LED Bulbs

[Soapy Sam]

The rest of the bulbs in my house are CFL. The newer ones are much better technology than the first generation lights. I have no complaints about them at all. In fact, I can't remember the last time I had to change one. The need for having a stockpike of spare incandescent globes is over, as is having to continually change them.

I'm often told the later bulbs are better. Ironically, because I have a stockpile of CFLs of just the sort you don't need, I'm not prepared to buy more. My wife uses a couple for table lamps. Personally, I would bin the lot.

My tungsten bulb failure rate over 26 years was less than 1 bulb every two years, from a batch of 20 I bought in 1983 or 84. Several were on dimmers, which I suspect protects them from peak voltage at switch-on. I dropped one bulb when installing it- cost about £0.4 at the time. I never experienced the high failure rates I hear of. Maybe just luck.

In contrast, I was the person who changed the CFLs in the staircase. These were never switched off, dropped about 50% in light level (by the measure of my SLR light meter) in six months or less, often dropped as low as 25% before failure which was generally less than 2 years.

Part of the return on the low power globes is the reduced infrastucture needed because power consumption has reduced. In Australia, infrastructure needs have been dramatically lower than expected partly due to the lower demand. (That didn't stop them building it using outdated projections, but what is there will last longer than anticipated).

In the UK we are adding new infrastructure all the time to cope with the distributed nature of &*^%$£! wind farms. Don't get me started...

 

[Jrrarglblarg]

You do know that those go out when you close the door, right?


At least, they're supposed to.

Yes, dear.








The energy savings in these discussions are about the long-term total savings over the lifespan of the product. Every time I open the fridge a pair of incandescent heaters turn on. The filament is hot, the glass envelope is hot, the reflector gets hot, the illuminated surfaces are being hit with mostly IR, and every bit of heat you create needs to be pumped back out of there after you close the door. In addition to the obvious thermosyphon of cold air falling out of the fridge and pulling room temp air inside, the heat globes can create enough heat to kick over the thermostat. The usual bulbs installed are 25 or even 40 watts, in pairs. That's 50 or 80 watts of mostly-heat you create inside a box you pay good money to keep cold. I have kids, so the number and duration of refrigerator "heating cycles" is greater than for single people, couples employed outside the home or adults in general. I've stopped using the 25w bulb pair and instead have a single 15w in there to cut the amount of heat created.

I'm sure there are LED lights out there that fit the refrigerator, but I just haven't seen them in my market yet. The ones I see are all specialty shaped envelopes and/or are too large for the application.

One location I've needed to keep replacing with incandescent is the range hood over the stove. I put a CFL in there and it died in a month. The heat, horizontal mounting and vibration were apparently outside the design parameters. And it flickered.

 

[Brian-M]

I have a timer on my front porch lights which turns the light on at dusk and off at midnight. Now I don't know if I'm phrasing it right but I believe a timer switch always has a very low current going to the fixture. With an LED it causes the bulb to blink on and off repeatedly.

Ah, I see. Because the timer doesn't have a neutral wire attached to it, it uses the load (light-bulbs) for the return path. The trickle of power it constantly lets flow through the bulbs us not enough to cause incandescent globes to glow, but it is enough to let the CF lights flicker occasionally

 

[Brian-M]

Several were on dimmers, which I suspect protects them from peak voltage at switch-on.

I think I heard somewhere that reducing the voltage to an incandescent globe by 5% doubles the lifespan (but reduces the light output by more than 5%). Having the globes on dimmers effectively reduces the voltage.

ETA:

Every time I open the fridge a pair of incandescent heaters turn on. The filament is hot, the glass envelope is hot, the reflector gets hot, the illuminated surfaces are being hit with mostly IR, and every bit of heat you create needs to be pumped back out of there after you close the door. In addition to the obvious thermosyphon of cold air falling out of the fridge and pulling room temp air inside, the heat globes can create enough heat to kick over the thermostat. The usual bulbs installed are 25 or even 40 watts, in pairs. That's 50 or 80 watts of mostly-heat you create inside a box you pay good money to keep cold. I have kids, so the number and duration of refrigerator "heating cycles" is greater than for single people, couples employed outside the home or adults in general. I've stopped using the 25w bulb pair and instead have a single 15w in there to cut the amount of heat created.

Have you considered simply removing the light-bulb(s) from the fridge altogether? It might be a little bit dim in there, but if you've got the light on in the kitchen, you should be able to see clearly enough.

 

[Jrrarglblarg]

I like this place; http://store.earthled.com/

Thanks, nice link. They have a couple of A15 lamps, but 20 bucks + shipping is a bit steep. I'll keep looking at HD and the grocery store, now that I know they're starting to move through the market.

 

[JoeTheJuggler]

Have you considered simply removing the light-bulb(s) from the fridge altogether? It might be a little bit dim in there, but if you've got the light on in the kitchen, you should be able to see clearly enough.

Seems like a poor solution given that we do have light bulb technology for lights that produce very little heat and use much less energy.

