Surefire explosion

[McGizmo]

Morepower,
I follow your logic and also admit that my grasp on electronics at some not to deep of a level fails. But I do recall measuring some cells for voltage as well as with a ZTS which led me to believe that there is a disparity in contribution of those electrons from the individual cells. This was further supported by a number of tests I did on single cell lights where the ambient temp of the cell's environment was altered with obvious impact on runtime (based on ambient thermal conditions). In a series of three batteries for example and say we have 3n electrons/ sec going into the lamp, are you stating that 3n electrons also pass through the three batteries (I follow this far) but that each battery is only providing 1n of those 3n electrons?

I do find your comments comforting in the sense that there is implied a safety in the multi cell system that I was not aware of and that really, this event might be just chocked up to that (fortunately) very rare case of a cell just going bad, on its own, essentially.

 

[MorePower]

Morepower,
I follow your logic and also admit that my grasp on electronics at some not to deep of a level fails. But I do recall measuring some cells for voltage as well as with a ZTS which led me to believe that there is a disparity in contribution of those electrons from the individual cells. This was further supported by a number of tests I did on single cell lights where the ambient temp of the cell's environment was altered with obvious impact on runtime (based on ambient thermal conditions). In a series of three batteries for example and say we have 3n electrons/ sec going into the lamp, are you stating that 3n electrons also pass through the three batteries (I follow this far) but that each battery is only providing 1n of those 3n electrons?

I'm saying that if you have 3n electrons/second going into the lamp, you have 3n electrons/second going through each cell, as long as the cells are in series.

Voltage measurements of CR123A cells do not give a good idea of depth of discharge. Any differences you may have noted are likely due to a few possible causes.

1. Cell temperature can affect voltage, especially in cells close to the end of their capacity.

2. Initial capacity of cells will not be completely equal. It may be the difference between 1350mAh and 1339mAh, for example, but a difference that small can make a large difference in cell voltage near the end of discharge.

3. At higher temperatures, non-reactive components within the cell may break down or oxidize, and this can affect the voltage. To take an example from alkaline cells, at elevated temperatures, the manganese dioxide in the cathode can oxidize graphite and reduce cell conductivity, thus lowering cell voltage. MnO2 and graphite are both present in CR123A cathodes, so while I haven't done any work with respect to that, a similar situation may be taking place.

These are simply some of the possible explanations; there may be other contributing factors as well.

I do find your comments comforting in the sense that there is implied a safety in the multi cell system that I was not aware of and that really, this event might be just chocked up to that (fortunately) very rare case of a cell just going bad, on its own, essentially.

These cells are safe. Accidents can occur, but they are very rare. I have a number of lights that use 2 CR123A cells, and I can honestly say that I have never had a concern about this kind of incident happening to me because it's so very unlikely as long as high quality cells are used.

 

[McGizmo]

I'm saying that if you have 3n electrons/second going into the lamp, you have 3n electrons/second going through each cell, as long as the cells are in series.

.....

Thanks for your follow up and I believe I understand what I kept in the quotation but where I am still confused is the source and contribution of the electron flow as it relates to the individual cells here. Am I allowed to state that the individual cells are contributing these electrons? If not, what, they are providing the potential for the flow of these electrons? The energy to drive these electrons?

Do we agree that the three cells are providing the energy and work here and further that a differential in ambient thermal could result in a differential in efficiency and residual capacity once the circuit is shut down?

 

[LuxLuthor]

Are you sure?

All the SF12BB boxes have warnings about storage and use. That's the old white packaging as well as the current.

I've had SureFires with specific leaflets in the packaging on batteries.

WARNING Where there's light, there's heat. WARNING
An important word of warning...please read
[a whole load of safety warnings and recommendations]
It's so ubiquitous but I'm sure this leaflet in some form as been supplied in every CR123A powered SureFire package I've got.

And I'm sure it's in the manuals...

One of my M6 manuals (Rev. 6 4-1-2000, the first one to hand) states

Note: Use only Duracell DL123A batteries in order to achieve the high output expected from the M6 flashlight. Replace batteries as a set of 6.

