I was told to NOT use Eneloops..

[NoNotAgain]

FWIW I myself have had issues with a Fenix TK41 (containing 8 Eneloops) tailcap being hard to remove after long term storage, most likely due to gas buildup in the light.

I've been using the TK41 since first released by Fenix. Both the XM-L and XM-L2 versions. They've been fed Eneloops from day one. The only time the Eneloops have been removed is for charging twice a year.

I've never had issue with removal of the tail cap or head. Been using dielectric grease on O-rings and threads. Never got a wig of anything when opening the light, unlike using CR-123 lithium primary batteries.

I wish Fenix had never discontinued this light as it's the perfect light for leaving in a vehicle year round.

 

[Swedpat]

I have only experienced gas releasing once: it was with Duracell 2750mAh used in Fenix E20(the first single output 109lm version). In the early beginning of my flashaholism I taped together 4 E20s to get a for that time very bright 8AA light. It happened in only one of the lights, though.

 

[GoVegan]

Very likely not due to any Eneloop venting. Probably just the fact that threads sometimes get stuck after awhile if not properly greased.

I know venting batteries when I see the signs, these threads are normally perfectly fine and still are.

Either lube the threads, or eat some meat to give you enough strength to twist off the cap.

Really? Is that the smartest suggestion you could come up with?
For all you know, I could be Patrik Baboumian.

I tried to add some intelligent opinions to this thread and you deliberately try to insult and provoke me.

 

[nbp]

@ WITL - Personal insults have no place here. Keep to the topic at hand or do not post. Thank you for your cooperation.

 

[fyrstormer]

I know venting batteries when I see the signs, these threads are normally perfectly fine and still are.

Clearly you don't. First of all, your batteries would never recharge properly again if they outgassed a meaningful amount of their internal chemicals. Second, if outgassing were really to blame, then the problem would disappear as soon as the head (or tail) was unscrewed even a tiny bit. You wouldn't even need to unscrew it far enough to expose the O-ring. As soon as you unscrew the head even a tiny bit, you start enlarging the interior volume of the battery chamber and therefore start decreasing the trapped pressure inside the battery chamber.

If the threads are jammed throughout their length, that is probably a lubrication problem; you need to use a more aggressive lubricant that doesn't get squeezed-out from between the threads when you tighten them firmly.

If the threads are only jammed at the very beginning, that is probably caused by one of two things: 1) The aluminum changed size due to ambient temperature changes (even a tiny increase in temperature can jam threads that were already snug to begin with), or 2) the bare aluminum at the end of the battery tube cold-welded itself ever-so-slightly to the bare aluminum contact on the inside of the head.

 

[HKJ]

To address GoVegan's concern about outgassing causing the threads to get stuck: If outgassing were really to blame, then the problem would disappear as soon as the head (or tail) was unscrewed even a tiny bit. You wouldn't even need to unscrew it far enough to expose the O-ring, because as soon as you unscrew it even a tiny bit, you enlarge the interior volume of the battery chamber and therefore decrease any trapped pressure inside the battery chamber. If the threads are jammed, it's much more likely to be a lubrication problem;

This happens with NiMH and Alkaline, but not very often, I have only experienced it once in a flashlight. I do not know if it has happened during tests, I do not stay around while testing.
With LiIon it has happened during test multiple times, often it may be hard to seen on the battery and do not affect performance (At least not immediately). Some LiIon has a CID that disables the battery when it happens.

 

[fyrstormer]

Alkalines are single-use, so I can accept they would outgas a bit. Though it's equally plausible that the trapped gasses come not from the battery itself, but from chemical reactions between the electrical contacts and battery acid that alkalines leak all over the damn place in every device they are ever used in.

With NiMH...I don't know. Low-discharge NiMH batteries have a layer of deionized water inside them, and I suppose that might be electrolyzed into hydrogen and oxygen and escape when the battery gets hot. But when any rechargeable battery releases any of its contents, it's a sign that the battery has been overheated or abused in some other way, or else it was poorly constructed in the first place. (the second one is unlikely to be a problem for Eneloops, but certainly other brands of rechargeable batteries can be hit-or-miss.) It is an incontrovertible fact of chemistry that a chemical reaction cannot be reversed properly if some of the chemicals escape.

 

[Gauss163]

Clearly you don't. First of all, your batteries would never recharge properly again if they outgassed a meaningful amount of their internal chemicals. [...]

You are apparently making guesses about battery electrochemistry and then claiming that anyone who disagrees with your guess is wrong.

Unless you can point to (reputable) studies that show precise correlation between volume of gas released vs. cell degradation, those guesses aren't worth much (and could pose safety risks).

Like HKJ (and others), I too have encountered Li-ion and NiMh cells that have vented. Some still worked with only minor degradtion. What volume of gas was released is anybody's guess (they were not in airtight enclosures).

If the manufacturer warns not to use a cell in an airtight enclosure then that is presumably because there is some failure mode that can result in large volume of gas expelled (very quickly), i.e. possible explosion risks. It is not wise to attempt to refute experts on safety matters (unless one has hard data to prove them wrong).

 

[Gauss163]

Noteworthy, from ChibiM's ENELOOP technican interview

---

7. "Don't use in airtight devices" some manuals say, what is the worst that ever happened that you know of?

Answered by Belgium employee:If they are severely discharged they will vent a bit of gas due to the chemical reaction, and in case of an airtight devices, this could build up pressure.

33. Once a battery is inserted in a device the wrong way around, and shorts, and gets really hot, how do you know if its damaged…

With an alkaline it is easy when it leaked it is damaged, with an Eneloop it will also be a bad sign when the battery starts leaking, however, it is likely that it could still work. So the best way is to charge and discharge an see how much resting capacity is inside.

