Explain to me the (de?)-evolution of LED lightbulb technology - Page 1
Forum section: electronics / general

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 03:13:59 am
content: Greetings,In 2014, I bought some Cree LED bulbs, some of the first mainstream varieties available. Not cheap - I think they were at least $10-15/bulb, at the time. I still have one circa-2014 100W equivalent Cree I use every day in my desk lamp. Anecdotally at least, they seem reliable.The construction of the early bulbs tended to be quite exotic - Fancy cast aluminum pieces, fancy connectors, and so on. Obviously, it was a technology in its infancy.From an electronics perspective, these bulbs had (relatively) complex driver boards with some sort of switch-mode driver. Board was usually crammed with big inductor, one or more electrolytic caps, an MOV, fusing, EMI filter, switching MOSFET -- All the normal stuff you'd see an a power supply connected to mains.Fast forwarding a few years, the market has reached equilibrium, seemingly at the absolute lowest cost implementation possible. These days, seems most bulbs have some simple capacitive dropper or some all-in-one current regulator IC.How did we get here? Why is it "acceptable" or "reasonable" now to go for these super cheap implementations but 6-7 years ago we needed to cram a full-blown AC-DC power supply in the base of a bulb? Have the LED chips improved? COB style LEDs?In my experience, the newer bulbs have poor reliability, but I can't tell if that's a result of their overall design topology or if they are just built like crap. Or both.Anyone able to summarize what happened over the last few years?Thanks.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 23, 2021, 03:19:48 am
content: Quote from: TimNJ on March 23, 2021, 03:13:59 amMostly just pushing the components harder to reduce cost, if you derate the power by dimming them or modifying them, they'll last a very long time.

author: sleemanj
author_rank: Super Contributor
timestamp: March 23, 2021, 04:03:47 am
content: Your cree bulb has not failed. Manufacturers want things that will fail so they can sell you another one.Bonus is that making them as cheap as possible...1. means they can sell more2. means they make more profit3. means they fail earlier4. goto 1

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2021, 04:43:27 am
content: The natural evolution has been greatly reducing the cost. This has resulted in approximately a 50% reduction in rated lifespan but has also nearly doubled the efficiency since the early Philips and Cree bulbs I bought. The modern LEDs are much more efficient which allows them to be driven at lower current. This reduces the complexity of the cooling required as well as simplifies the driver. Highly integrated driver ICs have resulted in simpler drivers with lower parts count.So far I can't really complain, even 15,000 hours is a long time, and some of the early 30k-50k rated bulbs have not lasted as long as they were supposed to. For a long time I had almost no failures but recently two of the Philips bulbs in my bathroom had gotten substantially dimmer, a teardown revealed the LEDs themselves had deteriorated. I had a couple of the larger 800 lumen Philips bulbs fail too, those had drivers fail, the LEDs look fine.

author: Berni
author_rank: Super Contributor
timestamp: March 23, 2021, 07:39:53 am
content: This is just the typical race to the bottom that happens once a technology becomes popular.At the start when LED lighting was new technology people found it normal to be more expensive, but they bought it anyway because its shiny new tech, perhaps they bought it mostly for that reason, not because the light bulb was actually that much more superior to what they already had. Most people didn't bother but those that did care ware prepared to pay good money for it. Most new technology starts off like this.But then as LED lighting gains popularity, the bulbs become ever more efficient more, the word gets around about how good they are...etc and more people become interested in this newfangled LED stuff. But they bought the bulb because of how much power this fancy new light is going to save them. But if they care about buying this bulb to save money they will buy the cheapest bulb they have at the store, they wont care about CRI or efficiency or lifespan. The end result is cheep bulbs sell better, so the competition will make an even cheaper bulb, the next competition will make an even cheaper bulb than that. Before you know it you will find two similarly looking 15W LED bulbs on the store shelf, one of them costing $2.99 while the other name brand costs $15, this makes the high quality expensive bulb seam even more overpriced, making them sell even worse. Eventually they just stop making these high quality bulbs because they just don't sell.This happens with most areas. Once market volumes become large enough the cheep low quality products come in and displace the expensive high quality stuff. Its a sad reality.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2021, 08:00:47 am
content: But in this case the "cheap low quality" bulbs are in many cases perfectly adequate and actually perform much better than the early expensive bulbs. The early bulbs were complex and expensive because at the time they were struggling to get 800 lumens out of something the same size and shape as the standard 60W incandescent bulb they were trying to replace. It was a big challenge to drive the LEDs sufficiently hard and get rid of the heat they generated in order to achieve reasonable life. An additional challenge is that CFLs had gained a reputation of not lasting anywhere near as long as claimed lifespan so the LED makers knew they had to over-engineer the early bulbs because if $50 light bulbs started crapping out long before they were supposed to that would have killed the market and they would never have achieved the volume necessary to drop the price.The bulbs we have now may be much more cheaply made and much simpler, but that means they are affordable so they have achieved widespread adoption. Gains in efficiency have eliminated the need for the complex and expensive cooling solutions, reduced the resources required to manufacture the lamps, and in the process they have become much more efficient, deliver better quality light and still last a very long time. At this point I have retired most of my early LED bulbs, not because they have worn out, but because the modern cheap ones offer dramatically improved performance in most applications, and so far despite having a much cheaper feel, they have not proven to be any less reliable. Changing burned out light bulbs is largely a thing of the past.

