My space is 2.5' x 2.5' x 4.5'. If my horrible math skills serve me as best they can, that's 6.25 sq. ft. of growing space.
I know that this is a small space and I could get away with one bar light but I was thinking I'd make two bar lights on 20" L x 4.9" W heat sinks, connected with aluminum angle, with 3 cob's each or just under 1 cob per sq. ft..
I will be drilling for the installation and using self tapping screws. I'd like the cob holders but I don't know if I need lenses with this type of setup. I see that
@REALSTYLES uses lenses on some of his lights but my understanding is that there is some light loss (or some other light limiting variable) that comes with using lenses. Being that my space is small, I thought I'd forego reflectors and lenses. The interior of the box will be bright white.
I will use either 1 or 2 drivers depending on which is the most efficient. I don't care as long as they are running at the best possible efficiency and not "lagged" as
@PurpleBuz has said.
For light spread I thought I'd leave a space between the heat sinks of about 8" or so where I'd install a "platform" of sorts, made from a thicker piece of white plastic with a rubberized bottom, like non slip mouse pad type material/neoprene, for the heat sinks and whatever else is needed for that space.
I've got a bunch of high end computer fans that I used creating my last box so I thought I'd use a couple of those, with a fan speed controller I have, for active cooling rather than passive. To
@bassman999 's point, there will be heat and I can adjust the speed of the fans to somewhat control that if the ambient temps are cooler. (keep in mind my box is in my garage due to Mrs. Giantsfan's requirements and as such subject to exterior environmental fluctuations)
I'd like to keep the light close to the plants, 12" or closer, but want to prevent stressing or bleaching while still getting the best efficiency (I'm trying to stop thinking watts) and thus give myself the best opportunity for lighting success. (I understand that for the first couple of weeks, I grow clones, that they will probably need to be a little higher until the growth takes off and that's just fine.)
What I don't know: (still)
1) What is the best spacing between the cob's for this setup. I visually go for symmetry but I don't know if that's a detriment or not in this arena. Is this best determined by how far from the edge of the heat sink the outside cob's should be placed? Is that 2" or 3"?
2) Given the desired distance from the lights I'd like the plants, 12" or less, what cob/driver combo would best accomplish this, without having to dim them, and be the most efficient option? The drivers could be dimmable but I'm trying to create this with the least "moving parts" and wouldn't be adding dimmers if I don't have to.
3) Where is the best pricing for these cob's and drivers? I've heard cutter.com.au with a discount code of "cutandroll" and I've heard of a guy named Jerry. I've researched digikey and mouser but they don't seem like a benefit. Are there advertisers/sponsors here to support for what we need to create lights? Mean Well drivers are what I'm getting is the best option.
I'm not concerned about a couple of bucks here or there in terms of cost of this setup but want the best value for the efficiency of the light then, obviously, the highest possible production minus the growing skill. (which I can do)
This light needs to last me for quite a while. I don't intend on improving it anytime soon as long as I'm getting the production I'd like from it or I intend to expand. (at this moment, I don't see expanding in my future) Two plants, 6 zips minimum. I could easily do that with a 400w HID in that same space. I've done better than that.
Finally, I've been on a couple of other forum's. 420 mag and a bubbleponic forum that is now gone. I got booted from 420 for joining the other. This is a great forum with extremely helpful people, it's awesome. Thank you for all of the time you've all put in helping me to figure this out. My mind simply doesn't compute the figures like it does for most of you. Know that all the help is sincerely appreciated. Thank you.