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What Happened to the 100000 Hour LED Bulbs? (hackaday.com)
668 points by jccalhoun on Feb 6, 2019 | hide | past | favorite | 498 comments

Lifetime isn't even my #1 concern with LED bulbs. It's strobing/flickering.

I film all the LED bulbs I buy in slow motion at 240 fps with an Android phone, and play the movie back on a PC with mplayer using the dot(".") key to move frame by frame. Here is a shot I made comparing 2 brands of LED bulbs: https://youtu.be/QbenId_F2RQ (Edit: yeah you don't have to transfer to a PC, just playing back in slow motion on the phone will still show the effect quite well.)

It's amazing how I find this way that most (but not all!) of LED bulbs flicker with a strobe effect at 120 Hz (frames alternate between bright and dim) because they have crappy power supply designs that fail to smooth the A/C voltage. As a result they flash one time during the positive phase and one time during the negative phase of the 60 Hz A/C mains frequency.

I find this unacceptable. Although not too noticeable in normal conditions, a 120 Hz strobing light is definitely noticeable when your eyes move or track an object illuminated by the bulb.

In my experience, Philips lightbulbs are one of the few brands that don't have this flaw because they take care of converting AC to a stable DC voltage internally. In fact they are advertised as such: https://www.amazon.com/dp/B07CFRCGKC "COMFORTABLE LIGHT: Our products meet strict test criteria including flicker, strobe, glare and color rendition to ensure they meet EyeComfort requirements"

LED flicker could prove harmful or fatal if you work with anything that rotates or reciprocates.

The rotating / reciprocating mass may appear stationary at some RPM.

Just a reminder to only ever use incandescent or halogen lights around machinery you can touch while in operation: drills, lathes, mills, slotting machines, etc.

Yeah, please don't rely on your eye sight to tell you if a tool is operating. Every time a tool is running you should know it is because you started it to a specific purpose.

Before you start a tool you should act out your planned motion. Then start the tool and only perform this motion. If something changes and you cannot complete the motion, stop the tool immediately. Following this and a few other safety tips I've operated power tools for years without incident and I'm legally blind.

> stop the tool immediately

Okay, but, say you've configured the tool wrong and now it's destroying your work. You stop the tool. How soon is it safe to grab your work away from the work surface—i.e. when will it go from "it's too dangerous, let it keep destroying the work" to "it's now slow enough to pull the work off of the tool while it's still—slowly—running, to save the work from further damage"? That's a thing you have to figure out with your eyes (and ears).

So I went of and did a tiny bit of research. Turns out there are LED work lamps designed specifically for lathes etc.

So, evidently, I may have over stated my initial claim about only using incandescent lights.

Still, it’s something to me conscious of.

Just how likely is this to happen though, it would have to be the only light source and be flickering with exactly the same frequency as the machinery is traveling at (which i assume for most devices varies a lot).

Not saying it can't happen but it does seem stupidly hard to achieve.

It's not true that it has to be the only light source. All of the light sources have to be the same type and on the same circuit, which is fairly common.

Many AC motors are synchronized to the frequency of the power line, by the same principal that turbines in the power grid are. So 60hz AC often means 30hz = 1800 rpm motor, and 59.8hz AC means 29.9hz motor. So if you have LEDs with a half bridge rectifier and your machinery is 180 degree rotationally symmetric, it will appear to not be moving, even if the line frequency fluctuates.

Pretty common, about as common as the wagon wheel effect in 24fps film movies. In just the same way, the item can appear to stop, run slow, or run backwards, just as with film. No it does not have to be the only light source, just the nearest one to the machinery.

Fluorescent tubes are most noticeable, LEDs a little less. Tungsten or Halogen are the only sensible option for workpiece illumination.

Or, of course, just use a LED that properly smooths out the DC. It's not hard to do, and a quality LED manufacturer should get this right. The only excuse for flickering is a cheap LED that cuts cost for circuitry.

Oh I agree, but a surprising number of LED bulbs have some degree of flicker, even from those makes you might expect to do better. A purpose made work lamp should get it right though. Hopefully. Maybe.

For my hobby stuff, I just bought a couple of spare halogens that should see me out.

I believe halogen is also tungsten.

It is. Just running at higher temperature. They tend to be marketed as something separate and distinct though.

I would imagine there's a higher-than-average chance of this because most AC motors are definitely syncronized with the 60hz (or 50hz) AC source. There's a chance the lights might also derive from this.

> There's a chance the lights might also derive from this.

If the light is flickering it's absolutely guaranteed that it's derived from this.

But it's hard to imagine a lightbulb that emits a short enough pulse of light to make something look stopped. Even an absolute garbage one-way rectifier will be emitting light more than a quarter of the time. That can make a tool look odd, but it won't make it look still.

If the light is flickering it's absolutely guaranteed that it's derived from this.

Not necessarily. If it's a 50/60 or 100/120 Hz flicker then yes, but LED lights with a cheap switching power supply might still flicker at the switching frequency, which could be say 400Hz or something.

You have to be intentionally wasting money to put in a transformer big enough to handle 400Hz, and once you get into the lots of KHz where a supply like that is happy I think your "please don't explode" capacitor on the transformer is enough to prevent flicker.

It doesn't have to be going the exact same speed, a multiple would do the trick too. It can also be dangerous if it's close to the same rate since it can then look like it's going slower even if not stopped.

Or the rotating / reciprocating object may appear to be rotating / reciprocating slowly in the opposite direction.

Even after 20 years in the metal fabrication industry that scenario still spooks me.

> which i assume for most devices varies a lot

Most will flicker at a multiply of the power line frequency (60 or 50 Hz depending where you live).

It's so common, that most digital cameras have a setting to set the power line frequency, so they can reduce the flickering in the footage.

Incidentally - many alternating current engines are also working with multiples of the powerline frequency, because it's easier that way.

This is uncommon but not rare. Have you ever seen wheel blur or other artifacting of such? It's very easy to make happen artificially under controlled conditions which means it can't be that hard to happen accidentally.

Edited to add: Have you ever heard of a timing light for an engine? This works exactly the way you are describing.

Timing lights for engines work this way for clarity: The distributor on an engine has a spinning rotor and a number of points (one for each sparkplug) on the outside the circle the rotor forms while spinning are a series of contacts across which electricity jumps to send voltage to the spark plug.

The timing light is then pointed at the flywheel on an engine, which has numbers or marks stamped into it. Each time the spark plug fires the timing light (which is hooked into that same current via induction) lights up for a brief amount of time to show at what timing offset the engine is currently at. (this all happens at hundreds of rpms a minute).

so I'm not sure it's the same

The effect might not be rare but getting hurt by it is incredibly rare. Machines produce noise and vibration. Nobody is going to be fooled and try to pull a moving part out of a lathe because of some LED lighting except in the most exceptional or bizarre circumstances.

Machine shops are very loud (plus you'd be wearing ear protection) and a lathe/mill that vibrates noticeably is either broken or incapable of performing the very task its designed for.

Nobody? That is a high bar. Mechanics tend to be pretty cluey, but for the effort of getting proper lighting why nobody should be taking that sort of risk. Sight is one of those fundamental lets-feed-in-useful-information sensors for keeping situations safe.

Most people spec'ing out machine shops are not experts in lighting other than more = better. This is a really, really low risk we're talking about. Like basically the stars have to align for someone to get hurt.

I started to write a lengthy rebuttal, but decided to go with something more concise.

Never underestimate the ability of machinery to rapidly render you dead.

Never underestimate the ability of otherwise intelligent people to intentionally disable safeguards, or guninely make mistakes.

No, it simply isn't that rare. You haven't been around wood shops and machinery much if you think that.

Are there any statistics on this? That seems like the obvious way to settle this issue.

So far, the discussion sounds like it's a theoretical possibility. If it's a real possibility, then it's something that should have happened a number of times.

You would also have to ignore or miss any other signs of very fast rotation, such as noise or air movement or the power switch being on.

It's easy to miss those signs too. It's common to have earmuffs and sometimes a dust mask on when using power tools, and power switches often don't clearly indicate state. Many start/stop control boxes don't have any visual indication of state at all.