author: tszaboo
author_rank: Super Contributor
timestamp: March 23, 2021, 08:51:02 am
content: Well, the thing is, I can go to IKEA, and buy a LED lamp for 1 EUR. 470 Lumen. Sometimes half the price of this. And it works.They also sell a bigger one, that is 1000 Lumen, you can change the color temperature, wirelessly dimmable, and has 11W rating, and it is surprisingly heavy, with polycarbonate housing.They also sell LED panels, with separate drivers, 34W, you can change the color temperature, wirelessly dimmable, about 7kg.I placed the first one in the garage, the second one in the bedroom, the third in the office. I dont think the quality decreased during the years. I think there is a larger variety to choose from. And it needs to be, because incandescent is obsolete and they don't sell it anymore.

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 12:36:51 pm
content: Thanks everyone. I understand the basic economics of it. Of course, the market equilibrium point gravitates towards lower cost.Quote from: james_s on March 23, 2021, 08:00:47 amWell, my experience is only anecdotal, but my experience with modern bulbs is a mixed bag. I've had a few go flaky on me, and a few outright fail. I understand that the simpler solutions are often the most reliable, as there is less to go wrong. But, I know I'm not the only person reporting early failures of modern bulbs labeled as "20,000+ hours".But, my suspicion is that the "topologies" used in modern bulbs are acceptable, but perhaps the parts are just underspecified and/or the quality control is poor on some of the cheap bulbs.My main point of curiosity is in understanding *what changed* between 2014 and now.Whathas gotten more efficient? The LEDs themselves? Why did the drive electronics go from complicated (50+ parts on the BOM) to completely minimalist (maybe 3-5 parts on the driver BOM). Did the ICs not exist yet?Thanks.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 23, 2021, 01:45:22 pm
content: On average my LED bulbs fail at maybe half the rate of incandescent or CFL A19-base bulbs. However, some packs burn out quickly while others seem to work. My voltage is around 124. I have a small collection of LED and CFL bulbs that I will eventually disassemble to find out what components failed.I just bought a couple Philips T12 F40 LED direct replacements. Nice color, no flicker, instant on. I will get more and try them out. They were maybe $7 each compared to $5 each for classic fluorescent.

author: madires
author_rank: Super Contributor
timestamp: March 23, 2021, 01:57:20 pm
content: I took a few apart which failed early because I was curious about the reason. The common issues are poor thermal design and cheap electrolytic caps.

author: MK14
author_rank: Super Contributor
timestamp: March 23, 2021, 02:04:04 pm
content: My understanding is that one single country, has introduced a law, so that the only Led bulbs allowed, are extremely long life (I'm NOT sure of the exact rules/law, so this could be WRONG), super efficient ones. So, seeing an opportunity, the manufacture(s) have produced such Led bulbs. But ONLY allow them to be sold in that particular country.BigClive found out about this, managed to obtain such Led bulbs and has done teardowns, reverse engineered schematics and measurements of 'our' Led bulbs vs those much better ones.I suspect, they don't even cost that much more to produce, so hopefully sell for reasonable prices.Essentially, they seem to have just doubled (or even tripled/quadrupled or more) the number of Leds, halved/quartered (approx) the current, and presumably/hopefully under-stress/underrate the power components, so that they can last perhaps 35,000 .. 50,000+ hours, at a guess.

author: madires
author_rank: Super Contributor
timestamp: March 23, 2021, 02:20:30 pm
content: Yep, those Dubai LED lamps are designed well. It's a pity we can't buy them easily outside of Dubai.

author: coppice
author_rank: Super Contributor
timestamp: March 23, 2021, 02:28:06 pm
content: People like compact lights, and lights that fit into traditional sockets. That usually means some parts are being roasted, especially if the lamp is used inside an enclosed luminaire. Its not the electrical stresses that kill the current cheap LEDs. Its mostly the thermal stresses.

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 02:46:40 pm
content: I love the filament bulbs, just wondering how we get away with a tiny 6x12mm or 8x12mm electrolytic cap in the base + some dinky looking diode bridge, while 5 years ago, the average LED light bulb had some monster 10x16mm cap, inductors, MOSFETs, all sorts of control stuff. We just don't need it anymore? Much better integration with new control ICs? In the early days companies were taking a much more old skool approach to doing constant current driver from mains?I've seen (I think electronupdate) do a filament bulb life test and they seem just as capable of lasting a long time, all things considered. I'm mainly just wondering where the heck all the control and power conversion circuitry went.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: March 23, 2021, 03:45:46 pm
content: I wonder if this race to the bottom price-wise results in LED bulbs that generate lots of RF noise? I wouldn't be surprised at all if it did.So now we have a product that generates two kinds of pollution: RF pollution and light pollution.

