LED Lights, Marketing vs reality. Mk II

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Re: LED Lights, Marketing vs reality. Mk II

Postby Bthree » Sat Jun 22, 2013 2:46 pm

Further to the above I have attempted to keep the ceiling sealed for heat gain or loss reasons and dust but halogen down lights are hot and cannot be covered with insulation bats ( transformers included ) thought I had finally found an answer to the heat problem but now the noise has got me.

Halogen 250 deg C .... LED 55 deg C operating temps
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Re: LED Lights, Marketing vs reality. Mk II

Postby zzsstt » Tue Sep 03, 2013 8:06 am

A further update on my findings with LED lights.

My LED's are continuing to fail and, according to my meter, to decrease in output. Not wanting to give up (sucker for punishment!) I have now purchased some Philips Master LED's to test. These are more expensive again, but as a "name brand" product they might be better.

HOWEVER....

As part of a separate project to drive off-the-shelf MR16 LEDs from a solar panel, I have been looking at power supply choices. In the course of that investigation I came across the detailed specs for the Philips LED's, which includes the failure rate analysis. Now as always this is largely based on calculation, because no company can wait for 20 years to give an accurate analysis, so a large number of units are tested for a short period of time and the long term failure rate is extrapolated. As we all know (and I speak as someone who did this as part of their job many years ago) this is not always representative of real life. As an example I experienced a batch of network routers that had a 0% failure rate in the first 12 months, followed by an 80% failure rate in the following 12 months! In the case of the Philips Master LED's they show a slowly increasing failure rate, starting at a rate of about 10% failed units per 10,000hours. 75% have failed by 60,000hours. So their stated 40,000hour life expectancy is based on about 50% of all units having failed (which they define as total failure or output reduction to below 70% of initial level) within 40,000hours.

Whilst this document is freely available, it is not part of the normal advertising for the product. I do think that it is interesting, however, and should be kept in mind that when we are told that "LEDs last for 40,000hours". All this really means is that from the results extrapolated from accelerated aging tests, 50% of LEDs will still be producing at least 70% of their initial brightness after that time.

When translated to the real world, this means that if the lights are run for 12 hours per day, which is 4380hours per year, we should expect (even on the manufacturers "best" figures) a 5% per year failure rate for quality LED's.

It should also be noted that the testing is at 25C, in a "simulated luminaire". It does not appear to include real life elements like dust, dirt, high temperatures and frequent switching, although they do document a specification for switching in another brochure.

Edit: It's also worth noting that they are very specific that this is a 12v AC unit, not for use with DC transformers.
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Re: LED Lights, Marketing vs reality. Mk II

Postby LEDMAD » Tue Sep 03, 2013 9:41 am

In the course of that investigation I came across the detailed specs for the Philips LED's, which includes the failure rate analysis


This was probably a standard LM-80 report. If you Google LM-80, there are a lot of details on it.

As part of a separate project to drive off-the-shelf MR16 LEDs from a solar panel, I have been looking at power supply choices.


Wouldn't a MR16 LED be the worst choice for connection to a solar panel? The internal electronics in MR16 LEDs expect 12V AC. But typical solar panels neither produce 12V nor AC.

Would make more sense to start with a standard DC LED chip with no electronics in it. For example, check out this older thread. living-green/topic3844.html
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Re: LED Lights, Marketing vs reality. Mk II

Postby zzsstt » Tue Sep 03, 2013 12:19 pm

LEDMAD wrote:Wouldn't a MR16 LED be the worst choice for connection to a solar panel? The internal electronics in MR16 LEDs expect 12V AC. But typical solar panels neither produce 12V nor AC.


Indeed, but the "pretty" kits are very expensive (>$300), and the Oatley kit mentioned in the thread you linked to (and available on eBay) is unfinished and ugly. And both have problems with heat, requiring cut outs in the ceiling to allow heat to escape. And thus breaking the insulation.

On the other hand a surface mounted or track style MR16 system is available relatively cheaply, can be installed with a couple of screws, and can use off the shelf MR16 LEDs. It still generates heat, of course, but does not require a hole in the ceiling because the lights are in free air.