Someone might hear the noise and feel the vibration but think something is broken inside because the drill isn't rotating. I'm not sure exactly how that would lead to an accident but it might.

Multiple light source of the same general characteristic (don't even have to be the same type of bulb) may produce this result.

The rotation frequency would have to be close to a relatively simple multiple (or fraction) of AC frequency but the way electric motors are contstructed if the piece is directly connected to a motor it is very likely it is true.

I can also imagine the sound and moving air being masked by safety gear making it even more likely to note the movement.

Oh, WOW!, I never thought of that! Thank you for this information. I thought I am very careful but it never occured to me this could be a problem.

such devices are usually not allowed in those cases. (speaking of DIN EN 12464-1)

I only buy Philips bulbs for this very reason, or from brands that advertise being flicker-free. With iphones, slow motion mode also makes the flicker very visible without the need to transfer to a PC.

Visible light impulses influence brain wave patterns (e.g. [1]), and it might not be beneficial to look at pulsed light with a frequency that is not well researched.

Same thing with screens, most LEDs are dimmed with pulse width modulation [2], so they flicker at most brightness levels except the very brightest one. Some iPhone X users claim they get a headache when looking at the phone at the lowest brightness setting (OLED is even worse in that regard than LED, IIRC).

1: https://clinicaltrials.gov/ct2/show/NCT03657745 2: https://www.eetimes.com/document.asp?doc_id=1281013

Very good points here, I would add that 99% of the monitors are also flickering when you dim their ligth. This is why i started using the iris[1] app on my laptop. Keeping the brightness at 100% in the hardware settings will eliminate the flicker, then iris dims the lights from your graphic card. I can work without eye oain thanks to this method. - [1] https://iristech.co

Oh, I had been looking for something like this for the desktop, thanks for mentioning it!

On iOS there’s a setting buried deeply in accessibility settings, I think it’s called white point correction.

I had a small bag of Chinese position light LED T10 lamps for my car my dad had given me. I would change them every three to five months because the LEDs would burn out. Getting sick of sticking my hand in narrow spaces to replace the lamps, I ordered two Philips Xtreme Vision 4000K T10 LED lights. They've beeen running flawlessly more than a year now.

>Some iPhone X users claim they get a headache when looking at the phone at the lowest brightness setting (OLED is even worse in that regard than LED, IIRC).

And on iPhone XS this is even worst. I wonder if there are any solution to PWM problem.

What I've found to help weed out the worst of the worst is to only buy dimmable versions of the bulbs. They cost more but because they have to support dimming they're almost required to have a better power supply to handle the usual triac based control that most dimmers have.

Not sure this always holds.

The worst bulbs I've personally seen for flicker were dimmable ones.

The non-dimmable variant from the same range had no noticable flicker.

Price paid also seems to be no indicator of quality – I've had premium LED bulbs from major makes, bought from a reputable wholesaler, that have died after 6 months within days of each other.

I've had cheap no-name imports that have lasted years and had no flicker.

A lot of "dimmable" LEDs are actually shifting the flicker pattern to dim the light (shorter on phases). This is for LEDs where the user dims per remote control. OP was talking about the older "legacy" dimming, where you have a wall-mounted knob that reduces the current. Works well with incandescent bulbs. But only few LEDs support this. If they do, their internal power converter likely won't flicker, because of their more thought-out converter?

However, there are also LEDs that support legacy dimming, but again translate less current into different flicker patterns...

I've been trying to switch to all-LED in a home with lots of legacy dimmers and it's been painful. Even on circuits where I've replaced older dimmers with new Lutron CFL/LED dimmers, I get flicker.

In other places I don't have dimmers but have low-voltage (12V) cans. Lots of flicker issues there too, presumably due to the 120->12V transformer at the can.

And then I have a light fixture that's both dimmed and a custom 12V setup. I've given up on finding a working dimmer/LED bulb (MR16 GU5.3) there. Probably need new 12V transformers?

Yes, the dimmable has been the worst for me so far, they just make them flicker more to give less light.

Confirmed. Have dimmable at work and home and they flicker like crazy.

We need IEEE PAR1789 bulbs! The department of energy has a great presentation on LED flicker and this IEEE standard for better bulbs, https://www.energy.gov/sites/prod/files/2015/05/f22/miller%2...

I'm really happy to see you post this. Everyone else I've brought it up too just says I'm crazy. I might be crazy but not about the damn flickering/strobe.

Especially when my dog bounces around it looks like she is in a strobe light. I did a couple of videos of it just to "prove" it in some fashion.


You’re definitely not crazy. HN also had a big discussion about it two months ago in this¹ thread as well.


¹ — https://news.ycombinator.com/item?id=18644590

I use a salt shaker and pour salt onto a plate - if I can make out single falling grain of salt on the way to the plate, I know this light source is not healthy for humans.

Hang on, how does that work?

The people who are crazy enough to think they can change the world are the ones who do.

A metal working friend told me recently that in Australia we're not meant / allowed to use fluorescent lights above lathes, as the flicker can disguise movement.

This is slightly worrying.

Yeah gas discharge lamps (CFL, neons, halides) will flicker at twice the mains' frequency on a single-phase circuit, makes it very dangerous to use them as e.g. factory lighting. You can mitigate that by using 3-phase power supplies, high-frequency controller, or by supplementing the basic lighting with incandescent bulbs around machinery.

The stroboscopic effect is really fun right until you're in a place with lots of moving parts at a multiple of the strobe frequency.

OTOH it's also used to fine-tune engine timing and such: set a stroboscope at a fraction of the frequency you want, the engine is properly tuned when everything looks completely stopped. Makes it very easy to notice mistiming.

Some turntables include a strobing light and rings of dots around the edge for different speeds. If it's spinning at the correct speed the corresponding dots will stand still.

Absolutely - the way he described it sounded like a horrendous accident waiting to happen, especially for smaller / home shops where the operator may not be aware of the problem. He was under the expectation that LEDs solved this problem, though he is using drop-in LED tubes that may have some better persistence through the off-cycles.

I do some occasional wood-turning, but usually augmented with ambient daylight - along with the dubious safety advantage of having a very noisy electric motor.

Plus I'm old enough to have used a timing light hanging off a distributor on my first car. Try explaining that to the kids of today. ; )

A friend of my mother's lost half a finger to a strobing light and a circular saw. It does happen!

Modern CFL drivers have frequencies in the tens of kilohertz.

The flicker is a thing from the past (or should be).

Shaking a hand with fingers spread out somehow works to spot flicker. If the light source flickers, you see oddly sharp finger positions in the air. It's not the most sensitive or easy to interpret method.

The John Cena method?

I remember doing this with CRTs

I calculated the airspeed of a rubber band this way once! My coworker shot a rubber band in my direction. I noticed three “shadows” of the rubber band as it passed by the CRT.

The CRT was a 17” running at 60hz. The rubber band sailed past in the span of about 2 screen refreshes, so it traveled that distance in 2/60 of a second. Distance was easy to calculate by the Pythagorean theorem or by holding a ruler to the screen, I forget which.

I completely agree, flicker has been the most distracting part of switching to LEDs, for me.

Here are two good sites that posted graphs of light intensity over time for a bunch of different bulbs: http://www.ledbenchmark.com/ http://sle.se/michael/led/ (Swedish)

Unfortunately, they both stopped updating around 2015. Anyone know of similar sources for more recent bulbs?

In the huge HN thread here¹, yeutterg mentioned² their Bedtime Bulb:

> “I am on a mission to make lighting healthy. That's why I made Bedtime Bulb: https://bedtimebulb.com/ It has the lowest flicker I've ever seen in a bulb form factor—even less than those claiming to be "flicker-free."

In addition to that, a few other database sites that test for flicker were mentioned here³.


¹ — https://news.ycombinator.com/item?id=18644590

² — https://news.ycombinator.com/item?id=18650624

³ — https://news.ycombinator.com/item?id=18646409

I've tested a bunch of bulbs for flicker with a handheld flicker meter and with a photodiode connected to an oscilloscope. It's funny that some of the bulbs out there claiming to be "healthy" have terrible flicker. One product from Soraa was flickering at over 50%, almost as bad as the cheapest/worst LED bulbs you can buy.

