Electronics > Projects, Designs, and Technical Stuff
New LED lights reliability
3roomlab:
--- Quote from: texaspyro on February 10, 2019, 05:02:38 am ---
My LED bulbs are old-school models with massive, very heavy heat sinks. Their light output is around 70 lumens per watt. Their light output exceeded the incandescent / halogen bulbs that they replaced. I have had one running 24/7/365 for 10 years. I have a sophisticated integrating sphere setup that can measure light output and color temperature. Periodically I check that bulb for light output... it is still virtually the same as when I first installed it... LEDs seem to be quite a bit more stable over time than originally predicted.
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how many watts are these 10year life par20s LED?
texaspyro:
--- Quote from: 3roomlab on February 10, 2019, 05:09:20 am ---how many watts are these 10year life par20s LED?
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8 watts, 550 lumens
I also have 45 Phillips 10 watt, 500+ lumen MR16 bulbs that replaced 50 watt halogens. They have a small fan in them! I expected to have noise and lifetime problems with them but I have never had to replace one and cannot hear the fan from 6" away.
My lightbulb changing stick is a very lonely tool...
3roomlab:
did you know how heavy was the heatsinking for those? like how much you think it weighs in your hands? 0.3kg ?
a fan that last years, the only one in my house that does that is KDK, that wont fit in a lamp :-DD
Kjelt:
--- Quote from: djacobow on February 10, 2019, 01:08:52 am ---Oh, FFS no. If you have to explain how a particular lightbulb works to Grandma Jones, then you have failed. Your lightbulb has failed. Your product is a failure and it deserved to fail. It's as simple as that.
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There are and always have been tens/hundreds of different bulbs with not only different wattage but also different shape, reflectors, angles, papplications.
The lightbulb book from 2005 is 400 pages with different bulbs, so when you buy a certain fixture in the past there was a certain shape and max. wattage bulb that had to be used.
Not that much has changed, except the number of companies making these bulbs at the moment has exploded.
--- Quote ---Do incandescents fail if they are switched too much? Sure. But people know that. And the incandescent manufacturers aren't making any new claims.
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The same for led bulbs, if it is not on the package that company is a con. All my Philips and Osram bulb packages state nr of hours and nr of switch/on/off , and that was never on any conventional light bulb package, i can tell you that much. So the information is better, BUT it also relies on the fixture you put it in, that is all I am saying and you can't print a booklet with 50000 fixtures and application now can you ?
--- Quote ---You make an interesting but ill-conceived point about n=1, that people should not form judgments from their very limited experience. Though this is true, I've got some news for you: that's indeed how they do it.
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No it is even worse, a couple of persons with a few experiences will put a review online that this brand and bulb is crap because it failed within 2 years and a million people read this and accept this as the negative truth, while the million of other people where the bulb still works as expected do not post a review online and state, hey it still works !
--- Quote ---LED manufacturers would be smart to design product that are extremely unlikely to fail in the promised time.
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Those were made 8 years ago, 11W led (then equivalent to 75W conventional lighting) with 400 grams of metal coolingfins surrounding it, could last 25+ years in any fixture with two cm of room around.
Very good thermal and electronic design, BOM was around $15 selling price $60 and almost nobody bought them: too expensive while it is still a bargain compared to conventional bulbs.
That is what I am telling you, consumers don't want to pay lot more money for their bulbs so the manufacturers have to follow the cheaper, less lasting commercial bulbs.
The US was worse than Europe, in Europe the margins 5 years ago were pretty good on led bulbs, in the US (probably due to higher china import competition) the margins were even then low.
--- Quote ---Finally, in my case, I have had 7 LED failures in 6 sockets in just over 7 years. It's more than large enough N to know that there is something amiss between the label on the package and reality.
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I don't know which brands you bought at which quality but with so many failures I would investigate other causes like quality of mains (spikes?), fixure (enough cooling), on/off switching times etc and after the results base your next purchase, this could well be that certain led bulbs are not suited for your particular application.
You can keep ranting against the manufacturers which could well be they sold you crap for cheap price
--- Quote ---I actually like LEDs and want them to work. There is a reason I keep buying them.
that I would not have this experience if I wasn't so damned stupid.
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I am not saying you're stupid, if you were than you would continue as a lemming buying the same led bulbs and experience the dozens of failures over and over again without doing a proper investigation of the cause of failure, experimenting with different kind of bulbs and seeing if some other brands or designs work better in your situation.
What I keep on telling people is that Led lighting is actually best off in a low DC environment and that mains environment is pretty crap for leds because they have to rectify the mains and that high DC has to be brought down again to normal led voltages (efficiency loss and heat) around 24-60V depending on the string of leds. And if you're string of leds is large (higher voltage) the chance is higher one of the leds fail. So assume all leds have the same statistical chance of failure, the chance of the bulb failing due to a failing leds is n times the amount of leds in the string.
Some modern leds fail closed then with current based drivers it is ok but cheap drivers are not current based and the remaining voltage falls over the remaing leds increasing the failure.
So if you think that I am a mains led bulb fanboy: absolutely NOT! Look at professional led lighting: all drivers that are digitally controlled current sources, with fancy protocols.
texaspyro:
--- Quote from: 3roomlab on February 10, 2019, 06:07:52 am ---did you know how heavy was the heatsinking for those? like how much you think it weighs in your hands? 0.3kg ?
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I suspect the PAR38 bulbs weigh around 0.6 kg and PAR20 bulbs weigh at least 0.3 kg, but I have not weighed them. It cost me around $40 to ship those recalled PAR20 bulbs back.
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