Reliability of LEDs: PF Members' Views and Experience

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In summary, you are complaining about the unreliability of domestic LEDs. You have been moved to ask for the current views and experience of PF about them. There are some interesting comments from PF on that thread.
  • #36
sophiecentaur said:
I really would like to know what is going wrong in my houses (this one and the last one).
My filament lamps never failed in 10 years. They must have been very old lights because they were significantly red-shifted, well back towards the introduction of electricity. Then the power authority, as compensation for increasing demand in the valley, raised the voltage by moving up a few taps on the transformer that fed my road. Filament lamps could not handle the overly-increased voltage in expectation of more customers. I had no choice but to move, as my lease had expired.

My new location was purchased with a dedicated 11kV to 240V pole transformer. The voltage was OK, but in hot weather the lights would flicker and I had block periods of RF noise on the line. That noise was a real nuisance at antenna farm. The problem disappeared if I plugged in a load like a 2kW electric heater, so I fitted steep RF filters on my side of the power meters and put up with it. But the 11kV overhead lines still radiated phased spikes of RF all along the road, to the accompaniment of the wandering clicks of the district's electric stock fences, and the 19'th harmonic of the local LF air navigation beacon, very recently extinguished in favour of GPS.

Over a couple of months the line fuses to my transformer dropped several times, so the authority finally replaced the transformer. Turned out that, an internal nut on the 11 kV primary connection had not been tightened properly. That poor connection had arced and produced the voltage spikes that eventually took out the insulation. It was then RF quiet, and the newfangled CFL lights, (the early RF quieter ones, with the internal ballast transformer), did not flicker at all.

Power prices climbed, so cheap and noisy light-weight, (how much does light weigh?), switching CFL replaced all the older lamps. Then along came PV with grid tie inverters. Now the RF noise floor has grown like grass on the spectrum analysers, it is continuous in this world full of switching converters. During the same period, processor speeds have moved from 3MHz to 3GHz, and there are many more of them. There is now a certain and secure place for spread spectrum techniques and digital receiver technology.

At the moment, my PV keeps me slightly in credit, but the power authority plans to significantly drop the price they will pay for my excess PV energy next year. The network charge is greater than my power usage, so I guess the next change will be off-grid, to 12V DC LEDs, powered from PV and battery technology.
 
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  • #37
Baluncore said:
... It was then RF quiet, and the newfangled CFL lights, (the early RF quieter ones, with the internal ballast transformer), did not flicker at all. ...
I was reminded of those old not-so-compact-CFLs yesterday. I had to replace a couple of the last filament bulbs along my garage door and entrance - these lights are on a timer, ~ 6 hours a day average. I noticed that one of them was the old, original not-so-CFL. I'm sure I got two of them as a promotion from the utility, and I'm pretty sure it was back in the 1980's. It is still working (though it takes tens of seconds to come on, but no problem for these lights on a timer). I really can't say how many hours are on it, it may have sat in a closet for some years, and I don't recall when I put it in that fixture, but it could have been a few years ago to as much as 25 years ago. It;s mate died just a year or so ago.

They are big and heavy and poor light, and slow to come on - but they were built like tanks!

Oh, the reason I had some filament bulbs in was my old timer required a trickle current through the filaments to keep the clock alive (it worked in a 3-way switch set up, and they designed it so it would not need a neutral connection, in case one was not provided in the box) - so I needed at least one filament on the string to keep the clock active, the CFL or LED wouldn't do it. But I had to replace that 2 years ago, and the new one needed a neutral, which I was able to pull easily, so I'm good with all CFL/LED now (6 individual lamps). The new timer also adjusts to the seasons (enter your latitude zone) , so now I'm ON at dusk time, and OFF at midnight - nice.

edit - it looks like this one (I need to get on a ladder and unscrew 2 screws to get to it, so I'm going by memory - I'll take a picture when/if it burns out!)
 
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  • #38
Standard flourescent tubes have been around for a long time.
They just don't look very cool.
LEDs are now better than they used to be, and actually do last more than one year.
 
  • #39
I think there should be a business opportunity for builders of new homes. They could include 12V or 24V DC for lighting only. It could be powered by a panel and and a battery, isolated from the grid, no rectifiers, wires run as twisted pairs, so that the DC would be extremely free from fluctuations. The light fixtures would be pleasant, versatile, low cost. very low energy consumption, and last nearly forever. They would stay lit during power blackouts. The homeowners would feel very green.
 
