The dirty secret of LED lighting is that while LEDs themselves last a long time, they only do so in the presence of good power supply design and good thermal design. If you cut corners on the power supply or thermal management, LEDs will burn out much quicker than older lighting technologies. The majority of consumer-grade LED "bulbs" available today are shitty on both counts, AFAICT.
Fluorescent lamps have the same issue with power supply (but not heating). And compact fluorescent bulbs had the same issue of only bad power supplies being available.
We urgently need some standards over electronics longevity, like the ones we have over power consumption.
It would be interesting if there were standard warranty terms (no fiddling with the tiny print) and shops had to post the product's price/warranty-year ratio along with the regular price. Maybe it would promote some competition, as people would start to think in the longer-term cost.
In Europe you can. I've always saved receipts and boxes of lamps (both for inventory and waranty purposes). It's been trivial to return lamps and get free replacements even after the 2 yr default warranty by claiming it broke to soon and giving a quick calculation how with say 4 or 8 hours a day I couldn't have hit the hourly mark at that point in time. Must have gotten at least a dozen free lamps. It is uneconomic neurotic consumerism on my part though. But I sure do hate how old fashioned bulbs were made illegal based on surely false economic lifetime projections of LEDs. On top of that half of the year I'm central heating and I couldn't care less what the source of my heat is.
Central heating especially can be much more efficient than simple resistive heating. Here, central heating runs on waste heat. You can also use heat pumps more efficiently than resistive heating. Incandescent bulbs are inefficient even for heating (to say nothing of the OTHER half of the year when you'd still be wasting massive amounts of energy.)
Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? What is the other source of inefficiency that makes them inefficient for this by-use? The overall replacement cost? Just curious.
> Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house?
Yes, and that mean an incandescent bulb is 100% efficient: all power used is converted to light+heat. But other systems can be more than 100% efficient - they can add more heat than the power they use. Or, in the case of central heating from waste, unused heat will probably have to be pumped off anyway, so using it is energetically free.
Most popular way to make electricity today is to heat up lots of water (via burning coal or uranium) to temperatures on the order of 500 degrees C (1000 F), and have the resulting steam power the turbine, which generates electricity by spinning magnets. This process is generally 20-40% efficient, that is, only 20-40% of generated energy is turned into electricity. The rest of the energy is waste heat of steam that cooled down so much that it's no longer economical to generate electricity from it (because the efficiency of the process goes down as the temperature difference between working fluid and environment goes down). The result is that more than half of the energy simply disappears in the thin air.
To increase efficiency, many cities run cogeneration plant, where the waste heat from electricity generation is piped into municipal heating system. In this scenario, the incandescent bulbs are wasteful way to heat the house, because it only uses 20-40% of the energy of the fuel, while municipal heating uses only waste energy to produce eletricity.
> Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house?
Yes.
> What is the other source of inefficiency that makes them inefficient for this by-use?
Heat pumps are more efficient at heating than resistive elements because they take advantage of already existing environmental heat, whereas resistive heating has to generate all of the heat directly.
Thanks for this insight. Never thought about this. I'm still on old-fashioned gas so in my case the only difference is one of gas being cheaper per joule even after the (in-)efficiency of burning than electricity. But indeed in the heat pump world you get more joules in heating than you put in in Wh of electricity. Still you should amortize the cost of pump per joule of heating. Bulbs were _cheap_.
> EU law also stipulates that you must give the consumer a minimum 2-year guarantee (legal guarantee) as a protection against faulty goods, or goods that don't look or work as advertised. In some countries national law may require you to provide longer guarantees.
If the package says something like "10,000 hours" and you haven't run it for that many hours and it dies in 2 years you can get it replaced by EU law
In the Netherlands (my country) this is interpreted as that you have a right to a functional product for the usual lifespan of a product. After the two years guarantee you're supposed to share the repair costs proportionally. The boxes of bulbs state the expected lifespan (most home appliances do not) so that's an easy starting point. Plus I guess my local DIY-shop just doesn't want to haggle with me and just gives me the replacement each and every time since I'm the only one asking. I'm unsure about how my online LED-supplier will react if in 3-5 years my LEDs burn out, but I've tried to choose a respectable brand and supplier.
The energy consumption one has only a set of standard measurements. Many countries require that the seller do the measurement and place the results on a large tag. Nothing more, and worked wonders.
At least one local store chain has a own-brand LED bulb, where the name of the store is printed on the bulb, and they advertise a 10-year warranty.
