Are LEDs really all that durable?

Art Vandelay

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Can you imagine what the reaction would be if an LED flashlight could only run 20 to 30 hours at best before burning out, like an incan? In addition, let's say these LEDs were just as likely to break when dropped as incans. What it would it be like if LEDs were just as likely as incans to insta-flash when turned on for the first time?

LumaPower and AmiLite have models with modular LEDs. The AmiLite has something very rare, a copper heatsink.
 
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ah-see

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Newbie a while ago did a very nice thread on LEDs and found that some of the earlier LED lights when overdriven degraded in output within a few handfuls of hours.

The first white LED's were not that bright so folks thought if you took a 100,000 hour white LED and over drove it by 2x, even if it lasted only 10,000 hours, folks would be happy. But--in real life, these LED's quickly degraded in output. (tried to search for thread with a sectioned white LED with brown damage in the phosphors right next to the die--but I did not find it).

So--there was (and still is) some bad experiences with LED's that were caused by improper use (overdriven, poorly heat sinked, no regulation, mechanically unsound mounting/manufacturing, etc.).

-Bill


Check out this link, it should help you with your brown phosphor question.
 

BB

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Thank you Ah-See,

That was the link I was looking for... Reading through the link and looking at the pictures, it appears that even current 5mm leaded white LEDs with epoxy encapsulation will not have near the life advertised.

From the micro-photographs, it almost looks like the phosphors+light+heat is acting like a catalyst and browning the Epoxy/Phosphor amalgam right at the boundary of the LED die.

Just right "next door" on the copper slug, where one would assume that the temperatures are virtually identical and there is phosphor/Epoxy mix right on the surface of the copper--there is no browning evident at all.

Lumileds using silicon as the encapsulation material has avoided much of this problem.

Anyone know what the new Cree's use as encapsulate or ran any accelerated aging tests (high current / high temps)?

-Bill
 

matrixshaman

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I've had LED lights since the late 80's IIRC when the very first white (more bluish than white but headed in the right direction) 5mm LED's and none have ever failed or burned out unless I fried them with incorrect voltage while experimenting. I've had other flashlights since the 1950's and nearly all of them had bulbs burn out - and some fairly fast. When Mag Lights hit the scene and I started getting MiniMags they burned out often and some from a mere low drop. LED's are way longer lasting and depending on how they are driven and how often used most will probably outlive you! Are there cheap setups that fail or poor soldering jobs and other problems? Of course but the LED itself if good quality will outlast the Energizer bunny a thousand times over. :D
 

cave dave

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Can you imagine what the reaction would be if an LED flashlight could only run 20 to 30 hours at best before burning out, like an incan? In addition, let's say these LEDs were just as likely to break when dropped as incans. What it would it be like if LEDs were just as likely as incans to insta-flash when turned on for the first time?
Gee, that sounds just like some of those "drop shipped from china for dirt cheap" lights that seem so popular around here.
 

Martin

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I'd prefer that LED products were advertised with their actual useful life and marketeers learned to do without the 100,000 h figure. In the long run, it's for their own sake as with growing popularity of LED lighting, more people will check if they get what has been advertised.
I'm looking forward to the LED bulb test that Stiftung Warentest (Germany) plans to do.
 

ringzero

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I can't think of that many and the ones I can think of have really poor heatsinking. (aka Maglight, Streamlight) And most of them are just retrofits to old halogen designs not really a ground up well thought out design.


Underwater Kinetics, Streamlight, and Pelican plastic body lights are not really poorly heatsinked. These lights are heatsinked sufficient for their light engines to run with high reliability at outputs of 40 to 60 lumens, which is what they are designed to do. The big MagLEDs have similar design constraints, although not because of plastic bodies.

I'm not greatly interested in buying higher output lights, but out of curiosity I do read the CPF threads on them. So, although I can't provide specific models off the top of my head, I have read reviews and analysis of them.

Wolf Eyes is the first that comes to mind. Wolf Eyes offers several heavy, aluminum-bodied lights with field-replacable light engines that are well enough heat sinked to run for hours at 120+ lumens, IIRC. There are similar higher ouput LED lights with field-replacable light engines available from other manufacturers.

For my L1T I carry a backup light engine, switch, and 2 batteries, It's called an L2T. :rolleyes:


It's always good to carry a backup light.