  • #40
Baluncore said:
o I guess the next change will be off-grid, to 12V DC LEDs, powered from PV and battery technology.
That's where i'd go too. Propane for refrigeration heat and backup generator.

Right now I'm leaning toward 12V backup lights as anorlunda described for my guest house. A friend built his new home with such a 12V light and receptacle in every room . He could handle a months long power outage with just a lawnmower engine and automobile generator salvaged from discards.
 
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  • #41
anorlunda said:
I think there should be a business opportunity for builders of new homes. They could include 12V or 24V DC for lighting only. It could be powered by a panel and and a battery, isolated from the grid, no rectifiers, wires run as twisted pairs, so that the DC would be extremely free from fluctuations. The light fixtures would be pleasant, versatile, low cost. very low energy consumption, and last nearly forever. They would stay lit during power blackouts. The homeowners would feel very green.
The services are very reliable in the UK, compared with many other parts of the world and it would be hard to sell the idea to many people. The economics of PV are pretty marginal if you're not making use of the feed in tariff. I would think that you may just be able to sell a big UPS to UK consumers if it were only in lighting and central heating circuit (I mean the pump and controller) but that would only be for non-urban sites.
@anorlunda: your ideas about this may be coloured by your marine lifestyle - very attractive but not accessible for most of us. :smile:
 
  • #42
anorlunda said:
I think there should be a business opportunity for builders of new homes. They could include 12V or 24V DC for lighting only. It could be powered by a panel and and a battery, isolated from the grid, no rectifiers, wires run as twisted pairs, so that the DC would be extremely free from fluctuations. The light fixtures would be pleasant, versatile, low cost. very low energy consumption, and last nearly forever. They would stay lit during power blackouts. The homeowners would feel very green.

Is there really much advantage? Doesn't an LED sourced with 12-24 VDC still need a switching circuit to convert that voltage to current? The switcher would be simpler with DC, since it would not need to store any energy between the AC cycles, and no flicker issues. But I'm not sure that would be worth the installation of a separate DC line. How much energy would be saved? Or do they just use a resistor to limit current (and waste energy)?

What I would like to see is, to have any new fixture or lamp fitted with the LED 'bulb' itself physically separate from the switcher/dimmer. That way, the heat of the LED would be kept away from the switcher, and as I understand it, heat is what kills the caps in the switcher and is a common failure mode. And providing caps rated for the higher temperature raises the cost of the unit. It would be nice to have standard components for this, maybe a third pin with a resistor that would tell the switcher the max current to apply, to support different wattage 'bulbs'?
 
  • #43
NTL2009 said:
Doesn't an LED sourced with 12-24 VDC still need a switching circuit to convert that voltage to current?
You refer to a transformer / voltage changer? That has to be done inside a mains voltage LED so having a low voltage distribution system would be virtually the same. Lengths of low voltage cable would (could) have 'significant' resistance and the bulbs could 'see each other' unless heavier wiring than strictly necessary were used. But a simple voltage regulator in each bulb could take care of that.
In fact, there is very little equipment in homes (outside of the kitchen / utilities areas) that actually use mains volts at all. There is good argument for changing the whole approach to electrical power in the home. The safety record of 'Wall Warts' (count how many there are in your living / media consuming /computing room) is not good and a proper central installation would be far safer.
 
  • #44
LEDs can be connected in series to better utilise the available supply voltage. That often makes a linear current regulator a reasonable solution.

LEDs need a current regulator, not a voltage regulator. A switching current regulator is no more complex than a switching buck voltage regulator. There is no need for the on/off PWM brightness control that produces the strobe effect.

LED light output is temperature dependent, so it would be good to compensate the regulated LED current for temperature. It could also fold-back the current to protect the LEDs from high temperatures that reduce LED lifetime and reliability.
 
  • #45
NTL2009 said:
Doesn't an LED sourced with 12-24 VDC still need a switching circuit to convert that voltage to current?

