Matching Drivers and COBs

CoB_nUt

CoB_nUt

Well-Known Member
ttystikk said:
Often, this is for the best. Everyone gets their chance to do things their own way and we get the benefits.
Click to expand...

Agreed and I concur. Im just selfish and spoiled in that manner. Was just cool as fuck to actually see,hear and learn along with people and knowledge thats actually somewhat tangible. Not hand-me-down bullshit.
 
bassman999

bassman999

Well-Known Member
fearnoevil said:
Well hell, so I was trying to understand what SDS was saying on his tutorial on dimming and now I'm confused (again, seems to be a perpetual state of mind when it comes to this stuff).

If I use a single pot to control 6 drivers, to find the right pot do I have to divide 100k/6, in which case that comes out to 16.6k. But the closest I can find on Mouser.com is an 18k, will that work? Frankly this sounds counterintuitive that the more drivers you add, the smaller the pot, lol.
Click to expand...
Slightly higher is better than slightly lower with my experience as there is a 10% tolerance on the actual impedance
 
fearnoevil

fearnoevil

Well-Known Member
bassman999 said:
Slightly higher is better than slightly lower with my experience as there is a 10% tolerance on the actual impedance
Click to expand...
Thanks Bassman, I keep forgetting about the tolerance, but, while that was my thought initially, when I read further it seemed that the guys were recommending going lower and then ADDING a resistor to make up the difference. I can't find the exact post, but as I recall someone wanted to run 7 drivers, 100/7=14.3 but since the closest pot is a 10k, the advice was to go with that and add a 5k resistor. This produced 100% power just short of the pot's max and of course only allowed dimming to something like 35%.

Another post, someone went went with a 35k pot when he needed a 33k, then he added a 4.5k resistor and it wouldn't work because he was over the max rating/amount. Now I don't claim to understand this much, but because of that I decided to go with a 15k Ohm pot (which was hard to find, lol, and not cheap), and then add either a 1.6k or 2k resistor (ordered both jic ;?). But if that's wrong, I'd be glad if you can get me on track.
.
 
Last edited:
fearnoevil

fearnoevil

Well-Known Member
Btw, in the instance above, if you do hit 100% output at say 90% on the pot, is it correct to assume that turning the pot all the way on that you could "overclock" the driver and maybe burn it up? If that were the case, to avoid accidentally doing that, maybe there's a way to rig a stop on the knob, say a pin installed on the knob that runs into another pin on the case/board it's mounted to. :confused:
 
bassman999

bassman999

Well-Known Member
fearnoevil said:
Btw, in the instance above, if you do hit 100% output at say 90% on the pot, is it correct to assume that turning the pot all the way on that you could "overclock" the driver and maybe burn it up? If that were the case, to avoid accidentally doing that, maybe there's a way to rig a stop on the knob, say a pin installed on the knob that runs into another pin on the case/board it's mounted to. :confused:
Click to expand...
No worry of burning the driver up, and another way is to add a switch inline to the pot and it will run full power when the switch is in open position
 
fearnoevil

fearnoevil

Well-Known Member
But if using a larger pot than the settup needs, does that negate the need for low-limit resistors, and wouldn't adding them create the problem that the other dude ran into with it not working?

And agreed, I think that I would probably just run my lights at 100%, UNLESS it somehow turned out that I end up creating a light with too much output, say over 1500ppf that mind end up needing dimming. And I could also see a need to dim when you're working in the grow room, these damned things are so bright it makes me feel sick (mild headache and some nausea, lol), and no sunglass of mine seem to help (even with baseball cap on and not looking directly at the light, it's just in my periferal vision).

That brings up another topic, what do COB users wear for eye protection?
 