I don't have a database, but I can say that most (but not all) filament designs are terrible for flicker--ours is an exception. Philips products seem to have gotten worse in quality over time, probably to remain competitive, but they are better than the worst. Ikea's stuff is pretty good overall. I don't have a consistent recommendation for low-flicker general lighting right now, as every brand has good and bad products.

Thanks to GP for the links, I completely missed that previous thread!

And, yeah, I tried that Soraa healthy bulb, and it was shockingly bad, given how it was advertised. Even the regular Soraa bulbs were disappointingly flickery, though less so. Also, just looking at the pattern it makes on my phone's rolling shutter, the wave is quite saw-toothed, and I wonder if that makes it worse? I have some Ikea candelabra bulbs which were always pleasant, and I was surprised to see they also left quite a visible flicker pattern on my phone, though much more sinusoidal/smoother.

It's a shame about the flicker in the Soraa bulbs, since the colors really did seem nice.

The Soraa bulb looked pretty sinusoidal on my scope when I tested it briefly. But it's a lot of flicker regardless.

What's interesting is that the bulb seems to have a nice build quality (from the outside, I didn't open it) and is quite heavy. I suspect they are putting a BIG heatsink in there, as violet pump phosphors tend to degrade quickly.

The other thing that irks me about this product is the "zero blue" messaging. Yes, I can confirm the spectrum looks like what they are advertising, with a peak around 415nm, almost nothing between 440-490nm, and then all the rest of the colors from green to red.

But, green light is just as bad as blue for sleep! The ipRGCs are sensitive to both blue and green (up to around 600nm) This bulb has a lot of green, more than a lot of other light sources. It also has a very unpleasant greenish color (IMO) and low-ish CRI, around 78 on the bulb I tested.

Is it better than a normal 600lm bulb for sleep? Yes. Is it novel? Yes. Is it good in practice? I don't think so.

That's right, the Soraa Healthy was very green! So, even without the flicker, the fact that it makes everybody look like undead zombies would be reason enough to disqualify it as a bedroom night light.

Haha, totally agree! If you are still in the market for a low-blue, low-flicker solution, may I humbly suggest a look at my product, Bedtime Bulb [0]? I know I basically bashed the Soraa product here, but not without technical justification.

[0] https://bedtimebulb.com/

> flickering at over 50%

what does that mean? Duty cycle is 50%, frequency at something Hz? Not being snarky - curious whether there is some kind of standard that your tool compares against.

A duty cycle 50% (or any percent really) isn't bad in itself, it's the frequency that is the culprit. Too low PWM freq and you'll notice it.

When I refer to % flicker, I am talking about the modulation % as defined by IEEE 1789-2015 and some documentation from the Illuminating Engineering Society [0][1]. More correctly, invisible flashing is known as the stroboscopic effect or phantom array effect.

Two factors are often used to describe flicker for lighting:

- Modulation %, a.k.a. % Flicker [The height or modulation of the waveform, formula is 100% * (A - B) / (A + B)]

- Frequency [self-explanatory]

Flicker Index is also used (refer to [1] page 7 for more info) but rarely.

Duty cycle is not considered relevant, as you mentioned.

Some tools designed to measure lighting, such as my UPRtek CV600 [2], spit out % flicker, frequency, and flicker index, in addition to a bunch of spectrophotometry metrics. It's also pretty easy to calculate the modulation % with an oscilloscope and photodiode, it's just Vp-p / Vmax.

IEEE 1789 [0][1] roughly says that the higher the flicker frequency, the more acceptable it is to have a high modulation %. If you look at the graphic on [1] page 18, you can see this relationship. The white area is considered unsafe, the yellow area is "low-risk", and the green area is "safe." I don't 100% agree with this personally, as most incandescent lighting, with around 6-11% flicker at 100-120 Hz, would fall into the unsafe or low-risk category. But the Soraa product is definitely in the unsafe category.

For reference, I plotted my product (Bedtime Bulb) against an incandescent A19, Lighting Science's Goodnight A19, and Soraa's Healthy A19 on an IEEE 1789 graphic [3] with a Python tool I'm developing, Beautiful Flicker [4]. You can see that this incandescent, measured around 10%, is on the border between unsafe and low-risk by this standard.

Hope this helps!

[0] IEEE 1789: A new standard for evaluating flickering LEDs?: https://www.dial.de/en/blog/article/ieee-1789-a-new-standard...

[1] Flicker: Understanding the New Recommended Practice (PDF) https://www.energy.gov/sites/prod/files/2015/05/f22/miller%2...

[2] UPRtek CV600 https://www.uprtek.com/en/product/SPECTRAL-COLOR-METER/CV600...

[3] IEEE 1789 Graphic Comparing 4 Light Sources https://github.com/yeutterg/beautiful-flicker/blob/master/ou...

[4] Beautiful Flicker https://github.com/yeutterg/beautiful-flicker

I don't think I could have wished for a better answer, thank you. Love it when a new area opens up to me like that! While I'm not active within lighting per se, some of our customers are, and this will help me understand the complexities of their products better. So, thank you, it does help!

So glad this was useful! Please let me know if there's anything else I can help with lighting-related. I'm super easy to find.

This concerns me. About a year ago I went onto a website and ordered 56 led bulbs for my entire house and thought I got a fairly good deal. They worked seemingly well but my eyes always felt strained when under them. Just took my iphone and can definitely see the flicker with slow motion. And when I look at items as I move my head across the room I feel like I can see it as you say and never really knew what I was experiencing before. As someone who always talks about having sensitive eyes to light I am definitely not happy about this and am now thinking about buying flicker free bulbs. Thanks for sharing.

Next time, a good resource is https://ledstrain.org/. I found it here in HN and is quite informative for makign decisions on what to buy.

I usually just move my phone really close to the lightbulb and watch the live camera view. At a certain distance/angle you can usually see the flicker as banding across the screen.

I saw a test in a Swedish newspaper lately that showed IKEA's cheapest lightbulbs as one of the less flickery ones in the test. IKEA art.nr 303.887.64. So much for the price to guide you.

Bought an IKEA led lightbulb for €3 and the packaging says it should last 15000 hours. Not bad really.

LED lights are alright. Lots of people think that everything used to be better but my memory is too good to fall for that trap.

I can spot a Cadillac or GMC vehicle on the road a mile behind it from the flicker of the taillights. It's terrible.

Agreed. Most car manufacturers' LEDs flicker (just look at any slow-motion video, such as those on Top Gear or The Grand Tour), but GM's are at a much lower frequency that is visible if the vehicle is in motion, or you are in motion.

I always wondered if anyone ever tried to encode information into the flicker pattern of LED tail lights. I can think of a lot of uses, good and bad.

Some people are talking about using LiFi or high-speed IR communication for vehicle to vehicle communication. Seems like a great idea, but you can do it at a much higher frequency than what GM is doing today, so it's not distracting to humans.

Why do they flicker? Are they AC powered?

You can dim LEDs by turning them on and off really fast using a process known as pulse width modulation (PWM). Ideally for something like brake lights you would use a constant current driver to control the light level to prevent flickering. I don't know why GM is using PWM, but I'm guessing they just use a cheap control circuit. I really hate their LED tail lights. Just moving your eyes from side to side is enough to easily see the flashing.

Also, due to leakage for large LEDs they are more efficient at higher current. That means that for a given power, you're better off driving them at a higher current for a shorter duration. You can increase the effective luminance without violating the power spec.

Cheap brands generally use some form of capacitive dropper scheme. These result in the 120/100Hz flickering but is cheap to produce as very little components are needed (X2 class capacitor, maybe some current limiting resistor(s) and a discharge resistor, bridge rectifier, or even skip the rectifier altogether). They are not to be used with a dimmer. Some info on them [1]

The switch-mode power supplies in proper lamps get the stuff done way better and there will be no noticeable flicker. Maybe in the order of several kHz in ripple which you cannot see.