No, that's not needed. There are at least 3 other ways.
  1. There are DC-DC IC chips, all solid state.
  2. There are also LEDs with built-in resistors for direct connection to 9V, 12V, 24V or more.
  3. Put 4 LEDs in series to connect to 12V. I did that to convert light fixtures on my boat to LED, and they worked fine for 8 years.

sophiecentaur said:
You refer to a transformer / voltage changer? That has to be done inside a mains voltage LED so having a low voltage distribution system would be virtually the same.
No, you missed the point of my post, no AC-DC conversion necessary. I should have been clearer. I meant panel=solar panel.

anorlunda said:
t could be powered by a panel and and a battery, isolated from the grid, no rectifiers, wires run as twisted pairs, so that the DC would be extremely free from fluctuations.
 
  • #46
anorlunda said:
No, that's not needed. There are at least 3 other ways.
  1. There are DC-DC IC chips, all solid state.
  2. There are also LEDs with built-in resistors for direct connection to 9V, 12V, 24V or more.
  3. Put 4 LEDs in series to connect to 12V. I did that to convert light fixtures on my boat to LED, and they worked fine for 8 years.
No, you missed the point of my post, no AC-DC conversion necessary. I should have been clearer. I meant panel=solar panel.

A DC-DC IC is a switching converter, isn't it? At least for high efficiency, it is. As @Baluncore points out, if you use a series string of LEDS and get the Vf close to the supply voltage, there won't be much loss if you go with a linear regulator. But this moves in ~ 3.3 V steps, so for 12 V that's about 9.9V, and a 2.1V R drop, so a 17.5% added power lost in the series connection. Let's say 12 W of LEDs, so 1 amp, so 2.1 W loss in the R, for 14.1 W total. For a practical dimmer, you'd use a transistor/pot wired as a variable current source. The voltage would not change much, but the current would, so dissipation while dimming would be lower. Maybe that is an acceptable trade-off versus a switcher?

Connecting LEDS to a voltage source just isn't a good way to go, and not practical for large implementations. You cannot run them near maximum output,you will have batch-batch Vf variation, thermal variation, supply variation - if you run them to maximize light out, the voltage source will provide too much current when you hit the likely thermal runaway in some units.

You got away with it by using 4 LEDs in series rather than 3, so they are not running near their typical 3.3 V at their nominal current ratings. So you are running them at low current. So it works, but not really something that could be done commercially.
 
  • #47
@NTL2009 , what about LED strips like in the picture below? I also used those on my boat.

I could cut them with scissors to have more or fewer LEDs in the strip. After cutting, I could still use both halves. I could feed the 12V from either end. The only thing on the circuit board besides the LEDs were the tiny chips about half the size of the LEDs with the number 212 on them. I assume they are linear current regulators, and they seem much too small to be switchers. Perhaps, the 212 are just resistors.

outdoor-led-led-strips-waterproof-led-tape-light-with-18-smds-ft-1-chip-smd-leds-3528-additions.jpg


When making long-life KISS-principle lighting, I see no need to attempt to get maximum light out of each LED. It would be perfectly fine to get only 50% of max light and simply include twice as many LEDs.

Edit: Here is the https://www.ledwholesalers.com/v2/index.php?route=product/product&product_id=240&search=strip+12Vto those 12v strip lights. $2.50 for one strip, 20 LEDs per strip, only 3 watts for all 20 LEDs. I used 3 of them cut into 6 pieces in the cabin of my boat, providing me with plenty of light.
 

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  • #48
@anorlunda - The tiny chips are not active regulators, those are just resistors in those strip lights. 221 is 220 Ohms.

I have a similar strip, just 2x checked, and mine have a 150 Ohm R (marked 151) in series with three LEDS, and 300 LEDS per strip (100 groups of 3).

My 12V supply measured 11.76 when loaded down, 2.36V across the R, and 9.4 V across the 3 LEDS (3.16, 3.02 and 3.22), so about 20% power lost in the R. That may be an acceptable loss and trade-off for an R versus active circuitry. I've heard of people having problems trying to use these in a vehicle. The car battery will run ~ 14V when the alternator is kicking in, and that puts almost 2x the voltage across the R (the Vf on the LEDS won't change very much), so almost 4x the power dissipation on the R, and almost 2x the current for the LEDs.

My point was that in practice you can't reliably/practically run LEDs without some sort of current limit (even if it is just an R). You may be fine with running at low light and making it up with extra LEDS (we can get away with a lot on a one-off implementation), but a cost conscious producer, expecting to provide a consistent product, can't just throw 2x the LEDS at it.

