Dollar Tree LED Bulb Tear Down

It is hard to remember now, but there was a time when electronics were expensive. [Adrian Black] found some 9W (60W equivalent) LED light bulbs at the Dollar Tree (a U.S. store where everything costs a dollar). Naturally, they cost a dollar, and he wanted to see what was inside of them. You can see the resulting video, below.

Apparently where [Adrian] lives there is a subsidy paid to retailers for selling LED lighting, so you may not be able to get the same bulbs at that price. Still, the price of these bulbs has dropped like a rock over the last few years.

It is interesting to see how you cut costs when your volumes go so high. For example, the bulb has two boards in it. They mate with an ingenious slot system cut into the boards themselves and then just solder together. There are 9 LED devices inside, each with three LEDs. The power supply? Just a bridge rectifier and a smoothing capacitor. There’s just not much inside.

When you think about electronic prices in the past, consider that the purchasing power of the dollar keeps dropping, too. A radio might have cost $50 in 1935 and a much better performing radio might cost $10 today. But in 1935, $50 would have been two months of rent or more. So the real comparison isn’t $50 to $10, it is more like $1600 to $10. How can you manufacture a bunch of plastic pieces, 9 LED devices, a capacitor, a bridge rectifier, an IC, two PCBs, and some resistors, put them together, stick them in a printed box, and ship them across the ocean and wind up selling them for a dollar? Keep in mind, too, the store isn’t giving them away, so the actual cost must be less (not counting any subsidy). Amazing.

We’ve talked about scaling designs, although few of us will ever get a design made in the numbers of something like this. Oh, and while we know this isn’t actually a hack, we think you’ll agree this is.

74 thoughts on “Dollar Tree LED Bulb Tear Down

  1. It’s always a bit tragic to run into such nasty LED drive circuits. I realize that that is pretty much the only place to go BoM shaving, once you’ve gone with low end LEDs; but it is also what is most likely to fail and/or kill the otherwise fairly durable(slightly less so for the phosphor-based white ones, but fairly long lived there and extremely long lived in the case of monochrome LEDs) LEDs and consign the whole unit to the trash well ahead of it’s time.

    I understand why people do it; but it is still sad to see

      1. LEDs don’t care about pulsed power, really only the eye does if it can detect 60hz flicker, which is mitigated by phosphor. LEDs really only care about average power making them too hot if too high.

        1. This is not entirely true. It’s junction temperature that matters, and the junction is both insulated and has low thermal mass.

          There are very specific duty cycles and maximum power limits on the data sheet for any LED. Exceed them and lifetime plummets.

  2. Heads up for readers in Ontario, subsidy event going on now until end of month, Canadian Tire has several variety 2 packs for $1 and Walmart has singles for 50c, 10 package limit, so you can get more at CT.

  3. One tends to forget, that an incandescent light bulb is actually a piece of art, and once was expensive high tech.
    Not only is tungsten a rare and expensive metal, it’s also very difficult to process, because of it’s high meting point and it’s brittleness.
    The suspension and contacting of the filament took many years and may errors to become perfect.

    Therefore I think, that LED bulbs have the potential to become much cheaper than it was ever possible with incandescent bulbs.

    1. I’m not sure the proverbial they ever got the contacting of the filament perfect, or if they did, they cheapened the process and made it imperfect again. I see a lot of incandescent bulbs fail by the filament not truly burning out, but coming detached on one end.

      1. Not to be a member of the Tin Foil Hat club, but those are controlled by a cartel, and manufactures must produce them so that they fail within a certain amount of time. They are required to do this. Otherwise nobody would buy light bulbs.

        1. Normally I would regard this as a conspiracy theory, but I have corroborative experience that you may be right. Here in Ontario we used to be able to buy long-lasting light bulbs from the Handicapped Society – I think they were designed for institutional use. They really did last much longer than regular bulbs and IIRC the increase in lifetime was proportionally higher than the increase in price.