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 04:43:59 pm
content: Here's an example of an circa-2013 LED bulb:Here's a slightly newer construction (circa 2016), less parts, but still generally high level of complexity:Now, LED bulb might just have a simple capacitive dropper like this one. Remind me what the downsides of these are again? Power power factor for one.Or some highly integrated constant current driver like this. But, as far as I know, these are linear constant current drivers, i.e. MOSFET/BJT operated in ohmic region to maintain constant current? Is it that LED efficiency has improved so much that burning a little power in the driver is less of an issue since the lumens per watt is better than it was before?

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 04:47:00 pm
content: And, adding the above point about linear constant current regulator. If it's effectively a linear regulator, then there's no real need (or less of a need) for EMI filter since there's likely no high frequency switching activity.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2021, 05:08:48 pm
content: Quote from: TimNJ on March 23, 2021, 12:36:51 pmThe LEDs themselves mostly, they have gotten much more efficient. This enables them to be driven at much lower current, which simplifies everything else. The efficiency of an LED drops pretty dramatically as you crank up the current and the early ones had to be driven hard to get enough light out of them. This meant a mechanically complex design to deal with all the heat since almost none is radiated along with the light as with incandescent, instead it all ends up in the die itself. Then there are many new ICs that didn't exist before, and due to the lower power requirements enabled by newer more efficient LEDs the drive circuits can be simpler as everything runs at lower current.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2021, 05:14:52 pm
content: Quote from: TimNJ on March 23, 2021, 02:46:40 pmThe filament bulbs have dozens of LED dies in series and drop close to the full line voltage across the LEDs at very low current, this makes it reasonable to use a simple linear regulator IC without crazy high losses. Compare this to an early bulb with perhaps 6-8 LEDs with a total forward drop of 30-40V being driven at 300-700mA, naturally it's going to require a more complex driver with bigger capacitors. A significant downside of many of the simpler bulbs though is that they flicker at line frequency, I find the flicker annoying and avoid those.

author: coppice
author_rank: Super Contributor
timestamp: March 23, 2021, 05:15:24 pm
content: Quote from: james_s on March 23, 2021, 05:08:48 pmThey are not just more efficient. In 2014 Cree and one or two others had solved the problem of rapid ageing, while most makes were far dimmer after a few thousand hours. Now it seems most LEDs fade very slowly.

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 23, 2021, 05:46:20 pm
content: Quote from: Sal Ammoniac on March 23, 2021, 03:45:46 pmThe super cheap non dimmable ones, at least in 120V land, seem to have gravitated towards a linear driver setup. Those are silent to the best of my testing ability (holding a AM transistor radio near a 100W one I got from the dollar store).I wouldn't doubt it if the more complex dimmable and smart bulbs with buck converters and radios of their own make all sorts of noise though.

author: ogden
author_rank: Super Contributor
timestamp: March 23, 2021, 06:06:53 pm
content: Quote from: TimNJ on March 23, 2021, 03:13:59 amCustomers who buy cheapest (***t) they can get - happened. It does not mean that quality products do no exist anymore. Such are simply out of scope for generic buyers who check only nearby grocery store or lowest cost Amazon/Aliexpress offers.

author: TimNJ
author_rank: Super Contributor
timestamp: March 23, 2021, 06:49:04 pm
content: Quote from: ogden on March 23, 2021, 06:06:53 pmWhile part of my question was indeed about the (possible) decline in quality, due to a "maturing" market -- and capitalism being capatalism and cheap-asses being cheap-asses -- really I was just wondering what explains the overall shift in design approach. I think the few replies above neatly explain it. But, I do agree, part of it is consumers un-willingness to pay a premium for something that actually lasts (no shock there) and manufacturers willing to make crap in response.But, to my main point, here's my summary of the above responses:Earlier LEDs required much more current for X amount of lumens. So, you probably couldn't just throw in one of these (modern) linear constant current drivers because the driver dissipation would probably be way too much. I don't have any ballpark figures to compare then vs. now, but makes sense. So, they went for switch-mode constant current driver with relatively high driver efficiency. Nowadays, larger number of LEDs in series + much improved efficiency means the forward current can be much lower, making a linear constant current driver practical.

author: andy2000
author_rank: Frequent Contributor
timestamp: March 23, 2021, 08:19:16 pm
content: Quote from: Sal Ammoniac on March 23, 2021, 03:45:46 pmI recently bought some new LEDs to replace some early ones that were starting to fail. Coincidentally, around the same time I noticed a lot of interference on a vintage analog TV in the next room that gets used to watch the news. There were very noticeable wide horizontal noise bars moving up the picture. It turned out that the new bulbs were causing the interference. The set is fed using a shielded coaxial line, so I was surprised so much noise was leaking in. With the coax unplugged, the usual snow was completely obscured by the interference.Out of curiosity, I used my spectrum analyzer to look at the interference. This was with just an dangling probe as an antenna. You can see the FM band on the left side, and a couple of ATSC TV channels on the right. The bulbs were generating interference over the entire spectrum up to about 500 MHz. Needless to say, they went back to the store. The old bulbs generated no visible interference.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 23, 2021, 08:39:06 pm
content: Quote from: andy2000 on March 23, 2021, 08:19:16 pmFeit. I could have guessed that. Those fail the quickest for me.