The other benefit is that it allows the re-use, or more correctly the continuing use, of an existing lighting system. In my case, for example, I have an MR16 track light in my kitchen which is used solely for "task lighting" whilst I am cooking. The "transformer" is in the roof space above. It would be a few minutes work to put a PV panel on the roof and swap to a driver that would run the lights all day on PV, and (given the right driver!) still allow the lights to be switched to grid power at night. This would use an existing system, at minimal effort, to use solar power and avoid running a circular fluoro all day. Win win win.

My mother in law has about 20 MR16's running all day, as do many other people. With the driver I am talking about she could replace them all with 7W LED's, fit a new PV+mains driver and run them all day from a couple of solar panels. And it could all be done in about 30minutes - 2 panels on the roof and swap the globes and "transformer". A few more electronics and a battery, and it would run all night as well!

Whilst I could achieve the same thing with a commercial "PV skylight" using a PV+mains driver, the cost is massive (there is a Solaro unit that does this, but I can't even find a price online which means it's scary expensive!) and it requires me to throw away my perfectly good circular fluoros and make holes in the ceiling disrupting my insulation.

As long term users of this forum may already know, I find it annoying that most of the "green" products sold are minor improvements on existing products and require the existing product (and all its embedded costs) to be discarded. In this case a PV+mains driver for MR16 LEDs would allow thousands of existing MR16 installations to be converted to solar/LED with minimal effort. But also minimal profit for the resellers.......
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Re: LED Lights, Marketing vs reality. Mk II

Postby LEDMAD » Tue Sep 03, 2013 1:23 pm

I don't think the argument that you should use MR16s for solar because they don't need a ceiling cut out is a very strong one. Pretty much any light can be hung from the ceiling.

Rather than having dozens of the 'special' switching drivers you mention it would make more sense to me to just have a standard PV inverter & mains power as required. They you can use any LED light, with any standard driver, including your existing MR16 fittings.
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Re: LED Lights, Marketing vs reality. Mk II

Postby offgridQLD » Tue Sep 03, 2013 3:20 pm

My mother in law has about 20 MR16's running all day, as do many other people. With the driver I am talking about she could replace them all with 7W LED's, fit a new PV+mains driver and run them all day from a couple of solar panels. And it could all be done in about 30minutes - 2 panels on the roof and swap the globes and "transformer". A few more electronics and a battery, and it would run all night as well!


Why is she running 20 x MR16 lights in the day time? Dose the house have windows? Performing surgery or dental work or perhaps using them for heating? ;) That's a lot of lighting at night but running all day.

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Re: LED Lights, Marketing vs reality. Mk II

Postby zzsstt » Tue Sep 03, 2013 4:33 pm

LEDMAD wrote:I don't think the argument that you should use MR16s for solar because they don't need a ceiling cut out is a very strong one. Pretty much any light can be hung from the ceiling.


The challenge is to find a nice looking "hanging" LED light, and I haven't seen many at a reasonable price. On the other hand, there are vast numbers of MR16 track systems and MR16 systems already installed, and replacement LED "globes" available at every supermarket. It is also worth noting that many of the "dedicated" LED lights being produced are based on non-replaceable light fittings. These are marketed on the basis of the quoted long life. That is fine, if it proves to be true and if fashions don't change, the house is not renovated etc. But to fit an expensive light that has to be thrown away when it fails after a year or two? Or because it no longer matches the decor?

LEDMAD wrote:Rather than having dozens of the 'special' switching drivers you mention it would make more sense to me to just have a standard PV inverter & mains power as required. They you can use any LED light, with any standard driver, including your existing MR16 fittings.


True, and by coincidence exactly what I have done. BUT it doesn't suit every situation, and it requires far more intrusion as it is basically a grid feed system. My approach would never rise above 12V (or whatever nominal panel voltage was) and is therefore a DIY task, as are the commercial LED skylights. It also allows the consumer to select from any of the thousands of inexpensive MR16 fittings available. Obviously the DIY aspect doesn't apply if you are dealing with a PSU for each halogen, as each is a 240V unit.

