Sunday, November 02, 2008

LED versus Halogen

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Part 2 of
LED v/s Halogen


Which do you think are the LEDs and which are the halogen bulbs?


I promised that I would come back to the question of LED (light emitting diodes) lamps, and that I would test a 5watt MR16 type LED against halogen MR16. This post represents my initial findings.

I bought a 5 watt led on EBay from a dealer called LinLin House Taiwan. The EBay page and transaction history are here:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260302204974

The advert claims that to offer a uniquely bright LED with a Cree element. The advert would appear to say that this 5 watt LED is as bright as a 50 watt halogen lamp. However, if you read the advert more carefully, with the eye of a lawyer, you will find that it is cunningly worded to avoid using any direct and clear description of the light output.






The wording of the above advert on EBay says:

In the piece near the photo:
"The brightness of our LED MR16 is double of other providers, and one 4.2 watt LED MR16 is able to replace one 50 watt halogen lamp - with similar light-out brightness as the above photo."

(Oh yes! indeed it can replace a 50 watt halogen - but it can only give just one quarter of the light.)

Further down it repeats the following:

"Many people are asking if the LED lights are bright enough to replace the traditional lights, especially for the 4.2W LED MR-16 whose power consumption is only 1/12 of traditional 50W halogen lamp. As soon as our 4.2W/2800K MR-16, which is dazzlingless design, were installed for the office lighting (as following photo) in Taipei, it is proved that our new 4.2W MR-16 is not only 2 times brighter that other LED MR-16 providers but also able to replace the traditional 50W halogen lamp to save 12 times energy."



Misleading Advert.

If the advertising authorities in the EU were to legislate on the above advert, I have no doubt whatsoever that the verdict would be that it be withdrawn.

Bottom line is that the advert is totally misleading, because the LED lamp in question is no-where remotely close to the light output of a 50 watt halogen. In fact, it doesn't even fully match the output of a 20 watt halogen lamp.

The photo below was taken by placing a white photo-mounting board about two feet from the lamps, and the shot taken from a distance of 5 feet from the board.



Pool of light on white photo-mounting board
On the left is the 5 watt LED on the right a 20 Watt Halogen
Which do you think has a brighter output?


Above is a photograph of the pools of light from the 5 watt LED on the left and a 20 watt halogen bulb on the right. You would not need to be a rocket scientist to figure that the 20 watt halogen is giving more light. The 5 watt LED comes close to the light output of a 20 watt halogen but certainly does not exceed it.

5 Watt LED does not match a 20 watt halogen.

The LED on the left above is claimed in the advertising to MATCH the light of a 50 watt halogen bulb. I say that it cannot match the light of even a 20 watt bulb. Unless I happen to have been sold a faulty LED, the advertising is totally misleading. I am contacting EBay and making a complaint on the basis of misleading advertising, and I am asking that the description is fully corrected or the seller removed.





The above photo is taken looking directly into the light of two LED MR16 type lamps, and two 20 watt halogen lamps. Not the way to tell the comparative brightness, but it gives an idea of the colour and light scatter. From the left it reads:

5 watt LED
20 watt Halogen
20 watt Halogen
3 watt LED



LEDs still have a way to go

LED lamps still have a way to go yet. A 5 watt LED can reasonably replace a 20 watt halogen bulb for light output. The colour is fairly good and the light output is maybe 10% less than the halogen. But with the cost of the LED you might think twice about the value.






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2 comments:

Dong said...

Well, judging from the way it is, I must confess I was once also mislead into believing that a 3 or 5 or 7 Watt LED MR16 can replace a 50Watt Halogen. There is no way possible! However, it strikes an interest to me, as I go on deeper into the technical world of LED lighting. First, we must understand that manufacturer’s claims on their LED products are totally not 100% accurate, and some are in fact way too misleading. From my understanding, the higher Wattage does not make the LED any brighter nor efficiency. In LED, we must refer to the lumens per watt (lm/W), and currently CREE has the commercially highest rated lm in the market, 100lm/Watt. Thus a one Watt CREE LED can be brighter compared to the 5Watt Taiwan made or china made LED, which most probably managed 50-70lm/W. I have therefore bought some 3Watt CREE LED MR16, and true enough, they are bright enough to really replace a 20Watt Halogen, and it will be a matter of time before they can replace a 35Watt halogen.

With regards to replacing a 50Watt Halogen MR16 with LED, as far as I understand, there is only one company that have actually produce a LED in the form of dichloric MR16, and REALLY pumping in lumens that matched the 50Watt Halogen! I personally tested it, and I was really amazed by it. The unique design, with their proprietary optic lens that equals the beam angle of 3 most common angle of the MR16 (20 Degree, 35 Degree and 60 Degree) definitely deserve my thumbs up. This is by far, the brightest LED product I have ever lay my hands on, that can replace a 50Watt Halogen MR16. The simple features that allows us to do a one to one replacement without changing our existing fixtures, or doing any modification works to our ceiling, terming it simplicity at its best!

Just sharing my experience!

Marc said...

sorry for the disapointment in LED's. At www.olino.org LED lamps are tested including the way they are tested and compared with each other. I didn't check if the English part of the site is exactly the same as the Flemisch part. Success