DiY LED - Cree CXA3070

nevergoodenuf said:
@SomeGuy- I really think your build is the way to go (running parallel), minus the Vero13. I like the Vero 29s:mrgreen:. Have you noticed any of your COBs brighter than another? I haven't. Are you going to build your next light in series or parallel? Parallel, is so much easier. Chose the wattage you want, and add COBs until you are happy with the efficiency or add more as you can afford them. This gives us the option of the HLG 320-36 and the HLG 600-36. One driver and simple wiring. Sorry I keep pushing this subject, but I don't think it is necessary to play with 200+volts with 18g. and smaller wire. I haven't heard anyone have any troubles running in parallel.
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that's what I've been looking for. thank you!
 
HEY STOP RIGHT THERE BUDDY!!!!!!!!! NO NO NO NO.

No parallel. I have a parallel light, here's the problem. Thermal runaway!!!!! When you have constant current (series), the temperature of each dice does not affect the voltage drop across each chip. In parallel, when temperature increases, resistance decreases, so the one chip that gets the hottest will be receiving a disproportionate amount of voltage!

That being said, my light has been on 18 hours a day for two years now, so it isn't going to kill your build necessarily. It's just one chip is slightly brighter and warmer than the others, I know it'll be the first to go, but whatever. I made my money back the first run haha.
 
And let me be the first to admit it, I did a build using 18g stranded wire with CXB 3070s @ 1400mA, those wires were on fire within minutes of plugging it in!!!!!!!! DON'T USE 18G STRANDED WIRE!!!!!!!!!!!!!!!!! I USED TWO DIFFERENT BRANDS, YOU WILL BURN YOUR SHIT DOWN!!!!!!!!!!!!!!
 
Queece said:
HEY STOP RIGHT THERE BUDDY!!!!!!!!! NO NO NO NO.

No parallel. I have a parallel light, here's the problem. Thermal runaway!!!!! When you have constant current (series), the temperature of each dice does not affect the voltage drop across each chip. In parallel, when temperature increases, resistance decreases, so the one chip that gets the hottest will be receiving a disproportionate amount of voltage!

That being said, my light has been on 18 hours a day for two years now, so it isn't going to kill your build necessarily. It's just one chip is slightly brighter and warmer than the others, I know it'll be the first to go, but whatever. I made my money back the first run haha.
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JuanCastro said:
On YouTube, growmau5 video talks about parallel, definitely worth the watch.
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thanks guys, I know that. but reading that a lot of guys didn't had a problem after all.
I do want to run them @ ~20w each. so i guess a slight thermal runaway is not so bad even if it happens.

btw, are COBs running more efficient the first ~30 seconds before they get hot? are there any charts for that?
the idea is to switch between cobs every n seconds to increase efficiency, reduce heat and spread the light more evenly ( like a non moving light mover)
 
Herbal_Essence said:
thanks guys, I know that. but reading that a lot of guys didn't had a problem after all.
I do want to run them @ ~20w each. so i guess a slight thermal runaway is not so bad even if it happens.

btw, are COBs running more efficient the first ~30 seconds before they get hot? are there any charts for that?
the idea is to switch between cobs every n seconds to increase efficiency, reduce heat and spread the light more evenly ( like a non moving light mover)
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Yeah dude, that is the case! That's what I use, I have five drivers hooked up to this bad boy:

http://www.rapidled.com/coralux-storm-led-controller-with-10v-analog-converter/

It does rapid switch-dimming with the variable cloud density setting!
 
Queece said:
And let me be the first to admit it, I did a build using 18g stranded wire with CXB 3070s @ 1400mA, those wires were on fire within minutes of plugging it in!!!!!!!! DON'T USE 18G STRANDED WIRE!!!!!!!!!!!!!!!!! I USED TWO DIFFERENT BRANDS, YOU WILL BURN YOUR SHIT DOWN!!!!!!!!!!!!!!
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18 gauge stranded wire should have been enough for cxb 3070s @1400ma. there must have been something else going on.
 
Yeah, cheap ass chinese wire from Lowes! I took the insulation off to see what happened, there wasn't even copper in sections of the wire!!!!!!! What the hell is that about?!?!?! Some of the length of wire was broken internally, and where there should have been copper, it was talc. I checked the continuity on my multimeter, and the wire didn't beep, but I just assumed my multi was cheap. Lol. I would just recommend using 16awg or 18awg solid-core. Just be safe guys, the extra couple bucks could save your house, your grow, and your life.
 
And the scary part was, it was on and running fine for five minutes, then I started smelling bacon. Just be careful, you don't have to be the guy that fucks up to wind up burning your house down. Shift-change at the cable factory? Sorry about the smoldering wreckage that was your house!!!
 
I have been reading and have yet to find any information on how the HLG A series drivers work. They supposedly have an internal potentiometer, but how would one adjust it?
 
there's a little mini-phillips pot adjustment under those little silicone dots. You just yank them off with your fingernail.
 
Queece said:
Yeah, cheap ass chinese wire from Lowes! I took the insulation off to see what happened, there wasn't even copper in sections of the wire!!!!!!! What the hell is that about?!?!?! Some of the length of wire was broken internally, and where there should have been copper, it was talc. I checked the continuity on my multimeter, and the wire didn't beep, but I just assumed my multi was cheap. Lol. I would just recommend using 16awg or 18awg solid-core. Just be safe guys, the extra couple bucks could save your house, your grow, and your life.
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Electricity travels on the surface of the wire. Multi strand wire has a higher surface area than solid core and can handle more current load. Your wire may have stretched during manufacturing or sometime after causing the break or it was just cheap crap. Always use good quality wire. It has become common for cheap wire to skimp on the copper such as 18ga worth of copper in a 14ga wire casing being sold as 14ga.
 
Dude, I'd say a good 75% of 18awg wire, or at least what's labeled 18awg, is strait up 20awg with 18awg cladding. Lot of bogus shit out there man, I've found 16awg is usually harder to counterfeit.
 
I've had a lot of problems with shitty speaker wire too, I think it's just a sign of the times. Thanks slave economy.
 
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