And

CAUTION
The SureFire M6 Flashlight is very powerful.... The Flashlight has a Lock out Tail Cap, one revolution of the Tail Cap locks out the switch. Make sure the lamp is OFF before storage to prevent overheating damage to the Flashlight or nearby objects...

And

WARNING
Lithium batteries can explode or cause burns if disassembled, shorted, recharged or exposed to fire or high temperatures.
Please handle with care.

I've not got the most recent packaging to hand (LX2, A2L etc). I'm sure I saw similar leaflets and warnings in the manuals of those...

Al

Al, I am 100% sure. I would be more than happy to scan the M4 & M6 owner handbooks, and side of box, including a still sealed SF12-BB that has the 5-2018 expiration that I got in January of this year.

The entire warning on the back side of battery box says only:

Batteries, if not properly stored or used, may cause property damage or personal injury. If a conductive material (e.g. jewelry, keys or coins) touches exposed terminals, it may complete an electrical circuit causing heat or even fire. To prevent such hazards, you must exercise special care in handling lithium batteries. Store batteries in a cool, dry, and ventilated area, and keep them in original packaging until ready to use. Do not place loose batteries in a pocket, purse or other container containing metal objects, do not store them with other hazardous or combustible materials. Do not disassemble or pucture batters, do not dispose with other waste unless permitted by applicable laws and regulations.

I got my L2 in January 2005, M4 in October 2005 and M6 in 2008. None have any of the warnings that you list. The Owner Handbook of M6 has a likely version print date on the next to the last page:

© SUREFIRE LLC 2001 ALL RIGHTS RESERVED 14150-13/01-1-02

The M4 has

© SUREFIRE LLC 2001 ALL RIGHTS RESERVED 14150-8/2-14-1-1-02

Both back sides of silver covers have 14089-1 in lower right corner. As you know these ship with a full set of batteries.

When I bought the E2D in January 2009 it had an insert "Warning: Read First" insert that starts "Where there is light, there is heat", and in the User Manual Rev A 3-2008, there is a Caution to not be left on unattended, and a Warning under the Battery Replacement section that is more complete than on the SF12-BB box. However this manual also does not explicitly say to always replace with new, fresh batteries.

My main beef is with the batteries, L2, M4, M6 having zero warnings regarding what you quoted. Say the word, and I'll scan and upload images.

Again, why would you expect a consumer should know about, learn about, or have a responsibility to find out and purchase a replacement lockout tailcap that you keep mentioning? SF has responsibility if that is safety/recall upgrade type issue...not the customer.

 

[Mr Happy]

The thing is that the same number of electrons will flow through all 3 cells because they are in series. Ie. you can't discharge the cell in the head of the light more deeply than either of the other cells.

I'm sure we have had this debate before at some length, but I do not agree with the statement above. The same number of electrons can pass through a resistor, yet the resistor doesn't get discharged at all. There are various electrochemical pathways through a cell and not all the current passing through has to pass via the expected discharge reaction. Under varying conditions of temperature and imposed electrical gradient other pathways for the charge carriers are possible that do not involve the same degree of discharge.

The theory of this can be disputed over and over, but the reality is that many people have repeatedly and consistently observed variable discharge of cells in series. Practical evidence is practical evidence.

When I have the time and patience I will do a quantitative experiment to measure this. If I find I cannot measure it with a meter I will admit I am wrong.

 

[McGizmo]

I admit I am in over my head here but lets suppose that instead of a coil of wire in this series circuit, we have four LED dice also in series. Now the same number of electrons, 3n, may flow through all four die in this circuit but that doesn't mean that the power provided by these electrons will be shared equally! By the same logic (could be erorr), I can imagine the three batteries not providing equal amounts of work, power, watts to this system either. You have three people all pushing the same car and they are all moving at the same speed as the car but you have no idea how much power each is providing nor if all three will be able to continue at the contribution of effort they presently are.

The cells may be matched at the start or they may not be. Even if they are matched at the start, they won't stay matched if one is operating under ideal thermal conditions and another isn't. I see no justification that a series circuit restricts components to equal amounts of energy being provided? It has a nice symmetry to it but that doesn't make it so, does it?

