Best amperage for COB's?

maps84

maps84

Well-Known Member
So this is the typical story of an HPS guy switching to LED tech because of efficiency and flexibility.
I've done some research and managed to get a basic grasp of how everything works, like cooling, how you wire chips, selecting and wiring drivers and putting everything together; so I might be good on that part.
I also went through most of the products available in the market right now and this is when I faced chaos.
I decided to go with COBs as it's perfect to fit a 2x4 flowering area.
At first I looked at the cree CBX3590 3000k 90CRI 72v Chips because that's what Optic 1 carries, however apparantly as for 2019 they're old tech compared to the newer BLX vero29's that put out more light.
OTOH Citizen chips that are suppose to be cheap are really expensive right now, while Luminous is cheap but doesn't compare to the veros.
There's also the Chilled Logic V2 100W PUK carrying Samsumg Chips. This light is supposed to smoke the others out of the water in several aspects. I'm really considering to get 4 of this ones if I can get rapid led to include it in their diy kit bundle.

All in All I'm sure the chips listed are great and should will deliver excellent results, Thing is I dont have a clue on how to actually run them. let me explain myself; some people underdrive or overdrives their LEDs for better/desired results and it all gets confusing from there.
I do understand that current measured in amperes determines the brightness of the LEDs, I just don't know the "Lucas formula" to it if there's any; but I'd really like to build the whole thing knowing what and why I'm doing it, instead of just going with a random bundle.
FWIW I'm leaning towards the Chilled logic V2 chips; 4 (four of them) on a HLG-320-48b driver; heat? well I have no idea what to expect. CFLs for cloning have proven perfect for me and I haven't decided on veg light yet. most likely a pair vero29 on a 2x2 tent, so I can flower some autos in there as well. is it a GO?

Thank you for your time and your inputs
 
GBAUTO

GBAUTO

Well-Known Member
confusing, ain't it.
I can only offer my own experience with building and running my own fixture.
My room setup is essentially two of your 2x4 areas. I originally designed a pair of 48"long arrays using 4 vero29 running @75w/cob. I ran that design for a season and it was a huge improvement over the blurple panels I bought when I started growing again. I did see that like HID fixtures, cobs tend to get high growth directly under the array but you get some drop-off at the edges.
I decided to add some Samsung F-strips as outriggers on each side of the vero's for this years season- all I can say is DAMN.
I thought that the results from last year were pretty good. This years crop DWARFS it.
The wattage you are planning should be good for your footprint-that's the easiest metric to use for comparison(power used). Most current tech diodes used in cobs, QB type fixtures, and light strips need approx. 30w/ sq ft to generate a sufficient light intensity.
I wouldn't try running most cobs over 75w/array unless you have enough height to prevent oversaturation under the fixture. Product of the forward voltage of the chip you want to use and the drive current determine the wattage. I run 140mm pin sinks on my Veros and they stabilize right at 50degC with minimal airflow in the room. The logic pucks are very efficient and are a good choice-at this level of components, differences only amount to a few percentage points. I choose the one that fits my budget and gets the job done.
 
GBAUTO

GBAUTO

Well-Known Member
maps84 said:
so basically I dont want over 50w on each chip right?
Click to expand...
This is where discrete diodes can offer better uniformity. To duplicate the efficiency and uniformity of discrete diode panels with cobs means you would need to run them at lower wattage and have more of them in a given area-costs add up quickly when adding heatsinks and related hardware.
 
Chip Green

Chip Green

Well-Known Member
One common hangup with growers making the change to LED I've witnessed is the propensity to obsess over efficiency. We certainly all want to get the most light, for the least amount of energy consumption. It's my opinion that, considering the smallish spaces most are outfitting, the whole lumen per watt factor is greatly overvalued.
 
maps84

maps84

Well-Known Member
mathewscott said:
When it comes to new technology always wait a year. It will be 25% cheaper guaranteed!
Click to expand...
So you'd lean towards the veros? They're not that cheaper than the Chilled V2 PUKs. What would you run in a 4x2 area?

