DiY LEDs - How to Power Them

alesh

alesh

Well-Known Member
G.N said:
I have CXA3070. Total number is 9, to be precise. Also, I have 3 units of HLG-185H-C1400A. So, I can power 3 CXA3070s, i guess...
I would like to cover 1 square meter if possible. That's my main problem right now. How to calculate needed number of CXA3070s or any other model of LED chips, according to area I want to cover?
Thanks for reply @alesh
Click to expand...
So I'll assume that you have 3000K/80CRI AB bin CXA3070.
At 1400mA, they're 43.3% efficient, each COB producing 22.6W of light (refer to this thread). Cree's 3000K 80CRI produces 4.87 µmol per each joule of radiated light, that means each COB at 1.4A produces about 110 µmol of photons each second. You've got 9 of them over 1m^2, making it 990µmol/s/m^2. There will be some scatter and absorption losses, so I'd say that 900 µmol/s/m^2 is more likely value. That's a good value and should grow some nice buds ;)
500 (maybe even less)-1200 µmol/s/m^2 averaged are acceptable values with the lower one maxing g/W ratio and the higher one maxing g per area ratio. Lower values could result in fluffy/not dense product and higher value could cause bleaching.
 
disengaged

disengaged

Member
Until I can afford a second pair of Vero 29's, can I get by with 2 x Vero 29's BXRC-35E10-L-23 (3500K - 80 CRI) on a HLG-120H-C1050?
How close to ideal is 4x Vero 29's at 1050mA for a 6 square foot (2x3) cabinet with a little supplemental blue and red LED? Will be using 2 x "30w" epileds full spectrum blurple on their own 700mA power supplies in addition to above.
Mainly growing green leafy veggies (so pondering 4000K) but would like to leave possibility for something more interesting...
I have a 600w HPS with conversion bulb but the cooling fan noise is main reason for not wanting to use it. Ballast isn't dimmable, so it is overkill for space available.
 
G

G.N

New Member
alesh said:
So I'll assume that you have 3000K/80CRI AB bin CXA3070.
At 1400mA, they're 43.3% efficient, each COB producing 22.6W of light (refer to this thread). Cree's 3000K 80CRI produces 4.87 µmol per each joule of radiated light, that means each COB at 1.4A produces about 110 µmol of photons each second. You've got 9 of them over 1m^2, making it 990µmol/s/m^2. There will be some scatter and absorption losses, so I'd say that 900 µmol/s/m^2 is more likely value. That's a good value and should grow some nice buds ;)
500 (maybe even less)-1200 µmol/s/m^2 averaged are acceptable values with the lower one maxing g/W ratio and the higher one maxing g per area ratio. Lower values could result in fluffy/not dense product and higher value could cause bleaching.
Click to expand...
Great, @alesh ! Now I get it.
Is there any recommended height for light? How far from the plants?

All this great information that is scattered around this forum deserves wiki of it's own. Would like to see that! Anyone thought about this? I would love to help with that kind of project.
 
don benosee

don benosee

Well-Known Member
alesh said:
So I'll assume that you have 3000K/80CRI AB bin CXA3070.
At 1400mA, they're 43.3% efficient, each COB producing 22.6W of light (refer to this thread). Cree's 3000K 80CRI produces 4.87 µmol per each joule of radiated light, that means each COB at 1.4A produces about 110 µmol of photons each second. You've got 9 of them over 1m^2, making it 990µmol/s/m^2. ......
500 (maybe even less)-1200 µmol/s/m^2 averaged are acceptable values with the lower one maxing g/W ratio and the higher one maxing g per area ratio.
Click to expand...
I wish there was one post/wiki with all this sort of information. Can anyone give me the same data for CXB3590 @ 700mA and 1400mA?
 
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brettsog

brettsog

Well-Known Member
A quick question regarding power usage, I have 3 vero 29s v2 3000k and a hlg 185h c1400b driver on the way. Do I need to dim the cobs or can I just leave the driver at full power so pushing 1.4a?
 
brettsog

brettsog

Well-Known Member
alesh said:
Even if you leave it open the driver's load will be somewhere around 75-80%. So no problem, you can.
Click to expand...

Cheers buddy

Will it affect the output of the leds in anyway not fully loading the driver as I can't quite get 4 on the driver
 
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Amaximus

Amaximus

Well-Known Member
Hey guys... Been lurking and reading a bit "here and there" regarding COB's but I'm just having a hard time wrapping my head around it all. I'm sure it's easy but until I've done it once I have a tough time visualizing or understanding what i need. So I'd like to start small...

