Hello Littlejacob, I'm in the states so will be buying the heatsink from here. I'm deciding between making one long panel with 8 or 10 COB or making two panels with 4 or 5 COBs on them. About the only extra expense of making two instead of one is the extra fan and apparatus. the advantage of two is I can always arrange the two to be end to end or side by side. My grow area will be 4x4 feet initially, probably larger somewhat later on.
I don't want the minimal light required to be effective, I'd prefer to have much more than needed for that, not only to maximize my yield but looking to the possibility of future expansion. I remember past HPS grows when I first used one 400W Hortilux and then went to two and then finally three, all serving the same grow box and the difference was impressive. So I do want more light than is necessary.
Looking at the comments and literature it looks like the CXB3590 is the most efficient COB to go with. Electricity where I live is expensive and I want to keep the carbon footprint small as possible, given I want the max intensity that's reasonable to achieve. The Vero 29 and CXA3070 look to be excellent but since I want to do my best at this time, again the CXB3590 seems right for now. Who knows, maybe next week something even better will come out. No sense in waiting to see though, you can wait forever by doing that.
I was surprised to see the videos showing how the light is coming from the COB, it was much like a laser diode or Star trek transporter beam
with obvious tunnels of light coming down from each COB. While the part of the plant directly underneath, getting the max light would be most happy, I wonder if it would be better to diffuse the light somewhat so all parts of the plant get a very high output.
The 3500K being most used is interesting, from what I've read, it's around 2700K for optimal flower and 6500K for veg. I'm wondering if it would be better to alternate between 3000K and 6500K Cree on the panel?
I have no idea what is "best", I'm just learning about LED and trying to make wise decisions and make my own panels. I almost bought some LED panels that sounded and looked ideal to me but learned here why they would have been a poor choice and why using the COB are a better option. So much to learn, so much reading of conflicting opinions...