Chip Green said:
One common hangup with growers making the change to LED I've witnessed is the propensity to obsess over efficiency. We certainly all want to get the most light, for the least amount of energy consumption. It's my opinion that, considering the smallish spaces most are outfitting, the whole lumen per watt factor is greatly overvalued.
Click to expand...
Well AFAIK, efficiency is the whole point with LEDs. having 65% lumens over 35% heat, out producing HPS (g/watt) is what we all wanted right? recently I've been reading about PAR and PPFD so you might have a point about lumen per watt, though I'd really like to hear your suggestions or real live examples.

The reason I chosed cobs over other lights is because they'd fit my 2x4 space like no HPS would. As for canopy management I'm planning on doing the old stinkybud set up where you run 4 cycles under the same light to get a harvest every 2 weeks or so.
 
Last edited:
maps84

maps84

Well-Known Member
GBAUTO said:
confusing, ain't it.
I can only offer my own experience with building and running my own fixture.
My room setup is essentially two of your 2x4 areas. I originally designed a pair of 48"long arrays using 4 vero29 running @75w/cob. I ran that design for a season and it was a huge improvement over the blurple panels I bought when I started growing again. I did see that like HID fixtures, cobs tend to get high growth directly under the array but you get some drop-off at the edges.
I decided to add some Samsung F-strips as outriggers on each side of the vero's for this years season- all I can say is DAMN.
I thought that the results from last year were pretty good. This years crop DWARFS it.
The wattage you are planning should be good for your footprint-that's the easiest metric to use for comparison(power used). Most current tech diodes used in cobs, QB type fixtures, and light strips need approx. 30w/ sq ft to generate a sufficient light intensity.
I wouldn't try running most cobs over 75w/array unless you have enough height to prevent oversaturation under the fixture. Product of the forward voltage of the chip you want to use and the drive current determine the wattage. I run 140mm pin sinks on my Veros and they stabilize right at 50degC with minimal airflow in the room. The logic pucks are very efficient and are a good choice-at this level of components, differences only amount to a few percentage points. I choose the one that fits my budget and gets the job done.
Click to expand...
thanks bro. really useful stuff in there! and since the puks are 48v and I'm going with the HLG-320-C1750 instead to run them in series instead of parallel. That's 48v x 1750mA so like 69.6 watts, I could go higher but again I don't know what to expect regarding temps.

Would a potentiometer (dimmer) help me drive/turn the current up and down?
Can you use "step" pots?
furthermore, even if the driver has higher current output (higher amperage) would I be able to set the driver to a lower current using a potentiometer? it sounds self explanatory, but how does it work? do you measure the actual current and determine a sweet spot for your system?

thanks
 
Chip Green

Chip Green

Well-Known Member
Yes, the efficiency is important, I just mean that many times, in the DIY realm, builders get caught up on having max efficiency, when in reality, even the 4th or 5th "best" emitters still produce ample light for the power consumed....
I myself use the strip style diode collections. Mostly Bridgelux EB series, and Samsung F series. I did exactly one COB build, and then got into the strips.
For design purposes, the strips offer further flexibility, some options even allow for running without any heatsinks at all.
I just find the strips far easier to work with.
 
GreeneryBob

GreeneryBob

Well-Known Member
For a 2x4 area, 4 of the mou5 pucks really rock. Having the added 660nm and mixed 3 and 4k diodes really rounds out the spectrum for a great seed to flower solution.


Tip. Keep the driver outside of your tent to reduce unneeded heat.
 
maps84

maps84

Well-Known Member
GreeneryBob said:
For a 2x4 area, 4 of the mou5 pucks really rock. Having the added 660nm and mixed 3 and 4k diodes really rounds out the spectrum for a great seed to flower solution.

well i will be flowering only. would that be ok or should i complement some specific spectrum?

Tip. Keep the driver outside of your tent to reduce unneeded heat.
Click to expand...
 
GreeneryBob

GreeneryBob

Well-Known Member
You can always geek out and do more and more and more but mou5pucks have a great spectrum.

I have that setup for a secondary tent and plan to add 730nm eventually
 
You must log in or register to reply here.
Top