Also; cheap off brands (looking at you china) sometimes have caps rated at 250V which is far from the peak mains rate of about 320V (in 220/230V countries).

[1] https://www.powerelectronictips.com/whats-stuff-capacitive-p...

I just went and tried to find a bright (1000-1500 lumens) Philips LED bulb with a cool temperature (3500-4500)... but it seems every Philips LED bulb is "warm white"* :/ That's fine for a living room, but not what I want in my home office, kitchen or bathroom.

* at least in the UK

I'm surprised no one has mentioned hte rise of flickering LEDs on cars - though I think in this case it's caused by PWM dimming.

I mean, it looks absolutely fine as long as the light source and viewer are both static - just a shame vehicles tend to be moving :(

I don't get why DLR LEDs needs PWM at all. It 100% can be done without, even with smooth light distribution.

I have electric heating and in the winter there is no energy benefit at all from LED bulbs. I want my incandescents back. They really feel comfortable in a way I can't explain.

They really do. I placed an incandescent on a floor lamp to use it for reading, and it's now the most pleasant light on my house by far. But it gives me anxiety to leave it on for a long period of time because I know it's a huge waste of energy. The second best are my Phillips SceneSwitches, which I really love but don't come in 100w.

Perhaps dimmable LED bulbs would be better in that regard? The LED dimmers on the market use a very high rate PWM (afaik) to prevent/minimize flickering at low brightness. I would guess that the dimmable bulbs are designed to work well with intermittent power and so wouldn't have the same problem.

Of course it's still hit or miss, compatibility between bulbs and dimmers seems to be very hard to judge without testing these days.

Dimmable LEDs are not automatically flicker-free. My father had very cheap dimmable ones, and I complained at every visit about the strobe effect until he bought flicker-free ones.

Most dimmers work via pulse width modulation [1], i.e. the power supply is switched on/off in a different interval (more off time means lower brightness). A true flicker-free dimmed LED has to be dimmed in an analog way (probably only feasible for "dumb" light bulbs). PWM of 20kHz or something might also work, but who knows what that does to brain waves.

1: https://www.waveformlighting.com/film-photography/an-introdu...

I can't find the source right now, but I read that the fastest cells in the visual pathway can respond at a bit under 500Hz. Part of the reason the ieee suggests a minimum PWM frequency of 3000Hz is, for signal processing reasons I don't fully understand, that's the highest frequency the brain could likely detect, given 500Hz "sampling hardware."

You might still get strobe effects where your 500hz sensing nerves eg get a 400hz signal from a 20khz source.

In my experience, dimmable bulbs are no better. Most of them still suffer from the 120 Hz strobing effect. That's because even though they might PWM at 1-10 kHz to control the dimming function, when A/C voltage crosses zero, the "on" state of the PWM can still be a lot dimmer than the "on" state during the A/C voltage peak.

I would think a good LED would need something like a full wave rectifier with a good smoothing circuit to minimize flicker. I bet a lot of the bulbs on the market cheap out on the electronics though.

My oven has a high / low switch for the LED lights and I can't have it on low because the strobe/flicker drives me nuts.

The bulb they link are listed as dimmable (flicker-free silent dimming) aside from the part they quoted.

Have to mention this¹ big HN thread from 2 months ago with lots of discussion about that exact issue.


¹ — https://news.ycombinator.com/item?id=18644590

I noticed the same thing when I was playing the guitar. The constant flickering combined with a vibrating string at a high frequency produces a nice looking effect [1], which can be observed with a naked eye (unlike the one in the video).

[1] https://www.youtube.com/watch?v=ttgLyWFINJI

Interesting, I used to be very bothered by computer CRT monitors set at 60hz refresh and bright backgrounds. I'd go into the Windows control panel (most often) and increase it as far as it would go at the given resolution.

Through trial and error I found that 72hz was acceptable/ok and 90hz and above was great. Other folks generally didn't notice, but sometimes could if I showed them to look sideways etc. This must explain why I've never knowingly been bothered by 120hz LED flicker, it is below my ability to consciously notice.

Curious, I took a look at several bulbs, with the mobile at 240fps trick described elsewhere. A new Feit dimmable, new Ecosmart non, a several year old Ikea, and a no-name CFL. All showed flicker except the CFL. All the LEDs flickered, but the amplitude was larger on the ecosmart. Feit and Ikea had a small amplitude.

Perhaps they are putting half the LEDs out of phase to get the smaller amplitude, or they should?

Small correction, the CFL did have some flicker, just small enough I didn't notice on first look.

Have you tried this with incandescent bulbs? They flicker at 120Hz too... since they are P=I^2R and driven directly from 60Hz lines. I don't know the amplitude variation that bothers you, but then I don't mind LED bulbs.

Of course it's not the LEDs that do this but the cheap AC-DC conversion bridge rectifier.

Yeah, but because incandescent bulb filament's retains enough heat to continue to glow between peaks, their flickering is almost negligible - especially compared to poorly designed LED and CF bulbs.

Philips has some solid products. Our old television used to be Philips and it lasted a full decade and a half - we only got rid of it to get an LED TV. Most of our light bulbs have been Philips all my life and they have generally lasted a good while better than other brands we have used.

Yeah I can immediately tell when an area is illuminated by LED lights when I spot the strobing/flickering as I move my eyes and the saccade reveals the slow frequency of the light dispersal (or however it would be worded). It's super jarring and can be a bit disorienting.

You say "don't have this problem", but given sufficiently unstable mains input, the Philips bulbs too will do this.

Source: I just had a problem with a malfunctioning light switch (not even a dimming switch, a plain two-state switch) wherein sometimes it would poorly complete the circuit, and one bulb out of the four on the circuit would start oscillating on and off. (If you removed the one bulb, another would start. If you plugged the first bulb back in, in the original slot or another, it would happen to the first bulb only.)

On an iPhone - at least the 6S I have - you don’t even need to record a video. Just switching to slow motion in the camera app will instantly show you flicker in the live preview, I assume because it’s interpolating frames from the 120hz input.

Never even thought about this problem, thanks for bringing it up

I was in a hotel room a while ago which had some seriously flickering LED lights, just everywhere; moving around you could definitely see it. Wasn't pleasant.

I tried this with my office lamps and saw the flickering so I bought the Philips bulbs you linked to. They just arrived and I filmed them but they also show the flickering when filmed on an iPhone in slow-mo mode.

Do I need to buy a specific model of Philips bulbs? Or is my Ikea lamp the culprit now? I paid a ton of money for a certified flicker free monitor so I'm very keen on making sure the lamps are flicker free as well.

+1 for Philips bulbs.

Lights is something that I used to cheap out on but no more. Not buying Philips bulbs is definitely 'penny wise, pound foolish'.

Also, Philips Hue!

I bought some LED string lights for my bedroom because they were cheap. They turned out to be incredibly annoying due to the 60Hz flickering. Staring at them, it wasn't noticeable but the moment you moved your head or moved something quickly you could see the strobe effect. I trashed them and bought some incandescent lights.

Ah! I'm glad someone found the same thing as I did regarding Phillips bulbs. Here's my old post: https://news.ycombinator.com/item?id=18645237

My Philips Hue bulbs visibly flicker when they are dimmed, but not when they are at full brightness. I never had that problem with the old style bulbs. I wonder if that could be fixed with a firmware update?

Theoretically, they could, but I don't think Philips really has a financial incentive to update anything that "already works"

Yes, I also have the flickering issue with some LEDs, and I can confirm that (to my eye) the philips LEDs I bought do not flicker. I also have a few OSRAM LEDs that don't flicker.

Our WeWork has them in the kitchens - I feel like I'm drunk whenever I am in there!

I've taken every single LED bulb that has failed on me to pieces and it's always the same failure mode. The heatsink compound isn't applied properly to the back of the LED board. The LEDs immediately in the gaps smoke out.

Alas this isn't a problem. If a lightbulb goes, Amazon send me a new one out now free of charge and tell me to throw the old one in the trash.

This is one manufacturer, prevalent on Amazon, the Long Life Lamp Company. Long Life my ass.