I've gone in and returned probably a dozen such bulbs without any receipt, just saying "hey, these are your bulbs, you say 10 year warranty, this is broken and they only came to the market 5 years ago".
Of course this only works now in the early days. If the date of manufacture was printed along with the store name, it'd be problem solved forever.
The LED lamps I use in my bedroom are serial numbered. When one dies they can see when they sold it and authorise a free replacement if it qualifies. I thought the last one to die had qualified, but when I got as far as pulling out my records I realised the one I'd been thinking of was actually still in its box yet to be installed, so this one lasted almost double its warranted lifetime.
Yes this. I have gone through insane numbers of CFLs and LEDs over the past ~20 years of being a homeowner. They fail, they buzz, they flicker, they fail more. I would have saved money and the landfills would be better for it if I just stuck with old incandescent bulbs that burn your fingers.
When led bulbs appeared on the scene I thought "well, that's gonna be the end of the oligopoly of incandescent bulbs". It made sense to me that those big old companies would totally fall behind.
But reality was that you had the choice between dozens and dozens of brands you never heard of before, and chances were high the one you picked just sucked. Amazon reviews were worthless because most people wrote them weeks after buying, very few people would come back if they failed after a year or two, and often by that time the company might have rebranded everything so you wouldn't know anyways. Not to mention how many people apparently are unable to recognize that atrocious 100hz flicker if the company cheaped out completely.
Long story short, all my led bulbs since 2015 are osram or Philips and I haven't been disappointed since.
> If you cut corners on the power supply or thermal management, LEDs will burn out much quicker than older lighting technologies
Really? As an anecdatum, I replaced most of the lights in our house with cheap LED globes a few years ago and so far not a single one has failed. Maybe I'm just lucky. CCFL lamps, however, have been terrible while using 3x the power.
Fortunately, the ~10W LED bulbs commonly used in households don't put out enough heat to be a huge problem.
The streetlights are putting out a lot more power (and thus heat), and thus need much better thermal management, which it appears they don't actually have.
Plenty do. Just not the ones in Detroit. Presumably the problems extends to all users of the E-Cobra system. But I don't think this is a general industry problem in LED streetlighting. It surely is a problem in consumer LED fixtures.
Led tech has improved in the last 5 years. So experience with led of 5 years ago might no be the same as led of today or even 3 years ago. My boss converted his house to led 5-6 years ago I did around 2 years ago. We had a huge discussion about it when our office was being renovated recently. He had to replace about half in the first couple of years of install I have had to replace none so far.
I put a variety of LED bulbs (Ikea dumb + smart, Philips Hue, some no-name brand of T8 drop in replacements) about four years ago and only one (an early Philips Hue) has failed — even that's a soft failure. Meanwhile I've lost one T12 and one T8 in that period (despite only having four FL bulbs in service). Plenty of the LED traffic signals around here have dead LEDs though. Those lasted a surprisingly short amount of time.
The thing is, as bad as the waste is — I'd much rather chuck out LED bulbs than CFL/FL.
I had a few batches that failed at a high rate. The most interesting one was a fixture with 3 candle-format LED bulbs that all failed at the same time! Clearly some power surge/power supply related event.
About 3 years ago I bought a ton (~20) of Cree LED lights. Almost all of them have failed at this point. The GE ones and the later Cree replacements have faired much better however.
Judging by the contents of the bulb bin at the recycling centre, its recessed light fitting that do the damage to leds, which makes sense I suppose.
I've had 2 led failures since I went fully led 8 years ago, one went soon after purchase and looks like a manufacturing defect, so that leaves one that could potentially be heat. Most of them are no names, most recent are Phillips though.
I paid 50 dollars per bulb for two bulbs about 8 years ago. They are still running. And then I paid 8 dollars for a bulb 6 months ago and it failed.
Or did it. I noticed that if you keep it on long enough after it turns off it will come back on. I think the fuse or something gets heated and it stops until it cools.
We had a loose connection of some sort in the electrical box to our house. Made for dirty power that fried probably 6 LED bulbs, and also the rectifier on our microwave.
In a recent power surge, most mobile chargers and LED bulb blew.
Nothing happened to incandescent bulbs or fan.
Luckily I had a power strip with surge protection on which all my expensive equipment were hooked. Power strip blew up but saved my equipments.
Edit: if you open your mobile charger you'll see 400v capacitor right after the bridge rectifier. On 220v mains this circuit needs to handle 310v but can survive upto 400v peak to peak.
