Naked Science Forum
Non Life Sciences => Technology => Topic started by: Geezer on 02/08/2011 07:00:14
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In the interests of science, I broke down today and shelled out $17.99 (inc. tax) for a new fangled 40W equivalent LED lightbulb. As it's supposed to run for 5.7 years (continuous operation I think), I'm putting the receipt in a safe place, and I may even have to put it in my will.
It seems to work pretty much the same as, er well, a 40W light bulb, except that it's a bit heavier (so it's NBG in my antique Anglepoise) and it doesn't seem to even get warm. Unlike CFLs, no warm-up time at all, and the colo(u)r seems just about right. If they can figure out how to get the cost down just a bit more, I think they will become quite popular.
Anyother suckers body else tried 'em?
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Yes, I have replaced a number of halogen (gu10) bulbs with LED (and the CFL equivalent).
I agree, they are very good, although the light is a bit harsher than than the CFL,s but does not need heating up.
Where they have really come into their own is with 12v (battery) systems - such as in my camper van and for chums that live off grid.
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Where they have really come into their own is with 12v (battery) systems - such as in my camper van and for chums that live off grid.
Ooooh! That's a good idea. I'll need to check that out.
Presumably there is some energy loss associated with transforming 120V or 240V to the low voltages necessary for LEDs. I wonder if we could reduce the loss more if we used, say, 12V DC for domestic lighting?
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We have leds in the boardroom here at my office - got a ten year free replacement deal as part of contract; as any replacement will require a fair amount of work the installer must be fairly confident that there is little chance of being called back!
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We have leds in the boardroom here at my office - got a ten year free replacement deal as part of contract; as any replacement will require a fair amount of work the installer must be fairly confident that there is little chance of being called back!
Keep very close tabs on their financials. The failure rate for these things is based on a boatload of extrapolation from a limited data set.
I'm quite optimistic, but only time will tell.
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curious if 40w equivlent bulbs set up as spotlights [reflective domes or however] so to shine the light on a black surface [metal?] & then compare the temp of the black metal from 3 different bulbs with IR thermometer gun. Assuming light color from 3 diff bulbs is similar , will the black surface vary in temp?
BTW, saw where GE made a combo quartz/CFL bulb to to brighten quicker.
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Old CFL package read," 10,000 hr bulb life & deduct 2 hrs for every on/off cycle
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well i live in Pakistan, where electricity is very expensive and very rare, most of the time we have loadsheddings due to excess energy consumption, so to reduce the bill cost i replaced all the bulbs in my home with this LED lights, it gave me a significant bill reduction, but then i got hands on a 1 watt bulbs and they are made in china and a single bulb gives of enough light to illuminate a room. got 10 plates of solar pannel which gives me 1 kWa for 6 hours, and for the rest of the day i had a 3 kWa generator. So this is how we are generating low cost energy at home.
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The key strength of LED lights is reduced power consumption. When designed properly, an LED circuit will approach 80% efficiency, which means 80% of the electrical energy is converted to light energy. The remaining 20% is lost as heat energy.
spammy link removed
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curious if 40w equivlent bulbs set up as spotlights [reflective domes or however] so to shine the light on a black surface [metal?] & then compare the temp of the black metal from 3 different bulbs with IR thermometer gun. Assuming light color from 3 diff bulbs is similar , will the black surface vary in temp?
BTW, saw where GE made a combo quartz/CFL bulb to to brighten quicker.
The metal will likely be cooler for the non-tungsten bulbs as they won't be emitting any appreciable energy in the infra-red compared to the tungsten - thus the total energy emitted (with the potential to warm the target) is lower.
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A white LED is basically a blue LED with a phosphor coating on top of it, to convert some of the blue light to red and green light. Mixed all together the eye sees this as white light. It is essentially the same method as a flourescent lamp uses, with the same drawbacks. It degrades with time causing colour shifting, and it is also very fast to degrade when it is overheated. Thus LED lamps ideally should be run at a die temperature of under 70C, meaning the metal heatsink the die is attached to should also run at under 40C, to keep this spec. Doing this in a housing that will fit in the same rough volume as an incandescent lamp is not feasable unless you only are going to dissipate 5W total, including the driver losses. As this would only give you an equivalent light to a 15W lamp, most are overrun to improve output, but then sacrifice the life of the LED chips inside considerably.
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Are you alright Geezer? From an environmental perspective LED's are quite bad. Now as they are becoming more popular due to their efficiency, as you know, it just spells more toxic pollutants in our systems.
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Are you alright Geezer? From an environmental perspective LED's are quite bad. Now as they are becoming more popular due to their efficiency, as you know, it just spells more toxic pollutants in our systems.