      1. I have had 13 of these bulbs in place for about 11 Months, some have been on 24/7 (close to 7920 hours) so they don’t just drop dead. They draw around 8.2-8.5watts and do provide decent amount of lighting power. Compared to a very similar designed Chinese bulbs that I purchased form eBay 2-3 years ago for $1 each these are far better. (yes some of these are also made in China, but there is a large quality difference. ) I did some basic math to determine if the cost was worth it. At .22 cents per kilowatt (Florida power prices) how long it would take to break even (just engery cost, vs bulb cost) by replacing the below types.

        Incandescent 900Lm 60w @ 8 hours a day -aprox 12 days
        CFL 850LM 15W @ 8 hours a day -aprox 38 days

  4. The heat kills the diodes just as much if not more than it does the power supply capacitor. Even if you move the power supply outside of the bulb, elevated ambient temperatures will dim the light within a couple hundred to couple thousand hours. It won’t break, but the lumen output suffers considerably.

    The trick is that the lifespan of the bulb is tested at 40 C in open air in an upright position with free air convection, and the brightness there is allowed to drop -30% within the Energy Star long term testing standards. Inside a fixture, an 8-10 Watt bulb with the socket down will quickly heat to 60 C or more, or as the reviewer points out: too hot to touch. That’s also too hot for the diodes, and the actual lifespan will be reduced.

    There’s no real workaround for this, as the properties of the semiconductors dictate what junction temperatures they can handle. You can add better heatsinking to keep the Tj closer to Ta, but it’ll cost you with diminishing returns, and you can’t have the metal heatsink surfaces exposed to the user because of electrical safety issues and regulations, so you’re always a bit gimped in how much heat you can remove from the bulb.

    Some manufacturers of “premium” LED bulbs even insert a tiny fan inside the bulb to keep things cool, but that’s just another thing to break down.

    1. Yes, the most sensitive thing to do would be to have a thermal sensor and dim the light sufficiently so you still get the lifetime.
      That would also easily tell the consumer that the fixture is improper for operation. And it would tell the fixture developers that their fixture is not appropriately cooled for the LED inside.
      But this does not sell more LED bulbs.

      1. You know what sells more LED bulbs?

        The rule of thumb that every 6 degree increase in temperature halves the life expentancy of the part, so running it at 60 C instead of 40 C, the 65,000 hour promise turns out closer to 6,500 hours, or instead of 23 years 2,3 years of use.

        It was the exact same shit with CFLs, which when placed in fixtures would last little longer than the incandecent bulbs they replaced. Though of course they didn’t blink out like the filament bulbs, but simply became dimmer and dimmer and slower to start until after about two years in use you had to replace it.

        I’ve since replaced all my bulbs with halogens, which unfortunately is also going under the regulatory hammer as well because it’s inconvenient that they actually do outlast the energy saving bulbs in real useful lifespan, and what they put out as heat is simply subtracted from my heating bill.

        1. > I’ve since replaced all my bulbs with halogens, which unfortunately is also going under the regulatory hammer as well because it’s inconvenient that they actually do outlast the energy saving bulbs in real useful lifespan, and what they put out as heat is simply subtracted from my heating bill.

          Of course we’d end up with someone shrieking about government conspiracies. I’m amazed you didn’t rant about them giving you headaches.

          Yeah, they put out heat “subtracted from your heating bill”…in the months you use heat, in your locale, genius. There are tons of people who live in locales where they don’t need heat, they need AC or fans. What about them, huh?

          I’m in a fairly northern latitude and I still haven’t turned my heat on since May. So from May to October-ish, those lights are generating heat that serves no purpose. Worse, during the summer months, that heat has to be removed by my AC.

          Here’s a fun fact for you: I’ve been slowly replacing every bulb I own with LEDs for 5-6 years now. And guess what I’ve never had to do? I’ve never had to replace an LED bulb. They’re all still working great. Of course, I didn’t buy $1 bulbs – I bought ones from Cree, on sale, that cost a bit more. They run cool because they have great heat sinking, or really good ventilation.

