Lighting My DIY COB Setup (in the making)...

[BigSm0]

This was discussed on a different forum. Either Cree is exaggerating their numbers or citizen is very conservative. I think allot of it has to do with testing temperatures. I also read about high temp spot testing and long term testing. You would think comparing 2 companies that basically sell the same thing would be much closer. The 1212 at 500ma should be 63% according to cobkits.

 

[Site]

100% working in the engineering industry i know how false manufactures information can be on fans and pumps etc so LED's and lighting with 'false' figures wouldnt surprise me at all...i suppose the only way to test them is to get PAR readings from a light fitting with the same driver, wiring, layout, heatsinks etc so its jus the COB's that have changed and use a meter to measure how much power is being drawn and if the PAR readings can be matched etc...either way you can tell they must run more efficient than HID lights due to the heat given off...i do always wonder if the lamp manufacturers 'falsify' their lumen outputs as well....as i dont see how a 400W lamp can emit 55,000 lumens when its only 30-35% efficient...

 

[BigSm0]

ill get some numbers by the end of the week. I have tested the citizen but not really done any specific mapping yet. My new lights will hit the online market soon and I'll surely need the numbers. I will have to do them bare as the bjb holders for citizen will give them a significant boost. The ideal holders with reflector adapter is a pile of crap. You could probably grow a plant with stray light.

 

[Site]

haha yea i wont be using any reflectors on mine...im too cheap and not sure what the gain would be apart from directing the light downwards a bit more...but i dont mind as light should reflect off the inside of my tent back onto the plant and im hoping my coverage will be good enough to not need it...

 

[Druid]

haha yea i wont be using any reflectors on mine...im too cheap and not sure what the gain would be apart from directing the light downwards a bit more...but i dont mind as light should reflect off the inside of my tent back onto the plant and im hoping my coverage will be good enough to not need it...

Why reflectors? Because inverse square law. Your tent walls are way out there.

 

[BigSm0]

I only use them in certain situations myself. Cobs are directional and optics decrease the total ppf. Par mapping with reflectors are very scattered since they bounce off them and shoot in all different directions as well as help focuse the light. Bjb holders have a small reflector on them while the ideal don't unless you add the adapter. That adapter never sits even and light shoots out all over the place.

 

[Site]

Why reflectors? Because inverse square law. Your tent walls are way out there.

yea i thought this but i was thinking similar to what bigsmo has said about LED light being directional...i just hope that it would be directional enough to not require them...

got some updates on my light after starting over a month ago...drilled all the holes to fit the CPU heatsink brackets...was a bit painful to get these lined up properly...partly due to me being a bit slack with all my measurements and drilling really...

also im not a bit paranoid that the bottom side of cpu brackets may block the light from the COB...im hoping its so close the light will go straight through and shouldnt have dispersed much to hit the bottom of the bracket...im actually more paranoid about a build up of heat and being a fire hazard than the small loss in light...

hoping to finish this up tonight....just need to attach the driver, just gonna use metal cable ties, was going to go a bit fancier but realised it wil do the job...then its just wiring and connecting up the CPU cooler fans to the fan controller and its ready to put in the tent...ive germed some seeds ready and waiting now....im still really hoping this gives me enough light in my 0.8x0.8m tent...i keep judging the output on lumens but it still gives me over 750 PPFD from the calcs...

 

[The Elvis]

 

[wayward1]

That's a lot of work you've put in there and looks good. Hope it pays off but if you did want/need more light in the future you could buy second driver and drive half the cobs at 1.4 amps or higher.

 

[Site]

That's a lot of work you've put in there and looks good. Hope it pays off but if you did want/need more light in the future you could buy second driver and drive half the cobs at 1.4 amps or higher.

thanks for the kind words! i think if i want or need some extra light I will go with a Meanwell HLG 320 C1050B and run them at 1050mA. This would drop the efficiencies of the 3070 and 3590's by 3/4% but would give me a total lumens output of 54,650 with a total PPFD of 1103.67 which may actually be a bit too much...will see how my first run with it goes...if i feel like i could do with some more light I will swap out the driver...ive got a spare HLG-185-C700A driver at home that i got for cheap on ebay so I was almost tempted to add extra heatsinks and run extra cobs if need be...was thinking i could run another 4 No. 72V cobs off it or something to save on quantity of CPU fans etc needed so would hopefully fit onto the frame ive already got built...