# hours of life for incandescent flashlight bulbs



## inluxication (Apr 5, 2004)

How long do incandescent flashlight bulbs last?

I have the impression that with AA M*gs, the bulbs don't burn out for a long time, but they go weaker and yellower in something on the order of 10 hours, i.e., after one or two sets of batteries. I wasn't scientific about this observation, so correct me if I'm off base.

I have no experience at all (yet!) of the brighter incandescents -- Pelican M6, Streamlight Stinger, Surefire G2 with P60 or P61 bulb, Princeton Tec Surge, Dorcy Spyder, etcetera. Will a bulb in these last for hours, or tens of hours? Hundreds? Will it fail by going dim, or burning out, or the one shortly before the other? Is it relatively constant across flashlights, or do you get longer life with higher quality gear (or shorter life with higher output)? Are there lists or charts of bulb lifetimes for "common" flashlights (common by CPF standards anyway)?

Forgive the newbie question -- I'm decently up on my LEDs, but I'm totally ignorant about this oldfangled incandescent stuff. A quick search here didn't turn up anything promising, and while Surefire and Flashlightreviews and so on talk about battery run time, I haven't seen anything on bulb life. (And at SF's bulb prices, it seems like a reasonable thing to want to know!)

Thanks.


----------



## analogguy (Apr 5, 2004)

The service lives of the bright incands bulbs are on the short end of the spectrum. The official run time for the Dorcy Spyder is 2 hours. The Streamlight Scorpion is about 5 hours. Surefire P60 module is 25 hours. The Pelican M6 is rated for 75 hours+. This is not to say that the bulb(s) you get in your flashlight won't last longer than advertised. Just don't fool yourself into thinking that the bulbs will last that long. Short service lives of the bulbs and batteries is the cost of admission for brightness.


----------



## inluxication (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

Analogguy,

Thanks for the numbers; that's really helpful. You said "official": where does one find such info? What are the numbers on the 2AA Mag?

Now I'm feeling annoyed with myself for having just ordered a Scorpion (5 hours you say, and about $4 per bulb, I found) rather than an M6 (75+ hours, $8 per bulb). (I'm less rueful about the 25-hour, $17 Surefire modules.) Can you cheer me up? Some other virtue of the Scorpion, besides being slightly smaller, slightly lighter-weight, and slightly cheaper?

Why the huge variation in run times? And what happens as the time comes: deteriorating beam, or poof?

-Greg


----------



## JohnK (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

Well, I've used several Scorpions for YEARS, through untold battery changes, and have YET to burn out a bulb. 

I don't believe I've heard (on this forum) about a short life of the Streamlight bulbs.


----------



## js (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

inluxication,

Do a search for SL scorpion bulbs/lamps, and you will find at least one thread on the subject. General consensus: the lamps last much longer than 5 hours. I'm not sure why SL is so conservative on this one.

Here's a general rule of thumb: for the highest output for a given power for a halogen incandescent the rated life of the lamp is on the order of 10-30 hours, and just off that peak the lifetime jumps to 50+ hours. Sacrifice just a little more lumens/watt and you can get hundreds and even thousands of hours. Many good incandescent lights have lamps that will last a long time, guaranteed. I am thinking mainly of the TigerLight lamp assembly and the Stream Light SL-20X and SL-35X, all of which are guaranteed for 6 months.

As for what happens at the end of life, it depends on power, I suspect. Low power halogens get tungstun deposition on the inside of the glass and go dim (such as Mini-Mag). High power halogens are more likely to burn up or go poof, especially if overdriven, although my first TL LA went dim, while showing scorching marks near the base. (TL offered to replace it under warranty, even though I wasn't the original owner of the light. Great company, TL.)

We should really get Ginseng's opinion on this, as he has a lot of experience with halogen incandescent lights. And also Chamenos and Size15s and many others will have a more informed opinion than I can offer. But, FWIW, this is what I have found so far.


----------



## jayflash (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

Let me reiterate what JohnK and js said: StreamLight's official lamp life seems to be very conservative. I think they want users to be prepared because even a new lamp can pop. Some seem to last forever and others don't. I've had my Scorp for almost a year and five battery changes on the original lamp.

