LED lamp life

[GrayHare]

My first LED lamp is dying at age 7 years. It now flickers when turned on and the light output has decreased. The bulb was rated for 50000 hours but I got only 15000 from it. What percent of expected life are others getting from LED lamps?

 

[braumeister]

It's highly variable, but the ones you buy today are much better than what was available seven years ago.

 

[CRLLS]

I don't keep track of which bulb was bought when. Mine certainly last longer than CFL's! I've had some in landscaping lighting that have been going for about 5 years. They run between 3 and 6 hours per night depending on the season. We replaced the incandescent bulbs that burned out every year.

 

[Sunset]

I don't track them, as they last so long and I only switched over from CFL's in the last 2 or 3 years now that the cost is $2 each or less.

All I know is one was flickering, and I took it out of the lamp, wiped the metal bottom and screwed it back it in and it has worked flawlessly for months.

 

[target2019]

(8) 60-watt equivalent LED bulbs cost about $20 at BJs. Expected life 20,000 hours.

The testing and lighting standards change, so it is hard to tell why one particular bulb failed. How built, housed, temperature, etc. all affect life.

We have a a very old CFL in a table lamp. The fixture is a monstrosity. But it is definitely more than 25 years old. It is not used for more than a few hours each day.

 

[Chuckanut]

Here's what I was told about estimating bulb life. The manufactures set up a test of 100 bulbs, turn them on and start counting the failures. When the failures hit 50, that number of hours is assumed to be the 'average' and is what they publish.

Is the above true? I have no idea.

I do know that most of my CFL's seem to get less than the advertised life, though they still last a lot longer than incandescent bulbs, and use much less electricity. LED bulbs I suspect will vary with the brand since the electronics are often the most vulnerable point from what I understand.

 

[braumeister]

Here's an interesting article from the NY Times in 2009:

How Long Did You Say That Bulb Would Last?

But what does a 25,000-hour life mean? As it turns out, no one is quite sure yet. The definitions surrounding LED lamps, a nascent technology, are still being made up as we go along.

When a manufacturer says that an LED lamp will last 25,000 or 50,000 hours, what the company actually means is that at that point, the light emanating from that product will be at 70 percent the level it was when new.

Why 70 percent? Turns out, it’s fairly arbitrary. Lighting industry engineers believe that at that point, most people can sense that the brightness isn’t what it was when the product was new. So they decided to make that the standard.

And from another more recent source:

Moreover, an LED bulb's lifespan is practically infinite. Manufacturers typically estimate a bulb's lifespan based on three hours of use per day. By that measurement, an LED bulb will be as good as new for at least a decade, manufacturers say. Under the same conditions, an old-fashioned lightbulb may work for only about a year before burning out.

 

[ERD50]

Here's what I was told about estimating bulb life. The manufactures set up a test of 100 bulbs, turn them on and start counting the failures. When the failures hit 50, that number of hours is assumed to be the 'average' and is what they publish.

Is the above true? I have no idea. ...

No, it's not true. It has nothing to do with failures. See braumeister's post about LD70.

And a further clarification. Don't expect the LED bulbs to last anywhere near their LD70 rating. The problem is there are electrolytic capacitors in the switching circuits. Those caps degrade over time, and heat is their enemy. While LEDs produce less heat than a filament bulb, it is still enough, and contained enough when you cram all that in the size of an Edison style bulb, to lower the life of those caps.

I don't have time now, but I could provide some detailed technical articles on those caps and the temperatures in the LED bulbs. It's not a pretty picture.

I'm looking forward to getting past the idea that the LED has to be a direct replacement for the Edison bulb. If we put the power circuitry in the base of the lamp, for example, and just the LEDs where we want light, the heat would be isolated, and all those components will be happier. I plan on building a few of these for myself from components (strip LEDS in a lamp, small/cheap 'wall wart' style power supply in the base. Sometimes, with new technology, you need to break away from the old paradigms.

It's a shame that the marketing of these 'lifetime' ratings is allowed. When you set up someone for this artificial hope, then they are disappointing in the technology, instead of being thrilled with it.

-ERD50

 

[RobbieB]

I'm thrilled with LED's, they work great and use less energy. The price continues to drop as the tech gets better and the manufacturing gets bigger.

Only 15,000 hours eh? Bummer.

When was the last time a filament bulb lasted that long? And cfl's take an annoying time to get bright.

The future is LED!

 

[GrayHare]

Only 15,000 hours eh? Bummer.

When was the last time a filament bulb lasted that long?

For the price of this one LED I could have bought a couple dozen incandescent bulbs, the total of which would have lasted much longer than 15000 hours.

 

[RobbieB]

By all means then, use incandescent bulbs forever.

 

[ERD50]

I'm thrilled with LED's, they work great and use less energy. The price continues to drop as the tech gets better and the manufacturing gets bigger.

Only 15,000 hours eh? Bummer.

When was the last time a filament bulb lasted that long? And cfl's take an annoying time to get bright.

The future is LED!

