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LEDs - Do the Benefits Outweigh the Cost?
7x7 asks: "We keep hearing about the latest and greatest thing to come out of LED technology, and every article seems to give an over-view of the topic. How LEDs consume little electricity and last a long time, etc. However the manufacturing process involves super hot ovens and expensive componants. Do the requirements necessary in the manufacture LEDs and LED componants out-weight the requirements for standard bulbs over 10 years? One LED light can last ten years, but contains dozens of LEDs. Has anyone seen or performed an evalutation to see if the trade-off is really anything to speak of?"
Fluorescent lights are much more cost-effective and last just as long.
Repeal the DMCA!
nt. :)
I wish the bulb that burned out in my truck's dashboard had been an LED to begin with.
It cost $95 to change it.
--I am an extreme flashlight fiend, I mean I got dozens of them. My LED flashlights are just a sheer joy. The bulbs don't burn out or pop in temp extremes, I got literally years of normal use off a set of batteries. Most of them will run for days if you just turn them on and leave them on, I've tried it. a regular flashlight lasts a couple of hours max usually. I took one of my first ones, a ccrane model, and read several books at night on one set of batts, just to see how they did "real world". Just outstanding.
I switched several years ago from 12 vdc incandescents to fluorescents for my interior lighting in my RV I live in,got a good boost in performance, but as soon as the LEDs get a scosh cheaper in a normal 12 vdc config for area lighting I will switch to them instead.
Previous Ask Slashdot discussions on LED lighting, LED Light Fixtures for the Home? and Which LED Flashlight Do You Use?
I've got a fever and the only prescription is more COBOL.
It seems to me that if the power usage of those LEDs is much lower than that of a bulb, then yes, there is a very good chance of the LEDs being less damaging to the environment.
Don't underestimate the power savings you can achieve over a ten year period.
I suffer from attention surplus disorder.
Incandescent light bulbs, as we all know, are highly inefficient, emitting ~95% of their energy as heat. Fluorescent bulbs are much better, but still emit radiation in a line-emission spectrum far wider than that of visible light. As far as I know, LEDs are geared to one frequency, and are therefore very power-efficient. No matter how much it takes to manufacture something (within reason), if it is more efficient, it will pay off in the end.
I think the question asks about the total cost of manufacturing/consumables used to run LEDs vs fluorescent vs incandescent bulbs. I'd also throw in the environmental impact as well.
Incandescence are pretty simple to make now and don't contain much in the way of harmful chemicals, just glass and tungsten (older ones used a leaded compound for the base.) But the monetary and environment costs of the electricity are high.
fluorescents contain mercury, but I don't believe they are too hard to manufacture (correct me if I'm wrong.) They are currently the cheapest to run from an electricity point of view, but LEDs are rapidly (yes, there is more electrically efficient lighting out there, but not in the brightness range that most offices and homes require.)
LEDs use some nasty chemicals to manufacture, but the end product is fairly harmless (it contains tiny amounts of some harmful things, but the LEDs last such as long time that, imho, the impact is very small when depreciated over its lifespan.
From a battery-operated point of view, LEDs are the way to go. Fluorescents require some bulky voltage and signal conversion and don't run the battery completely empty. LEDs are strong, light weight, and very energy efficient. Plus batteries contain their own nasty chemicals. I just can't wait for portable fuel-cells!
Very true, but it depends on the purpose of the light.
In the kitchen, use Flourescents. Cheap & effective.
But how about for your car dashbord or some other DC-powered device? Seems like an LED light in your car roof could solve that "Ooops, I left the interior light on all last night, and now the battery is dead" problem.
That said, I still think LED installations have a way to go. Whenever it rains, I see a bunch of cars where 30% of the LED lamps are dark. The LED's probably work fine, but I bet that the connections have corroded due to the rain and smog.
"Can of worms? The can is open... the worms are everywhere."
As always, it depends on the use.
I haven't seen anything about manufacturing costs, so maybe I'm not answering your question, but in use:
In traffic lights, a burned out bulb is a hazard, and expensive to change.
