Approve my build? Numbers seem slightly off

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Nugtorrent

Member
So, I've decided to delve into a 3x3 cob build and trying to maximize efficiency at the wall. I was hoping to pull off a HLG 320H-c700 with 12x CXB 3590's, but when I divide the forward voltage of the driver with 36v it comes out to driving 11.8888 cobs.

Whats confusing is when I calculate other drivers, they always seem to end up slightly lower.

Ex: HLG 185H-c700, forward voltage @ 286v, comes out to 7.94 cobs when divided by 36v. And yet almost every build with this driver/cob combination runs 8 cobs to that driver.

Are they slightly more powerful than listed? or is the minimum drive current of the cob closer to 35ish?

Thanks.

edit: Also debating a hlg 240h-c700 to run 9 cobs instead for the lower buildout price, that crunch says it can run 9.91 CXB's. would I lose efficiency not running the 10th cob?
 
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N

Nugtorrent

Member
I really wanted to build a light with low current, 1.4 ma is twice the draw from the wall right? I mean aside from running less cobs and driving them harder, I thought they were less efficient at the wall.
 
thetr33man

thetr33man

Well-Known Member
You loose a bit of efficiency but not as much with the citizens as you would pushing the cree harder. Not many people using cree chips anymore, they are overdue for an upgrade and the vero and citizen chips are better right now, especially when you consider the cost difference. You could get a bit better efficiency by running them at 1050 if thats important to you. Ive got some on passive sinks at 1750 and they are doing great.
 
N

Nugtorrent

Member
thetr33man said:
You loose a bit of efficiency but not as much with the citizens as you would pushing the cree harder. Not many people using cree chips anymore, they are overdue for an upgrade and the vero and citizen chips are better right now, especially when you consider the cost difference. You could get a bit better efficiency by running them at 1050 if thats important to you. Ive got some on passive sinks at 1750 and they are doing great.
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Could you PM me a bit about your build? Just the bare bones (in particular the cob model, driver and a link to your passive pin cooling) Thanks man, down to save some $$
 
CobKits

CobKits

Well-Known Member
Nugtorrent said:
edit: Also debating a hlg 240h-c700 to run 9 cobs instead for the lower buildout price, that crunch says it can run 9.91 CXB's. would I lose efficiency not running the 10th cob?
Click to expand...
no just driver cost

9 work better in a square anyway

also

thetr33man said:
ditch the 3590s and use citizens at 1400ma, I just cut your cost in half!
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you dont need to run citizens at twice the current to equal a cree

there are plenty of chips that cost half as much as a cxb and offer equivalent performance at 700 mA

so you can cut your chip cost in half and still run 700 mA
 
M

Manfromthenorth

Well-Known Member
You can always dim them down there are conversion tables that will tell you what with what will give x amount of mill amps. This could be verbal diarrhea so proceed with caution.
 
CobKits

CobKits

Well-Known Member
if you want to put 12 cobs on a driver you can use a low voltage driver in parallel

then you wont have the voltage match issues and also you wont be running holders out of spec over 250V
 
V

VegasWinner

Well-Known Member
Nugtorrent said:
So, I've decided to delve into a 3x3 cob build and trying to maximize efficiency at the wall. I was hoping to pull off a HLG 320H-c700 with 12x CXB 3590's, but when I divide the forward voltage of the driver with 36v it comes out to driving 11.8888 cobs.

Whats confusing is when I calculate other drivers, they always seem to end up slightly lower.

Ex: HLG 185H-c700, forward voltage @ 286v, comes out to 7.94 cobs when divided by 36v. And yet almost every build with this driver/cob combination runs 8 cobs to that driver.

Are they slightly more powerful than listed? or is the minimum drive current of the cob closer to 35ish?

Thanks.

edit: Also debating a hlg 240h-c700 to run 9 cobs instead for the lower buildout price, that crunch says it can run 9.91 CXB's. would I lose efficiency not running the 10th cob?
Click to expand...
At the lower power the cree will deliver just below the 36v and 12 will work just fine. The 320H runs over 300w that measn 12 cobs will run at 25w and be just fine. @REALSTYLES does the same with a C700 driver. I also run C700 for veg, better than bright and lower amps too.
 
N

Nugtorrent

Member
Was looking up lights and stumbled on the timberlights web site, they got a citizen buildout, 300w 1.4a with 6 cobs for less than 500....that is really attractive. I'm finding it hard to find the individual pinned heat sinks at a decent price, most are 20-25 each. The kits seem decently priced.

Edit: Lies, priced it out.

I would prefer to run a 300w, 700ma light.

CobKits said:
no just driver cost

9 work better in a square anyway

also



you dont need to run citizens at twice the current to equal a cree

there are plenty of chips that cost half as much as a cxb and offer equivalent performance at 700 mA

so you can cut your chip cost in half and still run 700 mA
Click to expand...
What chip would you suggest for the 320H @ 700ma that is cost effective?
 
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Manfromthenorth

Well-Known Member
citizen 1212 they work well from what I can see here cobby speaks highly of them and so do many others here and are 14.75 plus when you order from cobby use the riu code, his customer service is the best I have ever had. My .02
 
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N

Nugtorrent

Member
Who is cobby?

Everywhere I look online the CLU 1212's gen 6 3500k's @ 90cri are sold out.....sucks :(

edit: Found cobkits.com and entered the RIU discount. went with CLU 1212's gen 6's at 80cri. Doing the mars 2 conversion that I saw growmau5 do on youtube, two panels running 6 cobs each. Eventually I might reuse the cobs for a proper build with some meanwell drivers and stuff. Thanks!
 
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