 

[LuxLuthor]

The thing is that the same number of electrons will flow through all 3 cells because they are in series. Ie. you can't discharge the cell in the head of the light more deeply than either of the other cells.

I also believe this is not accurate. Despite my being 100% certain that there are different residual voltages of primaries inserted from same batch/box at the same time because I have measured them numerous time with my Fluke 189 DMM, and it repeats in the same pattern time after time. It ignores the difference in electical conductance pathways within individual cells related to the cumulative and changing internal resistances, and heat influences relative to cell position on a stack of serial cells.

 

[tsmith35]

So are Surefire CR123 batteries more dangerous than protected rechargeable li-ion cells such as AW protected RCR123s? Would some type of basic protection circuit integrated or added to the CR123 cells be possible?

 

[Nite]

5 years ago when new to SF lights, I bought a G2. when I used it for long period of time it would heat up and shut off before 60 minutes. Maybe only 40 minutes at a time. I hated that..a sudden shutoff with no dimming as soon as it got hot., Nitrolon is a terrible heat sink.

Turns out the surefire batteries, I only use SF cells, have a thermal shutdown protection circuit that shouldve prevented this incident.

We all agree he had the light on his belt and it MUST HAVE been turned on long enough to get hot enough to fry a cell into a runaway or simply overheat the light to a heat level hot enough to burn your fingers even for a brief moment of contact. +140F Also couldve been cell reversal etc...almost all theories require it being on and getting hot.

why didnt the SF battery shut down when it got hot enough?

Do older battery station cells have that feature? It was suggested one might not have been SF

Yes I have seen this happen in this forum somewhere, a single cell light going into runaway with a single CR123a recently also.

I guess we will never truly know why this happened. we simply know every possible cause.

 

[Size15's]

LuxLuthor,
It is obvious that SureFire has used a variety of user manual styles over the years, with a variety of different approaches. Some more comprehensive than others.
Some of the silver card Owner Handbooks I have do have more detail but the one for an M6 like yours does not. It's got a "Where there's light, there's heat" safety leaflet tucked in it so I assume it was supplied with the M6 also.

I've just had another look for the latest packaging I've got (LX2/A2L/Minimus) - it must be in my office at work. I'll have a dig around when I'm next in.

The current SF12BB packaging warning text is what I'd expect. Perhaps it could go further and state only to replace whole sets and not to mix batteries.

Whatever the inconsistencies of the past SureFire is promoting battery safety now.

Some would argue that having to go to the nth detail is forming part of the reason why things are having to go to the nth detail in a negative feedback loop where the consumer stops thinking for themselves and common sense is anything but common. There is a general feeling on this side of the pond that the US style litigation culture that forces "Warning this coffee is hot!" and "Warning these peanuts may contain traces of nuts and where packaged in a factory that also processes nuts" has much to answer as people become ever more detached from the responsibility for the consequences of their actions.

The fact that it has to be stated to replace batteries in whole sets and not to mix batteries is really rather demoralising. :sigh:

 

[Beamhead]

The fact that it has to be stated to replace batteries in whole sets and not to mix batteries is really rather demoralising. :sigh:

I see this basic warning in the instructions of many lessor advanced items using less volatile batteries/cells.

 

[Mjolnir]

LuxLuthor,
It is obvious that SureFire has used a variety of user manual styles over the years, with a variety of different approaches. Some more comprehensive than others.
Some of the silver card Owner Handbooks I have do have more detail but the one for an M6 like yours does not. It's got a "Where there's light, there's heat" safety leaflet tucked in it so I assume it was supplied with the M6 also.

I've just had another look for the latest packaging I've got (LX2/A2L/Minimus) - it must be in my office at work. I'll have a dig around when I'm next in.

The current SF12BB packaging warning text is what I'd expect. Perhaps it could go further and state only to replace whole sets and not to mix batteries.

Whatever the inconsistencies of the past SureFire is promoting battery safety now.