          1. >”. There are tons of people who live in locales where they don’t need heat, they need AC or fans. What about them, huh?”

            Let them use LED bulbs if it saves them money – that’s a no-brainer. If it actually works, it works, and nobody can take that away from you.

            Didn’t have to ban my incandecent bulbs for that. Oh, but they did, because the CFL/LED bulbs are a fucking scam.

          2. Fun fact: it actually was the incandescent light bulb industry (read: Philips) that initiated the ban. More money could be made if everyone was forced to switch to something new.

          3. The point is that while you can buy decent LED bulbs for $20 of whatever they cost now, that’s not what people actually buy.

            The low-end LED market is based on the point that the consumers won’t know if a product is good until they try it, so you’re guaranteed at least some sales every time you re-package your shit-bulbs and sell them under another name. The consumers are always trying to find a cheaper way out, so there will always be people buying the $1 specials, getting dissapointed, and then trying something else.

            The humble incandecent lightbulb was standing in the way of all these China Export (CE) blinkers they wanted to push on the shelves, because it was too good for competition: it offered 100% CRI, instant on/off, dimmability, no loss in light output with age, insensitivity to cold and heat etc. things that the new bulbs simply lacked, and furthermore the incandecent bulb was getting too cheap to sell because everybody could make them, so they had to get rid of it.

            So they invented this whole cock and bull about energy saving for the environment – where household lighting is actually only responsible for 15% of the bill, and households themselves represent about 15% of the electricity demand in the first place, so they were splitting hairs by banning incandecent lightbulbs in domestic use – it’s completely ineffective in the larger scheme of things – and to add insult to injury: regular long fluorescent tubes are just as or more energy efficient than the new LED bulbs, so for anyone actually looking to save money: don’t need to bother with the LEDs.

            So how can you not find the lightbulb ban at least a good example of powerful lobbies driving corporate interests instead of consumer interest?

          4. As for my personal use, my windows face west, so between about june to late august, I don’t actually need to turn the lights on until after 10 pm, if at all. The kitchen, garage, and bathroom are lit by tubes. I like to photograph, print and paint, and the weirdly shifting and changing color balances and indexes of the LED/CFL bulbs are just a nuisance.

            Again, I had no problem, why did I have to suffer?

          5. I feel for you Dax I really do, what I’m going to do for you, is take this box of incandescents here, and put them away in my basement…. and wait until you’re desperate enough to buy them off me for $50 each… no thanks required, I regard it as a service to humanity.

          6. No irony. I probably will. I’m already looking at different options for retrofitting my lights with different sockets, because the -industry- is still allowed to buy incandecent bulbs in special form factors.

            So the people who use the most energy are still allowed to waste it, and the people who matter the least in this matter are thrown under the bus.

    2. Part of the problem is we are using sockets designed for tungsten bulbs. The only thing they are concerned with is providing electrical connections and holding a bulb in place. It would be nice to have a modified socket design that also sinks heat which may actually work better in an inverted position

      1. And a nice reflector/diffuser for the light, to hide the ugly bulb and the point light source away from eyes.

        But the socket debate is moot from the manufacturer’s standpoint, because there’s no way for them to enforce that their LEDs can only be installed in suitably heatsinked fixtures, nor do they want to demand it because that would diminish sales by caveats and small prints like that. It either works or it doesn’t, which means it “works” and hush on the details.

      2. Besides, the sockets and fixtures we’re dealing with are designed to withstand 60 – 100W of heat – while the LEDs produce approximately 10% of that. Any kind of fixture, just putting a shroud around the lamp, will shield it enough to cause the LED to mildly overheat especially in the summer, because they just can’t take the temperature.

        For example, the Luxeon flipchip white diodes cannot achieve lower than 20 K/W mounted on an FR-4 board with a 2 oz copper layer for heatsinking , which means that if the lamp is sitting at room temperature around 25C, the circuit board is probably a balmy 40 C, and the 1 Watt chip on it is a toasty 60 C, and the actual diode junction inside is probably approaching 80-100 C. You don’t need to raise the temperature much from ideal conditions before the whole thing starts to cook.