The idea of running 12/24 VDC around the house is interesting. Most of our stuff that is plugged in the wall is low power. Looking around, the kitchen does use higher power stuff (toaster, counter-top u-Wave), and my wife uses a blow-dryer for her hair in the bathroom. Other than that, the vacuum cleaner ('Hoover' to some of you), but outlets in the hallways might be sufficient. Hmmm, then there is my "hi-fi" stereo - that's got a big-honkin' amp. SO I don't know, you still have to run power every where, and with the lower voltage, the wire size won't be that much smaller, then you still need some 120 V (North America) outlets - not sure it pans out in the end.
 
  • #49
NTL2009 said:
Looking around, the kitchen does use higher power stuff (toaster, counter-top u-Wave), and my wife uses a blow-dryer for her hair in the bathroom.

Indeed 10% of the 'things' consume 90% of the power. Some could be switched to gas , and the stereo could become a Class D amp .

Here's how son handles the toaster issue since moving to a boat -


a 1kw inverter would run the things you mention one at a time.
 
  • #50
Hah-hah! I'll suggest that to my wife! I suppose that technique works to dry and style your hair too?

I was also thinking that for some of those things, a battery charged from the 12/24 V could drive a high power appliance for a short while. Still don't think it would catch on, but interesting to think about.

I've got a few smaller class-D switching audio amps. Really impressive what they can do in such a small package. I haven't looked into any hi-fi, high power beasts though, I think I'll look around.

Here's the two types I have - the smaller one to power some small bookshelf speakers for a small TV, and the larger one is hooked to some bigger stereo speakers on another TV, and to some small, but high quality speakers for a stereo in the bedroom.

https://www.amazon.com/dp/B0049P6OTI/?tag=pfamazon01-20

https://www.amazon.com/dp/B004JK8BDK/?tag=pfamazon01-20
 
  • #51
Glad you approve of his technique.

NTL2009 said:
I was also thinking that for some of those things, a battery charged from the 12/24 V could drive a high power appliance for a short while.

yes a big car cranking battery can deliver a kilowatt for a short while. A couple kw generator woouldn't be outrageously expensive if only run during high demand times and one arranged his household activities around the generator. That's easier for a single guy, though.

I must say this TI board looks interesting. 20 real watts is a lot of sound for a living room. Small enough to hide in something else..
https://www.adafruit.com/product/1752
 
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  • #52
Baluncore said:
I see two electrical problems.

1, The environmental temperature. ...
This. The latest LED bulbs have a label, something like 'not suitable for enclosed light fixtures', or the reverse.
 
  • #53
I just came across this video. It is instructive the way the guy speculated on failure causes, and how he tracked down the actual failure modes.

 
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  • #54
In my experience, neither CFLs nor LEDs like the heat. Also, the more powerful the bulb, the shorter the life if ventilation is even slightly impaired.Sometimes you can switch designs to a 'skinny' type. Sometimes, you can adapt things. eg Here in UK, we have a zoo of Edison screw and traditional 'bayonet' fittings. ES, SES, BC, SBC etc. Faced with a light fitting that always ran hot and ate bulbs with grim regularity, I bought a BC/ES adaptor, switched to the other type of bulb. With the bulb now two inches further from its too-snug base, it runs sufficiently cooler to last much, much longer. Still, 'Due Care, Please' !

I'm not impressed by 'halogen in bulb' lamps. Although they give a brighter, bluer light, they do not last much longer than a standard incandescent. If you really want a long-lasting bulb, such as for some-where that is hard to access or essential for safety & cold-starts, consider incandescent 'rough service' types. They sacrifice efficiency for endurance...

Sometimes, you can combine different lamp-types in a multiple fitting. We have a tall stair-well where the lights fitting is really hard to reach, but essential for safety. Ordinary Incandescent lamps burned out too quickly, 'rough service' were too dim. CFLs took too long to strike in the cold, would flicker unpleasantly. Powerful LEDs died young. Worse, a family member had photo-sensitive epilepsy; any flicker was unacceptable...

Some lateral thinking produced a solution: I fitted two CFLs and a 'rough service' incandescent. The latter's prompt illumination masked the former's start-up flicker. As LEDs have improved, I've since replaced fading 'rough service' lamps with low-powered LEDs...

FWIW, I've begun replacing our suspended ceilings' 4-foot (1200mm) and 5-foot (1500mm) fluorescent tubes by their LED equivalents. Trial basis as yet, but they are slimmer, much safer to handle and give a nicer light temperature. Just remember to replace the fitting's 'blinky' starter with the 'bridge' device supplied !