Brake lights and taillights are dangerous to lose, and they get shaken around. That's why in many cars if your brake or taillights go out, your dash lights go out too as a reminder.
Flashlights are typically low temperature bulbs where incandescents are more inefficient, especially after the battery voltage starts to drop off. Besides, they get dropped, so LEDs are a win there too.
Fluorescents are the most effecient, but for household lighting I don't like their color or sixty Hertz visible hum. (Any specific recommendations for a compact fluorescent that has a good color & a nice ballast that doesn't flicker sixty times a second?)
The LED geeks know LEDs aren't always better as far as power consumption goes.
http://www.pioneernet.net/optoeng/LED_FAQ.html#Q7
http://misty.com/people/don/lede.html
I saw a nice use of LEDs in a remote campsite. There were solar collectors on the roof of the bathroom, and little banks of a few LEDs that lit the bathrooms at night.
An LED seems smaller, but the incandescent in a mini-maglite puts out much more light than a white LED of the same size.
Assembly is the reverse of disassembly.
.. please send 29.95$ for my new book, "Taking over small countries using only a swiss army knife, a magnifying glass, and a small RC airplane"
--I really am not fond of the multi tools, most of them anyway. Survival "kits" I don't have either, but I live a survivalist lifestyle, as opposed to a non-survivalist lifestyle. Ya, I could probably stock a small complete army/navy/camping/neat stuff store. heh. And then some.
Don't seem to have a nintendo or gameboy or X box though. Got a *few* radios though........
The politicaly correct non-scary to city folks term is "preparedness", or more slangish "prepper", (yechh) but seeing as how I've been into it since even before kurt saxon coined the term, I'll stick with "survivalist", it fits. Boy Scout motto on steroids basically, "be prepared" as opposed to "oh me oh my, someone please do something and save me from......" - fill in the blank.
And I don't live in a van down by the river, I live in a nice RV -old but nice and geeked out- on a mountaintop on a million buck estate. It ain't mine but seeing as how I can do most whatever I want to do and actually make my living off of it and don't have to punch a clock and all..it's OK I guess. The commute ain't bad. It's my way to try and stay semi retired. Semi. I never want to quit work, but I enjoy not pulling 60 hours a week for basically jerks doing something I don't like anymore.
We do have a pond here though. It's the sort of place people pay some nice cash to go spend a couple weeks vacation. Closest neighbor is a retired IBM mainframe guy, he's about 1/2 mile away, on another baby mountaintop. A traffic jam is when some local's cow gets out and stands in the middle of the road.
I know I'm getting trolled and razzed on this sub thread, but LED lighting I have some familiarity with, thought I'd throw in my 2 lumens worth. I think they are worth it, especially as how the price has dropped and they have the near white bulbs now.
Now what the HECK is that characters name on SNL? I remember the skits but forgot his name.
Same here. Most of the x-many (16?) bulbs in the dashboard of my 1995 Escort were burned out, and I resorted to a clipped-on LED flashlight for a while (the light from which is actually much more pleasing than the stock, "working" lightbulb situation -- the LED cast a very nice pool of light). Girlfriend pressure --> 'fixed' but what a hassle. Even with the borrowed labor of a car-fixing friend, it was a royal pain.
...
It's unconscionable to stick such inherently perishable parts (incandescent bulbs) into such an inherently inaccessable, inherently expensive (in time and money) spot. Many (most?) new cars are at least using some sort of electroluminescent stuff instead, maybe some are using banks of LEDs, I don't know
And rube goldberg as it sounds, I liked the flashlight for one other reason: it was simpler to click it off when I wanted than to find the rheostat for my dashboard, which is located in a tricky spot.
timothy
jrnl: http://tinyurl.com/c2l8yr / foes: http://tinyurl.com/ckjno5
ya, the flicker can be bad, and fluorescents really mess up radio reception and transmission if they are close to the antenna. Ditto for over the air TV, too. I use 12vdc ones I get from the auto parts store, they don't *seem* quite as bad as 120 vac fluorescents of similar wattage, but I can't really say that for a fact, as if there is a difference it's marginal. Definetly better mileage from the storage batteries though, went several years with the incandescents (and little TV, radios, etc), that meant re charging the storage batts every day, with the fluorescents switch over I can have twice as much light and the batts only really need topping off every few days. But now I have solar PV so they get topped off quietly anyway. Hate having to run the engine or genny if it's not necessary.
