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Associate

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Are CFLs Really Designed for Longer Life?

05/05/2008 5:10 AM

I converted most of my home to CFLs 2 years ago with the purchase of around 20. I reckon I have replaced 75% of them in that time. Some survive several years .. most last a year or so and many are dead within weeks.

The worst one so far was a new dimmable version I bought 2 weeks ago which died after 3 days .. around 20 hours or so use. It was not used to dim a great deal since it was a fitting with 2 normal non-dimming CFLs and I figured it would be bad for them.

I'm starting to get annoyed with the text on the sides of the boxes claiming 15000 hours life since I think I am yet to have a single one last that long .. its not really an MTBF is it.

This is ausralia BTW .. so we are running them on 240V .. I'm wondering if the lifespan is better in the US than over here .. maybe the peak voltages involved are hust too much. The circuit is basically the same as a Philips app note I found online.. www.nxp.com/acrobat_download/applicationnotes/AN00048_1.pdf

The last one I dismantled to have a look at .. it appears to have had an insect get between base-emitter of one of the drivers .. may or may not be the cause of the failure.. it looks like the other transistor has an open base-emitter. So I'm not blaiming this particular one on the manufacturers .. I have about a half dozen dead ones here that I am going to investigate though.

I have not ripped the dimmable one to bits yet as I am going to attempt to get some warranty yet .. or at least get a good whinge to the supermarket to start with. There is No warranty infoon the box of course .. just the blanket claim of 1500 hours lifespan .. HAH!

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#1

Re: CFL Lifespan truthful ?

05/05/2008 8:04 AM

That is bad... I'm in the UK and I've been using CFLs for way over 10 years now and not a single one has packed up...

A few have got so dim over time that I've replaced them, but then the lifetime quoted by the manufacturers is until the light output reaches 50% of the original output, I think...

So I've never had one fail, only grow dim and that is on 240 ish volts...

I would take them back to the shop or manufacturer with a carefully worded letter!!

John.

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#12
In reply to #1

Re: CFL Lifespan truthful ?

05/06/2008 7:18 AM

better to just tell them the problem, nicely. Most often they'll just say go and get some more. Best not to build resistance be getting huffy too soon. When buying CFl's try to find customer service number on package. Again, be nice and explain. You'll probably get replacements and/or coupons in mail...and an apology too. As for dimmer types...best to avoid new gimmicks until they're on market for some time and proven. Let someone else pay for free R&D "market" testing of the latest and supposedly greatest. BTW, dimmers is a good approach...to extend the life time and conserve power usage of incandescents.

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#2

Re: CFL Lifespan truthful ?

05/05/2008 8:50 AM

I have had similar bad experiences with a number of CFL bulbs I have purchased. I started saving the packaging and receipts, so I can return them to the store for replacement, or send them back to the manufacturer (if it's been too long for store return). Financially, it's really not worth the effort to send back to the manufacturer, but it's the principle, if no one makes them back up the warranty, they will continue to inflate the expected life of the bulb. I do have some that have gone for quite a few years, but they seem to be the exception. I also think that the majority of failures that I see are electronics failures, not the fact that the tube itself is "used up". I have actually fixed a couple, but most are too difficult to get into. My opinion is that the numbers they put on these things are not considering "real world" conditions, such as poor design, manufacturing defects, cheap components, etc. There is also the end user to take into account. Most of these numbers are based on a certain "on" time per day, meaning turn it on, leave it on, then off, repeat. The more on/off cycles you put them through, the shorter the life.

There's been a lot of discussion about the real vs perceived benefit of CFL. You do have to factor in the higher initial cost, the disposal issues, the mercury hazard of a broken bulb, etc., not to mention that if you get less life out of one that you do with an incandescent, there's no way you are ahead!

I'd like to see a good review on these bulbs, so I could make a more informed decision when purchasing. I would like to find some manufactured domestically, but I probably couldn't afford them!

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#3

Re: Are CFLs Really Designed for Longer Life?

05/05/2008 10:22 AM

When I moved to a new home in January of 2007, I re-lamped the entire house (40+ bulbs) with CFL's, inside & out. I have not had to replace a single unit yet, despite several being in sub freezing temperatures and asked to start on a regular basis (they take a little longer to reach full bright, but no failures). I purchased contractor packs of Sylvania bulbs from my local Lowe's and my net cost per bulb was less than $3 I have not attempted the dimmable versions - I retained incandescents in areas I wanted dimmability or instant-on. I'm waiting for the LED technology to mature before replacing the lamps in those areas.