I must agree with the comments that power spikes are a lamp-bane. I've fitted several plug-in spike-catchers around the house, the type with a tiny pilot-light warning if protection is active. They seem to help...
 
  • #55
Nik_2213 said:
FWIW, I've begun replacing our suspended ceilings' 4-foot (1200mm) and 5-foot (1500mm) fluorescent tubes by their LED equivalents.

I also found the following video an hour ago. It may be helpful to you.



Heat may well be a factor. The interior space of a fluorescent ceiling fixture is very much larger than the interior of a bulb, so hopefully the LEDs will run cooler than in a bulb.
 
  • #56
I skimmed through this thread again and I'm struck how, typically of Engineers, the replies were about reasons and possible workarounds. Why aren't you / we all totally disgusted about it and writing rude letters to suppliers? The prices of these devices are only justifiable if they actually last as long as the numbers written in the blurb. The public are being taken for a ride here.
 
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  • #57
sophiecentaur said:
I skimmed through this thread again and I'm struck how, typically of Engineers, the replies were about reasons and possible workarounds. Why aren't you / we all totally disgusted about it and writing rude letters to suppliers? The prices of these devices are only justifiable if they actually last as long as the numbers written in the blurb. The public are being taken for a ride here.

I did talk about prices and brand in #6. It's worth repeating. If you buy a brand name like Phillips, you're much safer.
anorlunda said:
You can't expect a company like IKEA to have the same kind of product engineering and testing as a company like Phillips. IKEA needs the flexibility to switch suppliers if necessary, and when switching they can't take a year or more to investigate and qualify a new supplier. They must depend on the statistics of customer complaints and returns to know when a product they sell is faulty.

LED bulbs at very low prices are sold in bulk on alibaba.com . I presume that they are bought by retailers who know next to nothing about the manufacturers.
Here's an example link to an alibaba ad for LED bulbs, €0,21 ($0.25) each in quantities of 60000 per day.. Use your own imagination to think of who buys them, and what names they stamp on them before sale.
 
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  • #58
sophiecentaur said:
Why aren't you / we all totally disgusted about it and writing rude letters to suppliers? The prices of these devices are only justifiable if they actually last as long as the numbers written in the blurb. The public are being taken for a ride here.

I think it's " the curse of the computer age" .

Windows has conditioned two generations that "workarounds", excuses and patches are the norm. Keyboard anonymity enables surreptitious and underhanded behaviors.
If societal values of excellence and virtue aren't dead they're on the critical list.
We need a Robert Pirsig revival .

[End Rant]
 
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  • #59
sophiecentaur said:
I skimmed through this thread again and I'm struck how, typically of Engineers, the replies were about reasons and possible workarounds. Why aren't you / we all totally disgusted about it and writing rude letters to suppliers? The prices of these devices are only justifiable if they actually last as long as the numbers written in the blurb. The public are being taken for a ride here.
This is far from the first thread on the subject - I suspect I started some myself. I've expressed disgust in the past, but I've never been a letter-writer. I don't know that it does much.
 
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  • #60
anorlunda said:
I just came across this video. It is instructive the way the guy speculated on failure causes, and how he tracked down the actual failure modes.
One open LED kills the whole string; I guess it is too much to ask that they be wired in parallel?

Heat hasn't seemed to be the issue with the LEDs whereas the CFLs I've lost have looked from the outside like they were overheated(discolored plastic). One thing I've done that seems to help is most totally enclosed fixtures have insulation on the top, inside surface. Ripping it off helps dissipate heat better.
 
  • #61
Might it be that LED bulbs with the circuit at the base might run hotter when hung upside down. I'm thinking heat rises. Heat rising to the base has a harder time escaping than heat rising to the globe.

I can't comment on CFLs. I never owned one.
 
  • #62
russ_watters said:
One open LED kills the whole string; I guess it is too much to ask that they be wired in parallel? ...

Yes, I think it is too much to ask, at least for consumer grade.

LEDs are current devices. Put them in parallel and you will get current hogging and probably thermal runaway to destruction (or at least uneven light from each LED, which would hurt efficiency). To avoid that, each LED would need its own current supply, and that's just not practical with a lot of LEDs in a cheap lamp.And 12 separate switching supplies may have a higher failure rate than the series string of 12 LEDs shown in the youtube link.