If it's any consolation, I'd buy another Scorpion IMMEDIATELY if mine was lost or damaged beyond repair. I like almost everything about that light. Others prefer the TL-2 with the twist-on switch and lack of rubber armoring. I prefer the switch action of the Scorp and that the rubber keeps it securely in my pocket. I've lost other, smooth, lights from my pockets.

BTW if the lamp comes loose into the head it's easy to retrieve with a tweezers, hemostat or micro-needlenose. Tip the head so the opening is down and grab one of the bi-pins. I spread out the leads on all my bi-pin lights to prevent them from coming out when dropped.


----------



## inluxication (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

jayflash: I was initially impressed by your year and 5 battery changes on one bulb, until I realized that at 1 hour per set of batteries that's still only the 5-hour life analogguy stated!

js: I still don't find a thread with much on bulb lifetimes. I'll keep searching, another time. There is this one on Surefire lamps (at that price they must be lamps, not bulbs):
click here for the link

One posting gives the useful tip that running bulbs on dead batteries kills the bulbs fast. If that's true, it would explain my latest Mag experience: I had set up some time-lapse movies of a AA Mag, an Inretech LED conversion, and a Starlite LED. Of course the incandescent's batteries died first, and its bulb ran in infrared mode for many hours after. I was surprised at how yellow this new bulb had turned, but maybe IR is bad news.

I had read somewhere about long-life household bulbs essentially being higher-voltage ones run at lower voltage -- much the same as what you said about flashlight bulbs. In the household case, it went on to say that the bulbs are more efficient when run hotter, and long-life bulbs' extra electricity cost outweighs the savings in bulb replacement (if not the convenience). And efficiency is a lot more important for battery-powered flashlights.

Thanks for the low-power / high-power failure info; interesting.

js and jayflash both talk about SL's conservative bulb ratings, but again, where is this official info?

Thanks all of you... keep the info coming...

-Greg


----------



## inluxication (Apr 6, 2004)

*Re: hours of life for incandescent flashlight bulb*

Why oh why do some forums show up for me with reasonable, wrapped lines, while others (like this one, now) have unreadably long lines? Why do some allow me to edit my posts and others not?


----------



## Double_A (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

I'm not sure if I understand why this is such an important issue to so many people. It comes up often for discussion.

My experience is that I've never had a problem with ANY flashlight burning out it's lamps at what I considered an excessive rate. Matter of fact only my Minimags ever needed more than one replacement in all the years I used them. I dunno, I use flashligths daily but, I guess I treat them better than most people? But even my 12yr old 9P which I've dropped a few times over the years still has it's original bulb.

GregR


----------



## inluxication (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

Double_A,

It appeared to me that my Minimag bulbs, while none has ever burned out, seem to yellow quickly. I imagined that with higher-powered flashlights, the bulbs _might_ go very quickly, and with Surefire lamps at $17 or more a piece, bulb life seemed to be an important issue. If the general experience is that bulbs last "a pretty long time", then it's much less important.

Still, if indeed a Scorpion bulb lasts 5 hours and an M6 one 75, had I known this I might have chosen the Pelican instead of the Streamlight -- mostly for the reassurance that it won't burn out during a night hike or some other relatively protacted use. 

Also, coming from the world of 50,000-hour LEDs, this was simply an obvious thing to wonder about. I appreciate all the good information you "incan" guys are giving.

-Greg

PS: The question might come up less often for discussion if the answer were easier to find! For instance in a FAQ here, or in flashlightreviews.com.


----------



## jayflash (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

For security or necessity it's always recommended to have at least two good lights. "Two = one & one = none" is often quoted on this fourm. I've had two lights fail and was glad that I had a third one. Granted, that doesn't happen often but if you're going to rely on a light for safety, then take two plus extra batteries and lamps for incan lights.

Keep in mind that LED's and their circuits can fail, batteries will leak, and switches can break. A blown incandescent lamp may not be much of a problem with lights that contain a spare inside, like the Scorpion. Of course it will help to have a backup light along to see well enough to change a blown bulb.