I think for most purposes LEDs are much better though. One place I really want bright incandecent is working at the bench, need that bright hot light, just no substitute for that fine detail work, soldering, etc.
It was Matt Foley, played by Chris Farley. He lives in a van down by the river.
Unfortunately, the problem in my case was that the "check engine" light wouldnt' function. And here in California, a functioning "check engine" light is required to pass the emissions test.
;)
But the truck is a '91 model so it's possible they hadn't ironed out bright yellow-led's yet back then.
A high-efficiency red LED puts out about 2.5 mW of luminous energy in its emission band, and consumes 120 mW of power. That's 3% efficiency. The rest is dissapated as heat. Incidentally, that's why LEDs have a large footprint (the luminous area is very small); so the heat can spread out and the junction characteristics don't change. Incandescents emit light energy outside the visible band, unlike LEDs. This is where most of the power goes, not heat. Thus, incadescent lights achieve about 15 lumens per watt, flourscents get about 50 per watt. Contrary to popular belief, LEDs are in between, the high efficiency models get about 25 lumens per watt.
The most efficient LED right now is %32. You can't buy these yet... they will be used in lights that operate like flourescent lights since they emit UV. This will be the ideal, long-lasting but low power light source.
LEDs are not economical when a flourscent light with electronic ballast can be used in the same situation. In scenarios where the extra electronics required by a flourscent light are too bulky or not enough power is available- this is where LEDs shine. That is why they are the flash-light champs.
Fuck Beta. Fuck Dice
LED lighting is the way things are going. Oh, did I mention the '.'?
I find that hard to believe, since most people have already praised the LED flashlight with regards to its long life at the same intensity over the lightbulbs. Also, the "light energy outside the visible band" you say light bulbs emit is infrared which is basically heat. It should be obvious since the bulbs use the Joule effect to heat up a tungsten/wolfram coil to incandescence, which emits the light and gobs of heat.
Bike lights (taillights, headmarkers and on some models of high-end headlights, instrument lights) have used LEDs for years. They really conserve on batteries and are quite bright (I can see the glare of my LED taillights on the road behind me in my helmet mirror at night). Most of the cities in northwest Oregon and ODOT have changed to LED arrays for traffic signals, since they don't burn out as often as incandescent, even when being bounced around by a storm (most intersections have traffic lights on overhead stringer lines, not poles, so they can properly position the signals over each lane). TriMet is phasing in LED signals on busses (they hate driving around busses with a burned out left blinker as much as you hate getting stuck behind them that way), and has
Help us build a better map!
LED lights are getting better
http:\\www.limileds.com
main points to know about lumileds
the light is cold to touch (heat is still generated - but through a heat sink)
coloured lights are alot more efficiant then any other type i know of
the 5W white leds are not rated for a very long life but all the other 5W and all the 1W are rated for 100,000 hours.
a swith mode power supply will probabily be need to drive them efficaintly which adds to the already high cost.
Did you misread the part where I said LEDs are the winner in flashlight choice? This is because they beat incadescent lights in lumens per watt numbers (the numbers get worse for incadescents too as they get smaller, like in flashlight bulbs). They don't beat flourescent lights, though. That was my point.
Light bulbs emit infrared, radio, microwave, and ultraviolet light (as they are blackbody sources). The heat from the filament is not easily conducted away into the base of the bulb or through the gas inside. Hence, much of it radiates away in the form of photons. The infrared radiation is re-absorbed by the glass in the bulb itself and causes it to heat up some (in addition to heat transfered by conduction). But it still passes much of the infrared, ultraviolet, etc. energy out into the room. They don't heat up as much PER WATT when compared to LEDs.