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#4
In reply to #3

Re: Are CFLs Really Designed for Longer Life?

05/05/2008 10:48 AM

I'll have to remember Sylvania! I think the majority of mine have been GE or Lights of America (made in China, of course). I would like to try the dimmable, but they are hard to find, and when you do find them, the cost is too high.

I, too, am waiting for the LED technology to come down in price. With all the minuses that CFL's have, LED should become the dominant technology.

Tom

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#5

Re: Are CFLs Really Designed for Longer Life?

05/05/2008 5:09 PM

I bought cheap ones and they didn't last...

I bought some 'good quality' ones.... I just had one go..it started flickering and stunk like mad...the electronics had cooked. At least a filament bulb doesn't stink the house out. when it fails.
As far as I'm concerned the jury is still out.

Del

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#8
In reply to #5

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 12:34 AM

How can you tell 'good quality'? My first impression is to avoid 'made in China', but I haven't seen any...

I too have been using CFLs for at least 10 years, and usually mark the install date, so I have some idea of how long they last, but there is a wide variation...

I have NOT had Electroman's experience. Mine usually last around 2 years; some longer, some only weeks.

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#9
In reply to #8

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 2:49 AM

Yup...even the 'Brand Name' ones (eg GE ...hey thats a palindrome!) are made in china .

Del

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#6

Re: Are CFLs Really Designed for Longer Life?

05/05/2008 9:06 PM

It looks like the consensus may be .. good quality ones will possibly last a long time and cheap ones are probably not worth the price of the box they come in.

I don't think I have had a single one need replacement for losing light output. They simply do not last that long.

All of the ones I have purchased have been from the lower end of the price range .. around 2 or $3 each ( in packs or 6 to 12 usually) with the exception of the dimmable one which cost $20.

Maybe its as simple as the lower cost ones having sub spec transistors compared to better quality versions. I may have to dismantle a new cheap one and use a curve tracer to check out the transistors..

Either way .. I think I may have to spend a lot more on my globes in future, my early purchases where pricier from memory and they have fared little better over time.

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#7

Re: Are CFLs Really Designed for Longer Life?

05/05/2008 11:04 PM

I've purchased the GE bulbs, and they've gone gut up inside a year, and one of the bulbs burst into flames when the base blew!

Scared the bleep out of my 20-year-old son, and didn't make me a happer camper, either!

Looks like I'll either have to buy better bulbs, or up my fire insurance!

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#10
In reply to #7

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 4:51 AM

Locksmith Al: You ahve just given me cause for a few sleepless nights. I am now in the UK until June when I return to my wooden house in the mountains of southern Spain. I have solar power and nothing else but a petrol generator at that Spannish retreat. I have used CFL's in the house for over a year now as I only received around 4.5kWh per day from my solar panels.

I have to leave some lights on (and the fridge) to drain some of the stored power in the 12 24v batteries while I am away from the house for extended periods (like now - 3 months).

The thought that these CFL's could explode in flames gives me a cold sweat. Hopefully my very isolated wooden retreat will still be intact when I return.

By the way, I do not cover the panels and disconnect the system because I don't know enough about it to do that, and I want to leave some lights on so that people think there is someone there (especially at night) should anyone decide to break in! I suppose if they did, though, at least the fridge would be on so that they could have a nice cold can of something!

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#13
In reply to #10

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 7:19 AM

There are no really good ways round that problem......Batteries need to be cycled, but NEVER overcharged as then they just gas off the water, ruining the battery....

LED lights generally make less heat and are also available in 12 volts....

I would cycle such batteries between 12.65 volts and 13.2 volts, not any lower and not any higher when you are not there.

12.6 volts is the level at which batteries start to sulfate and 13.4 and higher starts gassing....

There are 12 volt movement detectors and also 24 hour timers, for caravans and the like...it would be better if you used them a bit to make your place look more inhabited....

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#16
In reply to #13

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 9:10 AM

Andy Germany: Thanks for that. Please note that my system is 24v.

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#24
In reply to #16

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 7:48 AM

No problem, simply doubling the figures will give the correct values PROVIDED that both batteries are identical in every way including age!!!

There is lots of lead acid info on the web, read it all!!! There is too much for a blog!!

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#19
In reply to #13

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 7:12 PM

I think you are recommending a "waste load", to maintain the batteries of our friend.

I have a Lava Lamp that burns an old 40 watt appliance bulb. Possibly our friend has some Lava lamp around.

I myself have not had good luck with CFLs and appreciate the recommendation of Sylvania.

I suspect that as time goes on LED lighting will overtake the CFLs.