----------



## Quickbeam (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

"For instance in a FAQ here, or in flashlightreviews.com."

Fuggedaboutit! I'm not posting any kind of comprehensive table about incandescent bulb life on my site. They're so unpredictable in reliability, the first time someone saw "25 hour bulb life" for a SF assembly and it popped on them I'd get a nastygram about how "I bought this POS because of your review and the bulb blew after using it twice..." etc. etc. etc.

They last as long as they last and that's about it. Always have a spare handy.


----------



## inluxication (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

Quickbeam,

Aw, c'mon, not even if I beg? cajole? plead? flutter my eyleashes seductively? /ubbthreads/images/graemlins/wink.gif What about flattery?

Your site is probably the most useful single resource for choosing a flashlight. (Really.) You include "advertised" battery lifetimes, even when they're as unrealistic as they tend to be for unregulated LED lights. So never mind a table, but what about including the manufacturer's own lamp claims in the individual lights' reviews?

In the same way that you refer people to your milkbox lumen-meter, you could refer them to a small tutorial on the nature of probability distibutions, the memoryless exponential model for bulb life (or we can skip that part) and the fact that rated lifetimes are simply expectations, and any single bulb may last longer or less long. And if people gripe? So?

I live in hope.
-Greg


----------



## Emilion (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

More than 6 hours of light from my SL NF2's original blub, and still working fine~

More than 50 hours of light from the PT Yukon Xenon, still looking good.


----------



## inluxication (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

I'm impressed. Thanks for the info.


----------



## jbrett14 (Apr 7, 2004)

*Re: hours of life for incandescent flashlight bulb*

Well, I too have been guilty of putting great emphasis on the lifetime of LEDs vs. incans. For the past year and up until a couple weeks ago, I have been on the LED kick. Even though I love these LED lights, I have always felt like I was being shorted on brightness for outdoor use. After reading through this forum and becoming a bit more comfortable with the idea of using incan lights, and now after owning a couple, I have come to realize that if you want brightness, you must go with incans. It's kind of like buying a car. If you want a higher performance car, you're going to sacrifice MPG. You can't have both. For those who prefer brightness, or performance in that car, the sacrifice becomes irrelevant. I want bright light and as of now incans and incans only can provide that kind of light in a small sized flashlight. LEDs have certainly gotten brighter, but still don't compare to the incans. These guys here who support incan lights make very good points. If you are truly engaged in an activity that requires the dependency of a flashlight, you are certainly going to be carrying more than one light anyway, along with spare bulbs. The whole idea of a flashlight is to create light, and in most circumstances, especially outdoor activities, the brighter the better. This is why I have recently gone back to incans for outdoor use. However, I do find my LEDs, especially headlamp, very useful at work, where runtime of batteries becomes more important. We all, including myself at times, tend to get caught up in the awesome specs of LEDs, on paper, and lose focus on how the actual light will be used. My guess is that very few of us actually use our lights outdoors for more than 15 minutes at a time anyway, but yet we go to great lengths to acquire that light that has a runtime of a billion hours. Please note: I am mainly talking about lights for outdoor use and not lights that one would need for indoor work or close-up work such as electrical or plumbing work, etc.


----------



## Double_A (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

[ QUOTE ]
*inluxication said:*
Double_A,

It appeared to me that my Minimag bulbs, while none has ever burned out, seem to yellow quickly. I imagined that with higher-powered flashlights, the bulbs _might_ go very quickly, and with Surefire lamps at $17 or more a piece, bulb life seemed to be an important issue. If the general experience is that bulbs last "a pretty long time", then it's much less important.

Still, if indeed a Scorpion bulb lasts 5 hours and an M6 one 75, had I known this I might have chosen the Pelican instead of the Streamlight -- mostly for the reassurance that it won't burn out during a night hike or some other relatively protacted use. 

Also, coming from the world of 50,000-hour LEDs, this was simply an obvious thing to wonder about. I appreciate all the good information you "incan" guys are giving.

-Greg

PS: The question might come up less often for discussion if the answer were easier to find! For instance in a FAQ here, or in flashlightreviews.com. 