        1. And some of the bulbs are really really bad

          >”The ambient temperature during the whole set of illuminance measurements was 23.2 – 23.3 deg C.The temperature of the housing gets maximally about 61.5 degrees hotter than ambient temperature.”

          >”The packaging claims 50,0000 on-offs and 35,000 hours lifetime. I’ve had 2 of these and both went within 2 years. I estimate we used them for less than 3,000 hours and less than 2,500 on-offs – ie only about 5-6% of the claimed lifetime.”

          The manufacturers don’t care. Let them break – the government is paying subsidies anyways, the consumers have to buy these shitty bulbs because nothing else is allowed, and anyone who’s trying to question the point of it is labeled a heretic anti-progressive and promptly gagged.

  5. I usually see the “60 W equivalent” bulb at Dollar Tree but I have also seen one that says it’s dimmable on the box. Most say that they are NOT dimmable in the fine print. The packaging for the harder to find bulb is different so keep your eyes open!

  6. I don’t think your analysis of the value of a dollar really works. You are using the cost of rent as some sort of absolute fixed point of value. Rent, manufacturing, shipping.. these things each have their own separate fluctuations in supply and demand. If you could have some fixed unit of value then the value of a dollar vs unit will change over time as will the value of rent vs a unit and electronic vs unit. All of these things can change separately by vastly different amounts or even change in different directions.

    If you really want to understand though I would suggest searching YouTube for a video showing the construction process of the vacuum tubes in that 1930s radio. Look how much labor is involved and compare it to today’s manufacturing methods. It almost tempts one to thing we should go backwards as a way to end unemployment. Except… when we know we can do better… that would be like employing people to dig holes just to fill them back up.

    1. It kind of reminds me of some discussions I have had with people regarding living in different parts of the world. One place might have higher incomes but also a higher “cost of living”. Many argue this makes them equal. When it comes to the things which are necessary for “living” this is probably true. But… take a hypothetical person say.. living in some big city paying $2500/mo rent and another living in a small town paying $500. Their incomes vary proportionally so each “feels the same pain” in paying the monthly bill. Now say they both have their eyes on buying the same new 3d printer or game console or laser cutter or whatever non-essential item… Are they really in an equal position to do so? I think not!

      1. >”or whatever non-essential item”

        I think the key point is right there.

        What you’re complaining there is that not all people have access to the same trivial luxuries, which is kinda… silly – as the main reason they are considered desirable is for the manufactured consumerism and status. Boo hoo, I can’t buy a diamond ring!

        1. Or non essential marine batteries, electronics, solar panels etc etc. Non essential is largely ambiguous. I don’t imagine many people reading HaD rushing out to buy diamond rings.

    2. >”Except… when we know we can do better… that would be like employing people to dig holes just to fill them back up.”

      Not exactly.

      Consider that you have one unemployed person, and one machine that manufactures radios. On the whole, the cost of any radios you produce is also going to include that one unemployed person, for whom you have to pay welfare because you can’t just off him.

      So, wouldn’t it make more sense to at least have the man make a couple radios in exchange for his upkeep?

      Furthermore, as the men are the consumers of the radios, the number of radios needed scales with the number of people who need radios – and while one machine might make all the radios, this added productivity brings no benefit while there are unemployed people who could just as well meet the whole demand for radios. It only adds the cost of the robot.

      Having machines replace human laborers is simply more costly than the human laborers, and the choice is not about some sort of neo-ludditism, but whether you want to pay more to have the free time, or pay less and have a job for everybody who wants to work.

      At some point in the past the argument of automation was for freeing people to other more gainful enterprises than assembling radios by hand, but now the population is four times as much and most people find themselves with nothing productive to do, so they don’t, and we can’t just give them the money for sitting on their asses because it would instantly lead to abuse. Yet they need some sort of income, so they turn into “services”, in other words, to enticing other people to consume more in order to catch a part of the stream of resources for themselves as the middle man. This is a lose-lose situation.

