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LED bulbs #188718 08/28/09 06:36 PM
Joined: Feb 2002
Posts: 2,233
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harold endean Offline OP
Member
Has anyone found LED bulbs that are good? Will fit a regular Par 40 recess down light fixture? That can be dimmed? Will fit in a sloped ceiling fixture (or eyeball trim)? Any websites out there to check out? Any thoughts?


Thanks

Work Gear for Electricians and the Trades
Re: LED bulbs [Re: harold endean] #188727 08/29/09 12:11 PM
Joined: Mar 2004
Posts: 947
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twh Offline
Member
I've installed a few and have a few in my own home. I don't think they have a lot of uses. They are best when they are lighting against total darkness. Outside is okay, night lights are okay, and I have a walkway between the house and garage with sky lights, so they are only on at night. I can't imagine wanting to dim them. They're already dim. I wonder how they hold up to vibration.

Re: LED bulbs [Re: twh] #188729 08/29/09 03:21 PM
Joined: Mar 2005
Posts: 1,803
Alan Belson Offline
Member
Here's a good German site for browsing the latest technology on LEDs.

http://www.dotlight.de/products/en/...0-white-with-3-x-CREE-XR-E-GreenLED.html

Look at the prices though! These are never going to be more than novelty illumination at those costs. And the 40-50000 hour life is when they have dimmed to 50% of their 'new' brightness.


Wood work but can't!
Re: LED bulbs [Re: Alan Belson] #188730 08/29/09 04:56 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
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I've toyed around with a few varieties of LED bulbs. I suggest that you have a chat with a professional lighting supplier / contractor; chances are he has a few at home, or in the shop, that he's playing with.

The verdict? These bulbs are like politicians; they promise far more than they deliver.

The key, of all things, heat dissipation. Simply put, they get the brightness by forcing all manner of power through the diodes - meaning the electronics need truly massive heat sinks. Stick that PAR replacement in a recessed can, and you've just cut off air flow around the fins. That's how LED bulbs work: light out the front, heat out the back.

As for the light itself: LED bulbs cannot produce a 'spot' or 'beam' of light that is in any way comparable to the usual PAR bulb. Rather, it's a far less focused, "softer" spot. That may not be a bad thing; it all depends on what you're trying to do with the light.

Let's not forget that lighting is every bit as subject to the whims of fashion as are womens' skirt lengths. We have all seen passing fads for track lights, troffers, parabolic reflector grids, strip lights, indirect lighting, and -latest- recessed lighting. Who can say what the customer will want next year?

Re: LED bulbs [Re: renosteinke] #188737 08/30/09 01:47 AM
Joined: Feb 2004
Posts: 1,435
Lostazhell Offline
Member
Just driving around town and seeing the condition of many of the LED traffic lights makes me skeptical that all the kinks have been worked out when it comes to creating & manufacturing LED clusters viable for commercial & residential applications. At least 30-40% of the LED upgraded traffic lights around here are either partially flickering or partially out. Some are so dim I find it hard to imagine they meet FHTSA and DOT specs (Ironically it's the red that always has the dim issue as well, and over here, at some rather crazy intersections at that)

Re: LED bulbs [Re: Lostazhell] #188738 08/30/09 07:44 AM
Joined: Mar 2005
Posts: 1,803
Alan Belson Offline
Member
And don't believe the "equivalent to" on manufacturers' packaging and ads. Look at these figures for CFLs- They are producing just over half of the claimed lumens output after 10 minutes warming up when new, making the much vaunted 'savings' a sick joke. I expect the claimed output from leds will be found lacking too.

http://www.telegraph.co.uk/news/wor...saving-light-bulbs-offer-dim-future.html





Wood work but can't!
Re: LED bulbs [Re: Alan Belson] #188739 08/30/09 08:08 AM
Joined: Mar 2005
Posts: 1,803
Alan Belson Offline
Member
...furthermore, to achieve the long life, a CFL should remain on for at least 15 minutes, otherwise its life will be no better than an incandescent. So the bathroom, garage, utility, pantry, cupboard and other short-visit rooms will eat bulbs.

And CFLs dim over their life. The 'standard' for the claimed 'life' is when the output reaches 50% of new. With tungsten bulbs you simply tossed them out when the bulb showed signs of darkening or it went phut. On that basis, the mean actual output over the life of a CFL will only be around 30% of an 'equivalent' tungsten bulb. At ten to twenty times the price, the low energy bulb is a scam. mad
The fact is, Joe Public doesn't want them, which is why so many Eu-Pocos are giving them away.


Wood work but can't!
Re: LED bulbs [Re: Alan Belson] #188741 08/30/09 10:35 AM
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Posts: 947
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twh Offline
Member
If the lumen output isn't accurate, do they also misrepresent the wattage input?

Re: LED bulbs [Re: Lostazhell] #188742 08/30/09 11:41 AM
Joined: Feb 2003
Posts: 359
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mbhydro Offline
Member
Originally Posted by Lostazhell
Just driving around town and seeing the condition of many of the LED traffic lights makes me skeptical that all the kinks have been worked out when it comes to creating & manufacturing LED clusters viable for commercial & residential applications. At least 30-40% of the LED upgraded traffic lights around here are either partially flickering or partially out. Some are so dim I find it hard to imagine they meet FHTSA and DOT specs (Ironically it's the red that always has the dim issue as well, and over here, at some rather crazy intersections at that)


I wonder if there are different specs for LED traffic lights in Canada? Driving around my city I have not seen any flickering clusters and only a few with small missing LED segments. We range from -40 in the winter to the high 80's in the summer so I wonder if the lack of year round high heat gives us better results?

Red signals are the worse ones for bulb life because they are the ones that get the most use in a signal cycle from what I have been told.

Amber gets the least use so I have seen here that when a signal head gets upgraded the Red and Green will be LED and Amber remains a bulb. Only new signal heads are a new complete LED set.

Re: LED bulbs [Re: mbhydro] #188743 08/30/09 11:51 AM
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Posts: 359
M
mbhydro Offline
Member
Alan, its not only the EU-Powerco's giving bulbs away, at the start of this month I received a bag full from our powerco.

Manitoba Hydro is only pushing Power Smart devices to get people to conserve so they can sell more power at a higher price to the US power companies in North Dakota.

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