LED lighting

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Went to Homebase today to buy a light switch and left with 16 5W GU10s for £1 each from the clearance bin. I now have 11 installed in the kitchen. They're far brighter than the old 50W halogens and the colour (warm white) is fine.
 
Black Hole said:
Well stranger, were have you been (apart from Homebase)?
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Still here, still watching. These days my Hummy use has diminished under the combined onslaught from Tivo, iPlayer and usenet, so I'm not so concerned about making the HDR-T2 jump through even more hoops. It's still in fine fettle, though.
 
In case anyone's interested, Asda currently have a 3-pack of 6W LED candle-style bulbs for £12 (roughly 30W equivalent).
 
Tsk. I've just fitted an Asda LED bulb in an outside light. The packaging claims it is "warm white", but it looks pretty cool to me! Not keen, the bulbs I fitted in the dining room are a better colour. I was thinking of using their candle bulbs elsewhere too - I'll give that a miss then.

I saw an article somewhere that says (in street lighting applications) the LEDs with more blue in them are more efficient, but have the effect of greater glare. I use a street where a length of it has been fitted with LED lamps, and I have to say I prefer the high-pressure sodium lights on the rest of the street.
 
I am now sold on Auraglow LED bulbs to replace ordinary lightbulbs. The best are 16w, and roughly 100w equivalent. There are dimmable versions that work with both leading and trailing edge dimmers, dimming to zero in leading edge mode.

WeMo, etc, smart lights are also good, but I find I need two in a Y splitter to replace a 100w bulb, they are just too dim for anything but the smallest room.

As for GU10, I have replaced all those with Spectrum 10w, which is high, but the only way I could get enough light. Three in the bathroom, five in the kitchen, eight in the conservatory.

At last, LED is fit for purpose!

Edit: The first Spectrum gu10 has failed.
 
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That is cheap! 1500 lumens from 12w seems good, but longevity is the question. Still, at those prices, ...

I am not sure 1500w (Edit: meant lumens!) is 100w equivalent, though, maybe 80w. They are sold out online.
 
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I've measured the lumens at 1450 using a smartphone App. (No exactly high tech.), only had it a few days so I can't confirm the 25000 hours just yet :)
 
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Mike0001 said:
I am not sure 1500w (Edit: meant lumens!) is 100w equivalent, though, maybe 80w.
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I think think you're correct about the equivalent lumens figures, I did a comparison and got this :-

LED 12Watt (actual 13.4W) = 1504 lumens
Tungston 100W (actual 96.1W) = 1702 lumens
Tungston 60 W (actual 57.8W) = 1217 lumens

All measured at the same distance (slightly closer than before), the actual lumen figures are probably not accurate, but the comparison is useful
 
Bear in mind that the light distribution is different too. The LEDs emit downward mainly, for a pendant fitting, whereas incandescents shine nearly all round, so you get more light on, and thus off, the ceiling. If you measure the light at just a few points you need to take account of the area the output covers as well.
 
This "lumens" business is a bit tricky, I'm not sure I've got my head around the details.

An Internet search gives the definition of the lumen as:
Google said:
the SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.
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and the definition of the candela as:
Wikipedia said:
The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1683 watt per steradian.
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So, a light source is only 1 lumen if it emits 1 candela in all directions. What use is that if the lamp has a non-uniform output? Then a lux is supposed to be one lumen per square metre - which sounds more useful if trying to compare the amount of illumination falling on a surface, if the surface is at a constant distance for comparison, but still seems to be based on an assumption that the source emits evenly in all directions.

I'm frazzled. To solve this I will have to do some deeper reading.

Meanwhile, the photometer app is presumably measuring light through its camera, and will give a difference reading according to how far it is from the source and what angle it is at on the source's polar diagram, so I am not at all clear it is actually measuring lumens. This is why I used shadow comparisons when I was comparing lamps a while back.

:confused:
 
MikeSh said:
Bear in mind that the light distribution is different too. The LEDs emit downward mainly, for a pendant fitting, whereas incandescents shine nearly all round, so you get more light on, and thus off, the ceiling. If you measure the light at just a few points you need to take account of the area the output covers as well.
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All bulbs were in an anglepoise lamp, so to some extent the illuminated area was roughly the same, but I take your point, the real tests are done inside a globe with multiple sensors on it's inner surface
BH : photometer app is presumably measuring light through its camera
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No, the Lux meter App. uses the ambient light sensor rather the camera, but there are many things it does not take into account, e.g. colour of light etc.
 
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In the modelling world you can buy electronic speed controllers (typically from Chinese eBay suppliers) with ratings of (eg) 300A. These are actually, well maybe, peak rating for a fraction of a second. Probably good for 10A continuous. We call those ratings Chinese Amps.
Given the opaque nature of illumination theory I suspect a lot of the numbers that we see on packaging may be Chinese Lux/lumens/candelas.
 
There is a Chinese website called Dealexteme that I use occasionally, they sell rechargeable batteries that are marked as (and described as), 2500mAh AA, for example, with a note in the description reading "actual capacity = 1800mAh", sort of dis-honest and honest at the same time
 
My guess about brightness was subjective. I only ever buy bulbs with an angle of illumination of at least 120°, ie, wide angle, and I have found the ones with a nominal rating of around 2000 lumens to be closest to an incandescent 100w bulb. If you squeeze the angle down to 60° then within their beam they appear brighter, but that is not what I want.

Like BH, I am also confused by the various measurements, but to me the total light output seems the most important factor, so we might all be enlightened :laugh: by BH's further reading.

I loved the rechargeable AA example, by the way.:roflmao:

http://www.dx.com/p/ultrafire-rechargeable-1-2v-3500mah-aa-ni-mh-batteries-4-piece-pack-145075

They even use "...", very honest, but how 3500 reduces to 1300 I have no idea!
 
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