Course of action in the event of a LED failure?

I have pontificated about backup for the things I carry in the event of failure. I have spare B90 battery sticks, LAs, and switch for my 9N. My only lithium battery powered incandescent flashlight, the ASP Taclite, carries a spare bulb at the end of its battery tube. More CR123s are in a Trekker. More CR123s are in a Time Capsule along with a second bulb and a switch cover. A backup switch assembly resides a stainless steel carrier.

I figure to be able to change ANY critical part in those two flashlight products WHEN they fail.

Before I jump on the LED flashlight bandwagon for "tac apps," I need to know what I can do if the LED itself malfunctions.

Please spare me the technical aspects of the VERY long lifespan of a LED, I won't understand it anyway. /ubbthreads/images/graemlins/smirk.gif /ubbthreads/images/graemlins/tongue.gif

If an incandescent bulb goes poof, I have the ability to easily change it if necessary. Can I do the same for a LED or do I have to submit it to the maker and wait a few weeks until they fix it?

damn.
i don't think i've heard of a LED going *poof*..

not including cases of them getting fried.

good question.

Well....if you had mad soldering skills...and can solder tiny contacts with bullets flying over your head...I can see carrying an extra Luxeon would be a good idea...

Besides that..I guess let's say in the example of a L4...you can carry an extra KL4......and replace the Z57 for a normal LOTC? That oughta safe proof it....but still..like blindedbythelite said....I don'tthink I've heard of LEDs going *poof*..nor even "crash"

Murphy has followed me a few times in my life. I TRY to be prepared when he's around.

haha. well maybe in the case of LED's, laws were indeed made to be broken. /ubbthreads/images/graemlins/grinser2.gif

Never had any soldering skills. Backup lights are always a good idea but it seems there should be something that an average user devoid of any technological skills can do to fix a LED flashlight if it fails.

The best way I'd know to draw a parallel would be between things like solid state radios and the older vacuum tube radios. At one time it was quite common for a radio to quit working. If you knew nothing of radios, you took it to the shop. Generally, you or the repairman would identify which tube had burned out and replace it. That didn't mean other things didn't malfunction, but it was generally a tube, or damage from the heat of the tube. Back then, as a backup, you might have some additional tubes, just in case.

Today, the vacuum tube has been replaced by a solid state semiconductor, the transistor. They don't burn out, since they don't require the heat to operate, yet they perform the same duties. They can go bad and stop working. But, it's due to factors other than is an anticipated result of it's operation.

Similarly, the incandescent lamp, which is a sort of vacuum tube also, has been replaced by a solid state semiconductor, the light emitting diode. Like the transistor, they don't burn out, since they don't contain a filament nor require the heat to operate, yet they too perform the same duties. They too can go bad and stop working. But it would also be due to factors other than is an anticipated result of it's operation.

Neither the transistor nor the LED is by necessity mounted on a "quick disconnect" connector like vacuum tubes and incandescent lamps. Some are, but not because it's replacement is assumed. More often than not, transistors and LEDs are hardwired into the circuit the same as other permanent components of a circuit.

Either can go bad, the transistor radio, or the LED flashlight. Backups of either, if needed, would more likely be an additional entire unit. Of couse some like an Arc or a Surefire are built in modular form to where the faulty module (head, battery tube, etc.) can be replaced.

That's a good analogy; vacuum tube vice transistor. I grew up when tubes were prevalent. I guess that's why I still like to carry my incandescent flashlights so much.

well. i had another reply here but it disappeared.

/ubbthreads/images/graemlins/icon3.gif

i mentioned the similarities between Surefire interchangeable LED heads, and replacing a bulb.. just carry an extra head for the body you have.

and replacing drop-in modules, such as EverLEDs, BadBoys or MadMaxes, etc.. just carry an extra drop-in module..

same principle as replacing a lamp/bulb.. they just don't store as easily.

Carrying an extra head would seem the way to go. Like the Surefire bulb and reflector LAs, they will require more space for storage than just a single bulb.

right.
maybe someone will design something to store an extra LED head or module.

however, 2:00AM isn't my brainstorming time of the day, so i'm gonna leave that to someone else.

Re: Led failures

I think the problem of worrying about LED failure is no different to worrying about weapon failure. It can and does occur! Whilst you plan for it and train how to deal with these problems you can never be 100% certain that you'll be able to avoid a failure. In these circumstances it is vital to have a back up plan. Heck, most electronic weapons systems have a lot of redundancy built into them incase of component failure. In the case of a LED light, IMHO the risk of failure is much less than with an equivalent incandescent. I almost always have two lights on me for just such an occurrence (and I dont work in a tactical environment). I would think in your case that the most prudent course of action would always to have available at least two lights?

