Longevity of unused halogen bulbs

747LeftSeat

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So I have some H9 bulbs that I purchased approximately a decade ago but I have never used them. Assuming they still work, can I expect a shorter life from them than I would expect from equivalent brand new H9 bulbs?
 

night.hoodie

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They'll either >poof< immediately, or last their design life-- the only real degradation they could suffer that impacts life is if the envelope seal is broken.

I wonder if there is a process that could be uncovered, developed by CPF members for CPF members, that could almost eliminate the unpredictable instaflash issue. I know SoftStart drivers help, but, inexplicably, as popular and as desired as SoftStart is, one must dig and beg other members for these now old and used drivers.

What I have in mind is a little crazy... but what the heck? Anyone think it would be helpful to throw a a cleaned and cold Halogen lamp into the oven and bake it at some ideal temperature for a spell, then while it is still hot, put it in a flashlight and fire it up? Could this reduce instaflash?

Also, my understanding is that freezing some materials down to very very cold temperatures for a few days, then allowing them to slowly return to ambient temperatures, can make those materials stronger than otherwise, extend their lifetime considerably. I know this works for guitar strings, and some will advertise they use this process. The kind of freezers producing the kind of low temperatures I am referring to (30K-50K, or whathaveyou) are neither common or cheap, but some will have access to them, possibly through their work in science at universities or larger sciency corporations.

Neither idea practical for the necessary invested time and cost (of gas, or electricity, and the equipment), for a speculative and unknown and unpredictable increase in lamp life? But could either method work, in theory?
 
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Alaric Darconville

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I wonder if there is a process that could be uncovered, developed by CPF members for CPF members, that could almost eliminate the unpredictable instaflash issue. I know SoftStart drivers help, but, inexplicably, as popular and as desired as SoftStart is, one must dig and beg other members for these now old and used drivers.
The softest start in the world is not going to help when the fill gas has been replaced with normal atmospheric gasses. Read again carefully:
the only real degradation they could suffer that impacts life is if the envelope seal is broken.
Once that seal is broken, even in the tiniest manner, the fill gas (which can be pressurized up to 14ATM) gets out, normal air gets in, and the filament will burn up. Maybe you could bring it up real slow and watch for signs of the filament starting to burn, but properly stored and not dropped or flexed bulbs will be fine after long-term storage.
 

night.hoodie

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Well, I grant you my reading comprehension is low, but I did not disagree with your statement, and my reply is germane to the first half of what I quoted from your post, even if the ideas are fantasitical fantasy. I hoped you might address the content of my post rather than (I do it too, sometimes all night long) correcting someone on the Internet who is wrong. Why do we do it? Sometimes it helps. Sometimes it is just fun (I suspect that is your reason). But sometimes, at least I know myself, it is compulsion. I fight with the compulsion-monster within, usually it wins.

Here is my second attempt:

I wonder if there is a process that could be uncovered, developed by CPF members for CPF members, that could almost eliminate the unpredictable instaflash issue. I know SoftStart drivers help, but, inexplicably, as popular and as desired as SoftStart is, one must dig and beg other members for these now old and used drivers.

What I have in mind is a little crazy... but what the heck? Anyone think it would be helpful to throw a a cleaned and cold Halogen lamp into the oven and bake it at some ideal temperature for a spell, then while it is still hot, put it in a flashlight and fire it up? Could this reduce instaflash?

Also, my understanding is that freezing some materials down to very very cold temperatures for a few days, then allowing them to slowly return to ambient temperatures, can make those materials stronger than otherwise, extend their lifetime considerably. I know this works for guitar strings, and some will advertise they use this process. The kind of freezers producing the kind of low temperatures I am referring to (30K-50K, or whathaveyou) are neither common or cheap, but some will have access to them, possibly through their work in science at universities or larger sciency corporations.

Neither idea practical for the necessary invested time and cost (of gas, or electricity, and the equipment), for a speculative and unknown and unpredictable increase in lamp life? But could either method work, in theory?
 
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-Virgil-

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Those are interesting ideas, night.hoodie, especially the chill treatment -- I think you are referring to this kind of process. I don't know if an intact bulb would survive the very low temperature (would the glass crack, break, or craze?) but surely the tungsten filament itself would. Now: when would the cryo-treatment best be applied? To the filament wire before it's cut and coiled into a filament? Or after? If after, should it be done before or after the filament is welded to the filament supports? If after, would the cryo treatment possibly cause the filament and/or supports to warp in troublesome ways? In other words, assuming there's a benefit to be had, what steps of wire processing risk undoing the benefit? The simple question isn't so simple any more.

I don't think there's merit to the idea of baking a bulb in the oven. It wouldn't be able to reach a relevant temperature; the filament would still be effectively "cold" as far as inrush current goes, and inrush current + a weak spot in the filament = flashout.

As far as correcting people on the internet goes, that's been the subject of a cartoon panel you have probably already seen. If not, though, hover your cursor over the panel and see what pops up! :)
 

Alaric Darconville

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The differences in the coefficients of thermal expansion*​ of the metal, plastic, and glass used in a bulb could mean that you'll create that microfissure in the seal by attempting the cryogenic process.


*Metals, plastics, and glass often expand and shrink at different rates from each other​
 

LeanBurn

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The bulbs should be able to withstand below -40F...I have not yet heard of a need of special cold resistant headlamp bulbs in Alaska or Nunavut where they instantaneously ignite them several hundreds of times over the period of a winter.
 

night.hoodie

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thx Virgil, Alaric
fairly beaten, no easy instaflash defeat in there. Maybe with massive R&D, some benefit could be gleened, and always be 10 years off from any commercial viability. But then less lamps would flash, less lamps would be sold, industry could collapse, people starving, islands disappearing, mass hysteria, etc. Not worth the risk. Probably much easier to get LED to output a spectum identical to incan.
 
