Optimizing LEDs / the dilemma of tall enclosures / tank build log (possibly pic heavy)

Hi budgetlight growing friends,

Hoping to share a build in progress, as well as pick your brains with some light questions. I’m in the process of figuring out and optimizing a grow cabinet I’ve had up and running about 5 months now. So far it’s been working decently, but has a long way to go. As you can see, only half the tank is operational at this point in time.

My struggle right now is optimizing lighting, particularly at the base of the cabinet. I currently light with 3 arrays of 12 x 3W Cree XP-G arrays on heat sinks, no optics, with separately wired fans connected to a computer power supply. It’s a horrible nightmare of wires (4 different drivers), but the main issue is insufficient light at the base of the enclosure which is quite tall, 4ft to be exact. I designed it that way to maximize vertical space for pendulous spikes, and I have the plant rack mounted at an angle to capture as much overhead light as possible, but it’s not quite enough.

I’ve been toying with two different options for a while now, which I tried to illustrate below.

The first picture is my current setup. Now I’m trying to figure out is what’s more efficient / effective - increasing overall overhead light (image 2), or trying some sort of setup where I mount additional lights at an angle (image 3). I’m leaning towards 3 right now.

I’ve tried tall vertical tanks before in the past, using a bank of T5s mounted sideways. It was unsuccessful for other reasons, but I from the light perspective, I think it worked pretty well:

(Lights seen on right)

I’m mainly posting because those LEDs are deathly expensive, and I’ve gone through so much DIY hell (aka failures) I was hoping to possibly gather some thoughts before making the leap this time.

Does anyone have any thoughts on this?
Experience in lighting tall tanks in order to maximize grow space?
More on top, or distributing some at an angle?
And if the angle approach:
Thoughts on mounting heavy LED heat sinks + fans?
Waterproof LED enclosures? Would something like this work?
Would passive cooling be sufficient (e.g. can I do away with the fans) if I go with the newest Cree LEDs?
Will post updates to this build as I figure things out. Currently working on several components:
Light hood - build of two wooden frames, awaiting glass inlays. Currently lights are diffusing through the 6mm polycarbonate, which is very not ideal.
Drainage basin - currently water is just dripping down onto the base and evaporating (I have some shamwows to mop up the water). Again, not ideal. Building a wooden drainage basin, and coating it with this stuff, but in retrospect possibly should have tried to get a custom aluminum basin built instead. Oh well! We’ll see how it turns out, but hard to get out to the wood shop with –20C outside!
Thanks in advance for any input!
[EDIT] Can supply light level readings tomorrow

-Calvin

Hi, I'm thinking if you used some optics/reflectors, you could direct light evenly through the enclosure.

Using the 3rd image, just the one light array on the angle, with some optics directing light towards the bottom of the cabinet.

..Welcome to BLF! :)

Would a diffuser work?

You could go for the third option, with the additional light and use (30deg?) TIR optics for the extra array to get the light down to the bottom of the cabinet.

Another possibility is to find a way to make all the panels (top/side/even the bottom) of the cabinet white, so that the light does not escape from the cabinet. With the same amount of light, the light level inside the cabinet will very significantly increase, and will also be more evenly spread. Just whitening the side panels already will make a big difference

I clicked thinking it’ll be a thread on a tank decked out with a whole bunch of lights instead of a barrel LOL

Welcome to the forum diwade29. Those sure are some nice looking plants and grow tank. From the looks of them, the plants towards the bottom look quite happy. It looks like the top row is getting too much light. Maybe it just light saturation, but they don't seem to have much green leafy material. Maybe you just rotated the plants.

You pose an interesting question. I think I would try not angling the plant holder and then having several emitters spaced along one or two thin aluminum flat bars. Each bar would hang vertically on a hook. That way you could move them out of the way if you had to. Just an idea. I have never tried this.

Thanks for the replies - much appreciated.