Doug

Re: Led failures

i think it would be important to understand what makes incandscents and LEDs fail. note that whilst incandescent lamps will "burn out" and quit working instantly once the filament breaks due to prolonged use, LEDs will instead dim steadily throughout their lifespans.

with LED lights, instead of guarding against physical impact like you would with an incandescent lamp, you would have to guard against exposing the LED to reverse polarity, overpowering the LED and burning it up, and preventing the regulation circuitry from being exposed to an EMP strong enough to take it out.

to answer your question, i think most LED lights are by nature very resistant to failure, so your only backup would be to carry extra bezels if applicable, and extra lights if not /ubbthreads/images/graemlins/smile.gif

Re: Led failures

If the Led fails...forget it. Reach for your back up light...whatever that may be. Thats how to deal with Murphy...in this case anyway. You could carry an extra head I guess...but it would be expensive...

Re: Led failures

I have had 5 LEDs fail on me. All are 5mm. I got all of them from C. Crane. Every one of these went into strobe mode where none exists and never left (they are not supposed to strobe). All of the products were made by Tektite and are all direct drive. Not even a small resistor for protection.

1 PR base 2 LED 4.5 volt bulb
1 3 LED 4.5 volt bulb for petzls
1 CC Trek Light (2 LEDs)
2 CC Extremes (1 LED in reflector, focusable, 3C)

In each case, 1 LED failed (malfunctioned). Second Extreme was warranty replacement for first one, and second one went into garbage. There have been design changes since my experience. Perhaps this was more common a problem with Tektite products (too common). Certainly enough to warrant a design change (adding a circuit).

Once I put batts in the Trek, I will see which one is strobing, and snip it out of the light.

I haven't had a Luxeon emitter fail or malfunction on me. Perhaps this is due to better QC by the flashlight manufacturers. Neither have my my Lightwave Illuminator nor 4000 failed on me. Only those listed above, and the Extremes had less than 30 minutes use per light when the malfunction occured.

In the case of a L4, the KL4 is pretty small, so not a problem there...but with a L5 carrying an extra KL5 it would be like carrying a miniature beer can and L6 with extra KL6 would be.....a miniature pint beer can /ubbthreads/images/graemlins/smile.gif

now that's my analogy

Have a backup light, like what some here say. Then for your backup light, have a backup as well, and another to backup your backup backup light, so on and so forth... Always a good excuse for more lights!
Well, your backup may or may not be the same light, but make it something small that you wouldn't mind carry around as a backup. Anyway, most flashaholics I know carry more than 2 lights on them somehow or rather, so if all the lights really fail at around the same time when you need em, then you'd better start finding out what Murphy has against you!! /ubbthreads/images/graemlins/wink.gif

Re: Course of action in the event of a LED failure

_,

The likelihood of a well built LED light failing is so slim that I think a back up redundancy for this reason is unwarranted. A back up due to loss or damage in use is a different story. Due to their reliability and longevity most LED flashlights don't have user replaceable LED LA's. There are a few exceptions to this. Also one should consider that the life expectancy of a LED is measured in a half life and not in terms of catastrophic failure such as a bulb burning out.

The Pelican M6 is designed in such a manner that the LED module is user replaceable or at least I believe this will be the case when they come out. A couple of the Streamlight Luxeon lights also have easily replaceable LED LA's. If you are willing to go with a "garage shop" mod, I can set you up with a Pelican M6 and as many LED LA's as you want. These LA's are roughly the same size as the incandescent LA and can be interchanged at will, in the field, without any tools.

- Don

Re: Course of action in the event of a LED failure

I also had a 5mm LED go into strobe mode before failing completely. However this was in a flashlight I modded myself where it was directly driven by 3 N cells with no resistors or other circuitry. I always wondered if it was a bad LED or if the hardware I used was stressing it somehow. The replacement LED has worked fine for several months.

Re: Course of action in the event of a LED failure

If I may be so bold, lumping seriously overdriven 5 mm LED's in with sophisticated constant current LED circuits is not a reasonable catch all for the reliability of solid state lighting tools. LED's can suffer accumulative damage as well as catastrophic failure as a result of being subjected to too high of voltage. In addition to overvoltage from unprotected circuits, ESD can also shorten the life of unprotected LED's. The Luxeons have some built in protection whereas the 5 mm's do not. If a flashlight in hand becomes part of the path of static discharge, I would think it quite possible for a LED to suffer if it is "in the way".