Build Your Own LED Grow Light

blazinlow said:
So bear with me as I have no experience with LEDs. I have a small 2x2veg tent for cloning/veg that I bought some cob lights for. I got luminus cxm22 gen 3s and a hlg-240h-c1400b driver. I was originally planning 3 lights on this driver but ended up buying a 4th led/ heatsink etc as it was free shipping over 220$ so basically the 4th light was free. I'm confused now what the best route is. I don't think I can run the 4 lights on the driver I purchased but unsure? Any advice? Should I just keep the 4th as a spare? More I'm researching this the more confused I am and thinking I should have chosen different cobs altogether possibly. Thanks
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no bud, you cant, only 3. You want to use the 320h-c1400 ($88 ) model, plus you can max out the 1400B for 300 watts (75watts each) or the 480-c2100 ($144)for 120 watts each, but you need active cooled heatsinks,

You could use the 3, no problem, they would do very well in the 2x2.. Luminus are awesome cobs,
 
Mayne said:
no bud, you cant, only 3. You want to use the 320h-c1400 ($88 ) model, plus you can max out the 1400B for 300 watts (75watts each) or the 480-c2100 ($144)for 120 watts each, but you need active cooled heatsinks,

You could use the 3, no problem, they would do very well in the 2x2.. Luminus are awesome cobs,
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Thanks for your reply. I'm happy to stick with the 3 as that was my first plan it was literally at checkout I noticed the shipping was the same price as getting the 4th assembly and buying the 4th assembly made the shipping free. Again thanks for your advice.
 
blazinlow said:
Thanks for your reply. I'm happy to stick with the 3 as that was my first plan it was literally at checkout I noticed the shipping was the same price as getting the 4th assembly and buying the 4th assembly made the shipping free. Again thanks for your advice.
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your going to love them, here is about 275 watts of 4, this is day 49 from seed, started 12/12 ,,day 21 official flower
day49-day21flower-fri3.png
 
Mayne said:
your going to love them, here is about 275 watts of 4, this is day 49 from seed, started 12/12 ,,day 21 official flower
day49-day21flower-fri3.png
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Looking great. I'm just using mine for cloning and veg and then they go into my 4x4 rdwc 1000hps tent to flower. I'm planning on switching my 4x4 to a 4x8 for my next grow as with the dwc and 4 plants I can't get to the rear spots. At that point I might switch to LEDs also but it's pricy for a 4x8 and power draw isn't a huge concern for me so I might just get another 1000hps for now. Again thanks for your replies
 
I added a picture of what I'm thinking about doing for the flower tent to give me full access to 4 plants in the dwc with w scrog. Any opinions on the layout and would 2 1000watt hps bulbs be too much? I also have a 600 I could add another if it's better. Thanks
 

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So the new light is working well but I'm not sure it's as bright as it should be. Is using 51.5volt cob chips causing me to only get half the output? Can anyone tell me what wattage I'm getting to each light? Thanks for any help
 
No, a very small change in voltage can cause a very large change in current. Multimeters are relatively cheap. You can buy a suitable one for less than $10USD. Some tool rental shops, and hydroponic shops may actually have a light meter available for rent. A PAR meter would be best.
 
that was comparison with the Perfect Sun mini, but i used it on my luminus cobs, and the numbers also matched. I had to use a milk gallon cap to make up the height difference with the meters, so they were level with the surfaces of the meters. add 10% to get pretty close to apogie 500
 
I'll have to look into getting one. I wasn't super concerned at this point. More just trying to figure out if I'm getting 20 watts or 70 watts lol. Seems if a meter is the only way to get a idea it would be quite difficult to plan out a large build as it could end up half the power expected. Thanks again for your input all
 
get a kill-a-watt meter, like $20 ZON. plug you light into it and tells how much power your using
 
blazinlow said:
So the new light is working well but I'm not sure it's as bright as it should be. Is using 51.5volt cob chips causing me to only get half the output? Can anyone tell me what wattage I'm getting to each light? Thanks for any help
Click to expand...


Do you have a potentiometer on the driver?



You can find the actual power draw with calculations based on the info in the datasheets for the COB and the driver.

This is not a business of throwing chicken bones and guessing :) it's electricity and it's based on logical mathmatics.
With the right numbers the calculations will be close to spot on every time, you just have to know how to find those numbers ;)

COB:

Max. current = 2,2A
Forward Voltage = Min. 48V, max. 55V

Driver:

1,4A max. current
Output voltage 89V - 179V
Efficiency 94%


CXM22gen_FC_vs_FV.png

CXM22gen_FC_vs_FV.png


So, ~53,2V @ 1,4A, right?

53,2V * 1,4A = 74,48w DC -> 74,48w * 1,06 (driver inefficiency factor) = 78,95w AC draw per COB -> 78,95w * 3 COBs = 236,85w AC draw total with driver maxed out.




You can calculate the total Lumen output as well, which can be useful when comparing LED units.

CXM22gen3_RLF_vs_FC.png

CXM22gen3_RLF_vs_FC.png


CXM22gen3_TypRLF_vs_CCT.png

CXM22gen3_TypRLF_vs_CCT.png



Looks like 123% to me, so just multiply the Typical Luminous Flux in first column based on your model of COB with 1,23 and then multiply by number of COBs.

So if you use 3 of the 3000K 80CRI: 8285*1,23*3 = 30572 Lumen if the junction temperature is below 85°C .
 
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