But power surges can be more than 400v, and similarly the circuit in CFL or LED driver can only survive very low band of power surges.
Unless you've surge protectors in your house actively scrubbing mains dirty electricity, you'll see your LEDs will not survive long enough.
LEDs don't survive because driver quality sucks and can't deal with mains fluctuation, and LEDs are very sensitive to temperature and voltage, little change in temperate or voltage, will drastically change the current going through the LED and will burn them.
I solved the problem of continuously burning my LEDs by running low voltage DC lines and using 3 level surge protection in my house. Now, I've several mounts for LEDs with fans which keep the temperature in control.
You need serious cooling for anything over 5w led. I am using aluminium heat sink with fan and my LEDs don't die.
He does tear downs of consumer grade led lights for (mostly for the European/UK market since that's where he's based). It's interesting seeing some the iterations that "cheap" devices go through as they are refined to the bare minimum of cost.
I want to pay for it so bad though. I am sick of LED bulbs randomly dying and randomly making noises. Why isn't there a longevity-focused LED bulb brand?
Longevity is antithetical to every accepted way of doing business nowadays because it doesn't generate a continuous revenue stream. Good luck getting capital to start a business based on products with longevity.
Every? There are are buy-it-for-life producers. Examples, Alden shoes, Snap-on wrenches, Fluke meters. With most Toyotas and Hondas you’ll tire of them before they wear out if keep them minimally maintained. Basic kitchen equipment will not fail over several lifetimes. A moderately priced stainless pan will last. Decent knives will eventually wear away from repeated sharpening but I bet if you bought one today it would be in your estate as long as you don't use it for pry bar or a screw driver
All the brands you just listed are not examples of "buy it for life" engineering.
I dunno about the shoes but Snap On isn't really great quality anymore. The Chinese have closed the gap. Fluke, Honda and to a greater extent Toyota are all steadily moving toward more disposable products.
The cheap Chinese kitchen stuff you mentioned is actually the most durable item because in order to stand up to occasional abuse without being damaged it needs to be so overbuild that it can last lifetimes. That's simply a function of the design requirements, not any particular manufacturer's attitude though.
"Snap On isn't really great quality anymore. The Chinese have closed the gap"
That doesn't mean Snap On isn't 'buy it for life' though. That means the Chinese are too.
You raise a good point though. Its very hard to evaluate a product that's supposed to last a life time, until you've had it a lifetime. So the benefits to a manufacturer are slow to accrue, but they're also slow to dispel, so there's massive temptation to cut corners and rely on that reputation, while lowering costs.
It'll be interesting to see how the EV market works out. You have a product that could last for life (with battery replacements). I suspect they'll be viewed, by the manufacturer at least, as disposable when the battery goes.
Fair point and good examples. But those are all old companies. How many new companies (companies formed in the last 10 years) make long-lived hardware products?
I really like Philips LED lights, but finding the right combination of a well designed power supply, thermal management, and high CRI is the elusive trifecta. It’s not surprising to give up one.
If you're looking for installed units, I've been really happy with my Brightgreen LED downlights. Of course, I could have literally bought a box of 10 low-quality Chinese import downlights from the local lighting store for the price of two of these, but the high CRI and really high quality driver made it worth it for me.
Not sure what availability is like in the US and other countries though.
It has to be a good source of direct current, literally. It has to produce a steady, constant amperage regardless of grid spikes and fluctuations. Given that the grid is AC, this requires a relatively complex circuit and more careful engineering than is commonly done for the power supplies inside bulbs.
Edit: Sometimes LED current is actually high-current AC with a square waveform, especially with dimmable bulbs. This is fine provided it's well-regulated and protected from spikes.
This is complicated by the fact that the temperature of the LED materially influences its electronic properties.
As a result you generally need to wire them in series rather than in parallel so that the current can’t differentially select the LED of least resistance and cause thermal runaway. Series wiring in turn cranks up the voltage requirements necessary to drive lots of power, requiring more costly components.
Oh, forgot to mention, different color LEDs have different forward current requirements, so have fun building a good and cheap driver for 100W RGBW.
LEDs can easily be wired in parallel as long as you use resistors to balance them. If you dial in the voltage real tight you can get away with minimal losses in the resistors. If you are really fancy you can use transistors and shunts to actively balance then for even more efficiency.