Are LEDs not a lot better than CFLs? They (should) last a lot longer (which means there will be a lot less of them in the dump), and they don't have any mercury in them, which is a bit of a problem with all fluorescent lights.
I must admit I'm quite impressed with the LED. Instant on, and it runs really cold. It does not seem to emit much heat at all.
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I found this article on LED's http://inhabitat.com/study-finds-led-light-bulbs-contain-unsafe-levels-of-carcinogenic-toxins/
I am all in favor of LED's as they are so efficient, I have been a big fan of them for years.
At University we had managed to light the whole stairway in the house by plugging in an old phone charger and linking them in series to that. I am not sure if what we were doing was safe but it certainly cut down on our electricity bill over the year.
I think Organic LED's might be the way forward, they use organic semi conductors instead of compounds that mostly incorporate Gallium.
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I found this article on LED's http://inhabitat.com/study-finds-led-light-bulbs-contain-unsafe-levels-of-carcinogenic-toxins/
I am all in favor of LED's as they are so efficient, I have been a big fan of them for years.
At University we had managed to light the whole stairway in the house by plugging in an old phone charger and linking them in series to that. I am not sure if what we were doing was safe but it certainly cut down on our electricity bill over the year.
I think Organic LED's might be the way forward, they use organic semi conductors instead of compounds that mostly incorporate Gallium.
I think there might be a teensy bit of greenwashing in that link [:D]
It doesn't say anything about the environmental benefits of LED lighting, so I have to assume it was written by those who think living in caves was "the good old days". (Not that I'm suggesting they are knuckle-draggers or anything like that.)
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I have not heard of green washing before.... although having read the article again I see that it does seem to be very particular in that it focuses on the negative aspects of LED's. Maybe it would be better to go back to caves except our arms are a bit shorter and we can light them with LED's [;D]
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I have not heard of green washing before.... although having read the article again I see that it does seem to be very particular in that it focuses on the negative aspects of LED's. Maybe it would be better to go back to caves except our arms are a bit shorter and we can light them with LED's [;D]
Greenwashing is the act of portraying anything that has any negative environmental implications whatsoever as "non-green". This tends to seriously limit the green options - erm, are there any?
Greenwashing is not so different from whitewashing, and hogwashing.
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So you could green wash everything! What man made thing exists that have a positive impact on the environment?
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So you could green wash everything! What man made thing exists that have a positive impact on the environment?
Precisely! That's why we should go back to living in caves. I'm old enough that it would not trouble me too much, as long as I have a reasonably soft place to sleep, and an adequate food supply.
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I know there are some pretty big caves around.... What about the problem of damp?
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I know there are some pretty big caves around.... What about the problem of damp?
Oh, that wouldn't be a big problem if the cave was on Mallorca.
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I have bought and used several LED bulbs in the very cheap range (3~5€) and power (around 1w consumption). They shed white light and some have small color differences, but I'm not picky about that.
Some of them have crashed after a time, not long. What I do them is to dismount the lamp and recover the LEDs individually for other applications (experiments, lanterns, and so on) since the usual breakdown happens in the circuitry and the LEDs are perfectly usable as individuals. (Most of the circuitry components are also reusable). Only in one case (out of 5) all the LEDs were burned.
They don't last the theoretical several years, but I have calculated that on a year average, the savings in electricity cost are worth the investment.
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i want to ask if this 8w led light bulb is too expensive <commercial links removed by moderator>
it cost 4.09 Luminous power is 10 times larger than general bulb, i never buy a bulb myself , how much is a general 8w light bulb?
but there also are some led light bulb is a little bit expensive like the new led spot light, it has very beautiful design and light effects, but it cost $7.5 , 5W LED SPOTLIGHT MR16 WHITE WARM WHITE 12V 30/60 DEGREE
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LED lamps are reportedly popular with indoor hydroponic marijuana growers - I guess that their high efficiency means that the electricity company does not get suspicious, and alert the police...
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I've invested in LEDs for some light fittings that are difficult to reach (on 15 foot ceilings). According the specification they will outlive me but I like to cost in my time and even at minimum wage they will save money over 10 years, regardless of the electricity consumption!
I've also advocated LED spotlights for an art gallery to reduce the airconditioning load and prevent spot heating of the paintings and tapestries, but there was some initial concern about their spectral quality - not sure how the public are adapting to seeing artworks literally in a new light, but then most of the stuff was painted by candlelight!
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Spectrum may be an issue in the future. I've been finding myself hunting for "good light" to read fine, low contrast print.
I'm slowly replacing all the incandescent lights in my house that I frequently use with either CF, or LED. I don't like the slow start, and limited lifespan, and fragility of the CF lights, so I probably will go with all LED in the future, at least if I can find ones that I can afford.
Perhaps a narrow spectrum lightbulb will also be safer on the artwork. Especially by filtering out all UV.