This how I would start......
Figure out your exact dimensions you want....Final Proof
Both veg and flower....
and then....
For Veg, you could get away with as little as 4 watts / sq. ft.....the ones I rely on for data and input like Supra, are using cloning stations with 2 watts /per sq. ft and up to 8 watts per sq. ft.....going for increased wattage will NEVER hurt, that is up to you....
For Flower, reports seem to favor no more than 35-40 watts / sq ft of light.....especially when using Vero 29's or Cree CXA 3070 and also the Cree big boys the CXA3570....
Now when you have an a final tally of your space, just multiply by the numbers...to get a rough idea of your total wattage from total square feet.....
Led
The diodes themselves are ran off DC constant current. The voltage will slight fluctuate either up or down depending on the temperature [temp droop] and this is why heatsinks [passive] or heatsinks/fans [active] are needed for stable cooling....basically like a CPU of a computer....
This is the general rule of thumb, as your amperage decreases, so does your voltage....Mainly because less heat is being produce because of less power and light is being produced more efficiently as byproduct of lower currents....
Datasheets datasheets datasheets, are Extremely crucial!!!!!! They will tell you exactly how much voltage is being produced at a certain current between the minimum and maximum amounts of current that the LED can handle.....
Typical currents for the high powered COBs are usually:
350mA
500mA
700mA
900mA
1050 mA [1.05 amps]
1400 mA
drivers
The drivers convert 110/220 AC to DC voltage/current. The LED's require constant current [Amps] while voltage will fluctuate over a slight range due to heat.....blah blah blah.....
Since voltage will fluctuate to some degree, I like to size drivers that have slightly more voltage than a cob requires.....
So for instance the Cree CXA running @ 500mA requires 34.2 volts @50c....while the same cob running @1.4amps needs just over 36 volts....
View attachment 3363475
Drivers these days can also be dimmed with no adverse affects to LED performance....take my setup 2x Vero 29 3ks and 2x CXA 3K AB's....I will be running them initially @ 600mA dimmed and be using about 80 watts, averaging 46% efficiency....So .46 x 80 watts = 36.8 PAR watts....but the same diodes undimmed can run well over 100 watts apiece and still average over 30% efficiency [some of the HID's are here] and push 400w's....
Okay...ramble ramble.....I just feel like, if you are going to build, understand....hopefully this helps and you are the inquisitive type, because it really isn't all that difficult it just has to sink in......
Buying Cobs
I like Bridgelux Vero 29 3000K for flowering [and they will veg too, if needed] and the Cree CXA3070 AB 3000K like mentioned above and of course by
@NorthernHize
I bought my vero's at Digikey
http://www.digikey.com/product-search/en?s=44064&FV=fff40008,fff80354,fffc03d0&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
I bought my Cree's from Amelia Liu on AliExpress, because they are are bitch to find in the states for a reasonable price....
[Now I cant find the link!!!!!]
Kingbrite
@REALSTYLES can be vouched for as well
http://www.aliexpress.com/store/product/CREE-3070-Original-CREE-CXA3070-diodes/324035_32285685458.html
I like 5K spectrums for
Vegging..The Vero's might be a better choice fiscally, especially something like the 5k Vero 18...Like I said earlier, you don't need a huge amount of wattage for great veg.....
Buying Drivers
I also mentioned earlier, maybe just babble, but scaling the power of the LED, thru dimming....
I like the Meanwell HLG's and the HLG 185H-xxx-C are the most desirable....High efficiency [91-94%] and will drive multiple cobs in series, depending on Current model selected....These can be dimmed either digitally thru PWM or analog thru power supply and Pot resistor or do nothing at all and don't dim them. Still one of the most efficienct and highest quality drivers that are used.....
There are a few:
1.4amps @ `132volts
1050mA @ 176 volts
700ma @ 264
500ma 370
For example: You decide your flower room ends up 6 sq ft and you want to run 30 watts per sq. ft...180 watts.....If we take the 1050max 176 volts example = 185 watts...Perfect...You can run 4 Cree CXA3070's on this one driver and have it equal nearly 180 watts....Reference the Cree sheet
above....@1050mA's you will need 152 volts [and there are 176 available]....just under 170 watts, so a little lower,
but I hope that illustrates the calculation
I also like these Meanwell LPC 150 drivers...They could run a few Cobs in series and are about half of the HLG line and if you don't want dimming, they could be a nice pick up
http://www.powergatellc.com/mean-well-LPC-150-power-supply.html
The Meanwell LPC 1400- 60 is popular to run a single Vero 29 or Cree 3070 @ 1.4 amps
http://www.trcelectronics.com/View/Mean-Well/LPC-60-1400.shtml
Going the cheapest is some Ebay finds
50watters
http://www.ebay.com/itm/50-W-Watt-High-Power-LED-Driver-AC90V-265V-50-60HZ-Waterproof-/181578939219?pt=LH_DefaultDomain_0&hash=item2a46f2bb53
Heatsinks
Active or passive or semi active?
The arctic 11+ CPU coolers are rock solid...they will easily handle over a 100 watts each...
http://www.newegg.com/Product/Product.aspx?Item=N82E16835186070
but if you want something more flexible....lots are using Extruded heatsinks from Heatsink usa
www.heatsinkusa.com
And here are the #'s calculated by SupraSpl for each of the various lengths
View attachment 3363475
Here is how we calculate using the above numbers...The general rule of thumb is use 25cm2 of heatsink surface when using active cooling and 75 centimeters squared for Passive cooling...
So for instance the 1st amount is 2.03" and for every inch there is 80 cm2 of surface length...So every inch would be enough cooling for 3 watts if actively cooled and just over 1 watt if passively cooled....
10 inches would be good for 30 watts [active] and so on.....
Use ball bearing fans if thinking about constructing this way...Sleeve bearings are cheap and will spit oil mounted horizontally and then DIE!