author: Rick Law
author_rank: Super Contributor
timestamp: March 23, 2021, 08:43:06 pm
content: It is to be expected. CFL light bulbs also went through this expensive-to-cheap phase.Nearly 30 year ago, I got a 4 pack of GE CFL, 60W equivalent lumans at about $15 each. Two of them are still working! The home HomeDepot/Walmart CFL's bulbs these days dies left and right at a youthful age. I've a couple of those ~3 year old CFL with so much brightness lost it is kept as emergency - in case I needed a bulb when stores are closed. Most of the others hardly last past 3 years old.I expect the HomeDepot/Walmart LED lights (60W equivalent lumans) to be dying of young age as well.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 23, 2021, 08:59:14 pm
content: Quote from: Tomorokoshi on March 23, 2021, 08:39:06 pmThat is my experience as well. Nasty things. Thank you andy2000 for sharing the interference spectrum profile.I found out that CREEs are still well done. I did a video a while ago about a 2018-era 60W equivalent bulb and it had a real constant current source.If you are interested, check the circuit at about 10:30 of the video below (in portuguese only, sorry)

author: amyk
author_rank: Super Contributor
timestamp: March 24, 2021, 12:20:09 am
content: Some more discussion on the Dubai Lamp here:https://www.eevblog.com/forum/chat/the-dubai-lamp/Capacitive droppers are cheaper and in my experience more reliable than the switching ICs. I have some lights using them and they've lasted most of a decade.BigClive also made this video not long ago, which is mostly about a related topic, but one thing caught my attention: lights withsocketed electrolytic capacitors:I don't think I've ever seen socketed capacitors even in equipment designed to be serviced, much less a cheap throwaway lightbulb.

author: james_s
author_rank: Super Contributor
timestamp: March 24, 2021, 01:04:09 am
content: I had a lot of Feit CFLs that didn't last very long either, I actually fixed a bunch of them at the time, it was a mylar capacitor between the two cathodes used as part of the starting circuit that would short. For LEDs I buy mostly Cree and Philips, I've generally had good luck with those. I have some of the EcoSmart (Home Depot house brand) bulbs from way back in 2010 and a few modern ones, all of those are still working surprisingly.

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 24, 2021, 03:27:40 am
content: They socket the filter cap and mains connection to speed up/cheapen assembly, those reflow compatible sockets must be cheaper than the cost and/or time of hand soldering.

author: floobydust
author_rank: Super Contributor
timestamp: March 24, 2021, 05:11:49 am
content: LED light bulbs are shit because of intellectual property. The LED array, the heatsinking configuration etc. are all so heavily patented you can no longer make a decent LED bulb without patent infringement litigation. So many lawsuits, with the norm being to sue the retailers as well.EPISTAR Files Second U.S. Patent Infringement Lawsuit Against Lowe’s06/2020over GE bulbs. Epistar (has over 4,000 patents) sued Lowe's Home Centers over the Kichler Lighting LED bulbs.Lynk Labssuing Home Depot for patent infringement.LED filament bulbs are really bad forlitigation.Nichia Files Patent Infringement Lawsuit Against Feit Electric In California01/2020filament bulbs.Seoul Semi, Cree, Epistar, Nichia, Feit, GE, Philips etc. they all are constantly suing each other and the retailers over their LED bulb IP.It's sad that LED bulbs are still struggling to outlast incandescent bulbs.Cree LED bulbs were terrible, not that Cree has ever been a profitable company but their bulbs barely lasted a year and LEDs failing, just pushed too hard.Next I tried Philips bulbs- which are total shit, the PCB and electrolytic capacitor inside badly cooked due to high heat, open-circuit LEDs. But the LED's are the best I've seen for CRI. The change to COB also makes the spot lights narrow. I can't get them to last more than about 3,600hrs. You would puke if I showed pics of the failed boards.Next, I tried Ikea bulbs and they are working great, many at the 7,000hrs point and still working fine. But only warm white is offered.

author: james_s
author_rank: Super Contributor
timestamp: March 25, 2021, 12:20:27 am
content: That doesn't match my experience at all. I still have Cree and Philips LED bulbs I bought more than 10 years ago that still work, even some that are very heavily used. If there are patent issues that doesn't seem to be causing any problems, loads of different companies are making LED filament bulbs in all different styles. Most of the market for general illumination bulbs seems to have settled on the aluminum core PCB with surface mount LEDs on it firing into a molded plastic globe.

author: MK14
author_rank: Super Contributor
timestamp: March 25, 2021, 12:46:05 am
content: Warning: Very long article, but fairly interesting explanation of the economics and stuff around Led lights.https://www.manufacturer.lighting/info/248/

author: MK14
author_rank: Super Contributor
timestamp: March 25, 2021, 12:51:30 am
content: Quote from: james_s on March 25, 2021, 12:20:27 amhttps://www.forbes.com/sites/laurendebter/2019/07/31/walmart-amazon-target-ikea-bed-bath-beyond-sued-vintage-light-bulbs/Quote

author: floobydust
author_rank: Super Contributor
timestamp: March 25, 2021, 01:15:40 am
content: Philips LED bulbs 800lm 2700K 8.5W I put a dozen into service indoors and outdoors for night lighting, so ~8-10hrs/day in various fixtures and outdoors -35°C to +30°C, indoors +22°C.They lasted about 1-1/2 year. On some the LED's have the "black dot of death" as BigClive calls it, the string went open circuit. But really, the power supply is a joke, it's baked phenolic with roast electrolytic. I had greater expectations for USD $4 each, so I'm calling them junk after all are dead now.I bought a massive PAR38 Philips flood light bulb and laughed it back to the store, all it has is a small COB spot like their MR16 bulbs, it's all empty space and glass lol.(did break the bridge rectifier taking it apart)edit: compare the thermal conductivity of many plastics and they are basically an insulator. Patents prevent plastic heatsink fins from being used.