If an LED fails shorted, the string will continue to light, as the current supply will remain the same through the other LEDs. But from what I'm reading open seems to be more common than short. But a short in all parallel LEDs would take out everything.

To protect against opens, a 3.9V Zener can be placed across each of the LEDs in the string (at higher expense of course). The 3.9V Zener would not affect the normally ~ 3.3V LED. But if the LED opened, the Zener would provide a path to the remaining LEDs in the string.

Offhand, I think failures in the driver/switching circuit are more common than actual LED failures. I'll see if I can find a reference for that.
 
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  • #63
Many processes and chemical reaction rates, such as the diffusion of material within a semiconductor, double for each 10°C increase in temperature. That can be used to accelerate the lifetime testing of new products. But it appears that the new wave of designers have failed to learn about the Arrhenius equation and accelerated testing.
https://en.wikipedia.org/wiki/Arrhenius_equation

When we operate a device in an environment at a higher temperature than specified, we must expect a reduced MTBF, a shorter life. A device that should operate for 1000 hours at 20°C can be expected to last only 500 hours at 30°C. At 40°C expect 250 hours and at 50°C expect 125 hours. At 60°C expect 62 hours and at 70°C expect 32 hours.

The rate of advance of technology is dependent and reliant on the replacement of the previous product generation. I guess the marketting industry knows you will not need to buy another unit until an existing unit fails. So it is really not surprising that improved cooling is not advertised as an advantageous feature.

Temperature sensitive electrolytic capacitors were the mainstay of consumer electronics repeat sales. Now that things have gone more digital and a few reliable capacitors are available, it is the unreplaceable battery pack that has taken over driving the model replacement economy. When the battery pack does not fail, the manufacturer programs lower performance to increase their sales, while they ignore the social, financial and environmental disaster they are going out of their way to cause at our expense.
 
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  • #64
anorlunda said:
Might it be that LED bulbs with the circuit at the base might run hotter when hung upside down. I'm thinking heat rises. Heat rising to the base has a harder time escaping than heat rising to the globe.

That's a fact .

https://www.edn.com/electronics-blogs/led-insights/4423570/That-60W-equivalent-LED--What-you-don-t-know--and-what-no-one-will-tell-you-
 
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  • #65
Baluncore said:
...the manufacturer programs lower performance to increase their sales...
Oh, what could possibly make you think that ...? . :oldwink:
 
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  • #66
jim hardy said:
Windows has conditioned two generations that "workarounds", excuses and patches are the norm.
Yes. It's all about 'conditioning'. In the not too distant past, we all "knew our place" and didn't question the way society was structured; we accepted our lives from birth to death. Nowadays, we are conditioned slightly differently and to different thingsbut the 'questions' are still not asked loudly enough.

I am struggling for the first time in years with a Windows machine and it is such a business just to get started. Apple, on the other hand, makes the experience warm and comforting - until things go wrong, at which time you realize they don't care just as much as Microsoft don't care. They just do it more prettily.
 
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  • #67
I'm really pleased with the direction this thread has turned. IMO, the intersection of engineering and economics is fascinating.

In this case, the topic is not at all new with LEDs. There was a time in history of incandescent light bulbs when consumers could find both "regular" low-cost bulbs and "long-life" bulbs on the store shelves. Long life came at the cost of higher price and lower efficiency. Over the years before the end of incandescent, consumer preferences drove the "regular" bulbs to improve their life, and the "long-life" bulbs to decrease their price. Apparently, the "sweet spot" optimum was somewhere in the middle.

To me, the fascinating thing about that story is that finding the "sweet spot" is an iterative process involving both manufacturers and engineers on one hand and consumer preferences on the other hand. In the case I just described, the optimum was in the middle. But in future cases, the optimum can be at any point, extreme low, extreme high, or middle. Engineering innovations can disrupt the balance as can changes in consumer preferences.

50+ years ago, I worked for General Electric. At that time, light bulbs were the cash cow that made the entire GE giant profitable. Back then, I may have been able to get my hands on GE marketing studies showing the data on consumer behavior. Alas, I didn't get access then and it is probably lost to history today.

But fast forward to this very thread. I can buy LEDs on alibaba.com for €0,21 each. They probably cost €0,20 to make and the manufacturer makes 5% profit. The retail price is €12,00. Somebody in the middle is making lots of profit. Suppose they made an improved long-life model that cost €1,00 to manufacture and sells for €1.,10 on alibaba.com. That increases manufacturer profit to 10%. But how would it influence retail sales prices and profitability? The answer to that question requires much more than engineering.