ETA: I see someone beat me to it: http://www.amazon.com/Ag-Eco-Refrigerator-Clear-Replacement-Classic/dp/B0056NJAZW

 

[Jrrarglblarg]

I think I heard somewhere that reducing the voltage to an incandescent globe by 5% doubles the lifespan (but reduces the light output by more than 5%). Having the globes on dimmers effectively reduces the voltage.

There used to be a product advertised as a "light bulb saver" that was, if I understood the package, just a carbon doughnut, ie, a resistor.
{one google later . . .}
One version was called "The Button" but there were also thermistor products and I think a diode or triac-based or voltage reducing product.

Have you considered simply removing the light-bulb(s) from the fridge altogether? It might be a little bit dim in there, but if you've got the light on in the kitchen, you should be able to see clearly enough.

I tried not having bulbs in the fridge and it annoyed me.I have a '50s kitchen. It's dark enough already. I currently have a heavily frosted single 15 in there. I replaced it with a 40w a few months back and it seemed too bright. I can't imagine having a pair of clear-glass 25w bulbs in there again.

 

[paulhutch]

I think I heard somewhere that reducing the voltage to an incandescent globe by 5% doubles the lifespan (but reduces the light output by more than 5%).

You heard correctly, that was the trick to high reliability aircraft panel indicators before LEDs became cost competitive. I designed a product that used aircraft grade bulbs as indicators back in the 80's and came up with a theoretical life span of 25 years. Just had a 23 year old unit come through the service department last week and the lamps still worked, although with about 30% less light output than new the customer wanted new lamps put in it.

There's a pair of tables giving under and over voltage data about a third of the way down the page at the following link. http://www.lumitroncorp.com/basics.html From the charts, 95% of design voltage gives 185% life and 84% light output.

 

[Olowkow]

I like this place; http://store.earthled.com/

Thanks for the link. They even have fluorescent tube replacements. I never heard of those. All this talk about LED's, I'm going to go buy a few. Something to try.

I found CFL's at a Dollar Tree store for 4/$1.00. (13 watt) Figured they would be junk, but I got 8, and tried a few. Just as good if not better light color than the ones I had bought for around $9.00 each.

 

[Jrrarglblarg]

There's a pair of tables giving under and over voltage data about a third of the way down the page at the following link. http://www.lumitroncorp.com/basics.html From the charts, 95% of design voltage gives 185% life and 84% light output.

Yep, that's partially why the "centennial" bulb and other very old lamps are still burning -- they are running at much lower voltage than they could. If you look at pictures of the filament of the Centennial bulb it's burning very dark orange.

 

[BenBurch]

Thanks, nice link. They have a couple of A15 lamps, but 20 bucks + shipping is a bit steep. I'll keep looking at HD and the grocery store, now that I know they're starting to move through the market.

Batteries Plus carries them.

 

[Olowkow]

There used to be a product advertised as a "light bulb saver" that was, if I understood the package, just a carbon doughnut, ie, a resistor.
{one google later . . .}
One version was called "The Button" but there were also thermistor products and I think a diode or triac-based or voltage reducing product.

Ah yes, the old Light Bulb Saver Button!!! $4.99 for package of 3!!! Pure hype, but of course they worked.

I'm sure those were just a series diode, which cut the voltage pretty much in half, in a "dual contact button" which one inserted into the socket before installing the bulb.

Make an ordinary bulb last up to 10 years! Of course, if you want the same amount of light, use a higher wattage bulb.

 

[kajata]

With the amount of time an appliance light bulb is on I don't think you would ever make your money back with an LED bulb.

 

[Brian-M]

I'm sure those were just a series diode, which cut the voltage pretty much in half,

I've tried that, it gave the globe a marginally perceptible but still annoying 50Hz flicker.

I suspect a commercial device would have used a triac instead of a diode. No flicker and no DC bias on the mains.

 

[tuxcat]

I think I will get an LED for my bedroom/office/lair and see what they're like. We've got a dim LED one in the smallest room at work which is pretty orangey-yellow but it's pretty dim. I don't fancy boy racer bright white-blue LEDs that Audis seem to be adorned in nowadays that's for sure. And no I'm not jealous just because I have a Pug 406 estate either.

Who moved the strikeout button? Grr.

 

[Christian Klippel]

I'm pretty sure that LED lighting is the future. A lot of the problems regarding color temperature have already been solved. Then, if one doesn't get the cheapest one available, quality is usually quite good and their power supply quite efficient.

I once played around with a Bridgelux LED module, warm-white, 40 watts. Even at half the rated power it was so bright that if you looked into it, you would have black spots in your field of vision for quite some minutes. And it was a really nice, warm white light.

However, as of now, please don't rush out to buy cheap LED lamps. Their quality is just bad, their efficiency is not what it could be, and some of them even pose the hazard of an electrical shock. OK, the latter might not be that much of an issue for countries with their "low-voltage" 115 volts

Fun fact: White LED's do not directly emit white light. The actual LED chips emit blue or UV light. It is just the coating that in turn re-emits the light as "white", pretty much like a fluorescent lamp.