 

[Swedpat]

The instruction "Don't use in airtight devices" seems to me very strange. What I know practically every quality flashlight and all in my collection are airtight. :thinking:

 

[MikeSalt]

So, according to a Belgium Eneloops employee, the response is that it 'could' build up pressure if overdischarged. Since most good flashlights have some form of undervolt protection or warning system, I shall be taking my chances. I think the phrase "Your Mileage May Vary" applies here.

Also, the size of an AA cell is about the same as a Bic lighter, so the maximum amount of flammable gas that could be produced is about the same as a lighter. Have you ever thrown a Bic lighter on a fire? The resulting 'pop' is hardly worth writing home to the parents about.

 

[Gauss163]

Also, the size of an AA cell is about the same as a Bic lighter, so the maximum amount of flammable gas that could be produced is about the same as a lighter. Have you ever thrown a Bic lighter on a fire? The resulting 'pop' is hardly worth writing home to the parents about.

That analogy by size doesn't work, e.g. you can find various research papers online showing that Li-ion cells produce a large amount of gas and tremendous pressure when they vent.

 

[fyrstormer]

You are apparently making guesses about battery electrochemistry and then claiming that anyone who disagrees with your guess is wrong.

Unless you can point to (reputable) studies that show precise correlation between volume of gas released vs. cell degradation, those guesses aren't worth much (and could pose safety risks).

Like HKJ (and others), I too have encountered Li-ion and NiMh cells that have vented. Some still worked with only minor degradtion. What volume of gas was released is anybody's guess (they were not in airtight enclosures).

If the manufacturer warns not to use a cell in an airtight enclosure then that is presumably because there is some failure mode that can result in large volume of gas expelled (very quickly), i.e. possible explosion risks. It is not wise to attempt to refute experts on safety matters (unless one has hard data to prove them wrong).

I am not making guesses, at least not of the totally-uninformed variety you are insinuating. What I'm doing is refusing to overestimate the risk of catastrophic failure. This forum attracts people who like to prepare for worst-case scenarios, so it is no surprise that overestimating risk would be a common pathology here.

Read your own post below to see an expert opinion that supports what I've been saying. I've highlighted the important bits to make it easy for you:

Noteworthy, from ChibiM's ENELOOP technican interview

---

7. "Don't use in airtight devices" some manuals say, what is the worst that ever happened that you know of?

Answered by Belgium employee:If they are severely discharged they will vent a bit of gas due to the chemical reaction, and in case of an airtight devices, this could build up pressure.

33. Once a battery is inserted in a device the wrong way around, and shorts, and gets really hot, how do you know if its damaged…

With an alkaline it is easy when it leaked it is damaged, with an Eneloop it will also be a bad sign when the battery starts leaking, however, it is likely that it could still work. So the best way is to charge and discharge an see how much resting capacity is inside.

As the technician himself said, the battery has to be abused before it will vent at all. (or the battery has to be defective in the first place.) And after venting (which is just another name for leaking as applied to gases rather than liquids), the total stored charge is reduced. My assertion is that a battery will never function optimally again after venting any of its internal contents (even if the degradation is tiny and barely noticeable); that is a simple matter of chemistry and mathematics, and the only way to dispute it is to disregard everything humanity has learned about chemistry. But then, there are people in 2018 who insist the earth is flat, so I suppose willful ignorance knows no bounds.

 

[MikeSalt]

That analogy by size doesn't work, e.g. you can find various research papers online showing that Li-ion cells produce a large amount of gas and tremendous pressure when they vent.

An 18650 cell (most common Li-ion) by volume is about 2 times the size of AA by volume, so it would be expected to be more devastating.

 

[Gauss163]

I am not making guesses, at least not of the totally-uninformed variety you are insinuating. What I'm doing is refusing to overestimate the risk of catastrophic failure 9...]

But your "estimates" are in fact guesses, unless you have a PhD in battery electrochemistry and/or you can cite reputable scientific studies that support your claims. The internet is littered with much false information about battery technology, including many false and misleading guesses.

Ditto for the other claims about explosion risks based on cell size comparison.

 

[Kestrel]

I am not making guesses, at least not of the totally-uninformed variety you are insinuating. [...]
I suppose willful ignorance knows no bounds.

After having a prior post in this thread heavily edited by CPF staff so as to remove a lengthy personal attack, writing the above certainly 'ups the ante'.

Everyone, please keep in mind that resorting to the practice of repeatedly hammering on others via the keywords 'you' & 'your', can often degrade a conversation to the point where CPF staff needs to redirect the conversation back to the topic at hand, rather than making the argument personal & going after other members.

 

[MikeSalt]

By the way, anyone that chooses to heed the directions on the packaging, I'm not out to convince otherwise. In fact, I think it is very sensible to heed the warnings. However, I personally judge that a very tiny risk, mitigated by the use of quality flashlights, quality chargers and good battery care, is worth it for the convenience that Eneloops afford. Besides, alkaleaks have the potential to leak and fail at the moment you really need your light, which may (I'm not saying will) outweigh the risks associated with out-gassing.

 

[Kestrel]

By the way, anyone that chooses to heed the directions on the packaging, I'm not out to convince otherwise. In fact, I think it is very sensible to heed the warnings. However, I personally judge that a very tiny risk, mitigated by the use of quality flashlights, quality chargers and good battery care, is worth it for the convenience that Eneloops afford. Besides, alkaleaks have the potential to leak and fail at the moment you really need your light, which may (I'm not saying will) outweigh the risks associated with out-gassing.

And with that excellent summation, I think this is a very good note to end on for the current thread - the behavior of Eneloops is certainly understood enough by most here, so as to weigh their advantages against some of the less-desirable alternatives.

Best regards,