How fast do white LEDs age?

[Davidc]

I've tried to find this out in manufacturer's data but no joy.

I put 2 'new' Electron Micro 4 lights on my bikes today.

With the same batteries transferred to the new ones they were significantly brighter than the old ones.

This design is a couple of years old and I'm reasonably sure they aren't made any more. If so the LEDs should be identical. (The old lights were geting tatty and the covers a bit loose fitting, so I bought two more as straight (least hassle) replacements as I've been pleased with reliability and brightness as be seen lights).

These lights have done a fair bit of service - estimate around 500 hours -and are about about 3 years old but I wouldn't have expected any loss of light output yet.

 

[gaz]

The lifetime of a LED light is normally rated over 25,000 hours and up to 100,000 hours.

Where the 'new' lights bought at the same time as the old?
Manufacturers often update the components of lights year on year.

 

[totallyfixed]

I have a friend who makes his own lights and has a doctorate from Cambridge [he lectures in engineering] who tells me that led's actually get brighter as they get older.

 

[Globalti]

You are probably seeing the result of 2 years of technological development. LEDs are one of the fastest developing technologies around at the mo.

 

[subaqua]

we had some that yellowed within 6 months of install. twice. manufacturer of units and LEDs are still trying to work out what problem is !!

 

[albion]

Manufacturers of LED backlights for TV' struggle because efficiency has increased so much less are needed and TV's sell less anyway.

Its a technology arms race and also why LCD TV's are now so low wattage for their large size.

 

[Kestevan]

If the old lights have been exposed to the elements for the last 2 years I'd expect that there could be a noticable drop in clarity of the plastic lense covers.

Micro scratches and discolouration from weathering can build up quite quickly on soft plastic.

 

[ColinJ]

If the old lights have been exposed to the elements for the last 2 years I'd expect that there could be a noticable drop in clarity of the plastic lense covers.

Micro scratches and discolouration from weathering can build up quite quickly on soft plastic.

I suffered from that problem with a front Cateye light which I used to carry about in my bag. When I came to use it, the lens had a circular scratched area in the centre and that created a noticeable dull spot in the beam.

 

[Davidc]

Interesting.

I don't know whether these new ones are recently manufactured or not. The light type is still around (hence me being able to buy them) so it's possible they are newly made, and that the new LEDs are brighter. These lights are on the bikes whenever they are on the road - they're the ones I use in daytime as well as at night - so will have been exposed to plenty of UV. It's not the plastic covers/ lenses as I've kept the one from the Dawes as it has black tape to stop the light shining at me on pitch black lanes.

The old ones aren't dim and are now in the spare parts box - still dazzlingly bright in fact - but the new ones are significantly brighter. if I'd kept the old ones going I have no doubt the rubber seals and plastic covers would give up long before the LEDs! The switches are also getting dodgy on the old ones.

Pity I can't donate the old ones to some of the Ninja light free zones I see riding around - they'd certainly be a big improvement there!

 

[Zoiders]

I find it's simple corrosion and oxidation of the contacts that seem to create a less bright LED light and not the LED it's self.

 

[Wobblers]

Would the LEDs in your light be the small 5 mm ones?

If they are, they're rated for 10,000+ hours life at a low drive current. The thing is, just about every light that uses 5 mm LEDs overdrives them to get more light, and that kills them very quickly. 500 hours use sounds about right.

 

[Davidc]

They are the 5mm ones. I've never measured the current, and don't know the specific LED type so wouldn't know if they were overdriven or not.

I asked the question from interest rather than because I'm too concerned. Those lights are less tha a tenner and good value if they last me 3 years. I'll get concerned if I notice either the CYO60 or the Hope V1 getting dimmer as they are real money.