The reason why series is more popular is actually because it is cheaper and(can be) more efficient. It's not uncommon for cheap led lights to just throw 40 leds in series with a dead simple "driver" (read: rectifier, smoothing caps, and a resistor)to run it right off 120V.
Not the person you’re replying to, but yes. Series config you lose the circuit if the LED fails open and it shuts the whole string down naturally.
Similar issues can affect parallel. If one LED fails open and you don’t adjust the current, you’ll start overdriving the other LEDs and shorten their lives...potentially dramatically. You could add current sense and shut down the board or even adjust current, but then costs go up.
Typical LED strips are small serial strings of typically three lights connected in parallel. That way if something goes wrong you knly lose a few lights.
I'm not sure where the OP is coming from because any halfway decent LED driver will accept a wide range of voltages, far more than the fluctuations seen on public lines.
LEDs themselves are very intolerant of voltage (well really current fluctuations, semi-conductors are weird), but that isn't an issue because the driver deals with that and large swings will kill the driver or kill the driver and LED.
LED tolerance doesn't really play into the scenario here. It's all about the driver.
I think he's asking if LEDs themselves can be more tolerant, since the drivers built in to LED bulbs rarely even rise to the level of "halfway decent."
I still don't understand this trend of replacing the sodium lamps with LED. The sodium lamps use roughly the same amount of energy, cast a light quality that is better for both humans and animals, and are already there, saving a bunch of money in doing replacements.
Why are all these cities undertaking huge renovations to go to LEDs?
Why would LEDs put Sodium vapor lights out of business?
Sodium lamps have the worst color rendering of any bulb. They produce a dark yellow glow which is generally a very low quality light. Additionally, there are serious waste disposal issues with sodium lamps. In particular, they have been known to start fires in the event that the lamp is broken and the sodium metal is exposed. The sodium can catch fire even in the event that the lamp is broken on the ground. For this reason it is safest to break sodium lights under water and then to subsequently dispose of the destroyed bulb. Lastly, HPS and LPS lights are monochromatic, so they can mess with your color vision if you look at them for an extended period of time.
Perhaps more importantly, in the last few years LED efficiency has surpassed that of even LPS and HPS lights and its efficiency improvements are progressing at a much more rapid rate. The largest selling point of LPS and HPS lights is the cheap selling price, the high energy efficiency (low operating costs), and the relatively long lifespan. LPS and HPS still retain these advantages over most conventional bulbs but they lose on all three counts to LEDs. In some areas (e.g. lifespan) they are drastically inferior to LEDs. The extremely low maintenance and replacement costs with LEDs is actually a major cost benefit over the long term. LED lifespan can be greater than 100,000 hours (more than four times that of LPS or HPS). Having to purchase one bulb versus 3 or 4 bulbs over the course of time is a significant selling point for LEDs. The bottom line is that having lost their traditional advantage of being the most energy efficient bulb on the market, there’s very little reason to use a sodium vapor light when LED lighting is available.
Just wanted to point out that the choice municipalities have made for street lighting is not really an LED technology limitation as much as different evaluation criteria.
For example, while sure, OSRAM advertises/sells street lighting LEDs that are broad spectrum (131 lm/W) [1] they also sell single-color LEDs like these amber ones that are actually even more efficient (141 lm/W) with an emission range almost entirely within 600-640nm [2].
This is almost as tight a range as LPS (which looks like about 580-610nm) [3], and it beats out HPS considerably [4].
This was a big deal in Tucson for a while. It used to be that there was a city ordinance that mandated public outdoor lighting was all sodium lamps because it was super easy for the local observatory to filter out that one frequency of light.
Warm white LEDs exist, with color quality exceeding that of sodium vapor in every way, but cities often use blueish LEDs because they're cheaper and more efficient.
As a person who has spent a decade as an amateur student of human color vision, let me state emphatically that “color quality” is a horrifically bad criterion for choosing nighttime street lamps. Nobody should be trying to read a book or critically evaluate photographs in the middle of the road at 3AM.
Street lamps should include as little short wavelength light as possible and should otherwise be as even (this means: use more lamps spaced closer and placed at lower height, diffused and shielded from the side) and dim as possible, so as to avoid causing distracting glare in people’s peripheral vision, and avoid causing high contrast between areas directly under the lamps and areas in shadow. Human vision is amazingly good at adapting to very low light levels. After adaptation, humans can navigate the environment by e.g. starlight, but at any rate can see just fine under sodium lamps.