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 25, 2021, 02:11:02 am
content: That's incredibly roasted, I thought those driver chips all had thermal throttling. Were the bulbs in enclosed fixtures? If so were they rated for it? I know that's a gotcha that a lot of people overlook with retrofit LED bulbs, though at $4 I'd expect them to be good for it.

author: amyk
author_rank: Super Contributor
timestamp: March 25, 2021, 03:28:22 am
content: 8.5W for 800lm, that's less than 100lm/W... but from the look of those pictures it seems a lot of the power dissipation was in the driver circuit itself.Quote from: BrokenYugo on March 25, 2021, 02:11:02 amThey do, they just throttle at averyhigh temperature.

author: james_s
author_rank: Super Contributor
timestamp: March 25, 2021, 04:47:34 am
content: Hm those are newer than the Philips bulbs I have. Mine are mostly the older remote phosphor types, I have some of the ones that look like a regular A19 lamp, some of the 800 lumen tri-lobe style and some of the mushroom shaped lamps with the oddly shaped white glass globe over the phosphor dome. I also have a handful of Hue lamps that look almost identical to those.

author: floobydust
author_rank: Super Contributor
timestamp: March 25, 2021, 05:00:22 am
content: The LED's are largely cooled by conduction, with the M-core board and glue to the aluminum tube.But the driver board only gets cooled by convection inside the small chamber, which is pretty much useless obviously. Even if it (driver) dissipated 1W the temperature must be pushing well over 100°C.IC isBP9916Cwith CL set to 235mA (2.55R) and ILED 118mA, IC rated max is ILED 200mA."The thermal regulation temperature is set to 140°C internally."The light fixtures are a variety, some large glass globes and metal top, like any typical fixture.

author: paulca
author_rank: Super Contributor
timestamp: March 25, 2021, 09:33:35 am
content: If you think cramming all that circuitry into the base of a lamp bulb is squeezing things...Remember a lot of LED bulbs now contain a bi-directional radio and MCU. Radio either RF433, Zigbee/Zwave or 2,4Ghz Wifi!The last B27 (UK Bayonet) Zigbee smart bulbs all had no visible circuitry in the bulb, just in the fitting. I dismantled a broken one (yes I had 3 out of 4 dead within 24 hours of use). Inside it looked like 240V LED string filaments with just a variable current limiter and a Zigbee radio board mounted 90* on to it. All within a 2/3" x 2/3". (Do not buy Innr bulbs!)The Philips Hue B27 bulbs and the E14 mini-candle bulbs (working fine) show no bulk beyond the tiny little cap, so all over above must fit into the E14 screw housing.. How in hell!

author: Siwastaja
author_rank: Super Contributor
timestamp: March 25, 2021, 10:45:50 am
content: Quote from: floobydust on March 25, 2021, 05:00:22 amQuite frankly, the only Right Thing To Do is just to make the driver part efficient and not dissipate such power.Modern white LEDs are some 40-50% efficient, we get that, you can't do much to improve it on the bulb level. You can go a bit higher by buying the most expensive state-of-the-art LED tech; or very crappy color rendition.But there is no real reason why the driver circuit has to be some 70-80% efficient only. IMHO, seeing a charred hotspot on the driver board is inexcusable. 1W driver dissipation in a 5W bulb is a disaster, IMO, because there is no reason to be that crappy. Make it 90% efficient to see some real gain in power savings, andadditionallythe cooling problem is solved.

author: madires
author_rank: Super Contributor
timestamp: March 25, 2021, 11:29:41 am
content: I think the big problem is that we are trying to replace incandescent bulbs with matching LED bulbs to keep the old lamp fixtures, The old bulb design is great for incandescent light, but not for LEDs. We should design new standard LED lights and fixtures to get the most out of LEDs. For example, I have several meters of 12V LED strips on aluminum U profiles. They stay cool and run great for many years.

author: amyk
author_rank: Super Contributor
timestamp: March 25, 2021, 01:22:13 pm
content: Quote from: floobydust on March 25, 2021, 05:00:22 amThat's a switching buck converter, not a linear regulator... so it should be more efficient?

author: TimNJ
author_rank: Super Contributor
timestamp: March 25, 2021, 02:37:34 pm
content: Quote from: floobydust on March 25, 2021, 01:15:40 amLmao come on, paper/phenolic board running at ~140C.

author: james_s
author_rank: Super Contributor
timestamp: March 25, 2021, 08:01:23 pm
content: Quote from: madires on March 25, 2021, 11:29:41 amThey are doing exactly that, but there are billions of existing lamps and light fixtures out there, surely you can't expect everyone to replace all of their light fixtures? There is a lot of vintage/historical/period correct fixtures out there too. LED lighting would take decades longer to catch on if not for readily available retrofit bulbs.

