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Chinese driverless COBs

BombBudPuffa

Member
Veteran
I have a few of these. I didn't use them long because they were nowhere near as bright as my citizens at the same watt but I'd say they're good for cheap supplemental lighting. Probably be great for veg.
 

methias

Active member
Died

Died

Thanks I sure hope I do too!!! Sorry to hear they've done so badly for you. Can you please tell me in what way they died? Did they just flat out stop working, burn up, develop dark spots, or what? What voltage and frequency is your AC? Do you have any idea what temperatures they were running at?

I would come to check on the girls and sometimes just dead. Sometimes flickering like a slow strobe. Their demise varied. I bought 4 50 watt 120 / 240 volt COBs. All running at 120 volts 60 hz screwed to aluminum heat sinks, with thermal paste (same I'm using now) and a 80x80mm cooling fan. 2 were full spectrum, 1 bright white, and 1 warm white.
Couldn't say exactly how long they lasted, but none made it through my grow.

With my 12 volt 350 watt power supply I'm doing some experiments with super bright strip leds right now. I just got a strip to test.
It has 42 white surface mount leds.
4000 lm
Viewing Angle 120
12 volt

They run cool.
I could just get a reel of it and wallpaper my hutch (32"x32"x80").

Still looking for top shelf 50 watt COB's
https://www.icmag.com/ic/showthread.php?t=355946
but strip leds might work.

Maybe the technology is better now than 18 months ago.
Good luck.
 

Klompen

Active member
Thanks for the info. I am definitely going to go way overboard for cooling. I can't see any reason they'd fail sporadically other than heat issues if they don't die immediately from manufacturing flaws. I'm going to make some large copper plates, probably about 3x4 inches or so that each COB is attached to and then the copper plates will attach to an aluminum structure with a large surface area and fans on it. I strongly suspect that keeping them cool is extremely vital for their longevity. I have seen an implementation of these that used water cooling but hopefully I don't have to go that far.

I may try one technique I saw where this Youtuber took a rectifier circuit and fed it with a large potentiometer. He was feeding it about 80V AC and the rectifier circuit was spitting out about 110V DC with only a 1V up and down ripple. He does high speed photography so that flicker they had was a big no no. I wonder if I could use a couple appliance capacitors and some other parts I have to build a similar setup. Hopefully that won't be necessary immediately though because I have an epic workload on my hands right now. We just got a new property so we can finally stop being homeless and we're building a small home ourselves and we have to do all the site prep. Plus, I have a hernia right now. Good times right?
 

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