cree led lumen drop off

do your Cree lights look dimmer over time?

  • yes

    Votes: 1 20.0%

  • no

    Votes: 4 80.0%
  • Total voters
    5
Tim Fox

Tim Fox

Well-Known Member
Way back before I built my diy cree cobs light with cxa3070 s I purchased some cree bulbs with standard light sockets thinking I could grow with a bunch of cree bulbs, but I was taught quickly around here and I returned twenty cree bulbs to home depot, but I kept a few of the bulbs and put them in places around my house,
I have noticed that the cree bulbs are not as bright as when they were brand new, they are about 1.5 years old
Can i expect my Cree cobs to have a fall off in light intensity as well?
 
Uberknot

Uberknot

Well-Known Member
Tim Fox said:
Way back before I built my diy cree cobs light with cxa3070 s I purchased some cree bulbs with standard light sockets thinking I could grow with a bunch of cree bulbs, but I was taught quickly around here and I returned twenty cree bulbs to home depot, but I kept a few of the bulbs and put them in places around my house,
I have noticed that the cree bulbs are not as bright as when they were brand new, they are about 1.5 years old
Can i expect my Cree cobs to have a fall off in light intensity as well?
Click to expand...

I would guess it depends on how hard they are driven and how hot they get.
 
NapalmD

NapalmD

Well-Known Member
It's funny you say that Tim, from my experience it seems like my cxa's have gotten more intense and brighter over the years as weird as that sounds and I never touched the dimmer once since the day they were built. I remember reading a while ago about the the possibility of them getting brighter and it sounded like b.s. but I think it rings true in certain circumstances.
 
Tim Fox

Tim Fox

Well-Known Member
This is the bulbs I think they are nine watts? But the bulbs look dimmer to me , so I wondered if the cobs would do the same?
 
JorgeGonzales

JorgeGonzales

Well-Known Member
This should make you feel better, it basically says that you can go at least 6-7 years at 18 hours a day, 85C before seeing a 10 percent drop.

And that number gets bigger as more hours are tested and they can extrapolate further out, probably landing around 8 years, and even longer when you factor in the lower temps you are surely running yours at.

Lightbulbs are a compromise, especially thermally.

image.jpg
 
Abiqua

Abiqua

Well-Known Member
Tim, how is the fixture located. That can have alot to do with it.

Also may be a cap going out on the driver. Weakest link in those bulbs.

Heatsink is really just the pcb as well, no dedicated heatsinking was ever used aka fins, just lumps. That's a sure bottleneck in some situtations.

I still use them faithfully after 3 years? only in a clone box and around the house, but I still haven't had one fail in any k temp out of 20 or so. :peace:
 
DesertGrow89

DesertGrow89

Well-Known Member
Tim Fox said:
Way back before I built my diy cree cobs light with cxa3070 s I purchased some cree bulbs with standard light sockets thinking I could grow with a bunch of cree bulbs, but I was taught quickly around here and I returned twenty cree bulbs to home depot, but I kept a few of the bulbs and put them in places around my house,
I have noticed that the cree bulbs are not as bright as when they were brand new, they are about 1.5 years old
Can i expect my Cree cobs to have a fall off in light intensity as well?
Click to expand...
Take light measurement readings when you first get them, and then take them at whatever intervals you want I think that would be the best way of finding out!
 
Tim Fox

Tim Fox

Well-Known Member
Abiqua said:
Tim, how is the fixture located. That can have alot to do with it.

Also may be a cap going out on the driver. Weakest link in those bulbs.

Heatsink is really just the pcb as well, no dedicated heatsinking was ever used aka fins, just lumps. That's a sure bottleneck in some situtations.

I still use them faithfully after 3 years? only in a clone box and around the house, but I still haven't had one fail in any k temp out of 20 or so. :peace:
Click to expand...
This is all good to hear, now I can just run the grow box over and over
 
frica

frica

Well-Known Member
Drop off with a proper heatsink should be very low.

Bulbs generally have much worse thermals, super small heatsink, enclosed, driver is also enclosed next to the heatsink and less efficient than good meanwells (most likely)

I bet money on it that the average COB on the average DIY set up runs cooler than a Cree bulb.
 
captainmorgan

captainmorgan

Well-Known Member
I've bought 20+ Cree bulbs and still use them 3+ years later. I've only had 1 fail and that was shortly after I bought it so it must have been defective,don't know if they are still the best bulb out there tho.
 
G

grouch

Well-Known Member
You might want to stop staring at your cobs lol. Maybe its your vision getting worse (hopefully not). But the household bulbs are engineered horribly for heat dissipation and I wouldn't doubt if they are getting worse. All the cheap led household bulbs I put inside enclosures failed fast. The ones I ran open fixture are still working
 
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