[/ QUOTE ]


I've wanted a FAQ for a long time. I see your point and I guess I have to admit that I too a long time ago was worried about the MTFB for lamps. 

I have a spare for each of my Surefires and over the nearly 14 or 15 years since I bought my 6P, lamp life has never been a problem. I have replaced only two lamps in over 10 Surefires in all that time. The first time was soon after I sold my 4 or 5yr old 6P to a co-worker for $20, he came back two weeks later and complained the lamp went out. I gave him the spare I had for it. The only other Surefire lamp I had go out was in my brand new M6 in the first 10 minutes of usage. Surefire sent me three to replace the dead one.

That is it, in nearly 15 years. I use some of those lights daily others weekly and others maybe once or twice a month. 

Oh yea I almost forgot. I convinced my company to get E2e's for 10 of our Emergency Response Team members. We've had 5 in use for 16 months now and another 5 in use for gosh maybe about 6 months. All being used and carried 3 or 4 days a week by each of us. No dead lamps.

GregR


----------



## inluxication (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

Basically, 0 failures except for occasional bad new bulbs (as others have reported too) and under, well, questionable circumstances. Very impressive indeed.


----------



## snakebite (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

keep in mind that the rated life is at a specified voltage.
for a short time with fresh batts you are overdriving it.
after the batts wear a bit you are below spec.
so it is hard to tell how long a bulb will last even with a rated life in hours.


----------



## Doug Owen (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

[ QUOTE ]
*js said:*
Here's a general rule of thumb: for the highest output for a given power for a halogen incandescent the rated life of the lamp is on the order of 10-30 hours, and just off that peak the lifetime jumps to 50+ hours. Sacrifice just a little more lumens/watt and you can get hundreds and even thousands of hours. 

[/ QUOTE ]

While the first part *might* be true, the second definitely is not.

Bulbs die because the filament evaporates. Bulb lifetime is *not* how long until it burns out, it's 'how long it takes XX% of the mass of the filament to evaporate'. You can sometimes see this inside old clear bulbs as dark or shiny deposits, more often near the base (and therefore the source, the hot filament). This is, in fact, one of the reasons normal bulbs are frosted. So the standard doesn't involve dead bulbs, but live ones run for a while until the average filament looses the 'fatal' mass. In general, the hotter the filament, the faster the evaporation, the shorter the life.

Now comes halogens to change the rules. This is a special gas, not a vacuum. This means more heat loss, so right off we need more power, lumens/watt goes down. But if we go higher still, as the temperature goes up (and with it light output) the temperature of the gas goes up with it. Evaporation is going up as well, of course. However the *hot* gas has the ability to cause a chemical reaction that can reattach the Tungsten gas atom *back on the hot filament*, rather than letting it condense out on the colder surfaces. Neat part is where the filament is hottest (it's weakest point) this action is highest, to a first order it becomes self healing.

Under drive a halogen and you revert to 'normal' lifetimes for incandescent bulbs (even lower, actually), and the efficiency (in lumens/watt) goes way down, much lower than 'standard' bulbs at the same levels. At these levels, these bulbs are clear losers.

The 'magic' chemical reaction no longer happens.

Likewise, running batteries flat on such bulbs is probably a bad idea WRT bulb life. While I can't cite such data, I bet that you can kill one faster by under driving it the 'right' amount. For sure doing so, takes lots of useful lifetime off the bulb.

Doug Owen


----------



## Double_A (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

I prefer Lithium batteries for a number of reasons, one being their flat discharge curve compared to standard alkaline AA, C, D cells. The discharge curve of those greatly increases the probiblity you will be powering a lamp cooler, for longer than may be optimal for a halogen lamp's lifespan.

Get an LED light to suck the last juice out of batteries, doing that with the incandescent will shorten your expensive halogen lamps lifespan.

I always try to remember the lamp "is" your flashlight, everything else is just there to help it do it's job. In my book demanding inexpensive lamps in an expensive flashlight doesn't make sense.