DesertHydro

DesertHydro

Well-Known Member
sixstring2112 said:
how tall will your plants be on these 4 x 8 tables? you could run 30 to 32 cobs over a 4 x 8 @ 35w each and kill it with just 1120w vs 2 x 1000whps.even if you chose 50w cobs your still well under the 2000w mark and the tables will be flooded with light.personally i dont think 50w chips are needed unless the plants exceed 4 feet tall.
one nice thing about multiple drivers is that if 1 driver fails in a 6 or 8 driver setup you wont miss it as much while you wait for a replacement.if you lost 1/3 of your lights due to a driver problem it will be more noticable i guess,idk i would look at where the numbers fall on eff and how much of each driver is being used
Click to expand...
havent really decided on how tall yet. i can either SCROG and supercrop to use less plants or i can run a SOG at 4 plants per sq/ft and no veg time in 3x3 rock wool cubes. no matter what i choose they shouldnt exceed 4' tall but then again this is a 2 strain seed run so there is no telling how they will act. either one is a valid option at this point since by the time my flower area is open my veg plants will be big enough to donate the proper amount of cuts or be flowered out to fill the whole 4x8. im about 30 days away from my flowering area being opened up. i cant help but get stuck on the wattage thing. ~1200W just doesnt seem like enough to cover a 4x8. i know it has been proven otherwise. im still thinking 1500-1800W which will still save me about 700w and a TON of heat. i can always dim the lights if its past the point of diminished returns.
 
BobCajun

BobCajun

Well-Known Member
fearnoevil said:
That brings up another topic, what do COB users wear for eye protection?
Click to expand...
It's the blue part of the spectrum that damages the eye, so blue blocker sunglasses would probably be best. If you can't find those then I guess orange or reddish colored glasses. And you just use a 100k pot and no resistor. That's what the actual data sheets suggest. Other people like to complicate things for no good reason I guess.
 
bassman999

bassman999

Well-Known Member
fearnoevil said:
But if using a larger pot than the settup needs, does that negate the need for low-limit resistors, and wouldn't adding them create the problem that the other dude ran into with it not working?

And agreed, I think that I would probably just run my lights at 100%, UNLESS it somehow turned out that I end up creating a light with too much output, say over 1500ppf that mind end up needing dimming. And I could also see a need to dim when you're working in the grow room, these damned things are so bright it makes me feel sick (mild headache and some nausea, lol), and no sunglass of mine seem to help (even with baseball cap on and not looking directly at the light, it's just in my periferal vision).

That brings up another topic, what do COB users wear for eye protection?
Click to expand...
Larger pot means no need for the resistors, but you cant trick into more power than it is designed for with more or less resistance.
As for light I dim lights when I am around them. I had trouble with HID lights because they cant be dimmed and the spectrum is so obnoxious
 
Gromax 3590B

Gromax 3590B

Active Member
No driver so i am going back in time. Crazy times back in 1993. Illegal house party's in Amsterdam when XTC was so new as partydrug that it was still legal. Good vibes and lots of a new kind of noise.

 
sixstring2112

sixstring2112

Well-Known Member
DesertHydro said:
havent really decided on how tall yet. i can either SCROG and supercrop to use less plants or i can run a SOG at 4 plants per sq/ft and no veg time in 3x3 rock wool cubes. no matter what i choose they shouldnt exceed 4' tall but then again this is a 2 strain seed run so there is no telling how they will act. either one is a valid option at this point since by the time my flower area is open my veg plants will be big enough to donate the proper amount of cuts or be flowered out to fill the whole 4x8. im about 30 days away from my flowering area being opened up. i cant help but get stuck on the wattage thing. ~1200W just doesnt seem like enough to cover a 4x8. i know it has been proven otherwise. im still thinking 1500-1800W which will still save me about 700w and a TON of heat. i can always dim the lights if its past the point of diminished returns.
Click to expand...
Go with 62w cobs if using cree use 1750ma drivers.if using other cobs your on your own lol.but at 62w per cob and 12 inch spacing you will be amazed and also use dimming drivers.imo 40w per is all thats needed.if you look at my last set of pics in my thread the biggest plant/colas in those pics are under 35w cobs @ 12in on center.gl
 
ttystikk

ttystikk

Well-Known Member
BobCajun said:
It's the blue part of the spectrum that damages the eye, so blue blocker sunglasses would probably be best. If you can't find those then I guess orange or reddish colored glasses. And you just use a 100k pot and no resistor. That's what the actual data sheets suggest. Other people like to complicate things for no good reason I guess.
Click to expand...
No. Blue doesn't hurt your eyes, UV does. COB LED emits none. Sunglasses are recommended if you find yourself looking towards the running chips a lot, but are otherwise not strictly necessary. If they make you more comfortable then by all means.
 
BobCajun

BobCajun

Well-Known Member
ttystikk said:
No. Blue doesn't hurt your eyes, UV does. COB LED emits none. Sunglasses are recommended if you find yourself looking towards the running chips a lot, but are otherwise not strictly necessary. If they make you more comfortable then by all means.
Click to expand...
Tell that to Cree then, smart guy.
 
You must log in or register to reply here.
Top