Especially, you need a good backup when your main light source may SUDDENLY STOP WORKING after being dropped onto a hard surface. And, after it suddenly stops working, there is no way to repair it out in the field.

Doesn't happen often, but there are plenty of reports of this happening to Fenix, Inova, even Surefire LED lights.

I carry and use Fenix, Streamlight, Inova, and Gerber lights that don't have field-replacable light engines.

So far, none of these lights have let me down out in the field. However, I carry these lights with the knowledge they aren't as ultimately reliable as my lights with field-replacable light engines.

.
 

2xTrinity

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With incans, I'm used to flashlights being near 100% reliable. If it doesn't work, change the batteries or bulb - that's it. Now we're stuck with sealed heads that don't allow you to change or repair LEDs (unless you want to freeze-pop the thing). I like that the Streamlight ProPolymers allow you to disassemble the head and even swap out the LED modules. I even like Maglite's solution better - a LED module that you can swap with the incan bulb in the tailcap.
I believe that components like LEDs should always be easily swappable -- as easily as unscrewing a light bulb, except in rare cases such as 1xAAA keychain lights where that might add unacceptable bulk to the light (even then, not having loctite on the head is still a big plus).

The reason is not just for the sake of the light-engines breaking, but also that newer more efficient modules come out later, the old lights could be upgraded without compromising the warranty and possibly the durability of a light due to a kludgy emitter replacement job at home. I expect the LEDs coming out 3 years from now to put the current stock to shame (as in double the present efficiency with much improved spectrum)

Another great feature I would love with some of my LED lights would be the ability to use different kind of LEDs interchangeably (such as a warm white, red, or UV modules)
 

Curious_character

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Glad to finally see a thread like this. I started the thread mentioned in the first post about my bad luck with Inovas. I agree with the posts blaming the electronics in the light vs the actual LED itself.

With incans, I'm used to flashlights being near 100% reliable. If it doesn't work, change the batteries or bulb - that's it. Now we're stuck with sealed heads that don't allow you to change or repair LEDs (unless you want to freeze-pop the thing). I like that the Streamlight ProPolymers allow you to disassemble the head and even swap out the LED modules. I even like Maglite's solution better - a LED module that you can swap with the incan bulb in the tailcap. Get the LED performance with a backup bulb. (I know there's no heatsinking and performance drops off quickly, so please no Mag bashing - there are enough threads like that already). I just want the performance and efficiency of LEDs with the simplicity and reliability of incans.
You might be a good candidate for a direct drive light. The secret to incandescent reliability is the minimal number of parts and connections. A regulated LED light is relatively complex, which in itself reduces the reliability considerably. But a direct drive light is about as simple as a common incandescent and, if you use NiMH or lithium cells, the light output is at least as constant as an incandescent.

There's no fundamental reason that a regulated LED light can't be made to be extremely reliable. But you're not likely to find really high reliability in the low cost consumer grade lights. Even the cheaper incandescent lights are terribly unreliable. I can't remember how many times I swore at a flickering incandescent light, banging it on something solid until the light would, momentarily, brighten up. I finally bit the bullet and paid about five times as much for a Maglight, and never looked back. It's unrealistic to expect either cheap incandescents or cheap LED lights to be exceptionally reliable.

c_c
 

asdalton

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You might be a good candidate for a direct drive light. The secret to incandescent reliability is the minimal number of parts and connections. A regulated LED light is relatively complex, which in itself reduces the reliability considerably. But a direct drive light is about as simple as a common incandescent and, if you use NiMH or lithium cells, the light output is at least as constant as an incandescent.

Quality of design and workmanship can vastly change the probability of per-part or per-connection failure, and therefore swamp the effect of different numbers of components.

I have seen only two flashlights fail by burnout of the LEDs themselves, and those were both direct drive. One was the old Nightbuster 8X, which had no regulator or resistors other than the batteries themselves, and the other was the SL Propolymer 7LED, which had resistors that were too small. Lights equipped with power LEDs like the Dorcy 3D should be more forgiving.

My switch failures are mostly limited to cheap incandescents purchased in stores. I also had to send my Pelican 2390 back for a flickering problem that was probably related to the switch. A couple of Mini-Mags deteriorated in performance slowly over the years due to oxidation of the switch contacts.

Electronics failures that I've experienced were almost exclusively limited to the Arc AAA (2003-4 era).
 
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