I'd like to build a small COB fixture for my veg tent. The tent is 2x3 but I'd like the fixture to be able to cover a 2x4 space for a future tent upgrade. Even though it's a veg tent I'd like the option to flower with this unit so I'd either want A: 4K COBS ( I suppose?) or B: a mixture of COB's (3K & 5K?) with a "veg" and "flower" switch. I have no preference, Whatever is easier. If 2 (or 3) 4K COBS get's it done, then so be it.

I'd also like it passive cooled but if that is not an option because of size or whatever then fans/etc are fine.

How many COB's do I need and which COB's should I use? I'd like to get the most efficiency/quality for the best price. And what driver would I use for whatever COB's are recommend?

Thanks for any answers anyone may provide. I know the answers are all here but I'm just having a tough time getting started. I think once I'm pointed in the right direction I can then proceed on my own... Until I have more questions... heh.
 
Meinolf

Meinolf

Well-Known Member
brettsog said:
A quick question regarding power usage, I have 3 vero 29s v2 3000k and a hlg 185h c1400b driver on the way. Do I need to dim the cobs or can I just leave the driver at full power so pushing 1.4a?
Click to expand...
You might try 4 on that driver and tell me about the results :)
 
brettsog

brettsog

Well-Known Member
Amaximus said:
Hey guys... Been lurking and reading a bit "here and there" regarding COB's but I'm just having a hard time wrapping my head around it all. I'm sure it's easy but until I've done it once I have a tough time visualizing or understanding what i need. So I'd like to start small...

I'd like to build a small COB fixture for my veg tent. The tent is 2x3 but I'd like the fixture to be able to cover a 2x4 space for a future tent upgrade. Even though it's a veg tent I'd like the option to flower with this unit so I'd either want A: 4K COBS ( I suppose?) or B: a mixture of COB's (3K & 5K?) with a "veg" and "flower" switch. I have no preference, Whatever is easier. If 2 (or 3) 4K COBS get's it done, then so be it.

I'd also like it passive cooled but if that is not an option because of size or whatever then fans/etc are fine.

How many COB's do I need and which COB's should I use? I'd like to get the most efficiency/quality for the best price. And what driver would I use for whatever COB's are recommend?

Thanks for any answers anyone may provide. I know the answers are all here but I'm just having a tough time getting started. I think once I'm pointed in the right direction I can then proceed on my own... Until I have more questions... heh.
Click to expand...
Hey man, long time.

It's cost me about £160 to build a 3 cob fixture with vero29 cobs, that's all in, heatsink, dimmable driver and fans and wires and bits. Should compete with a 400 hps if all goes well.

I'm still learning myself but it seems led is the way forward.
 
Meinolf

Meinolf

Well-Known Member
Supra claimed the driver will adjust the current a bit if the voltage is only a bit too high; he said his driver went to the full current when warmed up. If I had a -C1400 on hand, I would certainly try.
 
brettsog

brettsog

Well-Known Member
Meinolf said:
Supra claimed the driver will adjust the current a bit if the voltage is only a bit too high; he said his driver went to the full current when warmed up. If I had a -C1400 on hand, I would certainly try.
Click to expand...
Now I need to buy another cob :(

Man this hobby knows how to drain your pockets.

Before I go out and do something I regret could @SupraSPL or one of the other resident experts confirm this is possible?? Don't really wanna mess the driver up as it was quite pricey.
 
Meinolf

Meinolf

Well-Known Member
The worst that could happen is it won't light up because the driver goes into overvoltage protection mode. You might then dim down the current a wee bit on the -C1400. Else build a second light on a second driver with your single V29 or invest in another V29 and swap the -C1400 for a -C1050. I would not want to "waste" ~50W of driver capacity.

Besides, Supra has a thread "Matching drivers and cobs" where he talks about the ".9 problem".
 
brettsog

brettsog

Well-Known Member
Meinolf said:
The worst that could happen is it won't light up because the driver goes into overvoltage protection mode. You might then dim down the current a wee bit on the -C1400. Else build a second light on a second driver with your single V29 or invest in another V29 and swap the -C1400 for a -C1050. I would not want to "waste" ~50W of driver capacity.

Besides, Supra has a thread "Matching drivers and cobs" where he talks about the ".9 problem".
Click to expand...
For the time being I am just gonna stick with 3. No sense in adding to my task. Plus I like the fact I can run them at 1.4a at 50w ish. I didn't wanna bother with the dimming function, I'm not here to set records, just a little persy smoke for me n the missus :)
 
Simple Clean

Simple Clean

Active Member
I am looking to create a grow light with 6 CXB3070s. From looking at the "Matching Drivers and COBs" spreadsheet there are multiple options. I would like to use Mean Well drivers. Can someone give there thoughts on a driver or drivers combination to most efficiently power the 6 Crees?
Thanks
 
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