author: MK14
author_rank: Super Contributor
timestamp: March 25, 2021, 08:12:40 pm
content: I suppose if we redesigned lighting circuits from scratch today. We might make them 36V DC, then zero flicker (apart from any voltage regulator and current regulator effects), and minimal electric shock risk, only one household mains to 36V DV converter box needed (standard plug in (into a proper unit, not a mains socket), commodity unit, user replaceable), for all lighting circuits. The LED bulbs would then just be simple (low cost) LED chains (internally), and possibly a resistor or current regulator, inside the bulbs.Given the low wattage needed by modern LED bulbs, the power and hence currents should be low enough, that the 36V cables wouldn't need to be thick high current ones.LED bulb life expectancy should improve, because they would have less heat generated inside the bulb, and no need for much extra electronics, on top of the LEDs, except maybe a resistor and/or current regulator.Summary:A bit like the florescent tubes, holder. With its internal electronics (ballast), and user replaceable starter. You only need to change the raw tube, not the rest of the electronics.

author: madires
author_rank: Super Contributor
timestamp: March 25, 2021, 08:24:08 pm
content: Quote from: james_s on March 25, 2021, 08:01:23 pmThen we have to accept that we'll create more e-junk by using LED bulbs which fail early. Is this better or worse than using incandescent bulbs with a higher power consumption in old lamps?

author: Kleinstein
author_rank: Super Contributor
timestamp: March 25, 2021, 08:46:22 pm
content: The early LED lamps with still relatively low efficiency had sometime a cooling problem when used at same intensity. It's usually the higher power versions that fail early. Some fixtures just get rather hot and also the CFL lamps could failed early in those. With modern, more efficient LEDs the heat is usually not such a problem any more as the power is soemthing like half of what it was in the early days.If really in doubt, reduce the intensity and add a second lamp if needed.One sometimes see new lamps with fix installed LEDs - to make use of the smaller form factor. So it would make sense to get some new smaller standard fixture - still keeping the old E27 / E14 for old lamps.

author: TimNJ
author_rank: Super Contributor
timestamp: March 25, 2021, 08:55:49 pm
content: Quote from: madires on March 25, 2021, 08:24:08 pmI'm sure this has been studied and thought about many times, probably even on this forum alone. Still, here's my own thought experimentSupposing an 800lm LED lightbulb lasts 6 years running at 5 hours a day. Over six years the energy usage is about 55KWh. Let's say the life span is about 10,000 hours, after which you have to throw it out and replace it.If you used a 60W incandescent lamp for the same duration and hours per day, the energy usage is about 660KWh. Let's generously say it's lifespan is about 2,000 hours, so you'd need to replace it 5 times over this time.The missing pieces are: The energy input required to make each type of bulb and the environmental impact of each bulb when it's chucked in a landfill. I don't think you can put the latter in terms of energy...although maybe you can think of it as the energy required by some poor future human society to un-****-up the world the previous generations left them.--------Total Energy (LED) = 55KWh + (Energy to Make/Dispose LED * 1)Total Energy (Incandescent) = 660KWh + (Energy to Make/Dispose Incandescent * 5)--------Energy to Make/Dispose LED < 605KHh + (Energy to Make/Dispose Incandescent * 5)So, naively, it makes environmental sense to use an LED as long as the energy it takes to make one LED bulb is less than 605KWh + the energy it takes to make and dispose 5 incandescent bulbs. And I have no idea how to gauge how much energy is required to make an LED bulb. But, it seems like LED bulbsshouldmake environmental sense.

author: TimNJ
author_rank: Super Contributor
timestamp: March 25, 2021, 09:02:20 pm
content: Is the fact that you can get an LED lightbulb for $5USD a reflection of the amount of energy it takes to make it? At that price, is it reasonable to think that it really doesn't takethatmuch energy to make one?

author: MK14
author_rank: Super Contributor
timestamp: March 25, 2021, 09:09:27 pm
content: Quote from: TimNJ on March 25, 2021, 09:02:20 pmThat doesn't include the real world/life cost to the planet, on getting rid of the waste LED bulbs that build up over time.

author: TimNJ
author_rank: Super Contributor
timestamp: March 25, 2021, 09:13:21 pm
content: Quote from: MK14 on March 25, 2021, 09:09:27 pmQuote from: TimNJ on March 25, 2021, 08:55:49 pmI know this. I am talking about how much energy is required to make it. I'm saying that something that is sold for $5 probably can't have a ginormous energy input or else it would be reflected in the price, unless that price is subsidized in some way.Disposal and environmental impact is probably not easily quantifiable.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 25, 2021, 10:14:29 pm
content: LED bulbs SHOULD be simple and inexpensive and practically last forever, yet they are more expensive and seem to be bad for failing early. Even CFLs were better for life time.The failure mode I seem to often get is lights that just turn on and off. Like a cold solder joint somewhere. I heard that some may do it based on temperature if they overheat, but considering I rarely have my house hotter than 20C I doubt this is what I am seeing.