Some would argue that having to go to the nth detail is forming part of the reason why things are having to go to the nth detail in a negative feedback loop where the consumer stops thinking for themselves and common sense is anything but common. There is a general feeling on this side of the pond that the US style litigation culture that forces "Warning this coffee is hot!" and "Warning these peanuts may contain traces of nuts and where packaged in a factory that also processes nuts" has much to answer as people become ever more detached from the responsibility for the consequences of their actions.

The fact that it has to be stated to replace batteries in whole sets and not to mix batteries is really rather demoralising. :sigh:

The fact is that many people don't understand the basic workings of many of the things that they use. I would bet that most of the people who use headphones have no idea how they work or produce noise. Similarly, it is likely that many people don't really understand even on a basic level how batteries work, or what current and voltage are. Since Surefire is a much more widely known brand than many of the other brands that we, as "knowledgeable flashlight users" use, there are bound to be a fair amount of people using them who know virtually nothing about how the batteries function on a basic level, and therefore know nothing of proper treatment. It probably also doesn't occur to many people that batteries are fairly dangerous if their stored energy is released in a short amount of time; for them batteries are quite little cylinders that do some "fancy science stuff" to power their phone, flashlight, or other device, and that there is actually stored energy inside them.
Given the fact that most anyone can go into a sporting goods store and buy a G2 or 6P, I think that it might be prudent for Surefire to make sure that they are specific with their battery usage instructions. I agree that many times product labeling borders on stating knowledge that is common sense, but how to use batteries safely is probably not common sense for a large number of people.

 

[Bullzeyebill]

Yes, it is distressing that people do not know how to use what they use, and a manufacturer can be sued for any problems that can occur using a given product. What to do? Should each and every battery, or pack of batteries sold have a warning attached, much like prescription medicine we purchase? Warnings that will not be really read by the user? Or are we supposed to be considered educated enough about the world around us to be able to know how to use what we use? Quite a quandary it is. I know that fellow CPF'ers are versed in the uses of all the flashlight products, and accessories, including batteries, and would never blame any one else for the problems that they have with such products: this because there is so much information here on CPF, and if this information is not used, then shame on you.

Bill

 

[LuxLuthor]

LuxLuthor,
It is obvious that SureFire has used a variety of user manual styles over the years, with a variety of different approaches. Some more comprehensive than others.
Some of the silver card Owner Handbooks I have do have more detail but the one for an M6 like yours does not. It's got a "Where there's light, there's heat" safety leaflet tucked in it so I assume it was supplied with the M6 also.

I've just had another look for the latest packaging I've got (LX2/A2L/Minimus) - it must be in my office at work. I'll have a dig around when I'm next in.

The current SF12BB packaging warning text is what I'd expect. Perhaps it could go further and state only to replace whole sets and not to mix batteries.

Whatever the inconsistencies of the past SureFire is promoting battery safety now.

Some would argue that having to go to the nth detail is forming part of the reason why things are having to go to the nth detail in a negative feedback loop where the consumer stops thinking for themselves and common sense is anything but common. There is a general feeling on this side of the pond that the US style litigation culture that forces "Warning this coffee is hot!" and "Warning these peanuts may contain traces of nuts and where packaged in a factory that also processes nuts" has much to answer as people become ever more detached from the responsibility for the consequences of their actions.

The fact that it has to be stated to replace batteries in whole sets and not to mix batteries is really rather demoralising. :sigh:

Al, to some degree we are a victim of being a haven for lawyers, and is a significant detriment to the USA in many ways. Putting that more "Underground Forums" type topic aside, I don't think you are making a fair comparison to the dopey McDonald's Hot Coffee issue, or warning of nuts in packages of nuts--the latter is mandated on all nut containing products without exception, by the Food & Drug Agency after people with peanut allergies died.

Those examples are intuitively common sense based upon common life experiences. Safe guidelines on Lithium battery use are not intuitive, nor common sense, and fly in the face of a long history of battery useage.

Specifically, people are used to using Alkaline and NiMH batteries which do not have the dangers of Lithium cells. There is not the problem with mixing various brands within a light, or combining new with used alkaline or NiMH cells.

So if you are now introducing a new type of battery chemistry, you must go out of your way--especially if it is one that can explode and cause fires--to make it very clear that these cells have very unique and different properties and safety cautions.

