Lifetime on LED?

[SnowJim]

Hi!

I know that LED should last long, but how long are you expecting it to last? And is it possible to switch it when its finished?

BestRegards
SnowJim

 

[DM51]

Welcome to CPF, SnowJim.

I'll move your thread to the section where LED emitter characteristics are discussed.

 

[LEDninja]

I know that LED should last long, but how long are you expecting it to last?

It depends on the type of LED and how it is driven and what heatsinking it has.

Nichia developed the 1st 5mm LED and their testing showed UNDER IDEAL LABORATORY CONDITIONS it should last 100,000 hours (~10 years). Unfortunately 5mm LEDs are never used in ideal laboratory conditions for lighting and usually dim to 1/2 brightness in 6 months, useless in a year. In many bad designs they are dead in 2-3 weeks.

Power LEDs are better. I had some 1 watt bulbs running 24/7 last 3 years before I replaced them with brighter 2 watt Crees. The 1 watt bulbs showed no signs of dimming at that point.
Luxeon Is, Rebels, Cree XR-Es, SSC-P4s, Osrams should last 50,000 hours (~5 years) if driven at 350 mA or less. Many flashlight manufacturers drive these LEDs to 1400 mA and lifetime is shorter.
Luxeon IIIs and Cree XP-Gs should last a similar time if driven at 700 mA or less.

And is it possible to switch it when its finished?

All LEDs for lighting are soldered so you need good soldering skills to replace an LED.

 

[John_Galt]

It can also depend on other things. LED's need heat they produce to be pulled away. I believe most Cree LED's are rated to slowly dim to 70% original output, after ~50,000 hours, if the LED's temperature is kept below 80*C.

 

[Hugo2x]

:welcome:


LED's last very long, for how often 90% of the population uses there flashlights (5~25 a year), it is practically for ever.

This is from my on anecdotal findings of people who are flashlight enthusiast.

 

[SnowJim]

Thanks!

If it brakes, is it possible to switch it? For example on a Lenser P7 or fenix LD20?

 

[spencer]

Yes you can replace it but you will NEVER have to replace it. Unless you supply an LED with too much power and make it go POOF, it will take probably 50 years of nonstop use before it goes out completely.

 

[JohnR66]

It depends on the type of LED and how it is driven and what heatsinking it has.

Power LEDs are better. I had some 1 watt bulbs running 24/7 last 3 years before I replaced them with brighter 2 watt Crees. The 1 watt bulbs showed no signs of dimming at that point.
Luxeon Is, Rebels, Cree XR-Es, SSC-P4s, Osrams should last 50,000 hours (~5 years) if driven at 350 mA or less. Many flashlight manufacturers drive these LEDs to 1400 mA and lifetime is shorter.
Luxeon IIIs and Cree XP-Gs should last a similar time if driven at 700 mA or less.

I believe the white XR-E is rated to last 50,000+ hours to 70% lumens at 700ma. Looking at their "Long Term Lumen Maintenance" paper, it is a little more complex than that. To get 50,000 hours at 350ma would mean lots of abuse with heat according to the graphs.

 

[Gunner12]

Let's say you use the light for 8 hours a day, and will replace the LED after it drops below 70% of beginning output and the LED will last for 50,000 hours before it gets to 70% output. 50,000/8=6250 days, or 17 years and a month and a half of use before the LED gets to 70% output. The light will still be quite usable after this point. Unless you abuse the LED, I wouldn't worry about it failing.