author: james_s
author_rank: Super Contributor
timestamp: March 25, 2021, 11:22:51 pm
content: Quote from: madires on March 25, 2021, 08:24:08 pmWell like I said, I have not been experiencing this high failure rate. I started buying LED bulbs in 2010 and had fully replaced all the CFL bulbs in my house by 2012. I still have a handful of the original Philips, Cree and Ecosmart bulbs I bought way back then, even several that are in dusk till dawn service in outdoor fixtures. Since 2010 I've had maybe 5 or 6 LED bulbs fail and about that many more that I replaced due to the availability of newer bulbs offering higher efficiency, better light quality or other features like the Hue bulbs that can be set to a whole range of colors. Maybe I'm just incredibly lucky, I don't know, but I had a lot of early CFL failures while LED has been much more reliable. My mother has had a similar experience, in 2011 I put a 600 lumen Cree bulb in the landscape light by her front walkway, it's on a photocell and runs dusk till dawn every night, that same bulb is still working.

author: TimNJ
author_rank: Super Contributor
timestamp: March 26, 2021, 12:36:03 am
content: Quote from: james_s on March 25, 2021, 11:22:51 pmMaybe the rest of us are just buying crap.

author: madires
author_rank: Super Contributor
timestamp: March 26, 2021, 11:36:55 am
content: Seems so.We have (had) CFLs and LEDs of all generations, cheap no-name stuff, expensive brands, mid-priced bulbs - a good mix of everything. Expensive brands fail as well as cheap stuff. In nearly all cases it's caused by cooked drivers. Lamps with a closed design (glass bowl) or spot light lamps with tight cover up to the front create additional heat stress because there's barely any air flow around the bulb.

author: coppice
author_rank: Super Contributor
timestamp: March 26, 2021, 11:46:38 am
content: Quote from: madires on March 26, 2021, 11:36:55 amEnclosed vs open luminaires explains a lot of the differences in lifetimes people see. With CFLs its not just the roasted electronics that suffer in an enclosed space. The tubes blacken much faster, too. I'm not clear why that is, as the blackening is mostly due to ion bombardment and it doesn't seem like a warmer tube should increase that dramatically.

author: paulca
author_rank: Super Contributor
timestamp: March 26, 2021, 02:48:06 pm
content: So what about "Laser LEDs"?You know that next year, if not before, they will start pushing "Laser LEDs" every where. Already in automotive.I believe it's usually a beefy cob LED with asides lighting normally itself, get's a blue laser diode fired at it too causing a much higher phosphor discharge of light... and the laser optics can focus that light into a very tight beam.

author: madires
author_rank: Super Contributor
timestamp: March 26, 2021, 03:04:24 pm
content: Might be useful for stage lighting, light shows and such things. But at home?

author: paulca
author_rank: Super Contributor
timestamp: March 26, 2021, 03:14:06 pm
content: Quote from: madires on March 26, 2021, 03:04:24 pmProjectors. Projector spots. Wall lights, flood lights, outdoor lights. I can see decorative and civil advantages to tightly focused security lights, for example. We all have that one neighbour with the ****ng light house that goes off with every cat walking through his garden.

author: andy2000
author_rank: Frequent Contributor
timestamp: March 27, 2021, 03:42:44 pm
content: My biggest complaint about cheap LEDs is flicker. Many have little to no power supply filtering, so they're effectively 120 Hz strobe lights. There should be a standard for measuring flicker, and labeling should be mandatory like it is for brightness and color temperature.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 27, 2021, 06:03:28 pm
content: I thankfully have not run into that with household bulbs, but lot of Christmas lights sets are bad for that. I really wish it was possible to buy higher quality Christmas lights, even my "good" sets for the house that I paid more for are not that great as they are not as bright as the good ol C9s, and one of my sets died this year, it was only a few years old. Most of them you can't even change bulbs as they are all built in.

author: Zero999
author_rank: Super Contributor
timestamp: March 27, 2021, 06:59:06 pm
content: There seems to have been a wide range of personal experiences here.I replaced all of the bulbs in my parent's house with LED around eight years ago and barring a couple of really cheap Chinese ones, they've lasted really well. I've had a mixed experience. One of the LED filament lamps in my cooker fume extractor hood failed after only a couple of months. I accept a cooker hood is a bad place for an LED bulb, but the one in my parent's cooker hood lasted for years. One of the LED downlighter lamps failed in my kitchen, after around four years, yet the ones in my parent's kitchen lasted for much longer.I dislike linear regulators, in LED lamps. They're especially bad at higher voltages and temperatures, which will cause them to throttle back the current, if you're lucky. Capacitive dropper isn't a bad choice, as long as it uses a decent quality capacitor, with plenty of filtering to reduce ripple. Switched mode is obviously the best type of power supply and is worth the extra money.It should be easy to design and make an efficient LED lamp, which might actually be worth doing, if off the shelf units deteriorate, even if it's much more expensive.

author: RoGeorge
author_rank: Super Contributor
timestamp: March 27, 2021, 07:10:45 pm
content: Quote from: TimNJ on March 23, 2021, 03:13:59 amOr third.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 28, 2021, 12:37:48 am
content: Great video; thanks for sharing!