It should not be demoralizing to clearly inform people that these types of cells are totally different from what they have been using, and have a new REQUIREMENT to NOT mix various brands or new/used charge status cells of the same brand--because it is not intuitive based upon prior battery chemistry use and knowledge.

Finally, in the example described on the AR15 Forums, the light and batteries are older and as such he did not likely have adequate warnings either. It is not reasonable to expect a consumer to find out on their own that their light has the wrong tailcap. However you cut the mustard, there were not any warnings given to that guy, nor to me when buying the L2, M4, M6--as recently as 2008.

 

[MorePower]

I'll respond to these last few points, and then step out of this thread. I don't know what backgrounds everyone else is coming from and have tried to do a good job of explaining things. I can't prove via the internet what my background is and what I do for a living, but I know what I'm talking about when it comes to primary cells.

I'm sure we have had this debate before at some length, but I do not agree with the statement above. The same number of electrons can pass through a resistor, yet the resistor doesn't get discharged at all. There are various electrochemical pathways through a cell and not all the current passing through has to pass via the expected discharge reaction. Under varying conditions of temperature and imposed electrical gradient other pathways for the charge carriers are possible that do not involve the same degree of discharge.

One atom of lithium gives up one electron. That is the "electrochemical pathway" in this type of cell, ie. the half-cell reaction that occurs.

When I have the time and patience I will do a quantitative experiment to measure this. If I find I cannot measure it with a meter I will admit I am wrong.

I wish you all the best in your endeavor. I hope you have a meter that measures electron flow, as voltage of cells will not give you an accurate measurement of their depth of discharge, nor will it allow you to infer their remaining capacity.

I admit I am in over my head here but lets suppose that instead of a coil of wire in this series circuit, we have four LED dice also in series. Now the same number of electrons, 3n, may flow through all four die in this circuit but that doesn't mean that the power provided by these electrons will be shared equally! By the same logic (could be erorr), I can imagine the three batteries not providing equal amounts of work, power, watts to this system either. You have three people all pushing the same car and they are all moving at the same speed as the car but you have no idea how much power each is providing nor if all three will be able to continue at the contribution of effort they presently are.

Your car analogy would be more akin to 3 cells in parallel, and in that case a different amount of current could flow through each cell.

Cells in series can contribute different amounts of power, and therefore work, to the total, because P=VI, and the voltage (V) of individual cells can vary. However, since current (I) through each cell in series is the same, they each undergo the same number of redox reactions and therefore use up the same amount of active materials. Remaining capacity is determined based on starting capacity and the amount of material that has already reacted.

The cells may be matched at the start or they may not be. Even if they are matched at the start, they won't stay matched if one is operating under ideal thermal conditions and another isn't. I see no justification that a series circuit restricts components to equal amounts of energy being provided? It has a nice symmetry to it but that doesn't make it so, does it?

Since Power=Volts*Amps, and Energy=Power*Time, matched cells could supply different amounts of power and energy when run in series, but this would be be dependent on different voltages of the cells. The total capacity used up in each of them would be the same, however.

I also believe this is not accurate. Despite my being 100% certain that there are different residual voltages of primaries inserted from same batch/box at the same time because I have measured them numerous time with my Fluke 189 DMM, and it repeats in the same pattern time after time.

The OCV of a discharged CR123A cell can not give you a meaningful idea of its remaining capacity. Depth of discharge in a primary cell depends solely on how much active material has reacted, and how much the capacity was at the start.

It ignores the difference in electical conductance pathways within individual cells related to the cumulative and changing internal resistances, and heat influences relative to cell position on a stack of serial cells.

I think you're saying that my statement of equal electron flow through cells in series "ignores the difference in electical conductance pathways" etc? The way cells in series work is that the same number of electrons go through each of them. That's all there is to it. You can have a low voltage cell in the middle, or the top, or the bottom of a stack, and it'll have the same number of electrons going through it as every other cell in the stack.


If anyone would like to discuss these points further, feel free to send me a PM.

 

[Monocrom]

Returning to the possibility that one of the three cells used in the light might have been from Battery Station, it's possible that it could have been an older B.S. battery.