They have been replaced by Philips and Ikea LED bulbs now which the oldest are 5 years old now and still going strong.

Edit: one thing to note is the really cheap ones run pretty hot. They have 105 oC rated capacitors in them. If you look at the derating curves at the running temperature they are clearly designed to last just past a year.

I replaced around 25 bulbs in my house with cheap Walmart "Great Value" LEDs just under 3 years ago and they've all been fine. Previously, I had replaced around 4 bulbs with Cree LEDs from Home Depot, and half of those were dead within a few months.

The Walmart bulbs without any special pricing were way cheaper than the Cree bulbs from Home Depot, but even better, there was some sort of automatic rebate or something like that in cooperation with the local electric company that made the Walmart bulbs $0.17. By "automatic rebate", I mean that the bulbs rang up on checkout at $0.17. No rebate forms to send in or anything like that.

"Previously, I had replaced around 4 bulbs with Cree LEDs from Home Depot, and half of those were dead within a few months."

Were those the original Cree bulbs with the heavy, finned metal heatsink around the base ?

I currently have a bag of about 14 of those that I bought (with great enthusiasm) and that burned out (or turned weird purple colors) within 2-3 years.

New style cree bulbs appear to have these issues solved. In fact, I continue to buy them as they perform better than other (satco, fein) bulbs that I have. In most cases I get satco/fein as long as they have the color temperature and output I want, but if I am having issues with a dimmer, etc., I get a cree bulb.

Those early Home Depot Cree bulbs were definitely defective. We bought a ton of them and have since replaced nearly all under warranty... twice. The first round they replaced with identical ones, which also quickly failed. (Always the same; started with an intermittent flicker, which progressively got more severe and regular.) More recently we've gotten a new design back, which seem better. Fortunately, after the first ones, it's been as simple as replying to the email thread and telling them how many more replacements I need!

"Fortunately, after the first ones, it's been as simple as replying to the email thread and telling them how many more replacements I need!"

Could you tell us that email address ? I have a box of 14 original Cree bulbs that I would like to get replaced...

I'm in Canada, so I emailed creelightingcanada@cree.com. Looking at this page, it appears the US one is info@cree.com: https://lighting.cree.com/resources/warranties

Yes. I have six failed ones I need to send back. Power supply failures on every one of them within a year of installation.

The Cree bulbs have been a disappointment for me as well. There was so much buzz about then when they came out, but I've had so many where one of the elements fizzles out and kills the whole bulb because they are wired in series and the elements fail closed or very high resistance.

If I cared more I might try to take the bulbs apart in a way that I could get them back together and just bypass the failed LED with a resister to bring the bulb back to life (at 15% reduced capacity or so).

I have been very disappointed in how hot the bulbs run as well. It feels like they must be wasting a lot of energy to run that hot.

That's funny I had 3 LEDs die in a week and they were all great value. I believe I bought them 4-5 years ago. I've also had a cree die. Overall though waaaay better than incandecent or even compact CFL.

I bought about 100 regular incandescents in various wattages at Lowes before they were banned. I wish I had bought a lot more. They were about $0.25 per bulb at the clearance sale prices. CFLs and LEDs are poor substitutes from a quality-of-light standpoint. Also AFAIK there is no hazardous waste in a burned-out incandescent. You can throw it away with a clear conscience.

But you're using huge amounts more energy, I think that would rest on my conscience a little more.

Not if you have electric (temperature controlled) heating.

Can you not still buy halogens? I like the light they give out and while they are nowhere near the efficiency of an LED bulb, they last pretty long by incandescent standards and they are somewhat more efficient than the old argon bulbs.

The guy in the other comment apparently paid led .17$ and they are all still good after 3 years.. What is the percentage of survival of the incandescent light and how much electricity are you wasting until they die?

I bought a pile of cheap LED bulbs[0] when they first became available on Amazon Canada, and replaced every light in my home.

They've run cheap and cold for years now, without a single failure.

I suspect that there's some planned obsolescence in newer products.

0: https://www.amazon.ca/gp/aw/d/B01EN9L8YU?psc=1&ref=ppx_pop_m...

Similarly, I replaced all my bulbs around 2011/2012 after buying a new place and I have yet to have a single one fail on me.

These were fairly expensive, about $11 each (the going rate at the time), and were TCP brand, but it was unpleasant to read that newer bulbs might be far worse when it comes time to replace them, even if they are cheaper. I love the fact that they die so infrequently that I don't have to keep any spares around.

I have had good but not perfect luck with the TCP bulbs. I've had two or three die (out of perhaps 40 or so). They also have mediocre color compared to a newer design.

Nobody is going to deliberately sabotage their LED bulbs because nobody really has a monopoly on them. They probably use cheap components that are only rated for the warranty period, but that isn't "planned obsolescence".

Nobody is going to sabotage them, but they’re also not going to spend money making them list one minute longer than they really have to. If you’re focused on the short term or think reputation isn’t a big driver of your sales, then your product really doesn’t have to last very long.

I think it gets worse as time goes on, because manufacturers gain experience with the lifespan of their components and learn exactly where they can cut. If you’re not quite sure how long something will last, you’ll probably err on the side of caution and engineer it to last longer than needed in case you got it wrong.

A competing manufacturer can always offer a product that last longer and warranty it, and people might choose to purchase it depending on the price.

However, as the article notes, people may not be interested in paying a premium for a product that lasts 10y instead of 5y or 20y instead of 10y, since the tech can change or maybe it’s susceptical to other kinds of degradation.

For bulbs that are really cheap, people won't keep their receipts and warranty information. I think it will be hard for bulbs to differentiate by warranty.

If you buy at Costco, you can return them at any time in the future without a receipt. The return desk will lookup past purchases using your membership card.

yea if it fails after a year (vs. a few days) very few people are going to bother with or even remember there was a warrantee

The advantage of buying online.

Or Home Depot. Give them your email address and attach your cards to it and then you will always have the receipt.

I can't even trust that the company will be around in 5 or 10 years. Or that they won't come back with some BS why they won't honor the warranty, and how it's my fault the bulb is bad. Long warranties are basically worthless anymore.

But when that estimate is based on 3 hours a day, and you actually use the bulb 9 or 12 or 24, the balance shifts significantly.

That is true. It is not directly "planned obsolescence". But our whole economic capitalist system is based on the idea of consumption. That means that products by default do not need to last.

Philips vs. OSRAM

My flat has some sort of bad-quality switches and when switching on/off the lights I often used to have some failures when using classic light bulbs (I have no clue about electricity - in any case in some way when I press the on/off-button the transition seems to be "dirty").

4 months ago I bought a new lamp and decided to give OSRAM-bulbs a go (it's a well known brand in Europe but up until then I always used Philips) => 2 LED-bulbs failed within 2 weeks (I put in the 1st bulb => failed after 2 weeks => replaced it with a 2nd bulb => failed again after 2 weeks).

I then went back to using Philips-bulbs and the one I used to replace the last one which failed is still working now.

Philips seems to be, at least in my case, definitely better or at least more "lenient/tolerant" at least concerning my the switches installed in my flat.

Anybody having negative experiences with Philips or positive ones with OSRAM or the opposite?

> Alas this isn't a problem.

It is a problem in the sense that it creates waste and pollution. There is a cost to throwing things out, and for shipping things across the country without limit.

Goes in the WEEE recycling here and is recycled so the impact isn’t as high as it may be elsewhere.

I do agree with you fundamentally however.

Recycling of electronics does not have to be as good for the environment as it's made out to be. It can be pretty toxic stuff to melt and separate.

How much less is the impact?

two usage cases, one obvious to me but one wasn't.

the first being, areas with vibration meaning near doors and garage door openers. great locations to eat LED bulbs. this might be related to your heat sink adhesive issue.

the second is the upside down tulip light fixtures common in bathrooms, apparently they cook quite well unless ventilated at the top.

Do not buy "bulbs," they are hopeless. Just buy a whole fixture with a big aluminium PCB and directly bonded chips.

My friend's bathroom light that is now a strobe light and the landlord has yet to replace because it requires an electrician to replace the whole fixture would like a word with you.

