CREE CXB3070 + meanwell hbg-60 -1400 + MODULED MEGA 13450-B-HBG / COB PROBLEM

Hello.
Could someone help me to find the problem with this cob led?
with this set up , 2 of 4 units i have installed , are having problems.

is weird only two of 4 units installed are not working well.
other ones are working nice.

Could be a temperature management problem?
this is the second faulty unit , but still working fine .
the other one fi the half of the leds are not working, so i needed to buy a new one.

I m afraid to loose this one also. please any suggestion?


thanks in advance!

What kind of heat sink is that? thermal compound? fan on or off?

When i was testing my COBs I tried several temp tests just for kicks..
1) COB fastened to heat sink (active, CPU heatsink w/fan) with no thermal compound and no fan... temp got HOTTT (but shut it down before it fried). heat sink so hot could barely touch it.
2) COB with thermal compound and fan off,... temp got HOT, but less than 1st test, still too hot to handle... still shut it down after a few minutes
3) COB with thermal comp and fan on.. heat sink nice and barely warm to the touch.

so how hot does the heat sink get?

If i touch the heatsink. its hot but you can handle just for about 4 -6 seconds with both hands . so i think is too hot !?

measured temperature with my multimeter : heatsink is about 60-65ºcelsius.

used thermal pad as cree specs. 0,5 to 0.15 if i remember well.

thanks in advance!

https://led.cdiweb.com/ProductDetail/MODULEDMEGA13450BHBG-MechaTronix/574066/

this is the heatsink. I have been told is enough for this led with the hbg60.140 driver

tr909 said:

If i touch the heatsink. its hot but you can handle just for about 4 -6 seconds with both hands . so i think is too hot !?

measured temperature with my multimeter : heatsink is about 60-65ºcelsius.

used thermal pad as cree specs. 0,5 to 0.15 if i remember well.

thanks in advance!

Click to expand...

hmm not sure. not familiar with that driver. Heatsink seems up to snuff.

Guess it depends on where you're measuring the temps.. is there a temp probe point on that cob?

I would post this in the LED section, theres some very smart people there who can help you, your cob pictured looks damaged, did it come with those wrinkles or did you drop something on it?

To measure the temp , just put the probe direct to the center of the heat sink , do you suggest another thermal compound or other bigger heatsink?
specs of this heatsink Dissipated Power Pd: 57 W
My set up is 60w driver ( dimmed internal to 90% ) so it gives about 54W and the driver is not 100% efficient. so is giving about 50w.

i

I think the heatsink is enough for this set up . my be im wrong.

there is another heatsink :
https://led.cdiweb.com/ProductDetail/MODULEDMEGA134100BHBG-MechaTronix/574067/

Dissipated Power Pd: 75 W

but i think is not necessary .
what do you suggest?

nc208 said:

I would post this in the LED section, theres some very smart people there who can help you, your cob pictured looks damaged, did it come with those wrinkles or did you drop something on it?

Click to expand...

The cob is damaged after some moths of use. nothing dropped on it ,

tr909 said:

The cob is damaged after some moths of use. nothing dropped on it ,

Click to expand...

Months of use? Interesting, assumed these were just up and running. I found temps vary wildly depending on where you probe. Are you using a thermo couple? I'd say you got a dud, but the fact that two are messed up points to some installation issue. Either way. .. time for 2 new cobs.

5 -6 months of use.
im measuring with a multimeter with thermo probe.
is enough the heatsink im using?
thank you!

one question :
the two faulty cobs were installed just at the top of the closet , with poor ventilation as the image below ( right one)
that could be the problem?

the other ones are installed on different way as the image ( left side)

tr909 said:

one question :
the two faulty cobs were installed just at the top of the closet , with poor ventilation as the image below ( right one)
that could be the problem?

the other ones are installed on different way as the image ( left side)

Click to expand...

Too many variables... do you have an exhaust fan in your tent? Should be sucking out the hot air from the top/hottest part of your tent.

to be honest NO , and is a small closet ( 50x50cm ) , very small
this faulty cob is installed inside my brother`s closet, and im trying to find the problem.

I built four units , two for me and two for him , and only his cobs are not working well.
my set up is working fine , and my closet is bigger and better ventilation.

So i suppose the problem could be there.

My guess is those thermal pads aren't working. I had bad thermal results every time I tried to use them. This might be why they lasted a little while before going dead. I will only use thermal paste now. If you pull one apart and it doesn't look like the pad cooked to the chip or heatsink, then the pad isn't working.

nevergoodenuf said:

My guess is those thermal pads aren't working. I had bad thermal results every time I tried to use them. This might be why they lasted a little while before going dead. I will only use thermal paste now. If you pull one apart and it doesn't look like the pad cooked to the chip or heatsink, then the pad isn't working.

Click to expand...

Thanks for this , will try to pull one apart. and will take a look. ( before i will buy a good thermal paste) , and may be works better.
also a better ventilation inside the closet , because i don't think the problem is the heat sink. the cob led is working @54W ,

thanks so much !

FYI, there is group on facebook on DIY COB grow lights. I am considering building one as supplemental lighting.
https://www.facebook.com/groups/1126779020785389/?multi_permalinks=1168263106636980&notif_id=1515336718931685&notif_t=group_activity