While the new ones are now Made in the U.S., with tighter Q.C., it's very likely that quite a few of the older samples are still floating around.

A modern lock-out tailcap is a good investment. But someone who is not hardcore into lights isn't likely to replace the original tailcap on a 9Z that they have a great deal of confidence in.

 

[Size15's]

A modern lock-out tailcap is a good investment. But someone who is not hardcore into lights isn't likely to replace the original tailcap on a 9Z that they have a great deal of confidence in.

I acknowledge that.
Of course people will find answers if they ask questions.
But the point here is that people don't realise they need/should (etc) ask questions. If what they're doing is what they've always done and nothing changes then nothing changes. Until something changes... :huh:

 

[Monocrom]

But the point here is that people don't realise they need/should (etc) ask questions. If what they're doing is what they've always done and nothing changes then nothing changes. Until something changes... :huh:

Very true.

But we hope that the change is never so "intense."

 

[LuxLuthor]

I'll respond to these last few points, and then step out of this thread. I don't know what backgrounds everyone else is coming from and have tried to do a good job of explaining things. I can't prove via the internet what my background is and what I do for a living, but I know what I'm talking about when it comes to primary cells.

MorePower, I don't think you have to bow out of the thread, nor be coy about working for Rayovac in Madison as a chemical engineer.

Rather than surreptitiously throwing your credentials around as a sine qua non for incontrovertible assertions, since the hallmark of CPF is learning from each other, why not give some authoritative sources to explain what you are saying? 🙂

The OCV of a discharged CR123A cell can not give you a meaningful idea of its remaining capacity. Depth of discharge in a primary cell depends solely on how much active material has reacted, and how much the capacity was at the start.

Yeah, I was more using that kneejerk parameter as it relates to Li-Ion cells. However, I am still asserting that cells reach exhaustion/depletion at different rates in series, until proven otherwise. If it turns out I was wrong, no problem.

I think you're saying that my statement of equal electron flow through cells in series "ignores the difference in electical conductance pathways" etc? The way cells in series work is that the same number of electrons go through each of them. That's all there is to it. You can have a low voltage cell in the middle, or the top, or the bottom of a stack, and it'll have the same number of electrons going through it as every other cell in the stack.

I am sort of saying/questioning that...but I see this as a learning experience to build on what I think I already know, or quite possibly have my sanctum of certainty defiled. Either way, it is a useful exploration.

For example, it seems logical that externally heating a primary cell (i.e. in series--cell closer to the light source) would have an effect on the rate of unproductive chemical reactions within the electrolyte.

I have questions of the effect of heat on the structural distribution and isolation of electrolytic and separator components, as well as possible development of spurious electrical pathways (micro electrical shorts) resulting in direct electron passage from adjacent cells, bypassing some of the "one lithium atom=one electron" chemical reactions.

I don't know exactly at a structural level what is happening when heat lowers internal resistance, and how that is distributed among ohmic, capacitive, inductive resistance, and Warburg impedance within the cell, since this is just a passing hobby for me.

We may all be wrong, but given that electrons follow the path of least resistance from negative to positive, these are certainly relevant questions that seem to correlate with practical observations.

 

[LuxLuthor]

I acknowledge that.

Of course people will find answers if they ask questions.

But the point here is that people don't realise they need/should (etc) ask questions.

If what they're doing is what they've always done and nothing changes then nothing changes. Until something changes... :huh:

That is the heart of my point with you. Additionally, I am also saying that SF (and other companies with products using Lithium cells) does have a responsibility to give at least some simple warnings. I find it shocking that there are not more agressive warnings at least with the batteries that go out more regularly than old lights.

But if what SF is doing is what they've always done and nothing changes, then nothing changes. Until something changes--like a nice little personal injury lawsuit. I'm not singling out SF, but pointing out that consumers don't know what they don't know if they are not informed with a new lithium powered product. My SF L2 was my first experience with a high drain primary Lithium cell. I had no idea, and I read everything. Last time I rented a car, I stood there for 45 minutes reading every paragraph on every page, asking for clarification, before signing.