>requires an electrician to replace the whole fixture would like a word with you.

Kind of like how replacing a gas dryer "requires" a licensed plumber to make the gas connection or you're "required" to drive no faster than the speed limit at all times.

You're getting the runaround. If it was in a vacant apartment that they were showing to people it would already be fixed. If they cared about getting it done ASAP they'd either shell out the big bucks or ignore the law.

Edit: I think a lot of people on HN don't realize how simple swapping failed parts is. Swapping a failed water heater or electrical fixture (especially light fixtures) is a waste of the skilled tradesman's time and the customer's money. Even an incompetent landlord or maintenance service should be able to get it done.

I have experience in this (US Midwest) Most licensing regulation for these things are for professional commerce, and the more general the more they about demonstrating financial means to cover liability and/or a means of taxation, education or demonstration of work is of minimal to no importance. Aquiring general contractor licenses I often found myself using a web 2 fax service to submit pdf documents to a fax number... over T38/VoIP to the building department who could print the fax from their email as they required physical copies to be filed.

It's rarely criminal for homeowners to DIY within building code regulations, permits be damned. When the bank owns part, appraisal or home sales happen, insurance policies are involved non disclosure can be fraud.

My 2¢ on DIY from general contracting experience,

Water: Undetected water leaks can be fucking expensive, consider location and worst case scenario when making decisions. Don't use shit like AS SEEN ON TV toilet tank gaskets or tool free water valves in a production environment.

Gas: Thread seal tape is a lubricant that helps seat solid metal (usually) connections to create a seal, not a sealant. (can be welding agent for polymers)

Water, dish soap, spray bottle helps test connections.

Gases have different smells or lack there of, different densities (sink, rise, displace oxygen), can combust in different concentration ranges, etc so understand this.

Electric: Changing the load or adding potential for increased load on a circuit (new fixtures, receptacles, breaker, fuse, conductor, etc) could cause arcing and lead to fire in unexpected ways. Sections of copper wire get replaced with smaller gauge at some point over a properties history and then get sealed back up in a wall, among all kinds of other wacky shit. Understand the physics and dangers.

Connections are important, and common points of failure. They should be appropriately terminated and enclosed. Use the proper size wire nuts.

All: Valves, switches, and people are flaky so plan accordingly. Test shut-off or failsafe mechanisms and have a plan for the worst case scenario.

yeah, darn those pesky laws around liability getting in the way of some good old-fashioned handiwork.

The law once mandated that you hire the services of a licensed electrician to replace a lightbulb. Imagine if the same laws where applied to tech. Need to update Microsoft office? No way arround it you need to hire the services of a licensed IT professional! You might get electrocuted in the process not being a professional. So it all makes sense.

It's not really possible to burn down your apartment building if you fail at updating Microsoft Office, so that's one big difference for gas/electrical laws.

Cite please. Was that ever really a law anywhere other than Victoria, Australia?

Actually it is the law at every trade show I've ever exhibited at, just about to the point where you can't plug in anything without a union electrician doing it. One can usually get away with plugging in a laptop, but certainly if you need anything more than the single standard 10A 2-outlet power drop, expect to pay and wait for the official electrician (and they will kick you out of the show for violations).

Edit: I've seen this at least in NY, Florida, California

> it is the law at every trade show I've ever exhibited at

I've read that you can't move chairs, etc, either. I understand it's part of the contracts between venues and unions.

That's not a law, just an event venue rule based on their union contracts.

As long as you're just replacing the fixture and not running new line a handy man type person can do it legally.

Generally, a landlord wants someone licensed with insurance to handle something like that on the off chance something goes wrong. I was going to fix the fixture in my bathroom that was shorting a bit and burning out bulbs myself. Thankfully I called my owner and he had an electrician come in because it turns out a lot of the conduit above the fixture needed replacing due to age.

People who do handyman work for a living can and should carry liability coverage.

example: https://www.progressivecommercial.com/business-insurance/han...

The majority of people doing handyman work without a contractor license are effectively judgment proof so liability coverage is kind of pointless.

Judgement proof typically means you have no money/assets to come after, so even if someone wins a judgement against you they aren't getting paid. That's why you ensure you hire a handyman with liability insurance, so that there's something (the insurance payout) to collect in the event of a problem. Do you mean something else by judgement proof?

In some jurisdictions.

IIRC, Australia requires an electrician for even this sort of minor work.

> As long as you're just replacing the fixture and not running new line a handy man type person can do it legally.

That likely depends on local codes; not sure about light fixtures specifically, but I definitely have encountered variations in different cities in the same county when it comes to ceiling fans.

Few plumbers or electricians with a license are going to waste their time replacing your dryer or light fixture. They probably will send their (unlicensed) employee who's paid a couple bucks over minimum wage to do it. Their time is better spent on jobs that actually require their expertise. You know, the kind of jobs where you'd pay extra for a credentialed expert anyway. They probably will never set eyes on whatever you called them for.

Those laws (especially when combined with licensing requirements that exclude all but those who have a full time career in that field) are a massive hindrance to individuals and many businesses. They usually amount to little more than a potential transfer of liability. If your house burns down maybe you can try to point the finger at the licensed professional (good luck at that). The only thing it accomplishes is making it (slightly) harder for people who are habitually grossly negligent to keep working in that field. This is a non-benefit IMO because so much business is based on reputation anyway. The downside is that by artificially raising the minimum price access to access skilled labor you cause all sorts of work to be forgone because people can't afford it.

Plenty of house fires have been started by people who couldn't afford to pay an electrician but could afford an extension cord.

Edit: Since I'm apparently so wrong does anyone want to explain why. A down-vote without a reply is roughly synonymous with "your opinion is inconvenient to me but I cannot refute it"

> A down-vote without a reply

...is using the downvote correctly. Downvoting is for comments that are not productive contributions to the kind of discussion desired on HN, responding to any post that merits a downvote is increasing the noise-to-signal ratio.

Because the majority of HN reader have always either paid someone or simply never been involved with:

* Home rennovation (requiring city signoff)

* Home repairs

* Rental repairs

* Court over repairs or alterations to property

Why do you even need a landlord or maintenance service to swap a light fixture? Replacing a fixture is a bit more work than replacing a bulb, but it's not exactly hard.

It's a shame that ceiling light fixtures in the US are directly wired and screwed in.

In other countries (both in Sweden where I lived before and here in Japan where I live now) there are special ceiling power outlets, so replacing a light fixture is just a question of unplugging and plugging in again. Japan: https://farm5.staticflickr.com/4279/35698610491_8787f45eae.j... https://farm5.staticflickr.com/4230/35790814576_382943d360.j... Sweden: https://www.eldirekt.se/pub_images/medium/1890776__13222.jpg

There's a wide range of quality ceiling light fixtures that you just clip into place, and the LED chips are on a huge metal heatsink so they run very cool https://panasonic.jp/light/led/products.html

I used to think that, and I changed my mind. The fancy retrofit fixtures are almost universally flood lights where the diffuser is close enough to the ceiling plane that it’s visible from far off axis. The result is that the lights on the far side of the room cause unpleasant glare.

With a retrofit lamp, you can use a high quality trim baffle (these things cost about $12, are quite well designed, and are probably already in your house and put a civilized PAR30 or PAR38 LED in, and you get a much better light distribution.

Back when lamps were all standardized incandescents, fixtures could focus on quality. Now, with LEDs, I suspect that manufacturers focus on how cheaply they can build a driver and assembly that meets some minimum performance criteria. So, with retrofit lamps, at least the fixture design is separate.

(There are exceptions, of course. Very high quality dedicated fixtures exist, but they’re quite expensive.)

There's a lot of junk to be sure but tens of Philips & GE bulbs have been doing great for me for a couple years now. They don't run that hot either.

I was surprised at the early failures of my Sylvania bulbs. Had expected that going with a brand that has been in the light bulb industry for a long time, I would get decent quality, but they've all died in under a year. Now IKEA bulbs are my go-to, the mix of selection, quality and price is impressive compared to what I've seen but I haven't thoroughly researched this. Do Philips or GE do better?