Remember that my initial stimulus was a 12V track light with a single transformer powering 9 MR16's! Replacing one transformer gives free lighting all day.
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Re: LED Lights, Marketing vs reality. Mk II

Postby zzsstt » Tue Sep 03, 2013 5:03 pm

offgridQLD wrote:Why is she running 20 x MR16 lights in the day time? Dose the house have windows?


And you'll be glad to hear that she's a Green voter.....

Like many ("luxury") apartments, the lighting is all halogen because it looks good. This apartment, being 1/4 of the floor of the building, has a long dark hallway that runs from the front door to the main living area. There are windows in the living area and bedrooms, but the hallway has none. That's the first 6x50W'ers. In order to provide a "lit path" from the bedroom area to the kitchen, the way the switching was done means that the "hallway" circuit also includes 3 lights that are really part of the living area. From the hallway to the bedrooms is another small hallway with no windows, that's 3 more 50W'ers. The kitchen is "L" shaped, with a window at the end but the business end has none. That's another 6.

All the above lights (18) are on whenever the apartment is occupied. In addition, whichever room is actually being used will also have its lights on (bedrooms, bathrooms etc.) and the main living area will have it's 6 halogens on most of the time.

Sadly, and it pains me to admit it, I do have to say that most of the time there is simply not enough natural daylight through the apartment to turn many of the lights off. Even the bedrooms, which have windows, suffer from shading by the surrounding buildings and so have minimal natural light.

And this is before we consider the water that goes down the drain waiting for it to warm up because the water heater is in the basement, or when changing the temperature because the taps are about 3m from the shower head! Or the fact that there are only about 3 days a year when you can go without heating and cooling for an entire 24hour period.

But that's all par for the course with city apartment living. No, it's not the way I would do it, but it's what the luxury designers create.
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Re: LED Lights, Marketing vs reality. Mk II

Postby davidg » Tue Sep 03, 2013 8:28 pm

zzsstt wrote:But that's all par for the course with city apartment living. No, it's not the way I would do it, but it's what the luxury designers create.

Lets get sarcastic, it's the way bad luxury designers create without any thought of energy use, how, what when, why. :x smart energy management requires smart people that can actually think
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Re: LED Lights, Marketing vs reality. Mk II

Postby zzsstt » Wed Sep 04, 2013 8:00 am

davidg wrote:Lets get sarcastic, it's the way bad luxury designers create without any thought of energy use, how, what when, why. :x smart energy management requires smart people that can actually think


Indeed, but it is also what luxury buyers WANT. Admittedly they probably don't know any better, but when they pick up a copy of "Luxury Apartment Monthly" (fictional magazine, but think Vogue etc.) they do not see a single fluoro tube, they see masses of halogen. It makes their jewellery sparkle (really, it does!) and impresses their friends. And lets be honest, when you spend $3million on a "flat" and have >$30k per year "management fees" (the live-in caretaker who vacuums the lift for the 7 apartments in the building) then the electricity bill is not really relevant!

When I built my house I spent a great deal of time finding efficient light fittings that were also attractive. I even converted old gas lights to CFL to get the look I wanted and still be energy aware. But it was a lot of work. If I was designing a modern apartment to sell for $heaps in the real world I would still be looking at recessed downlights as the cheapest and easiest way to make something look good. So I can't really blame developers for doing the same thing.

We on this forum are interested in energy savings etc. We tend to start believing that other people are too. The reality is, I suspect, that very few people really care, and most of those who do are driven to do so by financial pressure which in turn creates a problem because they are unable to afford the newer energy saving items. Those who are not under financial pressure may profess to be green, they may even vote green (or at least say they will), but in most cases that's as far as it goes. The luxury flat I was talking about is owned by a lady who also has a house in the country. Both dwellings are "luxury" buildings, and she drives her (non-hybrid) car between them every couple of days. Neither building has a rainwater tank, though both have irrigated gardens. Neither building has any PV, or even solar hot water. Yet she is a firm believer in climate change, says she votes green and has sufficient disposable income to make both her houses energy and water efficient. I think I know the problem - saying she is green impresses (at least in her mind) her friends. But none of her friends will be impressed by a water tank............

The other issue of course is that (sadly) the retailers of anything energy efficient view "green" as a lever to jack up the price.
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