LEDs don't emit anything but a narrow wavelength. Unfortunately, many of the photons get re-abosrbed by the substrate. All of this gets converted into heat. Some of it is converted into microwaves and radio waves, but not much. This is because the large package area (and small power output compared to a light bulb) allow it to conduct the heat into the environment, either through the plastic package or through the thick metal leads allow into whatever its attached to. They don't get hot to the touch unless you put a lot in a small space.
Fuck Beta. Fuck Dice
the suv which was formerly mine (sold it, because of college being in milwaukee, and it being in california) passed smog tests as late as last summer, and it had neither a functional check engine light, nor a catalytic converter...
:)
it did fail once because the gas cap didn't seal though. (although there is no way in hell that the gas cap sealing made any difference in the actual operation of the vehicle (as opposed to the seal on the seal tester device))
of course, it was a '78 international scout.... so the emissions requirements are a little different than on a '91
Need a Catering Connection
Where, oh, where would we be without the karma whores?
"...we dont care about the economics; we just want to be able to hack great stuff."
People say this a lot here, but can you cite a source. A super-bright (2 candella) LED takes 15mA at 1.7 volts, that's about 25mW of power, so 1 Watt powers 40 LEDs. A standard 4-foot fluorescent tube is 40 Watts, so you can power 1,600 super-bright LEDs with the same power as the 40 Watt tube. I've never used more than 50 of the LEDs at once, but it sure seems like a few hundred would match the light output of the fluorescent.
From what I said, we know 40 Watts gives us 3,200 candella with the LEDs. What's the output of the 40 Watt tube? I have a 20 Watt ring-shaped compact fluoresent that gives under 1000 candella, so the LEDs are more efficient than that.
Jason
ProfQuotes
From the voltage drop you quote (1.7 V) that must be a single colour (probably red?) LED. The 20W flourescent is (I assume) closer to white. If you look at white leds they're far less efficient than the basic red and green varieties. The loss of efficiency puts them below flourescent lighting. I don't have any sources to hand to back this up I'm afraid.
Of course, LEDs can be used to make very cool light enclosures that can't be achieved with other technologies.
If we're talking car lighting (brake or tail lights) then LEDs win out easily, 'cos they've got to be red anyway.
Do the requirements necessary in the manufacture LEDs and LED componants out-weight the requirements for standard bulbs over 10 years?
Have faith in the free market. From a cost-payoff point of view, the only thing you should care about is the price you see on the shelf at Wal-Mart. Built into this price are all the costs associated with manufacturing, packaging, distributing, and selling the LED.
From an environmental point-of-view, I really don't know. The fact that LEDs are so durable and compact might mean a lower long-term impact, simply because the volume of manufacturing waste and consumer waste will be lower. Whether LEDs are more polluting per manufactured unit of weight, we'd probably never know due to trade secrets.
Healthcare article at Kuro5hin
I have a headlamp that uses LEDs or an incandescent in the same reflector. The choice is made by rocking the on/off button to the left or the right. A tap in the center is the full on/off. Girlfriend got it for me, came off the rack at walmart, around 20$. It is "cyclops" brand.
For flashlights, where incandescents typically have very low bulb life and you often are VERY screwed if the bulb pops - LEDs are king, and unless you want the equivalent of the largest of SureFires, they're more than bright enough thanks to Lumileds Luxeon line (Mentioned a few posts up, they make 1 watt and 5 watt LEDs.) I have a MiniMag that has had the bulb assembly replaced with a 1W Luxeon and DC/DC current-regulated stepup converter, it ROCKS. It can tangle with a 2D Mag in brightness, and handily beats said Mag once the Mag's batteries have been used for 20-30 minutes. The BB400 pill lasts 2 hours on 2 AAs, and it's constant brightness the whole time.
www.candlepowerforums.com has LOTS of great info on LED flashlights.
LEDs also make sense in many automotive applications. The more inaccessible the light, the more an LED makes sense. (Dash lights, etc.) Taillights make sense because LEDs don't have the warmup time of incandescents - In addition to looking cool and not burning out, the faster turnon time is equivalent to nearly a full car length at highway speeds. LEDs also make for great "courtesy lights" in cars.
For home use - Flourescents win in most cases.