I have only my anecdotal experience, but I'm happy with the Philips & GE bulbs. As I said, they both seem to run pretty cool. Philips makes what seem to be inexpensive-but-quality bulbs, as well as dimmable LED's that red-shift like incandescent used to. They also make a 60W yellow bulb that has very low blue emissions, uncommon for LED bulbs. Some of GE's LED bulbs have really high CRI which I like for making the basement more cheery.

One thing to pay close attention to on the package is whether the bulb can be run in an enclosed fixture. The package should always specify. Following this guidance and picking the right bulb for the fixture will help ensure you get the service life you expect. I don't think I've found any 100W equivalents that are OK'd for fully enclosed application, and 60W equivalent is like 50/50.

The last I looked at them, Ikea bulbs ran hot the packaging advised not to be used in small/enclosed fixtures because they could overheat. Do you find that to be the case with the ones you're using?

I have a couple of 2W/80lm ikea bulbs for bedside lighting, and they are room temperature.

I also own some 5W/400lm ikea bulbs for general room lighting and they do run warm, maybe something like 40°C ± 5°C. The fixture/thingy around the bulb is roughly the size of a fist.

The bulbs are pretty new so I can't say anything about the lifespan of the bulbs, but the price is reasonable, they are not the fancy smart bulbs.

I bought one of these for my basement hallway when I was finishing it out. My only concern is that a normal fixture has few failure modes; just the bulb. But if this fixture fails, I have to find a new one that will fit in the same spot. Hopefully it will last til I'm dead.

I've started doing this. Bought a large panel fixture and a separate high-quality LED current source and it has been absolutely great. Next time I build a house I'll probably run all the lighting circuits on a hefty 24VDC main power supply with small DC/DC regulators on every fixture. There's no reason nowadays why lighting circuits should be 120 or 240VAC.

power loss and price of copper is a good reason to bring 120/240vac as far as possible.

Like I said in a previous comment, with LEDs, power requirements are small and distances within a house are small. Coupled with a resonably high but safe voltage (like 24 or 36VDC), there's no reason why 14 gauge copper wire couldn't work just fine for a lighting circuit.

I wish there was more selection available of that kind of thing— when I last looked a year or so ago there was basically just one option at Home Depot, and it had the aesthetics of something you'd put in the laundry room.

Worse than that, though, it was unusable with a dimmer switch; the whole thing visibly flickered every few seconds. I felt bad returning it because I really wanted it to work out, but the quality just wasn't there.

I have an LED fixture that I got from home depot that is dimmable, no flickering. It's connected to a normal dimmer switch. I bought it about a year ago.

My other LED fixtures were ordered through aliexpress. The fixtures were fine, but the transformers that came with the fixtures all failed and had to be replaced (overheated, melted the plastic casing). This turned out to be tricky, because the LED drivers available on ebay and aliexpress are never the same, there are constantly new shoddy ones from noname brands, and the ones I had bought before tend to be nowhere to be found when I need a new one.

I didn't know that the fixtures themselves had dimming features. I put "dimmable" LEDs in my can lights in the basement, and I'm really unimpressed with them. They don't flicker[1], but they don't get very dim, either.

[1] Except after a power outage - then they eerily flash on and off like something out of Stranger Things.

That is the constant frustration of this economic model. Either you buy the driver (or the LED bulbs for that matter) from a shop in your own regulated economic area (like the EEA) and have them handle quality assurance (including the selection of the product) and warrantee, or you get the same product directly from China for a fifth of the price and have to handle the occasional failure yourself.

The sad thing is that the latter is still cheaper than buying from a 'local' shop.

I have had good success with, and have been happy with the quality of _MeanWell_ LED drivers and power supplies. You can get them through Mouser, Newark, Digikey etc.

Honestly I can't be bothered to replace the fixtures.

Edit: looking at the price of fixtures, the economic argument is poor as well.

This is in contradiction with the article, which says that the driver is the cause in 90% of cases.

EDIT: This was not entirely correct as the article says:

> The US Department of Energy (DoE)’s solid-state lighting program supports research and development of LED technologies, and their website contains volumes of data on LED lighting systems. Their Lifetime and Reliability Fact Sheet contains data on the failure rate of 5,400 outdoor lamps over 34 million hours of operation. Interestingly, the LEDs themselves account for only 10% of the failures; driver circuitry, on the other hand, was responsible almost 60% of the time. The remainder of failures were due to housing problems, which may not be as applicable for bulbs in indoor use.

Yeah well, cheap led bulbs don't have a driver, so obviously other problems kill them.

Some don't even have a bridge rectifier - just a couple of capacitors and that's it.

Actually, a single manufacturer having one dominant problem is not in contradiction to the industry as a whole having a different dominant problem.

... so what happened to the 100k hour LED bulbs?

It never answers the question. It has an anecdote about the author's own lamps that ran an estimated 15-20k hours with an advertised lifespan of 30k and have degraded to the point where they will replace them. That's n=1 and nowhere near 100k hours, or even 50k as the author mentions early-adopters will remember seeing advertised.

The article contains a lot of info, but does not actually answer the original questions it poses in the title and the second paragraph.

Closest I saw to an answer was the last sentence of the "Color Shift Happens But is Unpredictable" section.

>It’s possible that the reduced lifetime ratings we see on current bulbs simply reflect better knowledge about actual performance of existing LED technology over time.

It's implied in the conclusion that 100,000 hours are not necessary because the progress of technology results in more efficient, brighter, and higher CRI bulbs.

as with many such articles, the title is rhetorical and not intended to be answered.

Is it in this case. I presume that at one time there were actual bulbs which said 100,000 hours on the physical box. What specifically happened here? Do we have the same bulbs today and the marketing was wrong, or are bulbs today de-engineered?

I'm not positive on this one, but out seemed the article alluded to the idea that the 100,000hr life was measuring to LED failure and ignoring the possibility of driver failure, whereas now there are stricter standards both for measuring the potential of a driver to fail and measuring the lifetime of an LED as the point at which out drops by 30% rather than the point of total failure.

So, engineering lead of a (outdoor) led Luminaire manufacturer here. And our sales director used to work for one of the biggest Asian light bulb OEMs. Happy to answer specific technical questions out there that this article triggered.

Since the article never answered the question, do you know what happened to the 100k hours LED bulbs? Were the initial estimates just over-optimistic? Was it all marketing hype?

I can only guess that the marketing department wanted to put the biggest numbers forward against what was plausible calculations for the early LED lifetimes.

I know for a fact that some of the testing houses have done extended on/off cycle testing for some of the big box retailers looking to keep the lamp vendors honest on real lifetime performance of A19 class bulbs. I've been in such a test chamber.

So which led light bulb do you install in your house?

Ikea when the size is available, for reasons I cannot discuss here.

My guess is that is has to do with IKEA's improving smart home trend [0]. I like the fact that the work with all three major platforms so I don't necessarily have to be all in on one if I decide to switch in a couple of years: "Trådfri [has] compatibility across Apple HomeKit, Alexa, and Google Assistant".

[0] - https://www.wired.com/story/ikea-fyrtur-smart-blinds/

It has nothing to do with this. It has to do with details about the OEM for the Ikea product.

Leedarson? (according to http://wastonchen.com/3973.html ) Never heard of them, they make good LEDs?

Leedarson is an OEM for many light bulbs you've seen on shelves in stores.

Seconded that. I switched to Ikea lamps back in the CFL days and today use their LED bulbs and lamps with no problems at all. Of course they're not manufactured by Ikea, but whichever is the maker it seems a very reliable one.

now I'm curious

i've tried a bunch, and the ikea bulbs do the best in a variety of conditions:

- longevity - when used with a dimmer - when a large load is applied to the same circuit

Most other bulbs fail one of those, but I haven't had an ikea branded bulb do poor in any condition.

Do you have preference for a particular line of Ikea bulbs? (Ryet, Ledare, etc)

The higher end line (Ledare?)

More of a non-technical question, do you see demand for outdoor lights at the red end of the spectrum?

