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Re: New Homes & Downlights

PostPosted: Fri Jan 29, 2010 12:27 pm
by zzsstt
bradley.jarvis wrote:Unfortunately being efficient and long life is not in the interest of a capitalist society. However competition will drive qualities such as these over time (only if people buy good quality).


Entirely true, but sadly most people are no longer interested in quality. Almost always, if I want to buy a quality product I cannot do it locally. There are a few exceptions, Harvey Norman sell German kitchen appliances and the local 4WD shop sell quality products (as well as rubbish). Most people would rather buy cheap, but I suppose this is because they will not take care of the product so it will be ruined but they won't have lost very much. People are also encouraged to replace everything as a matter of "fashion", so why bother paying for a product that will last forever?

bradley.jarvis wrote:The trick is to find a product that is made by a company that has a reputation they want to protect, they have more interest in selling a good product that people are happy to buy and more importantly recommend to friends.


This used to be largely true across the board, but seems to have declined as the number of companies in any given field has reduced. These days if I want to buy a light (as an example), I have a choice of Philips, Mirramar (I think that's the name of the cheap brand) or if I look really hard possibly Osram. Most people will buy whatever is on the supermarket shelf. If it fails, they'll buy another one!

I believe that the internet has also contributed, as "service" has been reduced to cut costs in an attempt to compete with the box shifters. Equally it is not possible to rely on an internet seller even being in business in the future. At one point I started investigating the "eco" companies on the web. I found two major things. Firstly in many cases they come and go quite quickly, and secondly it is interesting how many of them seem to be "linked" via address or owner or parent company. I'm guessing they create a web site, sell until something bad happens, then shut down and reopen under a new name....


bradley.jarvis wrote:There is more than just hype that LED's are being used, I would say that they have a longer life than halogens, look at traffic lights for instance. I know that Vicroads have a pretty tough testing criteria (they were quite reluctant to start using LED technology at first), yet pretty much all traffic lights are now LED. Also most trucks now have LED tail lights, instead of cheap filament globes.


I have no doubt LED's are a better technology, but they are not yet a mature technology, and they are very expensive for domestic use - an LED trailer light is four times the price of a conventional one, but a domestic halogen replacement LED costs ten times the price of the halogen globe!. They have some very specific advantages for vehicle lighting, in that they are very shock resistant and happy across the fairly wide voltage range experience in vehicle electrical systems. Also, in both vehicles and traffic lights, a large number of moderately powered coloured LED's are used to provide a relatively low light output. Domestic units are very different, white LED's are a much newer technology than coloured ones, and the high output units are newer again.

I am quite sure that LEDs will be the norm in the future (until something better comes along), but for that to happen they will be made by Philips and sold by Woolworths, rather than made by an unknown company and sold from a web site...... Which brings me to an interesting thought:
bradley.jarvis wrote:The trick is to find a product that is made by a company that has a reputation they want to protect

Do any of the major players in lighting (Philips, Osram) have much in the way of domestic LED's, or are they all from the fly-by-night companies?

Re: New Homes & Downlights

PostPosted: Mon Apr 11, 2011 10:38 pm
by Sandivee
Just a few comments here on these posts.

When manufacturers say life span of 50,000 hours, it is usually means the chip will last for 50,000h to 70% lumen decay. In reality a lamp may have a quicker reduction to 70% like Eltina 10W CREE MC-E lamps and Philips 10W Luxeon Rebel lamps which are 30,000 and 25,000 hours.

Most manufacturers have a halogen equivalent rating but because of lm/w figures they are all very different.

The problem is some manufacturers don't measure the lamps lumen output and some do.

The Philips 7W lamp is only rated at 270lm, but is the closest thing I've seen to a halogen. Whilst the 10W CREE MC-E lamp is rated at ~560lm but is the same output as the Philips lamp. They both have roughly the same beam angle but Philips have tested the LAMP not the CHIP.

Re: New Homes & Downlights

PostPosted: Tue Apr 12, 2011 6:56 am
by zzsstt
Sandivee wrote:When manufacturers say life span of 50,000 hours, it is usually means the chip will last for 50,000h to 70% lumen decay.


I think you might mean 70% lumen maintenance, i.e. 30% decay.

70% decay, meaning that the light is only producing 30% of its original output, would long since have been thrown away!

If the LED industry is indeed using a 70% decay, as opposed to 70% maintenance (and I suspect that they ignoring catastrophic failures anyway) then we will be in for an enormous shock in a few years, because almost every other lighting technology uses about a 75% MAINTENANCE (25% decay) as the benchmark, which in turn means that the high quoted lives for LED's are completely false!

The rate of decay of LED's is variable based on temperature etc. It is normal to see about a 10% decay (90-92% maintenance) after about 6000 hours. The rate of decay varies quite significantly with the quality of the device. Because perhaps 70-80% of the energy used by the LED is converted to heat, and increased temperatures accelerate lumen decay, a device with poor heatsinking will decay far more quickly than one that remains cooler. Additionally the other components (reflectors, lenses) may also reduce the output, any metalized reflectors and plastics are especially prone to changes in optical performance.

It is also interesting to note that the life expectancy statements refer to the LED;s specifically. As you have mentioned in another thread, many manufacturers state the light output of the LED's and not the luminaire as an assemble unit. Equally the "life expectancy" statements probaly relate to the LED's (based again on some level of output decay), and do not include the other components.........

Re: New Homes & Downlights

PostPosted: Tue Apr 12, 2011 8:22 am
by Sandivee
Your right zzsstt, I meant lumen maintenance. I always end up saying decay for some reason.

Re: New Homes & Downlights

PostPosted: Wed Apr 27, 2011 3:18 pm
by Think Wise
The 270lm for 7W is still pretty poor.

Our most recent 16W down light is getting 750lm and its not a high end chip, some of the more expensive chips were getting around 900lm for the same wattage. You also have a much higher chance of the driver popping in a gu10 fixture due to the increased heat.

The 10W Eltina has a 95degree junction temperature! This is far too high for constant use, it would be lucky to get 30,000hrs they claim.

Re: New Homes & Downlights

PostPosted: Wed Apr 27, 2011 11:31 pm
by karlajensen
hmmm 30,000hrs is still three times the life of CFL and probably 10 times the life of an incandescent light.

Personally I'd cop that loss in life for a light that punches out that bit more

Re: New Homes & Downlights

PostPosted: Thu Apr 28, 2011 3:07 pm
by Think Wise
well 30,000hrs is pretty keen and that would be to death not 70% decay.

Re: New Homes & Downlights

PostPosted: Sun May 01, 2011 11:23 am
by Sandivee
Yeah, 270lm does look small on a piece of paper, but my point was you need to actually see the light... don't judge the book by it's cover.

The Philips 7W is the only one I've seen spot on 2700K and bright enough to call a true halogen replacement, both MR16 and GU10 rated at 40,000H. 10W MR16 was only 25,000H and has a small fan in there but is so close to a 50W halogen when you see the light output.

If you were really worried, just go for a Brightgreen D900, then you can't complain.... except maybe about the cost of the product, but hey, you don't get quality for nothing OR a 5 year warranty.

COLOUR TEMP AND CRI should be considered also - a lot of people don't really look at these when purchasing lighting products.... Brightgreen D900 has a 90+ CRI which is extremely good for LED. The cheaper products usually only have 70-80 CRI or don't even show CRI, and no point getting a 3500K light when you want a halogen 2700k colour.

If anything, the best guide i've seen to LED lighting is on Brightgreens website under Lighting School.

http://brightgreen.net.au/lighting-scho ... ing-terms/

Check it out for FACTS, not assumptions. :D