GregR


----------



## gwbaltzell (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

As stated elsewhere tungsten "boils" off the filament. This is at its worst in a vacuum bulb. The invention of the high vacuum pump is what allowed Edison to "invent" the incandescent lamp. I'm sure he was well aware that it was a race to who would be first. Most larger household bulbs today have either nitrogen or argon gas added back in to *reduce* this. Argon is one of the "noble" gases found in the rightmost column of the periodic chart below argon are two other noble gases krypton and xenon. When added back to a bulb these reduce boil off even more. Xenon being the best. Radon would be better but its radioactive and also has a short half life. Do not confuse a incandescent bulb with xenon with a xenon short arc lamp. Household bulbs are frosted inside to reduce glare (excessive contrast), small bulbs either for that reason or to eliminate the filament image and provide a more even light with a reflector. Less light makes it though a frosted envelope.

Just to the left of the noble gases on the chart are the halogens. I believe only two are actually used: iodine and bromine. I think iodine was the first used. The advantage here is that a certain temperature the halogen will combine with tungstun at a much higher temperature the tungsten is released. Fused quartz was the only thing originally that would work with the higher temperature and pressure needed to operate this cycle of the halogen combining on the surface of the quartz envelope and then being redeposited on the filament. There is no guarantee of the tungsten getting back where it is needed which is why these fail. Some newer lamps run with a special glass, a plastic coating and at a lower pressure. Only these are safe to operate without an extra safety glass that should also be made to absorb UV that passes through quartz. Some hologen makers say its OK to dim them but if any blackening occurs a full bightness cleaning cycle must be run. Some dimmers do this automatically.

The main trade off with incandescents is brightness and efficiency against long life. I use some 10 W 110V bulbs in a post light that have an indefinite life rating. They are about as bright as a regular 4 W. Replacement usually comes after about 6 years because of the darkening of the envelope (vacuum bulbs) or if I bump the post.

If you're wondering were tungsten is on the periodic table, look at the metallic group #74 W for wolfram.

George


----------



## Double_A (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

wolfram - that was the single question I got wrong on my Jr. High school test on the Periodic Table. Now at work everytime I walk past the gas cabinet labeled WF6 (tungsten hexafluoride) I smile and think about that test.

GregR

sorry to get off topic here


----------



## js (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

[ QUOTE ]
*Doug Owen said:*
[ QUOTE ]
*js said:*
Here's a general rule of thumb: for the highest output for a given power for a halogen incandescent the rated life of the lamp is on the order of 10-30 hours, and just off that peak the lifetime jumps to 50+ hours. Sacrifice just a little more lumens/watt and you can get hundreds and even thousands of hours. 

[/ QUOTE ]

While the first part *might* be true, the second definitely is not.

Bulbs die because the filament evaporates. Bulb lifetime is *not* how long until it burns out, it's 'how long it takes XX% of the mass of the filament to evaporate'. You can sometimes see this inside old clear bulbs as dark or shiny deposits, more often near the base (and therefore the source, the hot filament). This is, in fact, one of the reasons normal bulbs are frosted. So the standard doesn't involve dead bulbs, but live ones run for a while until the average filament looses the 'fatal' mass. In general, the hotter the filament, the faster the evaporation, the shorter the life.

Now comes halogens to change the rules. This is a special gas, not a vacuum. This means more heat loss, so right off we need more power, lumens/watt goes down. But if we go higher still, as the temperature goes up (and with it light output) the temperature of the gas goes up with it. Evaporation is going up as well, of course. However the *hot* gas has the ability to cause a chemical reaction that can reattach the Tungsten gas atom *back on the hot filament*, rather than letting it condense out on the colder surfaces. Neat part is where the filament is hottest (it's weakest point) this action is highest, to a first order it becomes self healing.

Under drive a halogen and you revert to 'normal' lifetimes for incandescent bulbs (even lower, actually), and the efficiency (in lumens/watt) goes way down, much lower than 'standard' bulbs at the same levels. At these levels, these bulbs are clear losers.

The 'magic' chemical reaction no longer happens.

Likewise, running batteries flat on such bulbs is probably a bad idea WRT bulb life. While I can't cite such data, I bet that you can kill one faster by under driving it the 'right' amount. For sure doing so, takes lots of useful lifetime off the bulb.