But the way cities roll out LED street lighting is to put a small number of widely spaced very intense blue lamps high up in the air, not diffused and with little shielding from the side.
Every parameter has been optimized (pessimized?) for blasting away people’s night vision and causing enough glare to make seeing into the shadows all but impossible.
Extremely low color temperature LEDs would be fine, but don’t really have any especially great advantage over sodium lamps. (Except maybe for getting some government subsidy money?)
I thought the wider spectrum of light coming from LED streetlamps means they can be run at a lower brightness to provide the same visibility, which means less overall light pollution (less reflection back upwards) and less power usage.
The little wild creatures don't appreciate that visibility. If the recent report on biodiversity loss bothered you, avoiding LED outdoor lighting is one easy action to take locally.
There's not a lot of biodiversity on the streets anyways, so that's not a big deal. but the little wild creatures do appreciate less light in the woods, which is what you get from less light pollution.
> For this reason it is safest to break sodium lights under water [...]
This sounds like dangerous advice. Sodium reacts exothermically with water producing NaOH. In practice this means it will violently boil and splatter strongly alkaline lye around. (Source: this is how my high school chem prof lost some of his eyesight.)
The City of Chicago is funding a replacement of all it's sodium bulbs with LEDs solely off the energy cost savings [1]. I'm unsure what sodium lamps you're referring to that use a similar amount of energy as LEDs.
> The sodium lamps use roughly the same amount of energy
"The new LED lights will consume 50% less electricity than the existing High Pressure Sodium (HPS) lights. When fully implemented the new fixtures are estimated to save the City $10 million a year in utility costs. By consuming less electricity, the City is helping reduce its carbon footprint. LED fixtures last up to two-three times longer than HPS fixtures."
> cast a light quality that is better for both humans and animals
"Compared to HPS lights, LED lights make it easier to see the contrast between an object and its surroundings; so one can quickly and more accurately identify people, vehicles, road debris or other things on the street or sidewalk. The whiter light also enhances peripheral vision and improves the quality of video resolution"
> The new LED lights will consume 50% less electricity than the existing High Pressure Sodium (HPS) lights.
Not sure how they're going to achieve that. LEDs produce 37 to 120 lumens/watt, HPS and LPS produce 50 to 160 lumens/watt. The sodium lamps lose out only because they are omnidirectional and a mirror is required to aim their light down, so some of the light is blocked by the lamp itself. But overall LEDs don't save 50%.
> Compared to HPS lights, LED lights make it easier to see the contrast between an object and its surroundings;
This is true, but it's a red herring. While that might increase safety in one regard, the light cast by an LED is very blue, which affects both humans and animals, making their bodies think it is still daytime. This disturbs the natural hunting and migration patterns of the animals, and more importantly, disturbs the sleep of the humans.
Sleep deprived humans are for more dangerous than ones that have a harder time detecting object edges.
Also, shouldn't we consider quality of life issues when making these changes, and not just efficiency?
The availability of cheap overkill LEDs is making cities worse... It's especially noticeable when walking at night in areas with restaurants and nightlife.
It's not just street lightning, but also private buildings (maybe they're after that prison yard look?) and cars (giving pedestrians and drivers free lasik, nice!).
Maybe these are OK for highways, but this sucks big time for everywhere else.
They are just as terrible for highways. Getting hammered by blue glare in your peripheral vision is very distracting and destroys night vision, making it harder for drivers to see.
(For the same reason, LED car headlamps are horrifically bad for everyone other driver on the road.)
I don’t understand why there aren’t isn’t strict enforcement of laws about headlights yet. Do the police and politicians not see the danger themselves in the rear view mirror when they drive on the road?
> Do the police and politicians not see the danger themselves in the rear view mirror when they drive on the road?
They don't realize there's a problem, or they've just spent a lot of money "upgrading" their vehicle fleets and don't want to consider that they've been ripped off.
The vehicles of my local police departments and state highway patrol have had all their safe incandescents replaced with blinding LEDs. Flashing blue LEDs on the roof of the cars, flashing blue-white LEDs mixed in with the flashing red and blue LEDs, and blinding amber LEDs to warn of road hazards. The vehicles have blue-white spot lights, and sometimes they have blue-white light bars on to blind everyone within a quarter mile of the scene.
I think the police officers think their new lights are cool.
OSHA [0] should intervene, but I don't know that I can make a complaint on the police officers' behalf...