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-Virgil-

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The bulbs should be able to withstand below -40F.

Give a click on the first link in post #8 ("this kind of process"). We're talking about much, much, much lower temps than -40.


headlamp bulbs in Alaska or Nunavut where they instantaneously ignite them several hundreds of times over the period of a winter

Minor nitpick: halogen bulbs don't 'ignite'.
 

Alaric Darconville

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The bulbs should be able to withstand below -40F...
Not -40F (or -40C, which is the same temperature). -300F (-196C.) About 77K. 0K is absolute zero, water freezes at 0C (273.15K), boils at 100C (373.15K), so 77K is *COLD*.

I have not yet heard of a need of special cold resistant headlamp bulbs in Alaska or Nunavut
Could it be because -40C isn't particularly cold as far as a headlamp bulb is concerned?
 
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night.hoodie

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I always assumed the reason for instaflash is a cold filiment self-destructing because of the fast temperature change to "on," whatever high temp that may be, and "cold" could be an ambient temperature of 85°F (been there, done that). IOW, I thought there was a temperature shock that damaged the filiment, breaking the circuit.

Now I'm not so sure why a lamp would instaflash. Though I have seen this instaflash phenomenon enough times, it has never been a brand new unused lamp (though heard reports this happens, too), so perhaps most flashes I experienced were just lamps at the end of their working life. Also I have never seen it occur if the bulb was very recently being used., but only with a light that sat unused many hours, and it seemed more often to occur with a fresh Li-ion cell. Also considered the cause may be high voltage/high amp shock.

So any can see why I made these assumptions: it's just from my personal experience, which is only a couple few years running incan.

Why does a bulb flash? I know it probably must do with the filiment, but every flashed lamp I have examined, the filiment appears intact (though I am half-blind, and the smaller something is, the less I see it).

So it seems easy enough to make these kinds of assumptions... but now I think maybe they're all wrong, its nothing to do with temperature, and there is something more subtle occuring causing the lamp to flash and die.
 
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-Virgil-

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It's because an unlit ("cold" in filament terms, not necessarily in human terms) filament has very low resistance, so the inrush current is very high, so once the weakest point in the filament gets weak enough that it can't carry that current (filaments develop thin spots and notches and pits with prolonged operation)...that's when it fails. The flash is the arc of electricity between the newly-broken ends of the filament.
 

night.hoodie

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That sounds perfectly reasonable, and I bet anything that could be the case a lot of the time, perhaps most of the time.

googling, I found evidence (of more detailed explanations) that the reasons a filament fails could be myriad... could be one or any number of reasons together... it is complex.

scientists said:
The behaviour of doped tungsten filaments is discussed with particular reference to the life-controlling processes in incandescent lamps. Since lamp failure is a complex phenomenon depending on many conditions, it appears that there is no single mechanism of universal validity by which the finite life of the tungsten filaments can be explained satisfactorily in all cases. It is suggested that, in addition to the nonuniform evaporation of the filament owing to local defects, other mechanisms, like migration and growth of the potassium-filled bubbles within the wire, and grain-boundary sliding promoted by unfavourable grain shape, may also contribute to the failure of incandescent lamps. Presumably, on the basis of a better understanding of the doping effect and failure mechanisms, further improvements can be achieved in lamp quality by optimisation of bubble dispersion, grain structure and other life-influencing parameters.
source: https://ieeexplore.ieee.org/document/4644578


Elsewhere, apparently EC&M magazine Oct. 1997 issue does a lot of explaining the reasons why, likely including, but also unrelated reasons beyond your explanation. If only I could find a digital edition to read the Q&A I found only referred to in a more recent online edition. I can't seem to get back that far on the mother site.
 
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mattheww50

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I always assumed the reason for instaflash is a cold filiment self
There are in fact a couple of issues involved. When cold, the resistance of the filament is shockingly low, if the supply voltage has a low enough impedance, you would probably be shocked at the instantaneous wattage involved (it isn't all that difficult to get to 100kw). At room temperature the resistance is actually quite close to a dead short, you don't need much a positive temperature coefficient when the operating temperature is almost 3000 degrees higher than room temperature to produce substantial resistance at operating temperature!. The other issue is perhaps a bit more interesting. Because of the way filaments are made (they are wound), they actually have a small inductive component,which typically holds down the cold inrush current a little (not much), the bind is that in some circumstances, it has the opposite effect. It depends upon the exact point in the cycle of an AC wave form where the switch is closed. In electronics this problem is often addressed by using an electronic device that only allow the current to start flowing at a zero crossing of the wave form. When I was a University Student, in the lab we had overhead 200 amp circuit breakers whose main function was safety, they were spec'd to open within 8 ms at 110% of rated load. That made them pretty exotic. The bad news was it was surprising just how often they tripped with loads that were under normal circumstances rarely exceeded 5 amps. I happened a lot when the load was a 700 watt Variac transformer.
 
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alpg88

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not sure how it is usable in cars, but soft start can be done easy with inrush current limiter, very cheap part, i use it with 1185 bulb, and 90w bi pin driven at 200w, better question is why bother, if car designers did not put one, it is not needed, if you do not alter anything. just use correct bulbs and they wont flash. messing with electrical system in a car can backfire, especially in newer cars.
 
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