      1. A person losing a job to automation looks for other work. There is no lack of demand for things that make life better, including higher quality goods, more attractive goods, fine arts, and a wide range of services.
        Your posts reveal an anti-capitalist bias that does nothing to make people’s lives better.

        1. If there’s essential quality improvements, the machines can make them as well. “More attractive” is a matter of manufactured demand, fine arts and “services” are a matter of manufactured demand again.

          It’s not about capitalism vs. anything else, but the fact that the displaced people have nothing useful to do. Eventually the capitalist too runs into the problem that nobody has any money to buy the goods made by the machines, because all that anyone can do to earn money is to make up some trivial dog and pony show to cheat money out of other people.

      2. “The factory of the future will have two employees, a man, and a dog. It will be the man’s job to feed the dog. It will be the dog’s job to bite the man if he tries to push any of the buttons.”

      3. “we can’t just give them the money for sitting on their asses because it would instantly lead to abuse”
        What abuse would that be? ( And keep in mind you just said people want to work.)

          1. Or: the point that people often overlook about the glorious star-trek future where nobody needs to work, is the point that resources are still limited and so the distribution of wealth becomes a matter of more or less tyrannical central government.

            People want to work as long as work is what provides them their income. The question is then about what sort of work you want them to do: trivial services which consume resources, or productive work that sustains resources.

            If the people are just given money for sitting on their asses, the situation becomes such that voting in certain ways, lobbying, rioting, bumping out welfare babies, crime, all sorts of pointless gambling schemes and scams, etc. becomes more effective and easier means to gain wealth than productive labor, and the society collapses to overconsumption as there’s nothing to keep it in check, which then gives rise to tyrannical regimes that strictly dictate what and how much everyone shall have.

            So if the factory owners are wise, they’ll throw a clog in their own machines.

          2. You put in some thoughtful points, thanks for the reply, but on this part: “all sorts of pointless gambling schemes and scams, etc. becomes more effective and easier means to gain wealth than productive labor” I say ‘welcome to our current capitalistic system’.

    3. Just hanging this here for everyone in this cluster of discussion.
      The “Luddite Horses” appear at around 3:33 are a pretty good analogy to humans nowdays.
      Except, unlike the horses, we keep breeding more humans rather than less.

  7. Considering what has been written about heat damaging the bulbs, they should be considered in some form of indirect lighting environment with the socket down or maybe sideways.
    Anyway, I don’t know it there are any local reimbursement programs, but I’m going to check Dollar Tree anyway.
    I just wish I’d snagged some of those wireless selfie modules HaD reported on around a year ago…

  8. For anyone who doesn’t want to waste SIX AND A HALF MINUTES of their life listening to Babbling Youtube Moron telling us things anyone with half a brain knows about LEDs like “you can drop them and they won’t break!!!”, the ‘teardown’ starts here:

    Skip these crappy bulbs; Cree sells well-ventilated bulbs that are regularly on sale for about the same. GE’s stuff should also be good.

    If you want maximum efficiency and light distribution, as well as no switching power supply noise: get the “filament” style bulbs. I don’t know what the failure rate on them is, but they have virtually zero power supply electronics, instead relying on having a long chain of LEDs in series. In theory that would make them pretty failure-prone, but I know a bunch of people with them who haven’t had a single one fail.

    Because of the packaging of the LEDs, the die transmits in almost a 360 degree sphere – and because there’s no heatsink or base with electronics, or even a PCB – light is transmitted in 360 degrees as well.

    I actually don’t want 360 degree transmission for a lot of applications. I’d really like to be able to buy an LED that directs light below the horizon, for outdoor fixtures, to cut down on sky light pollution, and another that is the inverse, for downward-hanging fixtures.