IMO it is much to simplistic to blame everything on greedy corporations. Consumers have a major say in what they are offered. Consumers can certainly be deceived and cheated in the short-term, but it is wrong to think that they are powerless.

p.s. History buffs should also remind us that this exact problem delayed by several years the "invention" of the light bulb by Thomas Edison (in 188? I forget the date.) There were lots of electric light bulbs around in laboratories for years before that. Edison's lab in Menlo Park NJ tinkered for years until they found a filament that gave a price-performance point that made the bulb an economic success. So in that perspective, this thread merely continues a topic that has been going on for about 135 years. :biggrin: Gotta run now, but I have a link to a free biography of Edison that I'll post when I get a chance.
 
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  • #68
I'm not as negative about this planned obsolescence scenario as some here.

Look at our cars - they last far longer than they used to, and require far less maintenance. Instead of regularly changing/adjusting points, timing, spark plugs and oil/filter at 3,000 miles, many cars require no sort of tune up and plug changes are at 50,000 or maybe 100,000 miles. Oil changes are 10,000 miles. It used to be an "event" to turn 100,000 miles on a car (with a xx,xxx.x digit odometer) - now it is routine.

Many of learned the importance of data backups the hard way, from the very unreliable floppy disks of the day. Today, hard drives and flash drives that are thousands of times larger are far more reliable and robust.

Yes, due to modern manufacturing techniques, the old style troubleshoot and component replacement just isn't practical. But it has lowered the cost of these products for us. And who would want a DVD player made with through hole components that a bench tech could replace - it would probably be the size of a bar fridge.

That said, I do wish some products were more modular so we could replace the module instead of the whole thing. I have had to recycle things because of a switch - but it is one of those surface switches that are integrated in with panel electronics, and even getting it apart to clean it was near impossible. But life goes on.

I think LEDs will (and have been I think) improving in durability. Now that the cost has come down, I think people will start looking for quality if it doesn't cost much more. People don't want to have to replace bulbs in hard to get places, and will pay for quality, and some manufacturers will market that.

I may have mentioned this before, but I think physically separating the LEDs from the driver circuit would be a very good thing. With the driver in the lamp fixture base, away from the LEDS, they won't heat each other, and there is more room for heat dissipation around the LEDs, and each will last far longer. And that is modular - replace the driver if it goes bad, replace the LED assembly if it goes bad. We could standardize on a nominal 24 V DC compliant source, with a 3rd pin that would tell the driver how much current to supply the LEDs (like use 1000 Ohm R in the 'bulb' to tell the driver to supply 1 Amp, and scale it up/down with the R value from there (100 Ohm for .1 Amp, etc). That would provide comparability and flexibility.
 
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  • #69
NTL2009 said:
Look at our cars - they last far longer than they used to, and require far less maintenance.
This is absolutely true. I think you have identified the inconsistency (or perhaps cynicism) of marketing. The huge number of potential car buyers and the high cost of a car (plus competition) has made the manufacturers use reliability as a selling point. Unfortunately, the Light Bulb is a bit like the mouse trap - low cost and not very sexy so people view it in a different light. (Ouch - sorry!)
 
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  • #70
NTL2009 said:
It used to be an "event" to turn 100,000 miles on a car (with a xx,xxx.x digit odometer) - now it is routine.

That is so. My last one had 285,000 when i gave it away and I anticipate at least that from my current one(it's at 203k now) .

Cars got so expensive it became necessary to design them so they'll outlast the loan .
What a boon for handymen - i buy $2,000 cars because they last me half as long as $20,000 cars.
With a $40 code reader and reasonably gentle treatment one can likely drive them to 300 thousand miles. Several in my neighborhood are past 400k.

As @sophiecentaur says - first marketer to make an advertisement demonstrating how his company designed his LED lamps to handle heat and prolong lamp life will start a groundswell.
As @anorlunda suggests - an outfit like GE needs brand loyalty . If somebody remembers a positive experience with a simple light bulb it'll affect his decisions on major appliances. I've had bad luck with Frigidaire appliances, probably that's why i notice myself avoiding GM automobiles. Subconscious is funny that way.

old jim
 
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