# Cold weather and my SF 9P.



## jehu (Oct 24, 2008)

First off i'm new here, and love these forums.
My question is this, I am an avid snowmobiler and ride in temps as low as
-12 deg F.
I have an SF 9P with Lumens Factory EO-9 lamps (380 lumens),
will the lamps hold up to being stored in my windshield bag and then
being turned on for normal use.
Or will they pop (instaflash) from the shock of huge temp swings.
Any info or experience will be appreciated.
Thanks, Jim.


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## Fusion_m8 (Oct 24, 2008)

I would stick to the standard P90 bulb and/or use an LED drop in(as backup) for such extreme outdoor conditions.

Lumens Factory lamps are high quality lamps that are as reliable as any other brand, use good cells like AW protected 17500s and you shouldn't have any issues with instantflashing.


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## jehu (Oct 24, 2008)

Thanks Fusion_m8.
I still have the standard P90 that came with the light,
maybe I need to test (sacrifice) that bulb this winter.
I was thinking LED, except for the lost throw that may be a great
cold weather option.
Jim.


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## RobertM (Oct 24, 2008)

I thought that I read on here before that the cooler temperature is not bad on incandescent lamps, but rather, heat would be more of an issue/harmful. Maybe someone else can chime in? I personally would probably stick to primaries rather than rechargeable for the extreme cold also.

Robert


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## Sgt. LED (Oct 24, 2008)

Incans are heat machines, they make plenty of heat and love it. :thumbsup:
LED's hate heat cause it kills them. :sick2:

You are not telling us that you are going out there without back-up bulb assemblies!

I have never had the dramatic temp swing blow a bulb on me but why take the chance, carry a spare.


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## jehu (Oct 24, 2008)

Robert, I use only primaries, your right rechargeables hate the cold
even the Mahas in my camera.

Sarge, I just purchased an SC-1 to carry with me.

Thanks guys.

Jim.


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## Fusion_m8 (Oct 24, 2008)

Yeah, I heard that about Li-ons, but this ski season when I was caught out in a storm, the AW Protected 17500s in my L6 held up with no problems. Just for kicks I even buried the L6 in a pile of snow just to see if the cells or LED would shut down, but all was OK even after 15mins buried in the snow.

However in Melbourne, Australia our coldest winters would not be anywhere near as cold as North America. That night of the storm, the weather bureau recorded an official minimum of -7.8'C, which is nowhere near as cold as it gets in the North American ski resorts.


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## ampdude (Oct 24, 2008)

Yea, that's not very cold. Also, leaving the light on while burying it is going to generate heat, I don't see why either would quit working.

When the light is subjected to extreme cold, like sitting in a vehicle or in your pocket and not in use is when I would worry about the batteries. In extremely cold weather I stick to primaries.


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## ugrey (Oct 26, 2008)

Get an LED drop in. It wont break or burn out, it will last longer on a set of batteries and it will be brighter for longer. Incandescents are obsolete for 2 or 3 battery SureFires unless it is nitrolon or an M3. I am waiting for the KL9 for my M3 and LEDs dont do so great in nitrolon because of the heat. The LED future is here for 6-9 volt SureFires. Jump on board.


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## Guy's Dropper (Oct 26, 2008)

I'd use a powerful LED light. LED lights perform better when it's cold than when it's hot. The main thing limiting high power LEDs is heat. You could probably do some things in cold weather with and LED that you usually would not be able to do.


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## Mdinana (Oct 26, 2008)

That's a great question! I'm in Michigan, and I guess I'll fool around this winter.

Why? Well, I'm spending a month in Alaska in April.... it'll be hard to replace anything if the lights fail


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## Yoda4561 (Oct 28, 2008)

I dunno, I'd seriously think that incans would be more resistant to cold exposure/thermal expansion. Sure LEDs are more efficent in extreme cold, but condensation in electronics, thermal stress, etc could lead to an early demise. I say bring the incan lamp and an LED spare , that way you've got yer bases covered


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## kelmo (Oct 28, 2008)

Cold weather will only add another 100 degrees F in temperature range shift from start to full operating glass envelope temperature. If the lamp is operating at 600 degrees F (I'm guessing) the increase in thermal shock is negligible.