I agree that LEDS are the future (and pretty good at the present). But don't expect 15,000 hours out of them That's a scam, won't happen (unless maybe it's kept in a -30C environment with plenty of air circulation).

LEDS are still problematic when it comes to dimming. Some work pretty well with some dimmers. The same dimmer may not work with a different LED brand. Color is a bit of a problem still, but getting better.

-ERD50

 

[6miths]

We had 60 w equivalent LEDs on sale for two months at Costco this fall for 75 cents a bulb. Hard not to bite the bullet at this price point.

 

[Sunset]

At the rate my CFL's and LED bulbs are lasting, I will never need to buy another..

 

[target2019]

At the rate my CFL's and LED bulbs are lasting, I will never need to buy another..

This is something I've noticed. When we moved into our house of many light fixtures, keeping incandescent bulbs in stock was a chore. Now we go long periods, and the stock of CFLs stays constant as I find LEDs that have better form for an application.

 

[bUU]

We lost an LED within a few weeks, and lost another (that had been in another socket) within a few weeks of swapping it with the dead LED. LEDs bulbs are susceptible to vagaries of insult put to them by poor quality lamps, just like any other electrical device. Their average lifespan doesn't take into consideration such imperfections in the environment within which they need to operate.

 

[gerntz]

I don't expect to have to change our LED bulbs in our high ceiling recessed lights ever again.

 

[folivier]

A couple things I like about LEDs are being able to get different colors of light (we like 4000k), less energy usage, and like gerntz not having to change the bulbs in the 11' ceiling cans as often. Oh yeah and trying to find incandescent bulbs that aren't halogens.

 

[travelover]

At the rate my CFL's and LED bulbs are lasting, I will never need to buy another..

I'm at that point with my CFLs. Costco had a partnership with the electricity supplier and sold them dirt cheap. I bought about 4 or 5 boxes which now are ironically obsolete as LEDs become cheap. I rarely replace a CFL.

 

[ArkTinkerer]

Three quick items from an engineer who used and abused LEDs as part of my job for a number of years--

LEDs, properly driven, have their life rated by when light output goes to half. Most will not burn out if driven at reasonable levels.

The LED bulbs you buy have circuits that convert the AC to DC to drive the lamp. There are components in these circuits that will likely fail long before the LEDs.

Lastly, I hate to disparage my profession but seldom are LEDs driven at reasonable levels (you get more light driving them hard). Seldom are the power circuits designed well with lifespan in mind. Many just don't know how to do it and the parts that will last longer cost more. These bulbs are designed for higher output at lower cost and built in countries known for substituting the cheapest part they can find--especially if it is not visible to the customer.

Replaced most of my household bulbs with LEDs and same for my mother. She has had to replace a number of bulbs. CREE had a guarantee so she would call and they sent her a replacement no cost. Most people probably didn't keep the packaging but mother and my wife did. Takes a week or two but those but they will honor the guarantee.

 

[Lsbcal]

For the price of this one LED I could have bought a couple dozen incandescent bulbs, the total of which would have lasted much longer than 15000 hours.

Have you added in your savings from reduced power consumption?

I just bought a few LED's to replace CFL's as they burn out. The 60W incandescent equivalents (10W actual, Philips) at Home Depot were $5 each for a pack of 2.

 

[RobbieB]

Yeah the above 60 vs 10 watts over 15,000 hours is 750 KWH. At 10 cents per KWH it's seventy five bucks.

 

[Beldar]

For the OP...

Our home is nearly totally LED. We have one lamp that has been ON continuously for over 3 years, no failures.

The only downer for me, as a SWLer and Ham Radio operator, is the RF noise generated by the lamps (in close proximity). So, no LED lighting near the radios. I can't control the noise pollution from the solar arrays in the neighborhood thought.

_B

 

[GrayHare]

Have you added in your savings from reduced power consumption?

This particular old LED lamp replaced a quasi-nightlight where I'd previously used a 15 or 25 watt incandescent. I bought this LED during the 2000-aughts in part to learn about the technology. It was sold as equivalent light output to a 40-watt incandescent, but to my eye it turned out to be more like 20, hence its relegation to quasi-nightlight duty. The color was very blue too. As we know, subsequent to the 'aughts LED price has come down, brightness increased, and traditional color (temperature) is available.

 

[JoeWras]

I think ERD50, ArtTinkerer and I have had a bit of experience in product engineering, and we have all experienced a bit of the old "lies .. and statistics" issue.

I take these numbers with a grain of salt. They may be quoting the light output numbers, but those are useless if the device fails. Somewhere in this mix I'm not sure if MTBF is being calculated. (Mean Time Between Failures).

There is a whole procedure for this measurement, which I doubt the cheap manufacturers are honoring.

In any case, MTBF calculation involves dealing with "bathtub curves" and normalizing things based on that. Devices need to be put into ovens to artificially stress the circuitry by running it at high temperature. You cannot just turn it on and see what happens because you can't wait 15,000 hours to do the test.

As ERD50 points out, the other circuitry is the problem, and it will fail. Many of us have boat-anchor LCD TVs due to a 10 cent capacitor failure. LED bulbs will have the same issue.