LED replacements for Halogen downlights - ISSUES

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Re: LED replacements for Halogen downlights - ISSUES

Postby Think Wise » Thu Aug 18, 2011 12:35 pm

There are a few more active cooled lights getting around (fan inside) that use up to 10w in the $30-$40 range, this is the only way you will get acceptable light outputs.

The only light under 10w that I would put in my house that uses a mr16/gu10 format is something with the new CREE MTG chip every other 'cree' advertised product could be put together by the guy next door.

What I see on these DIY forums is lots of people wanting to test everything out by themselves and this process gets undertaken by lots of people yielding different results.
All that needs to be found out about a product is the chip used and who packages it, nearly every other piece of information (color, cri, lumens etc.) can be then be attained. If you cant find out this information I would be staying away.

Or just bite the bullet and spend $80-$90 on a full fixture.
Picture attached is of 16w fixtures, this is just off my phone so its made some pretty severe light corrections in reality the room is probably too bright.
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Re: LED replacements for Halogen downlights - ISSUES

Postby zzsstt » Thu Aug 18, 2011 3:02 pm

Think Wise wrote:The only light under 10w that I would put in my house that uses a mr16/gu10 format is something with the new CREE MTG chip every other 'cree' advertised product could be put together by the guy next door.

What I see on these DIY forums is lots of people wanting to test everything out by themselves and this process gets undertaken by lots of people yielding different results.
All that needs to be found out about a product is the chip used and who packages it, nearly every other piece of information (color, cri, lumens etc.) can be then be attained. If you cant find out this information I would be staying away.


Whilst I understand what you are trying to say, it is very unfortunate that such a process only works in a world of utter honesty! The reason (some) people want to test things for themselves is that the days of manufacturer or retailer honesty are, sadly, long gone. The manufacturers "official test" results are almost aways, how shall we say, "optimistic"? The retailers figures are normally doubly so. The first generation of LED lights from a few years ago were, according to the manufacturers, the best thing since sliced bread and we should all rush out to buy them. When the second generation came along, we were told that the problems with the first ones (what poblems, they were the best thing since sliced bread weren't they?) had been sorted. And so we go on.......

At the end of the day, the buying public becomes split in to three camps:

1/ Always trust the manufacturer, no matter how bad earlier experiences were (gullible)

2/ Distrust the manufacturer, never buy the product again

3/ Distrust the manufacturer, but want to see for themselves.

I fall in to category 3, in that I have rarely seen a product (of any description) that is as good as the retailer claims, but I'm willing to try new things if I don't need to make an overly large commitment based on faith alone..... especially on faith in a person or organisation that have a clear motive (financial or otherwise) in selling a product or idea, as it is rare for a salesman to say their product isn't as good as it might be!
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Re: LED replacements for Halogen downlights - ISSUES

Postby Think Wise » Thu Aug 18, 2011 3:38 pm

I do understand this and your are correct there does need to be some levels of honesty but from a specifications point of view anyone claiming CREE which is nearly everyone these days. As soon as you know the model you can read through the spec sheet from CREE and do some quick calcs to see if things add up. Lens quality does come into it a bit but its mostly up to the chip.

The other thing to ask for is independent testing it only costs $500-$800 per model and any company worth their salt they will have it verified.
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Re: LED replacements for Halogen downlights - ISSUES

Postby zzsstt » Thu Aug 18, 2011 6:27 pm

Out of interest, if I was to look at buying an LED light how would I know anything about it?

The retailer tells me it uses the Cree MTG chip you mention. How do I know? The retailer tells me it uses a top of the range power supply that will last "forever". How do I know? The retailer tells me the heatsinking is over engineered and uses top of the range thermal compound. How do I know?

Moreover, when the retailer shows me the test results how do I know they have any relation to the product he/he is selling me? The solar industry abounds with talk of the "golden samples" used to get test result for a product that have no bearing on the run-of-the-mill production samples? As I have said in previous threads, the independent tester can only test the samples he is sent. A comparative test between a shiny new "golden sample" LED and a broken down T8 tube in a faded, cracked luminaire filled with dead files can be done in good faith and prove conclusively that the LED produces more light per watt. Unfortunately however diligent the tester, and however independent, the test was completely biased and has no bearing on either the LED that the customer will buy, nor the performance of a "real world" T8 tube.

Yes, I am cynical. But on the other hand I have been involved in product testing, and the way the marketing department manages to extract the best results from it. I have been involved with statistical analysis, and how to "prove" something based on mathematics alone regardless of what the data actually says.

It is also worth noting that a major issue with LEDs is their purchase cost related to their life expectancy. Unfortunately, as we have discussed previously, no matter what the Cree specs say, the life expectancy of the entire unit is based largely on the other components involved and the way it has been designed and assembled. That being the case, getting caught up with test results of light output per watt consumed by the LED itselfis only a small part of the cost/benefit analysis. If the power supply is massively inefficient and either it fails or it causes the LED to fail after a few months, then the purchase was a financial loss. This, of course, will never be reflected in the spec sheet of the Cree MTG, and whilst an "honest" manufacturer may have tests relating to light out vs. watt consumed for a normal production samples (rather than the 'golden sample"), such tests will not reflect the life expectancy issues relating to poor design or heatsinking. But then a retired (very successful) marketing executive once told me;

"You never want to sell a product based on facts. Minimize facts. It's much easier, cheaper, and more reliable to control image."

