More Cobs at lower watts or less Cobs at higher watts

ganjafather27

ganjafather27

Well-Known Member
So I'm just looking to bounce some ideas off of some of you knowledgeable cats.

I want to light a 4x4 flower tent and I'm wondering what the more ideal set up would be.

First, how many watts would be ideal? 700? More or less?

People say Veros are more efficient when running hotter, so does that mean if you ran a very at 90w, it would be as efficient at a cxb at 50w?

Ultimately I'm trying to figure out if I should run 9 Cobs at around 80-90w ea or should I go for 12 cobs at 60w ea?

Also what brand of cobs would you choose?

Thanks
 
Regardless of which cobs you choose they will be more efficient running more of them at lower wattage. Loose estimate, if your electrical rate is 12 cents per Kw hour the money you put in (running more cobs at lower wattage) is the money you get out in electrical savings over 5 years. If the juice is cheaper you may come out slightly better running higher wattage. If it's more expensive you may come out better running lower wattage.

That's just for the lamps alone. There's also AC costs to consider so it's not a simple proposition. Basic rule of thumb, if you plan to use the lamps for the next 5 years and can afford it, use more cobs.
 
more lower watt lights cover more area for less cost than higher watts...
more watts penetrate deeper in the canopy ? like hid's
 
Penetration equals out since you can get the lower watt ones closer. I saw someone say that you get about 10% more photons when you half the current and double the lights, so more light with the same electrical use. If you can afford it I would say go for the more cobs at a lower current.

If you google cob calculator, you can DL it and try different setups to see what kind of gain you might see.
 
ganjafather27 said:
First, how many watts would be ideal? 700? More or less?
Click to expand...
500-700

ganjafather27 said:
People say Veros are more efficient when running hotter, so does that mean if you ran a very at 90w, it would be as efficient at a cxb at 50w?
Click to expand...

every chip is different and there are all kinds of veros. a vero at 90W is certainly not more efficient than the same chip at 50W

ganjafather27 said:
Ultimately I'm trying to figure out if I should run 9 Cobs at around 80-90w ea or should I go for 12 cobs at 60w ea?
Click to expand...
9 cobs at 60-70W

ganjafather27 said:
Also what brand of cobs would you choose?
Click to expand...
i dont think theres anything substantially more efficient than $17 luminus cxm22 at that wattage. you can spend more on chips that are more efficient at higher wattages, but if youre only running them at 60-70W you'll see zero benefit from the more expensive chips
 
CobKits said:
500-700



every chip is different and there are all kinds of veros. a vero at 90W is certainly not more efficient than the same chip at 50W


9 cobs at 60-70W


i dont think theres anything substantially more efficient than $17 luminus cxm22 at that wattage. you can spend more on chips that are more efficient at higher wattages, but if youre only running them at 60-70W you'll see zero benefit from the more expensive chips
Click to expand...

Hey thanks a bunch for replying.

So what I'm seeing is running 9 Cobs will be plenty sufficient. Do you think you can help me pair a few drivers?

I'd like to have 3 Cob's per rail, and a driver on each rail. I'd also like to wire in series instead of parallel. I'm think an hlg-185 c, but which one? 1400?

Thanks
 
ganjafather27 said:
Hey thanks a bunch for replying.

So what I'm seeing is running 9 Cobs will be plenty sufficient. Do you think you can help me pair a few drivers?

I'd like to have 3 Cob's per rail, and a driver on each rail. I'd also like to wire in series instead of parallel. I'm think an hlg-185 c, but which one? 1400?

Thanks
Click to expand...
hlg185c-1400 is pretty much going to limit you to 36V cobs, if you want to run series with 3 luminus cxm22 you want the hlg240h-c1400b
 
CobKits said:
hlg185c-1400 is pretty much going to limit you to 36V cobs, if you want to run series with 3 luminus cxm22 you want the hlg240h-c1400b
Click to expand...
OK, is there a big difference between citis and cxm22?

And also what advantage would I have running 50v chips instead of 36v?
 
CobKits said:
not a big difference. if you want similar performance to cxm22 in 60-70W range you need to spend more on citi 1818 or 1825


50V chips are more efficient in that range
Click to expand...
Ah OK. I think I'll go luminous with the driver you mentioned as well. Would you recommend 80 or 90 cri?

Thanks again for all your help, I really appreciate it.
 
CobKits said:
im into 90 right now, works well for me
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Hey CobKits I've got another question if you don't mind.

If a driver is 148v and you run 3 36v cobs does that mean the driver will only run those cobs at 108v, or does it automatically run the cobs higher than 36v to get up to that 148v?

And how about for the rated power? If you run 3, 36v cobs on a 200w driver, does it send out the full 200w or does it limit it to less than 200w total?

Basically I'm trying to figure out if running the 250w drivers, with only 3 Cob's per driver, will be putting out 750w for the 4x4?

Thanks
 
ganjafather27 said:
If a driver is 148v and you run 3 36v cobs does that mean the driver will only run those cobs at 108v, or does it automatically run the cobs higher than 36v to get up to that 148v?
Click to expand...

im assuming since you quote 148V you mean constant-current drivers

they can only operate on their voltage/current curve (+/- a little voltage based on temp), so unless you get super lucky driver will always be operated below its max voltage

if you want to max out your drivers regardless of number of cobs use constant voltage drivers like -36A, -42B, -48A, etc
 
CobKits said:
im assuming since you quote 148V you mean constant-current drivers

they can only operate on their voltage/current curve (+/- a little voltage based on temp), so unless you get super lucky driver will always be operated below its max voltage

if you want to max out your drivers regardless of number of cobs use constant voltage drivers like -36A, -42B, -48A, etc
Click to expand...

How about 4 36v cobs on an hlg-185-1400? Would that setup be less efficient than 3 50v chips on an hlg240h-c1400? And which would pull more from the wall?
 
depends which chips.

but at similar currents, 50V and 36V of a given size chips have similar efficiency as the current per diode is about the same
 
without you specifying which chips, we can guess

4 36V chips at 1400 mA = 200 cob watts>215 at wall
3 50V chips at 1400 mA = 210 cob watts>225 at wall
 
ganjafather27 said:
So I'm just looking to bounce some ideas off of some of you knowledgeable cats.

I want to light a 4x4 flower tent and I'm wondering what the more ideal set up would be.

First, how many watts would be ideal? 700? More or less?

People say Veros are more efficient when running hotter, so does that mean if you ran a very at 90w, it would be as efficient at a cxb at 50w?

Ultimately I'm trying to figure out if I should run 9 Cobs at around 80-90w ea or should I go for 12 cobs at 60w ea?

Also what brand of cobs would you choose?

Thanks
Click to expand...
600w of chilledledgrowlights would be the best choice from my view. I am running 300w in 2x4 and killing it
 
CobKits said:
without you specifying which chips, we can guess

4 36V chips at 1400 mA = 200 cob watts>215 at wall
3 50V chips at 1400 mA = 210 cob watts>225 at wall
Click to expand...

oh sorry, I'm an idiot

I'm honestly leaning towards the Gen 5 1212s on your site. Ill save about 50$ in equipment costs after Heatsinks and drivers are equated.

I feel like the difference in efficiency is probably not enough to go with 50v cxm22 and the 240h drivers since 12 cobs should spread the light out a little more evenly.

I'm probably wrong though because I don't know enough about this stuff lol
 
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