Supposedly that's better for night vision, light pollution and various animals. But everywhere I go I see yellowish sodium vapor lights replaced with white LEDs.

I think it's a shame sodium vapor lamps are being replaced. Low pressure sodium (LPS) is actually highly efficient, provide a very soothing color for nighttime, and for me most importantly are easily filtered by astronomical observations (their spectrum is nearly a single line). Their size and unwieldiness is justified in utility street lightning setting.


We've certainly been asked about amber LEDs for coastal environment projects, so I think there is some demand. Amber LED performance, on the other hand, is a different story.

The lumens out of a legacy high pressure sodium lamp are very high. It is still an engineering challenge to get comparable lumens out of LEDs at price point the market will bear.

Is there a way for me to know whether or not an LED bulb will have a proper driver that does not throw away half the current and produce a "strobe" before I buy it? The flickering (in the presence of moving things) drives me crazy.

As above, look for architectural bulbs that are deep dimming rated (< 10% dimming). They cost more. I personally have had good luck with Cree, but probably the other top shelf vendors have similarly good products.

From the perspective of efficiency, defined as maximum perceived (by human eye) luminosity per watt used, what's the best color for LED bulbs? Is white as good as it gets, or is there any advantage with pure green LEDs?

Go look up scotopic vision, phototopic vision, and metamerism if you want a deeper dive on human vision.

Our eyes are most sensitive in the green, but green LEDs are not necessarily the most sensitive

The green LEDs are not necessarily the most efficient in terms of amount of light emitted per watt of energy used, if I understand correctly. Hence the question - is the increased sensitivity to green enough to overcome that inefficiency, compared to white?

Why do so many of the bulbs run hot? Like so hot you can't hold them in your hand if they were on when you unscrewed them. Isn't this a lot of wasted energy?

All bulbs produce heat, both from the LEDs and the electronics. Incandescent bulbs were blazing hot, too, and they radiated IR on top everything else.

A high efficiency LED assembly is still producing on the order of 50% light and 50% heat.

High efficiency is only 50%? Isn't that terrible? Are LEDs really that bad?

Incandescents used to be 5% visible light at best, with 95% of energy turned into non-visible radiation.

blazing is undertaking, the filament is over 2500K

Partly because they are running tiny cheap power supplies pushed near their limit, and also because many of the actual LEDs they use aren't nearly as efficient as they could be. Also available surface area, in order to fit in most standard bulb locations they need to be small leaving little room for adequately sized heat fins.

yes theres multiple kinds of inefficiencies concerning the external circuitry etc, but there is also the intrinsic inefficiency of current LEDs: some of the high energy photon are downcoverted to a low energy photons by phosphors, so there is non-radiative (heat) generation in the phosphor itself. In theory it is perfectly possible to use "quantum cutting" i.e. 1 photon -> 2 photons instead of 1 photon -> heat + photon. There is quite a lot of research on quantum cutting phosphors, both for LED's and for VUV excitation etc, so these higher efficiencies will probably come, but I don't know how far out in the future. If someone knows of commercially available quantum cutting phosphors (or products using them) I would be very happy to know about them for some physics experiments...

I think they might have began quoting the LED lifetime on boxes, which is still true, but in reality something else in the bulb usually breaks before the LEDs themselves. I guess manufacturers have either taken it upon themselves or have been forced to reduce the quoted lifetime since the famous 100,000 hours marketing.

Or they quote the lifetime figure for a single LED, but then wire up a dozen or more in series to make the light. Any one of them fails and the whole assembly goes dark.

If cost were less of a concern, what engineering changes would you make to the bulb?

#1 more die. More die means less current per die, which helps efficacy in a nonlinear way (google "LED droop") #2 better passives. Aluminum polymer caps, for instance #3 lower temps, in however you want to achieve that aim #4 some TVSS element if there wasn't one already


  1) Better cooling: non-tooth paste thermal compound, more space for heatsinks
  2) Not overdriven LEDs
  3) Introduce DC power lines (within the house/building) -   galvanic corrosion still might be an issue
  4) In lack of point 3 - more efficient AC -> DC converters, preferably with lower temp threshold, 
  having 150C default for the internal mosfet on 8pin LED driver is really high.
  4a) AC-DCs require quality passive components: coil and caps.

What's your take on why so many dimmable LED bulbs have flicker/buzz issues?

I've tried through 5 different MR type LED bulbs and every one of them had an extreme flickering issue. All of them were labeled as dimmable.

I've had better luck with the standard A type bulbs. But only because there were more thorough reviews available.

There's a myriad reasons why flicker and buzz occur, because there are a number of ways to achieve dimming. But all of this comes down to cost.

If dimming is important to you, there are a number of architectural grade bulbs that offer deep dimming to 5% or 1%.

Personally, for this application, I've had good luck with Cree bulbs of this type at home (on Leviton dimmers). And in the house of worship environment with Cree bulbs on Doug Fleenor dimmers (http://www.dfd.com/dmx8dim.html)

Second that Doug Fleenor recommendation. They make some fantastic lighting kit.

I'd also like to add that looking for lamps with the CEC Title 20 & Title 24 certifications should be helpful in finding bulbs that dim well, as California has much stricter regulations on dimming flicker and buzz than the rest of the country.

So, why do LED bulbs seem to last not as long as they should?

I think the parent article provides a reasonably accurate description of why

How do you predict product lifetime?

For LEDs, LM-80 data is used to extrapolate lifetime data via the TM-21-11 methodology. Its not great, but it is what we have. If you read the standard, it has pretty good summary of the drawbacks of the current approach to lifetime extrapolation:


But, in practice, other components generally fail before the LEDs have a (binary) failure.

There are standardized tests for all this stuff, as you might imagine. One in this case would be the LM80 test.

Source: https://www.amazon.com/LED-Lighting-Primer-Future/dp/1449334...

Thanks. For the lazy... it's explained here:


Do all types emit RF noise? What to look out for to avoid it?

Any bulb with switch mode hardware to control the LED drive current will exhibit RF emissions.

The cheaper bulb in the original article has linear current control. Inside the ASIC, this could be as simple as a BJT or FET in saturation with a (somewhat) controlled base/gate voltage, maybe with some temperature compensation.

The linearly regulated bulb will have less RF emissions, though you could theoretically still have a bit of rf trash from edge effects depending on the rectifier and filter cap.

Any bulb that has passed FCC Class B will have an upper bound on conducted and radiated emissions, but you can pass such tests on a wide range of margins, and therefore certification isn't useful to clarify which bulbs have the lowest emissions.

How much does it cost to make a LED bulb that runs no hotter than 45C at all times?

The trick is that you have passive cooling (a heatsink) in what could be a completely enclosed space (like a glass shade/globe on a flush-mount fixture). The heatsink can't be too big to occupy a similar volume to a 'normal' A19 bulb, or it won't be able to fit in lots of existing fixtures. I suppose we might see some bulbs try active cooling (with a fan on that heatsink), but people are already very aware of hums and buzzes from their fixtures, so it'd have to a quiet one.

I cannot speak knowledgeably to this for A19 type products, but generally there is no need to have such low temperatures to achieve good lifetimes. There may be temperature requirements this low for bulbs mounted in certain locations, but that is not a part of UL 1598 that I have in my brain.

Well, thanks for not answering my question in any capacity, I guess...

What do you recommend to buy if I want a ~2700 lumen, high CRI (>90), and non flickering bulbs for home?

I'm not sure for high CRI. See my comments elsewhere about Ikea otherwise.

What do you think of the Phoebus cartel? Is a form of it still continuing nowadays?

Can't speak to any of that. The appearance to me as a consumer walking around with an engineering eye, is that the early days of expensive higher end, store exclusive home LED bulbs (e.g. Cree at Home Depot) has given away to an all out price war.

What percentage of your sales is in RVs vs homes?

0% We do outdoor lighting for industrial environments

It’s dog hours, right?

What planned obsolescence do you engineer in to your fittings, etc.?

None. Our industrial customers require minimum 5 year warranty at 12hrs on per day, 365 days per year. We work hard to make both the lighting producing and mechanical aspect of the luminaires last.

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