LED LIFE SPAN

[ejgaribaldi]

DOES BLINKING WHITE LED LAST LONGER THAN NON BLINKING LED WITH SAME SPECIFICATIONS?

 

[Marduke]

Firstly, :welcome:

Secondly, please turn off your caps lock.

Thirdly, blinking an LED has absolutely no ill effects on it.

 

[bhvm]

A Blinking LED may last longer that steady lit one, Esp when overdriven.

It has the time to cool off for the fraction of Second,before going lit again.

 

[StarHalo]

One post after a year of membership?

 

[Patriot]

Ok, now that I've had my fun.........:welcome:


A LED will theoretically last twice as long if it's blinking with a 50% duty cycle. Since they already last an amazingly long time it's sort of a non-issue. Were you asking the question for any particular application?

 

[richardcpf]

Has anyone ever burnt out a led because of the lifespan?

A blinking led can provide longer lifespan, but that doesn't mean you should use strobe or sos to get your flashlight to last 20 years...:naughty:

Remember this: leds have infinite lifespan. unless you use the same led nonstop for many many years. which won't happen.

 

[kramer5150]

Has anyone ever burnt out a led because of the lifespan?

I have an XRE-R2 DIY that I was using in a poor thermal conducting host, running at 1400mah as a constant-ON task light. I think it has dimmed significantly over the past 18 months of use. This one was used as my garage task light... changing oil, sparkplugs, water-heater..etc...

FWIW, this particular light draws about 1.5A at the tailcap from a trustfire 18650. Its not as bright as my more recent Q5-WC builds.

I also have a Q2-DIY mod running direct drive off some of my higher resistance 18650 cells (intentionally to limit current) and it also is not as bright as it used to be. I did a ceiling bounce comparison with an M60 some time ago and I think it was in the ~150 Lumen ballpark when it was new. Its not nearly as bright as it once was, but its still bright enough to be serviceable.

Q2-DIY-DD

M60

 

[lrp]

Good to know!

 

[importculture]

Burnt out an L4 and have numerous fenix P2d's that have dimmed. But since a new model appears every couple of years or so I constantly rotate out older models. I know they say led's last for thousands of hours but I would love to know how much they decrease in brightness over a certain period of time. My old fenix's were used everynight sometimes for hours on end depleting used cr's and some have dimmed to nearly half of a unused fenix of the same model. It'd be great for a cpf'er to try and tackle this mystery.

 

[HKJ]

I know they say led's last for thousands of hours but I would love to know how much they decrease in brightness over a certain period of time.

The decrease in brightness is considerable faster if the led is running at elevated temperature. The specification might say: "When run below 80°C, the led will maintain 70% output after 50000 hours", i.e. it is safe to run the led die at 80°C, but above that value the lifetime will shorter.