> Not sure how they're going to achieve that. LEDs produce 37 to 120 lumens/watt, HPS and LPS produce 50 to 160 lumens/watt. The sodium lamps lose out only because they are omnidirectional and a mirror is required to aim their light down, so some of the light is blocked by the lamp itself. But overall LEDs don't save 50%.
I did a quick search and found their RFI [1]. They are reducing electricity consumption by 50% because they are replacing 40+ year old light fixtures that have 70+ year old wiring:
> In the 1950s, the City installed new lighting infrastructure citywide; utilizing mercury vapor lamps. In the 1970s, the City performed a system-wide lighting upgrade; replacing the mercury vapor fixtures with high-pressure sodium fixtures. This project was only a lamp head upgrade; the City retained the 1950s era electrical poles, wiring, and infrastructure. Over the years as underground wiring has failed, City crews have often replaced underground wiring with aerial wiring. In 2009, using available federal funding, the City replaced high-pressure sodium streetlight fixtures with more energy efficient ceramic metal halide fixtures along Western Avenue and Lake Shore Drive. That fixture replacement undertaking did not include upgrading the electrical infrastructure.
Nobody is going to “on the fly configure” color temperature of street lamps. It would add cost and complexity, be less energy efficient, compromise longevity, and is not a worthwhile feature in that context.
In practice, all “white” LEDs (even the very warm ones) consist of a blue LED + a yellow phosphor, and for efficiency reasons in contexts like street lamps the phosphor is never set up to absorb all of the blue light, which means that the intense blue glare inevitably is there clobbering people’s night vision.
It would be possible to make LEDs appropriate for street lighting, but the lighting industry does not currently sell them.
That's ONE way to make white LEDs. Another, more expensive but much better way, is to use an RGB LED and tune the driver to emit the color you want from the triad.
They're getting cheap enough now (insanely cheap, in fact) that it is now feasible to fit street lamps with them.
Imagine the use that could be had if you could change the color of street lamps on demand. Guide vehicles in an evacuation, direct police to a particular location by coloring a lamp red, or something. Direct ambulance by coloring a lamp blue. I don't know. Seems like it could be useful.
It's less about the LED being suitable for street lamps than it is about the lensing chosen to direct the light to the proper locations under the lamp.
> more expensive but much better way, is to use an RGB LED
This is better for displays (or maybe stage lighting, art projects, fancy effects, ...) but not better for standard room lighting, and definitely not better for street lamps.
Using street lamps as information sharing devices makes a cute 1 minute demo, and sounds cool to sci-fi fans, but in practice would be gimmicky and not very effective.
The actual light coming out of “RGB” LEDs necessarily has a quite spiky spectrum, because they overemphasize supporting a wide color gamut. They also include more short wavelength light than is desirable for nighttime use (compromising night vision). e.g. https://cdn2.goughlui.com/wp-content/uploads/2015/12/hue-def...
> It's less about the LED being suitable for street lamps than it is about the lensing chosen to direct the light to the proper locations under the lamp.
I’m not quite sure what you are trying to say with this bit. For best lighting, there would be more lamps spaced closer together, placed at lower height, orange in color and individually dim, and diffused and well shielded from the side. These are all features which would be helpful for any type of lamp.
Unfortunately, the LED streetlamps adopted by cities are high up, widely spaced, much too blue, extremely intense, and not shielded from the side.
The color rendering index of low pressure sodium bulbs is vastly inferior to that of a typical white LED. High pressure sodium bulbs are even worse in that regard.
For backlighting LCD screens, sure. But for street lighting, I don't want a good CRI. I want to minimize blue light, harsh shadows, and glare. The old yellow sodium lights were nice. The new LED streetlights around me are terrible.
A new supermarket by me installed all LEDs for the parking lot, and used warm white ones. You wouldn't even be able to tell they aren't incandescent without looking. I really hope more word gets out to not use "bright white" LEDs for outdoor lighting.
It depends on the type of sodium lamp. High pressure sodium bulbs emit light in an extremely narrow bandwidth around 589.3 nm, earning them a color rendering index of -44 (out of 100). Low pressure sodium bulbs broaden this range enough to earn a CRI of 24. These are the peach colored ones you are familiar with.
That's exactly why the light quality of sodium is better. Because at night you want yellow lights so you don't screw up the sleep patterns of both humans and animals.
It's generally my experience that street lighting is not very helpful while driving. It often reduces the contrast ratio between an object illuminated by my headlights and the background as well as the light fixtures themselves being a source of glare.