And that is the approach used by most companies to this day. So I'll still buy one and test it myself to the best of my ability......

However, as you point out, if the retailer of the unit is claiming performance above and beyond that which Cree attribute to the LED, then both the retailer and the unit can be written off!
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Re: LED replacements for Halogen downlights - ISSUES

Postby bpratt » Thu Aug 18, 2011 7:07 pm

One thing I have heard about some LED, in particular CREE lighting is RF noise generated from it.

Whilst many wouldn't know interference if it ran over them in a bus, it does create varying levels of problems for others.

So depending upon what you do, CREE LED's could be a huge problem for some. :(
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Re: LED replacements for Halogen downlights - ISSUES

Postby Think Wise » Fri Aug 19, 2011 10:01 am

zzsstt wrote:However, as you point out, if the retailer of the unit is claiming performance above and beyond that which Cree attribute to the LED, then both the retailer and the unit can be written off!


This is around 95% of the market yet people are still buying from ebay/deal extreme to trial this and trial that. I understand a layman is going to find it tough as to what to buy but anyone that is willing to research will most likely stumble across sites like these and find 100 different oppinions or 'tests' that some member has done. most being speculative. Even some of the multi million dollar companies I have visited have had a person in a dark room waving a light around to judge beam angles and light intensity.

I suppose my frustration lies in regularily reading these forums with the same questions being asked and different answers by 10 different 'experts'

The only solution I can pose is that for any tests that are done and posted there should be a few guidelines that are followed.

bpratt wrote:One thing I have heard about some LED, in particular CREE lighting is RF noise generated from it


As much as I think trying to help out is good this is completely incorrect the LED module has little if anything to do with RF. The association with cree and poor RF has to do with lots of inferior products claiming/using cree products with sub par driver modules.
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Re: LED replacements for Halogen downlights - ISSUES

Postby bpratt » Fri Aug 19, 2011 12:07 pm

Think Wise wrote:
bpratt wrote:One thing I have heard about some LED, in particular CREE lighting is RF noise generated from it


As much as I think trying to help out is good this is completely incorrect the LED module has little if anything to do with RF. The association with cree and poor RF has to do with lots of inferior products claiming/using cree products with sub par driver modules.



Yes, you're quite correct there... sub par driver modules.

But that is where some can not determine the difference between the LED and the driver, so lump it in with it being the LED rather than the driver.
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Re: LED replacements for Halogen downlights - ISSUES

Postby Think Wise » Fri Aug 19, 2011 12:43 pm

Yes you're right I honestly don't know how to solve that issue as there is so much junk getting around.
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Re: LED replacements for Halogen downlights - ISSUES

Postby zzsstt » Fri Aug 19, 2011 6:55 pm

Think Wise wrote:
zzsstt wrote:However, as you point out, if the retailer of the unit is claiming performance above and beyond that which Cree attribute to the LED, then both the retailer and the unit can be written off!


This is around 95% of the market yet people are still buying from ebay/deal extreme to trial this and trial that.


But you must remember that for most people price is a major driver. I don't know what the more upmarket "green" retailers are charging for LED's at the moment, but it wasn't long ago that the prices were up in three figure territory. Then factor in that in most peoples mind a higher price for "the same" product means either a rip-off, or paying for "the name" or simply added luxury. A Lexus costs far more than a Hyundai, but both will get you to the shops and back, both will break the speed limit and both will (in all likelihood) have much the same life expectancy. So if you offer the punter an LED for $15 from eBay, or an LED for $125 from "Superlative Green Lighting Inc.", and both are claimed to be "as bright as a 50W halogen", whilst only using "10% of the power", then you must accept that the vast majority of people will buy the cheaper unit. Especially because if they actually bother to do the math they will find that the $125 unit is unlikely to ever repay its capital cost, because nobody really believes they will last for anywhere near tha claimed 20 or so years. And that in turn is because most people have at some point bought CFLs with a "7 year life" and watched them all fail after less than 2!

These days (sadly) everything is disposable, cheap, and basically rubbish. People have come to accept that they pay b*gger all and have a product that lasts for a few months. They are bombarded by adverts telling them that the cheaper product is just as good as the more expensive one, so that is what they buy and that is what the retailers stock (which is why I can no longer buy quality tools or machinery and am still using stuff originally bought in the 1960's and before). Unfortunately that causes major drama's for anybody trying to sell quality, and inherently more expensive, products, whether that be tools, hifi, televisions or LED lights!

The knock-on from that is that a poor experience with a cheap LED causes the punter to lose faith in the technology entirely. But that's what happens when society is driven by greed, be that greed of the manufacturer, the retailer, or the customer (get more for less!).
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