author: Zero999
author_rank: Super Contributor
timestamp: March 29, 2021, 12:21:39 pm
content: Quote from: Red Squirrel on March 25, 2021, 10:14:29 pmI don't see the point in replacing CFLs with LEDs, unless it's in an application where it's going to be turned on and off lots, such as a toilet. The power saving is minimal and the quality of thelight isn't that much better. I only replace my CFLs with LEDs, when the lamp goes and it's easier to replace it with an LED. A friend to mine replaced all of his CFLs with LEDs around 8 years ago and gave the old lamps to me. One of them was a high powered one, around 30W I think, so I gave it to an elerly friend of my mum's, who's virtually blind and she's been using it ever since. It wouldn't surprise me if it outlasts her, as she's in her late 90s. If it goes before then, I might have to make her a replacement LED lamp, if I can't find a suitable replacement.

author: madires
author_rank: Super Contributor
timestamp: March 29, 2021, 01:14:36 pm
content: CFLs need some time to achieve full brightness after powering on. Some are quite fast, some need a minute or so, especially the long lasting ones. LEDs start with full brightness.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 29, 2021, 02:41:54 pm
content: Quote from: Red Squirrel on March 25, 2021, 10:14:29 pmI had one LED bulb fail in such way that when power is applied, it blinks very briefly, then stays off for approx two seconds, then randomly may or may not flicker a few times, then potentially turn on, or not.The LED bulb decided to time the approx two second delay to exactly match the time it takes to go through thought process: "hmm, the light switch seems faulty, let's try to push the switch further" then reach the switch and give it a firm press.Exactlyat that time, the LED bulb usually decided to turn on, confirming the assumption that the light switch is faulty. Every day it worked worse and worse, so finally I replaced the light switch. Guess the reaction when the behavior was just like before and it was just the bulb that required swapping.To its defence, the previous owner of the house did use said LED bulb for however long time in a sauna near the ceiling which is a colossally bad idea. I do have a few incandescents left for exactly that purpose.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 29, 2021, 02:48:08 pm
content: Quote from: Zero999 on March 29, 2021, 12:21:39 pmDepends, if the CFL has already seen a few thousand hours of operation, many are so dim that the 11W bulb produces hardly any light during first minute, and even then too little; especially if installed in a cold place like uninsulated attic or basement. Can be replaced with a modern 5W LED bulb with the additional benefit that you will be able to see something without first waiting for half a day (which a minute feels like when you want to do something instead of waiting for the light).I hate waiting for technology to start operate; such as Windows taking anything from 30 seconds to 3 hours to "install updates" before it allows me to use my computer. Even the varying 1 to 5 second delay of traditional fluorescents with mechanical starters sucks, and the 1-2 minutes of CFLs is beyond acceptable.Color rendition tends to be equally sucky with CFLs and LEDs. Both have better options available, but hard to find.Generally, I'm quite happy with how things are with LEDs. Incandescent bulbs were often crappy quality as well, very typical failure mode was cost-optimized fuse (proper bulbs have internal fuse) causing the bulb to fail explosively, bringing out the main breaker or blowing even a 16A gG fuse. Good riddance.And CFLs, pfft. Salesmen and packaging say "get 11W", but have to buy a massive 20W bulb to replace a 60W incandescent to get any actual light out right from start, then it's too bright after some time, until it's too dim after 2000 hours. And it weights so much and doesn't fit in half of the lighting fixtures. And most of the light goes the wrong way because of the stupid emission pattern. Add to that ALL the same roasty electronics problems we have now with LEDs.

author: themadhippy
author_rank: Super Contributor
timestamp: March 29, 2021, 02:57:54 pm
content: QuoteTry your local specialist indoor gardening shop.

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2021, 05:44:18 pm
content: Quote from: Zero999 on March 29, 2021, 12:21:39 pmI certainly found it worthwhile, at first I was buying LED bulbs to replace CFLs as they failed, but then I got tired of waiting and changed out all the rest. CFLs take a few minutes to warm up to full brightness, and frequent on/off cycles kill them rapidly. Most of the lights in my house get used briefly, walk into a room and turn the light on, turn the light back off as I leave, this was terrible for CFL because they would just be getting warmed up when I would turn them off. I find the color of most LED bulbs to be much more pleasing than that of CFL too, and they are considerably higher efficiency. The typical curly CFL is about 55 lm/W, much better than incandescent but even cheap LED bulbs are over 100 lm/W. It's economical to replace CFLs for energy savings alone unless it's a rarely used light.

author: Zero999
author_rank: Super Contributor
timestamp: March 30, 2021, 07:16:06 pm
content: I use CFL in applications where they're left on lots, so the warm up time is a non-issue.Yes, I've seen some go dim over time. Actually what normally happens is, as well as going dim, the colour shifts towards a bluish-pink, as the mercury is depleted. I've not had it happen to any of the lamps I've owned, but I've seen it before.

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2021, 09:38:08 pm
content: I have outdoor lights that run dusk till dawn every night and those always achieved the longest lifespan I got anywhere, CFLs would regularly last 8k-10k hours, often exceeding the rated lifespan but even then I would only get about 2 years max out of one. Since putting LEDs in those I've only had one fail, others are 10 years old now, so even for heavily used lights LED bulbs are lasting me longer.