Lighting Cob vs hps

[iampepe]

I have a 30in x 30in x 84in grow room. I think that my 400 watt hps is a bit much. I have a air cooled reflector but with the outside Temps getting into the high 80s I'm struggling to keep my room temp below 85. I'm wanting to build a cob light to get my Temps in the right range.

You'll be good, more than good in that space.

 

[Rusty_Shackleford]

Even if HPS is 30% efficient, it gives 120 PAR W. And it is.
And yes, on paper and in sphere tests.

Still more PAR W than 200W of 1212. Sorry guys, I also have these COBs but I cannot past this what some of you saying "200W of 1212 will be better than 400W HPS". No!

You can see numbers and text from Gavita here:
- https://chilledgrowlights.com/indep...ro-1000-de-hps-at-1000w-goniometer-lab-report
- http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0099010#s3

That's a gavita 1000 de. Imo it's apples to oranges compared to 400w fixtures. Efficiency is better, and output is better. Even if your math is correct, screw it add another 1212 for 250w get close to the par/w you listed and still use almost 200w less power and less heat. Problem solved

 

[Site]

I have a 600W HPS running alongside 8 Cree COB's (4 3590's and 4 3070's) at 700mA equalling around 200W...the 4 plants under either are just as healthy as each other...so 200W of COB can easily do the same job as a 600W HPS...

 

[Tommy boy]

Will 200 watts of cob light grow the same quality of bud that my 400 watt hps does?

 

[iampepe]

Will 200 watts of cob light grow the same quality of bud that my 400 watt hps does?

For sure, have a look around at the grows. I doubt any cob grower ever goes back to the old.

 

[Rusty_Shackleford]

Will 200 watts of cob light grow the same quality of bud that my 400 watt hps does?

Absolutely. Something else to keep in mind is you get better spread. 4 light sources compared to one is gonna be alot better coverage. More quality light to your babies

 

[Tommy McCain]

I have a grow space close to the same size as yours and I am using the same driver 185h- 1400 with 4 cree 3590's. I also run 1212's in a different location. I am unbelievably happy with both setups. I built the 1212 light most recent and designed it to add more COB's to the driver later. I now wish I would have bought a driver for my Cree 3590 light that would allow me to add more COB's for efficiency. I have a plan to add a couple of COBs to the 1212 light after a few grows, but my 3590 light (185h-1400 driver) is not able to be upgraded without purchasing a new driver. I think this is the best part of COBs is the cheap upgrade.

 

[Tommy boy]

Well I'm pretty much sold on building a cob light. Now I just need to start ordering parts. Should I go with passive or active heatsinks I was thinking I could control the temperature better with active heatsink what do you guys think?

 

[Tommy boy]

What do you guys think about color should I get 4 3500k or mix it up and get like one 2700k , 35OOK, 4000K and a 5700k for a full spectrum?

 

[Rusty_Shackleford]

I would go 3500K 1212 in 90cri if it were me (about to convert two old Mars with this). I'm not sure you would truly see a huge benefit to multiple colors, if any benefit. Could be the opposite lol. But 3500 is tried and true, great growth and flowers. As far as cooling, I'd try passive with oversized heatsinks, you can always add fans if you need more, adding four fans, wiring and all would be less than 40. Currently I'm active cooling (alpine CPU coolers) however I would love to try passive. Less moving parts= less room for part failures.