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8X Diode Murder fund

Slipstream

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So i pushed another 8x that i have up to 460mA and got 658mw ,

I had to use my hand to block out some of the glare from the bluray from overwhelming the camera.

its an old iphone ;)

 



ossumguywill

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So i pushed another 8x that i have up to 460mA and got 658mw ,

I had to use my hand to block out some of the glare from the bluray from overwhelming the camera.

its an old iphone ;)

Oh jesus christ. is it degrading enough to be noticeable over 1 minute or less?

will
 

Slipstream

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No .

Why would it degrade over a 1 minutes time?

One thing ,i'd like to mention, is that ive noticed is that around this current (460mA) the 8x seems to bo "topping off" as far as power output.
 
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Slipstream

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Oh ok i thought you meant permanent degredation, it goes up and down by 1 mw back and forth, but i think the ambient temperature may be the culprit for that.
 

ossumguywill

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Oh ok i thought you meant permanent degredation, it goes up and down by 1 mw back and forth, but i think the ambient temperature may be the culprit for that.
Ok that's what I thought, yeah I just meant to ask if it was unstable. Sorry about that :D
 

Canuke

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Ah, welcome back Igor! Glad to see you back :gj:

My humble speculation re: degradations: :whistle:

The pattern of immediate degradation followed by levelling-off, reminds me of MTBF data for mass-produced hardware. You get an immediate loss of those items that were defective, followed by a long "quiet time", and then finally a slowly increasing death rate as the devices wear out.

If we extrapolate this as if specific points in the diode were like single devices, the initial degradations we are seeing are the failure of the spots that were "weak" from the factory. If that's what we are seeing, it implies to me that the "dead spots" don't spread after they die -- perhaps the mirror material is much more resistant to that now.
 

IgorT

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Sorry for the update delay. I suffered a bad computer crash yesterday and almost lost the 50 hour data. Luckily Excel is smarter than me and i managed to recover it from a hidden autosave file.

In the meanwhile the cycling went on uninterrupted and the diode has passed 60 hours, so i'm posting a double update.



First the 50 hour data:



Ith = 34mA
Slope Efficiency = 1.3mW / mA
Absolute Efficiency = 20.55% Avg.
Po @ 348mA = 410mW = 90.41% of Initial



The PI line is the yellow one between the 30h (red) and 40h lines (green).
Basically, the power is still a tiny bit higher than it was at 30 hours, with just a tiny bit of degradation since 40h where the power magically went up.



Next the 60 hour data:




Ith = 34mA
Slope Efficiency = 1.294mW / mA
Absolute Efficiency = 20.41% Avg.
Po @ 348mA = 409.65mW = 90.33% of Initial



This time the PI line is pretty much on top of the red one from 30 hours. And the diode is producing practically the same amount of power as it did at that time.

It's as if no degradation has happened in the last 30 hours. That of course can't be true, but the diode didn't lose much power after the first 30 hours. Degradation can still be seen, but in tiny drops from the unexpected jump between 30 and 40h.



Looks like the diode becomes very stable in power after the initial rapid degradation phase. I've never observed behavior like that before, altho it is true i never recorded it in this much detail.


At this rate, this diode has good chances of lasting much longer! It could easily reach or exceed 100 hours now, which is impressive for this amount of power!
 

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Slipstream

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one of my 8x's died today.

~460mA - had about 30 min @ that mA - sudden death while it was on. tried to revive , only to get blueray light on each side of the diode , nothing in the middle.
 

daguin

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one of my 8x's died today.

~460mA - had about 30 min @ that mA - sudden death while it was on. tried to revive , only to get blueray light on each side of the diode , nothing in the middle.
:cryyy::cryyy::cryyy::cryyy::cryyy:

Peace,
dave
 

Slipstream

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Yeah I know , so much for pushing the envelope. chalk another sacrifice for the cause
 

jayrob

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It's a bummer when ever a diode dies on you...

But an expensive one hurts!

You had to know it was coming though at that current...
 

Flaminpyro

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sounds like the die has come up off the base or heatsink, try decanning it and soldering it back down !

Pyro...


one of my 8x's died today.

~460mA - had about 30 min @ that mA - sudden death while it was on. tried to revive , only to get blueray light on each side of the diode , nothing in the middle.
 

IgorT

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The diodes have reached 70 and 210 hours!

I'll post a double re-plot and some pics in the morning.


At this point i have to admit, i underestimated the 8x's. If an initial 10% drop in power is acceptable, they can be exceedingly reliable even at very high powers.

No wonder it's possible to set them to 500mW and more. Once the final number of hours are known, we can make a guesstimated plot of approximate lifetimes at different power settings, including those higher than tested.

It won't be a guarantee for anything, nor all too accurate, but it will provide a rough idea of what to expect approximatelly...
 

Slipstream

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So i changed out my dead 8x , into a 12x , i just exchanged out the diodes.. its shooting out 640mw . i would have thought the 12x would have been putting out much more than the 8x.


i do have to say that in the minute on , minute off tests , it doesnt get as warm as the 8x did
 
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