Led bulbs

[flynn]

I went to the supermarket yesterday to buy some replacement bulbs. I'm using low power Philips (5 and 8w depending on use) which are about 6€ a pop. I saw they also have LED bulbs which are about 15€ each.

I'm tempted to buy a couple of them just to try them out. Has anyone used or is using LED bulbs at home? If so, what's the light like? Considering the promised duration (10 years) it seems like a good deal and the power use is ridiculously low.

 

[Grall]

LED bulbs today (that I've seen) are pretty dim compared to other types of bulbs. Even standard fluorescent bulbs are dim compared to a 100W incandescent bulb, LED lights are much weaker in comparison.

The light is also very concentrated, and typically not uniform. Basically LEDs are like little flashlight torches that throw out light in a narrow cone, so when it hits a wall you'll see an enlarged projection of the tiny semiconductor die... LED lights are going to need some decent diffusors and much higher intensity before they'll become truly useful.

Anyone buying a LED bulb today for a lot of money are going to want to throw it away way earlier than 10 years, assuming it actually lasts that long.

 

[eastmen]

IT depends on what you use it for. I have one in my rooms that i normaly put on at night when playing games and what not. I wouldn't use them for main lights though. Unless they've inproved in the last 3 months since i got this one.

we also use one in my nephews room. But we use it as a night light for him.

 

[Simon F]

I'm tempted to buy a couple of them just to try them out. Has anyone used or is using LED bulbs at home? If so, what's the light like? Considering the promised duration (10 years) it seems like a good deal and the power use is ridiculously low.

Yes, I have 3x GU10 LED bulbs (i.e. spot lights) in my house as an experiment to replace some 50W halogens in light fittings. These are all single LED, 3W bulbs that I bought about 2 years ago and so technology will have moved on in the interim. They were relatively expensive at the time (I think maybe around £15-20 each) but, given that these lights are in the kitchen and on for a couple of hours a day, the saving in electricity should be significant.

IMHO, judging from the brightness, to replace a 50W halogen, I'm guessing you would need at least a 6W LED. Also, if you have mixed halogen and LEDs in a light fitting, like I do, you will notice that the halogens have a "yellow" hue and the LEDs "blue". The LEDs I have also have a much tighter spot, but that is possibly just the particular type I have. I'm sure some sort of diffuser would be useful on the bulb.

FWIW, I'm intending to buy more, higher power, LED bulbs when the halogens begin to die (which is probably soon).

 

[Silent_Buddha]

It's been a LONG time (well over 5 years) since I paid much attention to LED light sources. But do they still have the horrible effect of losing effectively 50% of original brightness in the first year or so?

Regards,
SB

 

[Mize]

I have an outdoor (away from rain) LED flood that is quite nice, but all the indoor ones I've tried were too dim to be useful.

 

[Blazkowicz]

It's getting there, though three bulbs for my current standing lamp would cost 45€ according to your prices.. compare with < 1€ for incandescent. (well, the heat wasn't really lost that winter)

it would be funny to have led lighting on a 50 year-old lamp.

LED spectrum according to wikipedia (for blue LED + phosphor kind, which I hope it is - RGB white LED are more spiky)
http://en.wikipedia.org/wiki/File:White_LED.png
quantum dots are an experimental new coating to get a better spectrum - let's hope they come, soon and cheap enough.
http://en.wikipedia.org/wiki/Light-emitting_diode#Other_white_LEDs

 

[Rolf N]

You could, and probably still can buy awful LED lights. My father has experimented with LED lights a lot, and ended up with real nasties, with gratingly unnatural light composition (basically two narrow splotches on the spectrum, orangeish+blue) and even ye'olde 50/60Hz flicker.

But tech has been improving a lot recently. I guess EU law providing a bit of a push has a lot to do with it.

I've started to see some pretty excellent LED bulbs around town, but haven't bought any myself yet. There's a nice 4000K E27 one at a local DIY market that seems as bright as I'll ever need and with an excellent light. It's 36€ a pop though, which makes me hesitate. Next time I'm there, I can look up the manufacturer, model and wattage. I think it was a Japanese company.

 

[Grall]

I would like to see a LED bulb using several dozen individual LEDs at least set in a spherical pattern, preferably 100+ of the roughly 1mm*2mm-ish SMD packages typically found on circuit boards these days.

LED lights' major achilles heel these days apart from poor brightness and bad color temperature/spectrum is their spread. With many individual light sources rather than just a handful, a more uniform halo of light will be produced.

