Rollitup

I would recommend the CXB3590 3500K CD 36V. If you run them at 1.4A you can use HLG-185H-C700 drivers and each COB would be at ~50W. You could put 4 of them on a long heatsink like the 3.5" profile from HeatsinkUSA. I would recommend 90 degree glass lenses.

If you run 1200W of that setup you will more than double your yield, good luck!

Thanks for the reply

How many COB's would I need for a 4x4 space? I currently am using a 4x8 space with the two 600w HPS and would replace the HPS with LED one at a time. Also how many of the 50w COBS and run off the driver you suggested?

Sorry I made a typo, if you use 36V COBs the driver would be HLG-18H-C1400. You could run 4 COBs on each driver for 200W. If it were my 4X4 I would install 500W, giving you 725 PPFD average. For comparison a 600HPS in a cooled hood in 4X4 would be about 460 PPFD. So you could expect a huge increase in intensity and yield (and plant hunger/thirst)

So If I wanted to replace both 1200w's of HPS I would need 6 drivers, 24 COB LED's, and 6 heatsinks with 3 lights on each heatsink? That sounds likes its getting in the $2,000 range really quick.

Also if I am correct about the upfront cost, why don't I just get 2-3 mars hydro lights and save a couple hundred bucks and time. Do these DIY lights work much better than what mars hydro can provide?

Thanks for answering my questions.

If you build what you described, you would be replacing 4 600W HPS setups, about doubling your yield.

If you want to save your labor and buy a prefab lamp I would recommend sticking with COB designs and avoiding small emitters. Check out Optic Grow Lights they use genuine Vero 29s running at ~42% efficiency.

I like the technology but no the price. The Vero 29's are nice but only cover 6 sq ft and I have 32sq ft so I would need 6 and at $1750 that's not gonna happen. I know you say stick away from the small emitters but I think thats all I can afford. Even with the Mars Hydro lights I should be getting better efficiency out of my lights correct?
http://www.mars-hydro.com/led-grow-light/mars-ii-series

Having experience with the Mars I would like to help you, you would need two of the 1600w models to cover your space or 8-10 of the 400w to get decent coverage.The company claim of 5x5 coverage for 1600w is just the lights reach. you would be disappointed once you hook up just one and would eventually buy another, and would be hitting harder to get anything above .6 gpw.

Now 2 1600w model costs $1200 and runs at 1560w. With cobs you be needing 20 cxb3590 @45 each and 5 mean well drivers @ 65 each they will be running at 50w each total 1000w. Just the cobs and drivers cost $1225 you could get the heat sinks for less than $200 and misc items $100w thermal paste connectors etc. Now you save 560w and pretty high intense light and definitely better yield than those 2 1600w mars led.

It gets time to get our heads around the efficiency factor and getting out of the idea of blue red leds, After mars I tried DIY blue red led it was better than Mars but yield increase per watt was minimal. Initial cost is paid with Power bills and high yield pretty soon. If you are stuck up with blue red leds go with Advanced LED or Hans or California Light works they are better efficient than the Mars

Can you link some link to websites where I can get the COB's for $45, i think the one website I looked at had them for around $65.