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## Juggernaut (Oct 28, 2008)

This is a good question, I have never seen anything on the operation of LED and Incans in extreme cold. I have once ran my Taskforce with a 18650 in the freezer for over an hour and a half, but I would think that would be a very good low temp light since the battery is isolated from the tube with cardboard and the P4 makes a good amount of heat at that point. When I pulled it out the battery felt room temp while the rest of the light was very cold. Though for ultimate reliability I would use sealed beam bulbs since they worked fine for automotive purposes for many decades in the coldest of tempters with wind blowing on them. So unless you like making some sort of 8x cr123 primary conversion battery “6 volts x 6 ah in one of the old Bigbeams lanterns I don’t think it would be practical :shakehead but it would run easily in -70 F degree weather:twothumbs.


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## ampdude (Oct 28, 2008)

kelmo said:


> Cold weather will only add another 100 degrees F in temperature range shift from start to full operating glass envelope temperature. If the lamp is operating at 600 degrees F (I'm guessing) the increase in thermal shock is negligible.



I think it's more like 1600F, isn't it? Google wasn't much of a help.


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## jehu (Oct 29, 2008)

I think Kelmo and Juggernaut have nailed it.
Especially the part about the headlights in auto usage.
Im probably over-thinking things a bit, I usually do.
Ill let you know how I make out this winter, I hope it's a snowy one.

Guy's Dropper and ugrey I used my Inova X5 last season and it worked flawlessly, but doesn't have the throw I like in the woods, so I got the 9P,
plus I always wanted a Surefire, and now I know what the buzz is all about.

Jim.


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## Team Member (Oct 30, 2008)

I have used my 6P in -25C/-13F with no problem. 

Now I have a C3 and I will take it with me when it´s time for some skiing. Temps down to -35C/-31F is not unusually then....could be interesting to see how it works..


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## electromage (Oct 30, 2008)

Think about it this way.... -12F is 248K (Kelvin) , and 77F (typical "room temp") is 298K. Those filaments operate at about 3,300K (5,480F), so the relatively tiny 50K difference shouldn't affect the life of the lamp at all.

Someone jump in here if I'm wrong...I don't have a degree in thermodynamics or anything, just going from free online info and basic math.


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## ampdude (Oct 30, 2008)

electromage said:


> Think about it this way.... -12F is 248K (Kelvin) , and 77F (typical "room temp") is 298K. Those filaments operate at about 3,300K (5,480F), so the relatively tiny 50K difference shouldn't affect the life of the lamp at all.
> 
> Someone jump in here if I'm wrong...I don't have a degree in thermodynamics or anything, just going from free online info and basic math.



That would be approximate color temperature, but I thought the operating temperature of the filament was lower, like around 1500-2000F. I don't know I could be wrong :candle:


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## electromage (Oct 30, 2008)

Well the color temperature of those lamps is rated at 3,300K. I've also heard that it's about as high of a temperature as incandescents can handle. I also know that the melting point of tungsten is 3,695K. By this logic, I assume that the color temperature is the actual filament temperature. It makes sense to me, but I'd like to hear from someone else on the subject.


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## ampdude (Oct 30, 2008)

electromage said:


> Well the color temperature of those lamps is rated at 3,300K. I've also heard that it's about as high of a temperature as incandescents can handle. I also know that the melting point of tungsten is 3,695K. By this logic, I assume that the color temperature is the actual filament temperature. It makes sense to me, but I'd like to hear from someone else on the subject.



Yea, I've heard differently before, but that makes sense to me as well.


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## ^^Nova^^ (Oct 31, 2008)

I would think the filament wouldn't be very robust if it is only 300 degrees away from it's melting point. :shrug:

Nova


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## Icebreak (Nov 1, 2008)

In extreme cold weather incandescent lights are a stellar application for illumination.

Operating temperatures for halogen lamp filaments is 2000 K to 3300 K (about 3100-5400°F), well below tungsten's melting point of 3695 K (6192°F).

The halogen cycle begins when the filament temp exceeds 4532° F. The cycle can complete when the envelope wall exceeds 752° F. I'm just guessing that others are right and that 9P is running over 5100° F.