 

[chavvdarrr]

Not long ago I read that current low power bulbs use mercury and also are not good for eyes if one stays close to a bulb (less than 50sm), with this problem supposedly fixed in current high quality (Philips etc) bulbs, not so with noname ones.
Anyone who has knowledge in this field?
Frankly I see nothing wrong with hundred years old proven Edison design...

 

[MfA]

Frankly I see nothing wrong with hundred years old proven Edison design...

Lousy luminous efficiency and lifetime.

CFL bulbs are essentially small small TL tubes, so if you're sensitive to the flicker it might annoy you. There is mercury in them sure and I have plenty of batteries with cadmium and lead too, shrug ... don't play catch with them and put them in the chemical disposal when they break (over here every household has their own box for stuff like that).

It would be nice if Metal Halide got cheaper though, top of the line luminous efficiency and pretty much the best CRI.

 

[Simon F]

Not long ago I read that current low power bulbs use mercury

IIRC, all standard fluorescent lights (and hence CFLs as well) use a tiny amount of mercury to create mercury vapour in the tube. It hasn't caused panic in decades that they've been in existence.

so if you're sensitive to the flicker it might annoy you.

Surely they are only flickering at the 100Hz (EU/Aus) power cycle rate (and 120Hz in the US?). I imagine you'd only see that if they were faulty or somehow beating with something else, say, a slow CRT?

 

[Grall]

also are not good for eyes if one stays close to a bulb

Only true if you're talking about halogen bulbs without UV filters. Fluorescent tubes/bulbs don't have this issue.

Frankly I see nothing wrong with hundred years old proven Edison design...

Sure, if ~90% INefficiency is OK with you then there's nothing wrong with them... Btw, tungsten is a heavy metal, and quite toxic to the environment (and people as well), so standard light bulbs aren't much better than fluorescent tubes from an environmental POV.

 

[CNCAddict]

The new Cree XPG LEDs surpass CFL in efficiency and have great color reproduction. They are a about $5 for up to 492 lumens in just one LED! They really are fantastic little gems.

http://www.cree.com/products/xlamp_xpg.asp

lighting application http://www.youtube.com/watch?v=GkVRX3h_A30

 

[MfA]

lighting application http://www.youtube.com/watch?v=GkVRX3h_A30

Well golly, he's chipper ain't he.

 

[Grall]

He's got a very squeaky voice, hehe... Seems to know his stuff tho. And those LEDs look mighty interesting too.

 

[BoardBonobo]

I live 100% off the grid and currently use a solar\wind->battery->inverter setup off which is fed an AC lighting circuit which makes very little sense considering the way I get power. I've looked into a direct feed DC lighting circuit to provide a floor level set of guide lights which is feasible but to directly feed any room with sufficient ambient light becomes very expensive.

 

[Rolf N]

Surely they are only flickering at the 100Hz (EU/Aus) power cycle rate (and 120Hz in the US?). I imagine you'd only see that if they were faulty or somehow beating with something else, say, a slow CRT?

Isn't one of the tricks of CFLs to chop power up into higher frequencies, to avoid the problem with the big choke? I've personally never seen a CFL flicker. Regular old ("long") fluorscents, sure, all the time.

You can check quite easily by waving your hand, fingers spread, in front of the light. If you see discrete "samples" of your fingers in a certain position, the light flickers. If it's all one blurry wave, it doesn't, not for humans anyway.

 

[Simon F]

Isn't one of the tricks of CFLs to chop power up into higher frequencies, to avoid the problem with the big choke? I've personally never seen a CFL flicker.

Oh, for CFLs quite possibly. I was only considering a worst-case scenario and was including standard fluorescents.

 

[flynn]

I've bought 4 1w Philips GU-10 LED lights for the living room, 8€ a pop. The original setup, before I rented this apartment, was 4 + 6 halogen lights, 4 on the left side, 6 on the right, for a grand total of 500w worth of lights, which is ridiculous.

I have a lamp I use when I'm reading in the couch, the rest of the time I just want some ambient light. The 4 lights on the right have died and as mentioned been replaced by 4 1w LEDs. The other 6 I might replace in the future as well. For what I need them to do they are ok, and if they in last 20 years as mentioned in the box it would pretty cool.

They don't cut it for cases where you need a lot of light, though, I would go CFL in that case like the ones I used in the kitchen (moved from 4x40w bulbs to 4x5 CFL)