks with 2.5" fins, those may be inconvenient to work with. :jointsmile:

Here are the heat sinks I found on Ebay. Nice. He has them in 10.125" wide. He just hasn't put that auction back up yet. $47 shipped per foot. 2.5" fins.

HEATSINK ALUMINUM EXTRUSION LARGE BIG 8.5" WIDE - eBay (item 170389589478 end time Oct-08-09 15:10:15 PDT)

His 8.5" wide one has only 1" fins. And is $68.50 shipped for two 8.5" x 12" pieces. Better?

I could do two lights...but would still stay at a max of 8 reds due to the extreme cost of going beyond that.

I have to be sure I get seeds so I know exactly what I'm working with. If the 15W can throw the light nicely, then 8 reds should cover 3'x3' effectively. I use a DR100 which is lined in all silver. Very nice. Light bounces everywhere!!!

A scrog with four plants is the most I think I could ever fit. Especially if the light is doing it's job. So we would be looking at covering a level 3' sq area. Best due to the LED's lack of penetrating power.

So what do you think? Two 8.5" sinks, 8 reds, 2 blues, one mastech, one 60-12, one 60-15, and two fans?

If I do that would I mount the blues on the inner sides of the bottom of the sink so they stay towards the center of the room?

If I were to put it all on one sink it would look like this. Coverage area at 6" above plants would be 1'-11" x 1'-9-1/8". Not so great......Two lights sounds better.