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Re: [APD] Off Topic: LED lights

Thanks for the post. I always find this stuff interesting. 
I have the same trouble with this article that I have with much of the "info" about "new" and improved bulbs -- whether LEDs, T5s, or purportedly new and improved products of any kind. I'd give the article, which appears to be largely based on press releases, about an 80% for accuracy and about 40% for lack of relevant info, such as for example, some actual figures on output and efficiency. E.g., LEDs are not encased in glass; the material is a kind of epoxy resin.
Some of the most confusing "info" about LEDs, especially from lamp manufacturers and vendors, are the claims about performance, specifically durability, and energy efficiency.
While low power LEDs can last for many years, the high power ones tend to be shorted lived with higher failure rates -- there's still heat to deal with.
Apparent claims that high output LEDs are more efficient than fluorescents, when you can find actual data, turn out to be false.
As for LEDs doubling in efficiency and brightness in the last 2 years, this is a marketing ploy known as a vacuous comparison. Compared to what? Their own LED products -- maybe those were relatively crappy LEDs. Certainly not compared to the better performing LEDs of the last ten or 15 years. What would be good to know about any particular LED is how much useful light it produces for a given energy input andin what part of the spectrum. Forget about what New and Improved Tide is newer than or improved upon (newer than anything older and improved upon, perhaps, lye soap shavings), the useful info is whether it actually clean clothes and if so, how well?
It's not difficult to increase the brightness of an LED package; just pack more diodes onto a single die -- of course, then you have to deal with the concentrated heat, so you have have to incorporate heat sinks into the lamp. Nothing new about that. What is "new" is that unit production costs have declined, making large output fixtures that are based on multiple LEDs slightly more economically practical for special purposes such as situations where down time or replacement is extremely expensive. In those situations, the longevity can outweigh the high product costs -- this has been happening for more than 2 years, depending on which manufacturer you are looking at.

----- Original Message ----
From: Liz Wilhite <satirica at gmail_com>
To: aquatic plants digest <aquatic-plants at actwin_com>
Sent: Friday, May 11, 2007 2:31:53 AM
Subject: [APD] Off Topic: LED lights

Lights are discussed so often by so many of us that I thought some folks
might find this article of interest:

I found this statement to be of particular interest:  " In the last two
years, the diodes have doubled in energy efficiency and brightness,
according to Greg Merritt, director of marketing for Durham,
N.C.-basedLED-manufacturer Cree Inc. In particular, LEDs that produce
a yellowish or
"warm" light similar to incandescents have improved."

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