I'm not sure if that's serious, sarcasm, or reducto ad absurdum. Regardless, I've actually looked in to published research on the matter in the past. I don't have links to studies handy, but here's what I remember finding:
Street lighting does not reduce car-car collisions, and in most conditions, does not reduce collisions at all. The major exceptions were pedestrian crossings without traffic lights, and when illuminating curves or obstacles. I don't recall finding a comparison between overhead street lighting and reflectors or marker lights for curves and obstacles, but it seems to me those might provide the same benefit with less glare, energy consumption, and light pollution.
LED lights are now common in suburbs as they sprawl into habitats. Migrating birds get confused as they fly over cities. Coastal cities and towns mess with aquatic animals.
My guess is LED lights are supposed to last a lot longer. The human cost of replacing lights is probably a lot more than the cost of the bulb. Labor is expensive.
Not really. The rated life of sodium is 24,000 hours, and LED is 25,000. With a lot of money you can get LEDs with rated life up to 200,000 hours, but that's not typically what cities are buying.
That's just the average rated life of an LED street lamp. But if you do that math, that's about 5.7 years at an average of 12 hours a day. So these lamps were probably rated closer to 50,000 hours. You can also get sodium lamps that last that long. It's just an average.
Not all are. In the county I live in, they are still using sodium lamps. The one exception I'm aware of is a pilot program at a commuter parking lot, where they use LED lamps.
LEDs last a long time. Apparently some other critical supporting component inside LED bulbs fail within 1-2 years.
Nearly every brand I've tried started flickering or dimming or failing in some way after 2 years of use despite the box touting 10+ years of life. Disappointing to say the least.
Same here. Multiple other brands have high failure rates in a short amount of time. In my case I think it is because of the poor quality mains power which suffers frequent spikes and outages during storms. Philips seems more robust to those conditions. They used to cost a good deal more but have come down to price parity with other brands.
Speaking of Philips, I had a compact fluorescent bulb from them last me 8 years. This was used as an open garage bulb that would usually be on all night and sometimes all day if someone didn't turn if off during the day.
This was in the 90's when compact florescent were not cheap in my country but we got tired of regular incandescent bulbs blowing due to the number of hours they were being left on.
I had the opposite experience. I have been using LED lighting for 20 years now.
Are you sure your brands are original?
Be careful if you buy in places like Amazon, at prices too good to be true, because they will be Chinese clones.
Yes, I've only bought LED bulbs at brick-and-mortar stores. I've tried GE, Walmart-brand, and Costco-brand. I have not tried Phillips which others here are recommending, so I'll have to give those a try.
The dimming seems like more of a feature to me. The over bright / sharp led street lights are a hazard. Same with the led lights on emergency and other vehicles.
LED streetlights are terrible. Sure, they look nice, but they don't provide much light.
They're always underspecced so you get a little square of light directly under the street lamp, but that's about it. Looks like early 3D videogame lighting.
Cities all over the country getting scammed into replacing their proven discharge lamp streelights for LEDs on the basis of TCO analysis that is predicated on false reliability figures. I'm sure some consulting firm is laughing all the way to the bank. Oh well, more cheap LPS fixtures for me...
I was recently in LA and drove down to long beach, every other streetlight was dead.
Maybe by the time they figure out what a disaster this is and have to redo it all, they'll do a better job at cutting out the light pollution.
As you are discovering, most people object strongly to the idea of removing streetlights. Darkness == the unknown == fear. Yet, many people live without streetlights, and we have lived without streetlights for most of our history. Although streetlights and other persistent night-time lights are useful, they are massively overused, and are increasingly being overused as they become more efficient.
I would hate this as a city dweller. Not being able to see what's 100m ahead of me, akin to driving on remote highways (with car lighting only illuminating their immediate surroundings), sounds depressing. In very dense areas, there's usually always some light from a nearby business that's on, but in other parts of cities streetlights throughout are very beneficial.
For example, a lot of them help light up signs to assist pedestrians with navigation. Others indicate the existence of smaller side streets that wouldn't be visible until a pedestrian reached them. Yet others help to identify tram or bus lines, which can very useful for pedestrians.
A city spending energy on lighting should have nothing to do with crime. It should only be considered when dealing with car driving safety.
Want to reduce crime drastically in a city, legalize all drugs.
Street lights aren't just for cars they light the area around for pedestrians too. The only place that's true is highways and even there street lights increase visibility drastically compared to headlights.