Greetings,

Chris

 

[tuxcat]

I'm pretty sure that LED lighting is the future. A lot of the problems regarding color temperature have already been solved. Then, if one doesn't get the cheapest one available, quality is usually quite good and their power supply quite efficient.

I once played around with a Bridgelux LED module, warm-white, 40 watts. Even at half the rated power it was so bright that if you looked into it, you would have black spots in your field of vision for quite some minutes. And it was a really nice, warm white light.

However, as of now, please don't rush out to buy cheap LED lamps. Their quality is just bad, their efficiency is not what it could be, and some of them even pose the hazard of an electrical shock. OK, the latter might not be that much of an issue for countries with their "low-voltage" 115 volts

Fun fact: White LED's do not directly emit white light. The actual LED chips emit blue or UV light. It is just the coating that in turn re-emits the light as "white", pretty much like a fluorescent lamp.

Greetings,

Chris

What is the best way to determine quality for lightbulbs? Brand names like Phillips? As I'm sure that just buying the most expensive isn't going to be a guarantee of high quality. What should I look for in a good quality bulb?

 

[BenBurch]

With the amount of time an appliance light bulb is on I don't think you would ever make your money back with an LED bulb.

But you'll never need to replace it.

 

[BenBurch]

I'm pretty sure that LED lighting is the future. A lot of the problems regarding color temperature have already been solved. Then, if one doesn't get the cheapest one available, quality is usually quite good and their power supply quite efficient.

I once played around with a Bridgelux LED module, warm-white, 40 watts. Even at half the rated power it was so bright that if you looked into it, you would have black spots in your field of vision for quite some minutes. And it was a really nice, warm white light.

However, as of now, please don't rush out to buy cheap LED lamps. Their quality is just bad, their efficiency is not what it could be, and some of them even pose the hazard of an electrical shock. OK, the latter might not be that much of an issue for countries with their "low-voltage" 115 volts

Fun fact: White LED's do not directly emit white light. The actual LED chips emit blue or UV light. It is just the coating that in turn re-emits the light as "white", pretty much like a fluorescent lamp.

Greetings,

Chris

Yes, bought a pair of $6 ones that were pretty bad. I suggest looking at the Amazon reviews and similar.

 

[Christian Klippel]

What is the best way to determine quality for lightbulbs? Brand names like Phillips? As I'm sure that just buying the most expensive isn't going to be a guarantee of high quality. What should I look for in a good quality bulb?

Good question, and of course not so easy to answer. However, there are a few tell-tales that usually come with cheap stuff.

First of all, avoid the cheap/cheapest eBay stuff you can find. Buying a bulb that allegedly has 40 watts from eBay for 5 bucks is surely going to be nothing more than a spohisticated chinese firecracker (sometimes litrally).

Next, while there are rare exceptions, try to avoid bulbs that are made of lots of standard 5mm LED's. Those are usually cheap LED's (you can buy a pack of 100 for 3 bucks or so, after all), wired in string(s) with a cheap current limiting resistor. Those bulbs and lamps have several problems. One is that they use cheap, single low-power LED's. Each of them has a (sometimes reather high) difference in how much light they emit (and what colour temperature). Then, if one single LED fails in a long string, the whole string goes off.

Then, get the bulb in your hand and physically check it. Does it have cheap, soft plastics that bend easily? Is the transparent cover not really a tight/strong fit (i.e. does it seem as if it can come loos or break easily)? Does the bulb/lamp have exposed contatcs or solder joints on/in the LED array that are possible to touch? If one LED fails, you have the full line voltage at that point, only going donw once a circuit (possibly through your body) is made, and then possibly only limited by a cheap resistor.

Good LED modules come on an aluminium carrier. There are multiple tiny LED chips mounted on that carrier, coverd by a single, thin blob of some (often yellow-ish coloured) silicone (edit: silicone-like, i meant). They are more expensive to produce, since a failure of a single LED chip on them makes the whole module go to the garbage bin. They cost more to use because they need some form of good cooling.

If you can afford some bucks for toying around, open up the LED lamps you got. If they have a switchmode supply they are usually much safer and better. That is because such a supply costs some money, compared to a cheap resistor.

The whole market is rapidly moving currently. I'm not that much into what brands are good and which are not, i simply build such stuff myself (what with electronics being my hobby and job and all that).

But more often than not, the usual rule applies: if it looks cheap, and if it is sold cheap, then it is cheap crap. And seriously, the problem with line powered devices it not so much the looks, or if there is a bit less light than with other products. The issue is that these thing _really_ pose a fire hazard and/or can threaten your life due to electrical shock. While even the cheapest switchmode supply is usually better than just a drop resistor, the problem with cheap switchers is that they are, well, cheap. Look at the innards of some cheap wall-wart style chargers/supplies that you can get, for example, from DealExtreme. There simply is no snowballs chance in hell that these things would comply with even the loosest of "western" safety standards.

Amd usually you get that exact same level of quality in cheap LED bulbs, just that that crap is now integrated into the bulb, instead of being an external plug...

Greetings,

Chris