Frankly I've stopped buying them since they are overrated as far as output, and even when they work, the glass envelope is so delicate they break more easily than regular lamps.

A fair amount of my lighting is from scooptype clip lights. Heavan forbid I move it.

LEDs will take off when they over power the light and then turn it yellow with gel or filter to replicate the pleasing quality of light we are accustomed to.

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#52
In reply to #7

Re: Are CFLs Really Designed for Longer Life?

05/08/2008 1:03 PM

No matter what CFl you use, be sure to grasp the base, not the tubing, when threading in and tightening in socket. I suspect this might be a cause with a lot of premature CFl failures.

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#54
In reply to #52

Re: Are CFLs Really Designed for Longer Life?

05/08/2008 3:25 PM

Hmmmmm I wonder if that is the problem???

In the UK most bulbs for dometic use are bayonet fitting, all the pictures I've seen on here show damaged bulbs with edison screw fittings!!??

John...

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#55
In reply to #54

Re: Are CFLs Really Designed for Longer Life?

05/08/2008 3:45 PM

It could be an indicator...here in the US, you almost never see bayonet-style home-use lamps, they're all screw-in. And, obviously, sometimes screw-up...

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#56
In reply to #55

Re: Are CFLs Really Designed for Longer Life?

05/09/2008 3:34 AM

Germany (most of Europe too) use Edison screw in bulbs.

Certainly putting pressure on the glass could be part of the problem, causing tiny cracks/stresses.....

Sadly some fittings are so made that grasping the base is impossible.....

Sadly, most of the modern fittings do not have the correct base for power saving lamps in the first place, its a lot of work to find a fitting for such lamps that also looks good.

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#57
In reply to #56

Re: Are CFLs Really Designed for Longer Life?

05/09/2008 5:18 AM

Electroman's response points up a (seemingly ironic) case where production cost cutting—i.e., use of bayonet fittings—might actually have had a benefit, possible one that was never originally contemplated!

My sense about the "bulb-to-base integrity" thing applies also as an explanation of the dramatic decrease in reliability of incandescent bulbs—where even minute sealing failures (loss of hermeticity) can lead to rapid filament (&or filament support) oxidation and failure...and to (so very many) bulbs (at all prices and under all brands) lasting only a matter of hours (i.e., hour fractions), if that. As to incandescents, it has also been my experience that, when purchased in multiple-unit packaging (the units of which presumably come from the same production lot), if one bulb fails prematurely, so will the rest—and at roughly the same time to failure! This indicates, to me at least, a diminishment (since former times) of workmanship—and of quality control—as:

  • light "bulbs" (of all kinds) have increasingly become "low-value-added" products, and
  • production has accordingly moved (ubiquitously) to 3rd and 2nd world countries. (Few would wonder why we no longer see US, UK, Deutschland, or even Japan produced light "bulbs".)

Another thing entering into my thinking about the matter is the almost universal use of push-in type "base" contact used in halogen bulbs...where the risks (and liabilities) attending sealing structure failures...are unable to be trivialized.

Concluding, my original post is meant (also) to suggest that, other than user care when installing, there is little that can be expected or done (apart from "enforcing" express or implicit warranties after the fact), to alleviate/counteract premature "bulb" failure problems; the production "economics" arguments given above weigh heavily against any manufacturer solutions—i.e., mfg design effort must, of necessity, focus on perceived performance (consumer market appeal) even if to the detriment of product reliability/ruggedness.

Andy, thanks for your input. Well done.

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#58
In reply to #57

Re: Are CFLs Really Designed for Longer Life?

05/09/2008 7:41 AM

"Another thing entering into my thinking about the matter is the almost universal use of push-in type "base" contact used in halogen bulbs...where the risks (and liabilities) attending sealing structure failures...are unable to be trivialized."

Too true. I had the glass envelope break away on a fair sized halogen bulb once some years ago. The circuit had to be de-energized to safely remove the remains. No triviality there, even 110V will bite hard enough to kill sometimes.

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#11

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 7:09 AM

The blanket claim is a warranty. Go to mfr, get a replacment...for all of them. It's always worked for me...even at the seller...even with incandescents. So try store first, then the manufacturer. Good luck with it.

Also, the things work better in lamps mounted upright that in fixtures mounted downward.

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#14

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 7:35 AM

I've had mixed results. Most of my CFLs are turned on and left on for several hours at a time, and I've not changed one in two years.

My strangest experience was in my last home. I had a bathroom that ate light bulbs. Incandescent bulbs lasted a month or less. I tried a CFL and it burned out in about six weeks. In the rest of the house, all bulbs lasted as predicted.

