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445nm been running all day at almost 1.1W

ndrew2505

ndrew2505

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i have a diode in a big block of alum hooked up to a 1400ma amc7135 driver from DX powered by a 5v 2A wall wart plug(old psp charger).. when i got up this morning i went to package some orders for the shop and cut a switch on that turns most things on for my work bench. that just happened to include the laser... i guess i forgot to cut it off b/c its been running all day(~8am-4pm) outputting a little less that 1.1W...(somewhere ~ 1.075W) :D
 





Holy shit, running continuously all day? I guess this diode is thougher than most people thought.

btw 1.1W sounds way lower than you'd expect at 1,4A. 5V is probably too low.
 
I've got two on my lifetime test rig that have been running 24 hours a day for over 4 weeks straight, one @ ~800mW and the other at ~1W. They're both still going strong with no observable degradation.
 
im pretty sure its not getting the whole 1.4A from the driver. i dont have a test load thats made well enough to measure that high of a current though. when i had it hooked up to a computer psu instead of the old psp charger is was doing 1.1W+. the charger actually puts out 5.2v and ive also had one of the fans from the a130 blowing on the alum block all day. the fan is powered by the 5v wall wart as well.
 
That's really good to hear. I may ultimately turn mine up.

-Trevor
 
These diodes seem to be very durable thus far.

If you check here, directed from photonlexicon:
445nm laser diode

All efforts and credit to Krazer at PL, he says he has ran 1.5A for over 48 hours straight on a 30C coldplate.
He also boosted the current to 2A for some time (check the page)
My very early experiments (and possibly a little premature) suggest huge or active heatsinking required for extended usage above 1W. The Nichia specs (well, the specs on the 9mm version of the same diode) recommend Max operating temp of 30C and they rapidly reached above that.
Perhaps some others might be able to chine in on extended usage on high powered (over 1.0A-1.5A) in their DIY handhelds?
 
erm.. why don't you check post #3... my 1W is running at 1.26A right now, it's got roughly 865 hours on it. Of course, the performance of one diode means little, but they really do seem very robust.
 
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Yes Electro I saw that, and I appreciate your response.
However a test rig isnt a handheld.
Without knowing what kind of heatsinking you have on said test rig, and anticipating that the said test rig would have superior heatsinking than a small piece of passive metal you would find in a handheld, is why I mentioned experiences with heat on high powered handhelds would be appreciated. Personally, I found a 20mm dia x 25mm long piece of alumium reached approx 40C in about 30 seconds at just over 1A. I didnt want to push it for any longer than that without knowing what temps the diode can handle.
Thanks.
 
You're going to be hard pressed to find a handheld with that kind of time on it.. if the diode will last 865 hours running CW in my test rig with zero degradation, it'll last nearly a lifetime in a handheld that gets run primarily in short bursts. Heatsinking is irrelevant, all that matters is that there is some. In the projector these diodes reportedly reach upwards of 80C.. that's hot. I didn't measure mine, but the array got quite hot to the touch. The projector claims a lamp lifetime of 20000 hours. Basically, unless you're running these at 2-2.5A or more in your handheld you're good for an extremely long time, barring a fluke diode..
 
It all depends on proper cooling people!

Assuming the equilibrium temperature is in the "safe" range, they should last for 10s of thousands of hours at up to 1.4 amps.

So this does not mean you can simply turn up the power on your handheld without problems. I've got a pretty small CR123 build and even though its a Ehgemus host with good heat-sinking I limit the duty cycle to about 1 minute because after that it gets pretty warm, and that's only at 800mA. If the outside of the host is warm than the diode is hot. Then the heatsink is saturated with heat and thermal conduction from the diode to metal slows down to the rate of the thermal transfer from the metal to the air. In other words, when the heatsink is cold, it will draw the heat out of the diode even if the heatsink gets no ventilation. Once the heatsink and diode are at about the same temperature then the diode will really start to pick up heat unless the heatsink can get cooled by convection.

They're only gonna last at >1amp currents if you can keep them cool.

-Tony
 
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I have a "GIGANTIC" piece of aluminum and some artic silver compound ready. I dont think 20lbs of aluminum should be a problem to keep a diode cool....
 
Xplorer877 said:
It all depends on proper cooling people!

Assuming the equilibrium temperature is in the "safe" range, they should last for 10s of thousands of hours at up to 1.4 amps.

So this does not mean you can simply turn up the power on your handheld without problems. I've got a pretty small CR123 build and even though its a Ehgemus host with good heat-sinking I limit the duty cycle to about 1 minute because after that it gets pretty warm, and that's only at 800mA. If the outside of the host is warm than the diode is hot. Then the heatsink is saturated with heat and thermal conduction from the diode to metal slows down to the rate of the thermal transfer from the metal to the air. In other words, when the heatsink is cold, it will draw the heat out of the diode even if the heatsink gets no ventilation. Once the heatsink and diode are at about the same temperature then the diode will really start to pick up heat unless the heatsink can get cooled by convection.

They're only gonna last at >1amp currents if you can keep them cool.

-Tony
Click to expand...

yes but if they are reported to be ok at 80 deg C you will be unable to physically hold the pointer before you reach critical temperatures ;)

that being said, do you really need >1W in a pointer?

1W of laser light is pretty hazardous, even reflected power from shiny objects could pose a vision hazard... I know its been said a million times on here, and I really don't want to preach, but seriously guys think about what your playing with before you turn them up to 11 ;)

even I personally would not feel comfortable waving around a 1W pointer and I was just working on my q-switched laserscope earlier (you want to see a laser light anything on fire? this is it lol... but she needs a new KTP :()
 
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