Kelvin as a thermal measurement and CCT are related. In the ranges we use for incans they are close. But because the filaments aren't actually black body radiators it's not the same. Like a flourescent lamp listed as 10,000K isn't really running at 17,500° F.

Incandescent lighting has proven to be successful for space missions. The dark side of the moon is less than -250° F. Astronauts sometimes operate in less than -140° F. As is true on earth, for mission critical activities incandescent light is an excellent choice for personal tasks.


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## LuxLuthor (Jan 3, 2009)

Icebreak said:


> In extreme cold weather incandescent lights are a stellar application for illumination.
> 
> Operating temperatures for halogen lamp filaments is 2000 K to 3300 K (about 3100-5400°F), well below tungsten's melting point of 3695 K (6192°F).
> 
> ...



Great information, Ice! It seems battery electrolyte limitations in progressively cold applications is the weak link for most consumers.


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## Kestrel (Jan 3, 2009)

Yoda4561 said:


> I dunno, I'd seriously think that incans would be more resistant to cold exposure/thermal expansion. Sure LEDs are more efficent in extreme cold, but condensation in electronics, thermal stress, etc could lead to an early demise. I say bring the incan lamp and an LED spare , that way you've got yer bases covered


 
I did some research for thermal stress issues in semiconductor modules as part of my undergraduate degree program - the thermal stresses (in this case, the shear stress between the die and the substrate) can be quite severe due the differential thermal expansion between the various materials. I'd go with the others here who figure that thermal differences shouldn't be as problematic with the incandescent system.

All theoretical though. Perhaps the most common failure mechanism might end up being theft, in that case neither will matter.:sick2:


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## kelmo (Jan 7, 2009)

Icebreak said:


> In extreme cold weather incandescent lights are a stellar application for illumination.
> 
> Operating temperatures for halogen lamp filaments is 2000 K to 3300 K (about 3100-5400°F), well below tungsten's melting point of 3695 K (6192°F).
> 
> ...



Bare in mind that the glass envelope temperature has to be sufficiently below its melting point to be structurally sound enough to withstand the outward pressure the lamp gas exerts on the lamp. So I don't think a 35 ºC shift in ambient temperature is a big deal unless there is a structural flaw in the glass itself.

Then again I'm not a structural engineer!


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## scottaw (Jan 7, 2009)

Just another non-science real world testing...I take my L1 skiing with me every time I go out, usually in my camelback, so exposed to whatever temp it is. I've skiied -30F for a good 4 hours at a time, light always fired right up. (I use primaries also)


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## leukos (Jan 7, 2009)

jehu,

If you want a little extra protection for your lamp in cold weather, consider purchasing one of AW's soft start switches for your 9P: http://candlepowerforums.com/vb/showthread.php?t=213751 Also, as others have said, carry a spare lamp and use primaries. There have been failures from the PCB's in protected Li-ions in cold temps (20 F and less). Problems come from bad solder joints that crack when the temp drops below freezing. LED lights that have a circuit board are not immune from this either, though a low drain LED light is probably more ideal given the loss of performance from lithium batteries under extreme cold conditions. I would probably say a direct drive LED light that runs on primaries would be the ideal cold weather light (X5 is not bad), but who am I to argue with NASA? I still prefer my incans no matter the weather conditions.


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## ampdude (Jan 9, 2009)

leukos said:


> jehu,
> 
> If you want a little extra protection for your lamp in cold weather, consider purchasing one of AW's soft start switches for your 9P: http://candlepowerforums.com/vb/showthread.php?t=213751 Also, as others have said, carry a spare lamp and use primaries. There have been failures from the PCB's in protected Li-ions in cold temps (20 F and less). Problems come from bad solder joints that crack when the temp drops below freezing. LED lights that have a circuit board are not immune from this either, though a low drain LED light is probably more ideal given the loss of performance from lithium batteries under extreme cold conditions. I would probably say a direct drive LED light that runs on primaries would be the ideal cold weather light (X5 is not bad), but who am I to argue with NASA? I still prefer my incans no matter the weather conditions.




I think the Surefire MN02 is a great cold weather lamp. MN03 or P60 is not bad either.


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