In short, LEDs are king for compact applications where large amounts of light are not needed, or where the beam needs to be focused (flashlights). Fluorescents win for applications where they can fit and collimation isn't necessary. (Fluorescents aren't anywhere close to a point source.)
LEDs won in the traffig light area long ago - They don't actually save that much power (As others have said, LEDs are less efficient than large fluors/incandescents, it just happens that they ARE more efficient in smaller lights and handle variations in supply voltage more gracefully if the circuit is designed correctly, namely because they only dim instead of dimming AND changing color.), but they DO save a large amount on bulb replacement costs. (Traffic light bulbs cost $$$$$ to replace, and even with equal power consumption LED lights pay for themselves in only 2-3 years just on bulb replacement labor costs.)
retrorocket.o not found, launch anyway?
... as soon as I either buy or make one. It's still cheaper to just purchase a finished product that trying to mod your own with those LEDs in a lot of cases. I've seen various strip 12 volt models but are still too expensive (60$ as opposed to under 10$ for similar). I figure whenever the first fluorescent burns out, that will be the time to look hard again and buy one LED replacement for trials. I have several backup of the fluorescents already, so that really isn't the problem. I tend to more use spot-directed than a general area light anyway. One is just for the keyboard at night, but now they got those cool lit up ones... hmmm, choices.... hmmm
DEFINETLY a consideration!
I was looking after last Christmas for LED in christmas strings but never found them on the shelf local. I think that would be the way to go, either string them around the ceiling or pack them into a home brewed fixture.
..as my voltage drops in the storage batteries it makes the fluorescents not turn on or work as well, and yep, that flicker gets much worse then.
Tell you a problem I have had. Gone through several of the cheaper LCD digital readout multimeters to use inline with the circuit to maintain better control/monitoring over the system. They just stop working after awhile. I know they aren't designed particularly for that task, but I am wondering now why they just stop, seeing as how they are pure battery, and I am religious about changing them in a timely manner. The LCD screens just always go bad, and I mount them inside away from the battery compartment or any weather extremes. I'm chicken to burn any more out experimenting with different brands. The only variable I can see is the "always on" as opposed to normal VOM use. The auto parts store dc dashboard volt meters I have seen on the shelf don't give me that two decimal place readout I want.
One day, we will be able to apply a photonic band gap material to the surrounding area of the LED material itself. This will hopefully reduce the wasted heat, and instead perfectly reflect those photons back at the LED material, where they can be reabsorbed and then remitted till they get emitted in the right direction. This could increase the efficiency to near 95+%.
Flourescent lights do put out a visual hum, but it is at 120 hertz, because you get light on the positive and negitave halfs of the cycle...
We are Dead Stars looking back Up at the Sky
So, here I am crammed under the floor of a computer room, 3am, re-pinning the host control cable of a MRI scanner. I've got my trusty LED pocket squeeze light in my mouth, my left hand is crammed under me somewhere and my right hand is doing its best fish out 1 cable from 50,000 that are all around me. I yell, "What color is the cable?", my coworker yells back "The RED one". Of course, my light is blue and I'm having the damnest time figuring out what color that is going to make the cable.
In the end, I just turned the light and used the force.
Noma "Forever Bright"
UPC # 0 63407 13802 8
Bought them on Clearance from Canadian Tire one year for $3.00
They are really quite cool. There are three strands of wire, one neutral, one string of red leds wired in one "direction" and another string of green LEDs wired in the other "direction".
The 120Hz flicker is actually quite fetching. As long as they are not in your peripheral vision though, otherwise they might just drive you batty...
John
--I'll google for them and see if I can grab a string!
> But the truck is a '91 model so it's possible they hadn't ironed out bright yellow-led's yet back then. ;)
They still haven't. Yellow emission can be acheieved, but they really, really suck compared to everything else. It's a materials issue. Nitrides and SiC can acheive efficient blue through near ultraviolet LEDs, AlInGaP and stuff can handle green and orange, GaAs makes very efficient emitters from red into infrared. But there have been found as yet no good materials for efficient yellow LEDs.