High End COBs vs $2 COBs...

MMJ Dreaming 99

MMJ Dreaming 99

Well-Known Member
CobKits said:
drivers are what you make of it. if efficiency is not your concern there are tons of cheap ones out there. might as well run the cheapest cob you can at full blast at that that point because a lot of those drivers are 80% efficient vs meanwell hlg at 92-96%

i think the $0.30/W for meanwell HLG is a steal as they last forever and you can hose them down
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If I email you at your site - can you give me a parts list for what is needed in Citizen COBs to take on a 1000 watt HPS for flower (3000 or 3500K)? O think that would be a good addition to your web site.
 
CobKits

CobKits

Well-Known Member
MMJ Dreaming 99 said:
If I email you at your site - can you give me a parts list for what is needed in Citizen COBs to take on a 1000 watt HPS for flower (3000 or 3500K)? O think that would be a good addition to your web site.
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9 cobs at 75W each, ~$550 including shipping and $30-$40 to build a frame. drivers have gone up a little since i did that screenshot as i went thru the huge stash of overstock.

i hope to have frames soon if i can get the cnc mill up and running
 

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muleface

muleface

Well-Known Member
@CobKits on the Getian 2828's in the 37.5 range, what did you say the l/w were at 45-50 watts?

also, this was a good discussion thanks for everyone's input...

I do have another question.

if i had 2 drivers and 4 - 36 v cobs, what is the difference here....

HLG-240H-C1050 running 4 cobs
HLG-240H-C1400 running 4 cobs

would it make any difference using one driver vs the other?
 
CobKits

CobKits

Well-Known Member
Well sure its considerably different in both efficiency and output wattage to run cobs at 1050 vs 1400 mA. and you can put prob 5 on the 1400 and 6 or 7 cobs on the 1050. overall wattage will be similar, but the 1050 will be more efficient (at teh cost of more cobs/holders and potentially heatsinks depending on your setup
 
muleface

muleface

Well-Known Member
CobKits said:
Well sure its considerably different in both efficiency and output wattage to run cobs at 1050 vs 1400 mA. and you can put prob 5 on the 1400 and 6 or 7 cobs on the 1050. overall wattage will be similar, but the 1050 will be more efficient (at teh cost of more cobs/holders and potentially heatsinks depending on your setup
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but if you were just running 4 on each driver, would it matter?

either way, could you provide a deep dive explanation on this? Honestly, i would like to see something like that here posted as sticky on the front page of the LED forum. Its the questions everyone asks and they get explained all over this forum, but in one off discussions. Not in a central place where everyone can just point to it for newbies.

I get how FV and wattage work.

an HLG-240H-c1050a puts out 119-238v so you could run 6 - 36v cobs on this in series. 238/36=6.6111 each cob would run at 40 watts (probably a bit more, i've noticed that a 240h will put out more then 250 watts)

I think in this setup each cob is running at 1050ma, if you did the same setup in parallel each cob would run at 175ma?
 
CobKits

CobKits

Well-Known Member
start by looking up actual forward voltage at the current you want to run at. Vf at 1050 will always be lower than 1400 for any chip

or you can use the easy way- the tables at ledgardener.com

muleface said:
I think in this setup each cob is running at 1050ma, if you did the same setup in parallel each cob would run at 175ma?
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if you did the same setup in parallel it probably wouldnt light up as youd be below the minimum driver voltage of 119V or whatever
 
Budies 101

Budies 101

Well-Known Member
From my understanding a cheap cob can be less than half as good as a good/decent cob. Basically, to get the same growth you will be running near 2x the watts and heat just to save what, 20-30% of the build cost? I mean, you will still need a driver and heatsink (possibly bigger heatsink) and all other minor cost parts. If that's the route you;re going, why not just take less risk of poorly made cobs and just use HPS/MCH?

I'd suggest buying mid grade cobs before buying trash cobs... Buy somthing you know lights up. I believe you can get cax3070s (top bin) for like 15$ off kingbrite, that's like 60$ for 4... That's a 240 watt possible light for apporx 200$. Again, if you buy 2 dollar cobs it might take you 8 to get near the same growth, double the heat, double the watts, more heatsink and who really wants to grow under blurple?

I don't know much about other Cobs but Citizen look good too and are way less $$.

You don;t HAVE to grow with CXB3590's top bin to grow extremely well, it's mostly for efficiency at that point and really only slightly better in the end.

Feel free to correct me if I'm wrong.
 
xX_BHMC_Xx

xX_BHMC_Xx

Well-Known Member
My CLU038s were $7 a pop, come from a quality manufacturer, and deliver 160lm/w(ish) at 700ma. Plus they're good all the way up to like 2.1a. I see no reason to waste money on low quality parts, regardless of where they come from.
 
muleface

muleface

Well-Known Member
xX_BHMC_Xx said:
My CLU038s were $7 a pop, come from a quality manufacturer, and deliver 160lm/w(ish) at 700ma. Plus they're good all the way up to like 2.1a. I see no reason to waste money on low quality parts, regardless of where they come from.
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can you give us a link to the specific chips you are running. $7 seems like a really good price.
 
nfhiggs

nfhiggs

Well-Known Member
Budies 101 said:
From my understanding a cheap cob can be less than half as good as a good/decent cob. Basically, to get the same growth you will be running near 2x the watts and heat just to save what, 20-30% of the build cost? I mean, you will still need a driver and heatsink (possibly bigger heatsink) and all other minor cost parts. If that's the route you;re going, why not just take less risk of poorly made cobs and just use HPS/MCH?

I'd suggest buying mid grade cobs before buying trash cobs... Buy somthing you know lights up. I believe you can get cax3070s (top bin) for like 15$ off kingbrite, that's like 60$ for 4... That's a 240 watt possible light for apporx 200$. Again, if you buy 2 dollar cobs it might take you 8 to get near the same growth, double the heat, double the watts, more heatsink and who really wants to grow under blurple?

I don't know much about other Cobs but Citizen look good too and are way less $$.

You don;t HAVE to grow with CXB3590's top bin to grow extremely well, it's mostly for efficiency at that point and really only slightly better in the end.

Feel free to correct me if I'm wrong.
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The perceived shortcomings of the "trash cobs" are greatly exaggerated:

1. Yes, they are less efficient - 100-110 L/W or so at full power compared to 150 L/W or so for the "good" cobs. But if you run them at 30-50% you can get into the 120-130 L/W range - not fantastic but comparable to MH/HPS efficiency. So the whole "twice the watts and heat" is just an exaggeration. They will run fine on "regular" sized heat sinks.

2. The supposed reliability issues are also greatly exaggerated thanks to one youtube video. I've purchased 20 of these and have not had one issue with any of them - NONE. They work. They have been working continuously for 6 months now.

3. They come in warm white, they are not all "blurple".

Cheap cobs are a good way to get your feet wet, and experiment a bit to find out what works and what doesn't, instead of simply following the herd. The great thing about the 2 dollar cost is you can easily replace them later with more efficient cobs and not feel like you're throwing away a ton of money.
 
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