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#15

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 7:44 AM

No, not really. CFl's are really designed for lower power consumption. That's why that's the thing they do most reliably...when they do anything. The rest is about trying to fix flaws, both actual and perceived.

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#17

Re: Are CFLs Really Designed for Longer Life?

05/06/2008 11:12 AM

Guys,

CFLs can be a real pain. Maybe one day they will be adequate but I am betting on LEDs coming good first.

Problems that I have encountered include:

1 Poor match of many CFLs with the physical envelopes of many bulbs. They are often too large for the fitting. So instead of using 50 + CFls I can only use 20!

2 Poor luminance. I have turned my study into a Downlighter test bed with a mixture of GU14s,( Mains voltage). CFLs and MR16s (12 volt) The CFL s are slow to start, have poor luminance and on the basis of this experiment I used MR16s for the next room that I was relamping. This study will get refitted with MR16s when I get a moment. Lik ethe external lights reviwed below, the brightness at ceiling level looks adequate, but trying to read at Desk level is hard.

Especially poor luminace of CFLs used in outdoor situations; eg I used to have a 150 watt Incandescent bulb at the top of my drive. I now have a 20/23 Watt CFL and the thrown light from it is pitiful. The percieved brightness at the lamp level looks adequate but try and find somethiing on the floor in the dark!!!

3 Life of the CFLs has not been that bad yet, Some have failed, I asume the left hand side of the of bathtub and others have yet to accrue sufficient hours for meaningful numbers. A fw years need to elapse before we can be confident of long lived CFLs.

4 LEDs when they finally arrive in a useful brightness and colour they could be useful -however they will all require an individual driver as I understand the science or physics This will impact the cost and also impact the envelope issues noted above.

5 One interesting development is CCFL (Cold cathode Flouescent) units which are certainly useful for low level lights. This the technology use for the backlight in most Laptops. I bought one in a Firesale at my local Electrical wholesaler. It is a fairly dim 5 Watt unit and cost me a whole pound! It could be useful where one needs a low level light!! It ought to have a good level of R&D behind it!

For me CFLs are NOT the answer to a maiden's prayer!

Sleepy

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#30
In reply to #17

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 10:25 AM

Your comment about less light than the manufacturers apparently claim is relevant. Manufacturers of CFLs always compare with so-called "warm white" tungsten, which means the tungsten bulb is running relatively cool and therefore inefficiently. I think that means that the radiant output is about 70% of a 'standard colour-temperature' tungsten lightbulb. However, if you want to use CFLs or warm-white bulbs to read by (apparently not common practice these days), you may find that you need the light to be brighter to achieve the same visual clarity - that is certainly the case if you are long-sighted**, as your eye focuses shorter wavelengths more strongly.

**Which diverts me to the unsuitability of Volkswagen and Audi's craze to use red illumination for the dashboard display - assuming that you need rapidly to transfer your attention between the road and the display; but if only that were the worst of their lack of attention to their customers' needs...

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#31
In reply to #30

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 10:31 AM

red illumination for the dashboard display .. <slaps furry head with paw>

A fair proportion of men have some red green deficiency with their colour vision...

(which can be a good thing as it will excuse you from choosing wallcoverings, curtains and the general nightmare that is soft furnishings... )

Del

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#32
In reply to #31

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 11:07 AM

Apparently someone told 'em red light is less degradative to the retinal pigments that allow night vision without telling 'em about the drawbacks to using red light... D'OH!

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#38
In reply to #32

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 2:33 PM

What are the problems with red light (in the car, not in a house!!) at night, I haven't heard.....

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#39
In reply to #38

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 3:03 PM

I haven't heard.....
There..you see they're bad for your hearing too

Del

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#40
In reply to #38

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 3:38 PM

Potential problems:

1) Harder to focus on red displays when having to look from road to dash repeatedly.

2) Less brightness, so may not be able to see readouts as well.

3) Red-green color blindness could be an issue, although 1 & 2 would trump this.

4) Law enforcement might mistake you for a rolling house of ill repute.

Potential pluses:

1) Red light does not degrade pigments responsible for night vision as rapidly.

2) I don't know of any others.

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#41
In reply to #40

Re: Are CFLs Really Designed for Longer Life?

05/07/2008 4:47 PM

"1) Red light does not degrade pigments responsible for night vision as rapidly."

Except that this is irrelevant, as night-vision is almost entirely restricted to the periphery of the retina. And (at least according to most countries' driving test regulations) decent