What a nightmare. Detroit installs LEDs in the hopes of saving money and power, then ends up with a bunch of lights that need to be replaced. (Also, lots of more trash to deal with.)
Ugh. I hope the right long-term changes happen where they are needed.
This almost sounds like a case where the city cheaped out (maybe the budget just wasn't there?), and went with a third tier supplier.
I noticed the article noted that units supplied from Cree, used in other areas of the country, are performing up to standards and not dying like the ones in Detroit from Leotek.
To me, it's one thing if you're a hobbyist or something looking to save some bucks so you buy cheap LEDs drop shipped from China via Ali Express, from some rando vendor and manufacturer. If one or more die, usually it's not a big deal.
But if you're building a product, or installing something commercially or at a government level, you should do yourself a favor and not go for the lowest cost. While I'm sure Cree LEDs are probably manufactured in China, too, they are likely made to a much different standard.
For all we know, Leotek is using relabeled parts that are marginal or failed to pass QA inspections at other manufacturers, but they got a great deal on barrels of rejected LEDs, and decided to go into the commercial light manufacturing business.
I honestly don't know who or what the company is. What I do know is the name "Cree" and their quality (which also comes with a hefty $$$ price/cost) - but "Leotek" sounds like a company you'd find in a random search on Alibaba.
Maybe that's an unfair assessment; sometimes when ordering a large volume of parts, you'll get entire batches that fail in the real world when they passed QA fine...
They bought from multiple vendors, following procurement rules, from a company in San Jose, CA (and a division of Lite-On), from a company supplying lights across the country, and the design was flawed, not the parts. Don't blame them when you know nothing of the situation.
> Founded in 1992 in California's Silicon Valley, Leotek is a leading global manufacturer of street, roadway, area and signal lighting products and solutions. Leotek streetlights were first designed and delivered in 2007 and the company now has more than 1.5 million installations across North America.
> In 2013 Leotek established a manufacturing facility in San Jose, California. [...] Leotek's lighting products are subject to 100% 2-hour "burn-in" reliability testing and comprehensive performance testing prior to shipment.
I'm not sure what your point is. Both appear to be, or were, subsidiaries of Lite-On[1], and the point is that it's not a no-name company that is drop-shipping rejected parts.
(The Chinese doesn't particularly help - I can't read much of it, and I can't find the source, so I'm unclear what relationship Shandong Jiahong has or had to Leotek)
What’s interesting is that Berkeley used some LEDs from the same company, and I assume they’re not facing the same budgetary pressure that Detroit was.
The bay bridge project could have sourced the main steel parts for the eastern span replacement from US manufacturers but chose to go with a foundry in Shanghai. The USW, with all the pro-union talk in the Bay Area, cheap was chosen. Money talks.
Cities are all facing budgetary pressure, or should be. We don't want them overspending arbitrarily.
The vendor promised a certain warranty. If the due diligence was done, and the cities were happy with the price paid and the terms of the warranty, hopefully the vendor stands behind the product.
So is the Detroit Public Lighting Authority: "We want to make sure that absolutely the taxpayers of the city are not being asked to pay anything more than they are legally obligated to."
But: '"This deadline has come and gone, and Leotek ceased all communications with the PLA," the suit reads.'
Company website has both:
"Leotek Electronics USA LLC",
and
"Leotek is a subsidiary of LiteOn Technology Corp."
I don't see how it's a contradiction - it's the same as Google LLC being a subsidiary of Alphabet, and LEOTEK ELECTRONICS USA LLC is listed as a Sub-subsidiary in LiteOn's financial reports: https://www.liteon.com/storage/document/document/2017lite-on...
I don't expect it would, generally heat reduces LED lifespan, but not cold. If it's really cold, LEDs will struggle to turn on, but AFAIK it doesn't cause any long-term damage. (You can get consumer LEDs designed to operate in very cold conditions, e.g. from FEIT.)
Maybe both companies guaranteed the same performance.
Am I wrong to think that not all is lost, all they need to do is change the bulb...and the major investments were the poles? Not trivial of course, but also not a total $180m loss
The pole head needs to be swapped out, since the LED is integral to the fixture, not a swappable lamp. This requires boom trucks/lifts and that work cannot be performed hot, so shutdowns need to occur. There are thousands of lights.
A union journeyman costs ~$65/hr in Detroit
A 50/50 split between labor and materials isn't unusual for electrical work