    1. “I actually don’t want 360 degree transmission for a lot of applications. I’d really like to be able to buy an LED that directs light below the horizon, for outdoor fixtures, to cut down on sky light pollution, and another that is the inverse, for downward-hanging fixtures.”

      I was talking to an electrician last week. Some time back he was replacing some outdoor lighting in a parking lot with LED equivalents. He was working late. He assumed the LEDs had the same angle output as the (vapor?) lights he was replacing. As he was finishing up, someone drove up and told him the lights nearly blinded him a half mile away while driving towards them. So, he re-adjusted the angles of the lights, something he wouldn’t have known/done if he hadn’t been working so late…

    2. Those filament types are the worst of the worst. The strings are suspended in still air inside a glass, effectively insulated so they overheat, and the lack of driving electronics and smoothing capacitors means they blink like stroboscopes.

    3. Just a reminder: in browsers when on the youtube site you can press a number key on your keyboard to jump to that percentage of a video. (press 2 to jump to 20% which in most cases bypasses the intro.)
      And if you click on the title of an embedded youtube you jump to the actual youtube page.

  9. The store IS likely giving them away, just like supermarkets have stupid cheap milk but expensive snacks, or fuel stations charge very little for normal pump gas but a fortune for a frozen coke and pie. Its likely not a loss, but it may be literally at cost to get you into the store regularly and (hopefully) buy other things you don’t actually “need” that are a much worse deal.

    1. A lightbulb that supposedly lasts you 23 years isn’t exactly the best choice for a throw-in product, because once everyone has one they won’t be coming back for more.

      Unless of course the bulbs are absolute kak, and not worth the dollar.

    2. Nearly everything at any Dollar Store is a manufacture overrun, that is subsidized by sale of the same products under other names at other outlets. The economics of dollar stores are interesting; a grab bag of expired product, obsolete product, and simple overruns.

      1. You forgot rejects and products that are intentionally bad to make them cheap, because you’re not worried about preserving brand image with a no-name product.

        You can always slip through an amount of absolute crap, because it takes time for the public to notice that it is useless and stop buying it. Recently the EU made a sting operation on LED floodlights by purchasing something like 92 different off-brand products from randomly selected shops, and about 80 of them failed to meet standards and had to be pulled off the market.

        Wait a couple years, and they’re right back at it.

  10. The “filament” bulbs are actually not just strings of LEDs, there is an inert gas (argon probably) to dissipate heat into the glass.
    I did notice that with mine at least there is a very slight (15-20 seconds) warmup period but this is probably simple thermodynamics or delayed phosphor saturation.

    Also they are typically blue LEDs (InGaN) coated with YVEuO5 or a variant which downconverts at a very high efficiency to green and red, suspended in a silicone binder.
    Hence the difference between warm white and cool white is a change in formula.

    I did come up with an interesting idea which is to apply the same mechanism to glass tubes for backlight replacements on older monitors.
    The step-up transformers can be simply changed and other parts replaced at the same time.

    1. But old monitors also often aren’t modern resolutions. And there sometimes is some burn-in.
      Still, why not eh, I mean they could easily produce them as a universal long light for all kinds of uses where a longer light is handy.

      However you theoretically could also stick one of those films that spread edge LED on an old monitor and convert to LED that way. I wonder if Chinese outfits sell such film and if an amateur could apply that evenly at home.

      1. Incidentally, you can buy the filament separately on Chinese sites as I recall from one of those tear-down video (bigClive?) so I’m not so sure your gas claim is correct in all cases since those filaments seem to work fine in open air.
        I wonder if you can passively (without opening a bulb) test for the gas somehow.

  11. The Grocery Store sav-mor in my town has some much nicer bulbs 2 in a pack for 1.98, the quality is much better and they are dimmable, go figure. Same price and the color output is much better, I’ll see if I can get the specs on it. I bought them out of the last few a couple months back and they got another shipment, the quantity is much better than the local Dollar Tree.

    I’ve taken a few apart, and converted one to a 18v drill pack work light by de-soldering some of the LEDs and re-configuring into a 3 parallel strings.

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