Doug Owen 

[/ QUOTE ]

Doug,

Great info. Thanks. I did know about tungsten redeposition to the filament; and I also know that you do NOT want to underdrive a halogen lamp too far. I was mainly speaking about underdrive and overdrive within the reasonable range or +/- 20 percent max. Here is the Wlech Allyn re-rating formula for lamp lifetime:

Lr = (Vd/Va)^12 * Ld.

where

Lr = re-rated life time
Ld = design life time
Vd = design voltage
Va = applied voltage

So you can see that the lifetime goes as the *12th power* of the ratio of design to applied voltage! So underdriving a 50 hour lamp by 20 percent means that ratio is 1.25^12 = 14.55 * 50 = 727 hours. I have seen WA lamps underdriven by this amount and they are still not in the dangerous, deposit-tungsten-on-the-inside-of-the-glass range. Not that I saw during the time used, anyway.
Now, overdrive a 50 hour lamp by the same amount and you get .112 * 50 = 5.6 hours.

See what I mean? Quite a difference. Two orders of magnitude. Of course, the re-rating formulas are only approximate, but still. I think my statement still has some truth to it, in the sense that the lifetime is HIGHLY non-linear with over or under voltage.

What do you think? Am I missing something?


----------



## gwbaltzell (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

[ QUOTE ]
*Double_A said:*
wolfram - that was the single question I got wrong on my Jr. High school test on the Periodic Table. Now at work everytime I walk past the gas cabinet labeled WF6 (tungsten hexafluoride) I smile and think about that test.

GregR

sorry to get off topic here 

[/ QUOTE ]

LOL

And by knowing that you see this everyday I suspect you work for a chipmaker. Looking at your location I think I'm right!

No, I didn't remember what industry I'd seen this associated with. I just knew I had and looked it up.

One of the few I can remember easily is Pb for lead because I know that lead use to play a major role in Plumbing whose name comes from the same source. Tin, on the other hand, I'm lucky when I remember its Sn.


----------



## pjandyho (Apr 8, 2004)

*Re: hours of life for incandescent flashlight bulb*

Where does HA III belong in the Periodic tables? /ubbthreads/images/graemlins/thinking.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif


----------



## Double_A (Apr 9, 2004)

*Re: hours of life for incandescent flashlight bulb*

Somewhere around Aluminum and oxygen /ubbthreads/images/graemlins/wink.gif

GregR

P.S. - GWB, your guess was right on target


----------



## gwbaltzell (Apr 9, 2004)

*Re: hours of life for incandescent flashlight bulb*

/ubbthreads/images/graemlins/hahaha.gif[ QUOTE ]
*Double_A said:*
Somewhere around Aluminum and oxygen /ubbthreads/images/graemlins/wink.gif

GregR



[/ QUOTE ]


----------



## gwbaltzell (Apr 11, 2004)

*Re: hours of life for incandescent flashlight bulb*

Don's Bulbs has a print it yourself slide rule for rerating line voltage bulbs.


----------



## turbodog (Apr 11, 2004)

*Re: hours of life for incandescent flashlight bulb*

I am in the minority. I am a heavy outdoor light user. It's typical for me to regularly run through 2 2-hour packs in my magcharger. I have had 2 bulbs blow in it in 2 years; my guess is that both were due to dropping on a concrete floor and being thrown onto a concrete floor quite forcibly.

I bought a boatload of used stingers once from a cop. Some had good batteries (high voltage, good runtime), and some had lower voltage packs. The high voltage ones had clean, bright bulbs... low packs had black bulbs. My personal stinger is about 2 years old and still on the original bulb.

I had a princeton tech surge that I ran on nimh instead of the recommended alkalines. The bulb blackened and blew after about 20 packs. Looks like the low voltage killed it, but I would like to hear from some other surge users.

What, you mean you guys can't recite the periodic table from memory... with atomic masses also (down to 3 decimal places)?


----------



## jbrett14 (Apr 11, 2004)

*Re: hours of life for incandescent flashlight bulb*

I am a new Surge owner and will post after I have used the light a while. By the way, does anyone make a belt pouch for this light???


----------

