Safelight LED life...will it die?

I finally got my first safelight from a trade..feel like need a few more, and i think my MUM likes it..asking more questions then usual...i think the glow mode is very intriguing..

BUT, the Nichia in there is rated to run for 100,000 hours.That means, 11 years contantly (assuming you change batteries every year and then leave it in glow mode). My question is, does that mean it will die after that? so essentially a safelight is only good for 10odd years because we can leave it on?

Crenshaw

ummm i didnt think it possible to leave even LED's on for over-extended periods of time. I think youd easily burn out the unit due to heat over time, rather than it living out its normal lifespan

The level that the LED glows is so LOW that I doubt it produces heat. I have a few from long ago and I don't notice any degradation in brightness. I'll bet they are about 10 years old and are the type you can't turn off completely, unless you remove the battery. It is the light that got me into LED's, long before I became active in CPF.

The fact that it can run for about 2 years [in glow mode] on one battery is an indication of how little current it uses.

As far as I know, the rating is given for the LED driven at what the manufacturer considers a 'normal' current. The safelight in find-me mode is running the LED so dimly that it would probably last a lot longer than that

And assuming that you did somehow run the LED CONSTANTY for 10 years at the normal (not glow) current, it won't simply die. It will just have some % decrease brightness compared to when it was new.

Marduke said:

And assuming that you did somehow run the LED CONSTANTY for 10 years at the normal (not glow) current, it won't simply die. It will just have some % decrease brightness compared to when it was new.

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And that percentage will be lower with a lower drive current.

I just cant seem to justify keeping it in glow mode all the time when its usually in my bag in an easily accesible inner pocket anyway..

I dunno, im reallly paranoid that my LEDS will eventually give out, which is why i bought a maccapsule for my long bow, im not using my ARC-Ls, etc etc...Am i being overly worried about this?

Crenshaw

Crenshaw said:

I just cant seem to justify keeping it in glow mode all the time when its usually in my bag in an easily accesible inner pocket anyway..I dunno, im reallly paranoid that my LEDS will eventually give out, which is why i bought a maccapsule for my long bow, im not using my ARC-Ls, etc etc...Am i being overly worried about this?Crenshaw

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I used to have a safelight but hated the fact that you could not turn it off (on newer models you can). It uses almost no current and so has almost no effect on emitter life, however it can be annoying if you are trying to be covert or if you just do not need that feature. As far as degradation...........I doubt that the "glow" feature would produce any measurable effect on emitter lifespan over a human lifespan. Some of the new models (where you can really turn it off) are still nice lights IMO. They are super durable and have really long runtimes........especially with lithium 9v batt's.

An LED decreases in brightness exponentially over the course of it's lifetime. 50,000 hours to 70% brightness (the "standard" claim for high power LED's) assumes normal currents and adequate heatsinking (this is by far the most important aspect). If there is little heat (as with the safelight), then the emitter should run it's course- that is, decrease in brightness at a decreasing rate. It won't just "pop" and loose it's magic smoke, if that's what you're thinking, it will get gradually dimmer, until eventually it's giving out no light.

crenshaw: 50,000 hours for high power LED's translates to about 5.5 years of constant use. Only those light's you can't turn off will be affected by this, no matter who is using them. Let's say you use it for 2 hours a day (which is a lot to put on 1 light), then you can expect 66 years of life until your average high power emitter drops to 70% brightness. Even then, it'll slowly decrease in brightness. It's hard to give a guestimate (as emitters themselves will also vary), but if something exponentially drops to 70% after 50,000 hours I'd guess it'd drop to 0% after 80,000 (complete guess, nothing to do with extrapolation, etc.), which is over 100 years at 2 hours/day.



I'd guess that running an LED at a lower current will increase its life, as that seems to make logical sense. Has there been any research done on this?

Guys there is simply no need to worry about burning out your led. Or for that matter even using them so much that there output is diminished just do the math they will last darn near forever!

Which Safelight model do you have? As someone mentioned, you can turn the "find me" mode off on the newer models. When the light is in the "find me" mode, just hold the button down until it turns off.

Randy

Oh i know you can turn it off, I am just wondering about the effect the glow feature has on the LED, as the glow feature IS meant to be left on

Crenshaw

I wouldn't be worried about the LED on the find me mode. Furthermore it wouldn't be that hard to just drop in a new 5mm LED if they exist years and years from now if it were to fade away.
I agree with others that the life hours is for the led driven at spec, and the find me mode on the safelights is so minuscule that I doubt it would affect the led's life in any noticeable way.
That said I have a CPF safelight from witt's end (and I'm sure he still has more available over on cpfm) and I keep it off instead of find me mode out of personal preference. Mostly because it sits right by my head as I sleep at night. I've been contemplating dropping an SMJLED in there but haven't made the time yet to try and figure out how to take the thing apart.

Crenshaw said:

I just cant seem to justify keeping it in glow mode all the time when its usually in my bag in an easily accesible inner pocket anyway..

I dunno, im reallly paranoid that my LEDS will eventually give out, which is why i bought a maccapsule for my long bow, im not using my ARC-Ls, etc etc...Am i being overly worried about this?

Crenshaw

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Yes, you are

You should use you flashlights, certainly not worry about the LED dying from normal use. Now, if the LED is being way overdriven or has a very poor thermal path, you might not use it for hours on end, but you're much more likely to have the switch or switching mechanism stop working than the LED itself.

Don't start a thread about switch lifespans now, please.

no need, we already have the

"surefire tailcaps :thumbsdow"

thread....:duck:

lol, anyway, dont you just hate those post office slips that tell you you have to go down there and get the package? argh, ill just have to go before work tomorrow

Crenshaw