Decided to Go Unprotected

[Shadowww]

Actually, airbags can increase the risks of certain types of injuries, too ... everything is a balance of benefit versus risk.

But airbags only deploy when there's actual crash, that is, when they're meant to deploy. While protection PCB can short cell out without the need to do so.

 

[DonK]

I agree wih all these potential scenarios, and two layers of protection are better than one BUT in this particular case I feel that the potential downsides of protected cells are not worth the largely redundant upsides.

The worst that can happen is that I lose a $10 cell. I'll take that chance for the benefit of using unprotected (more robust/reliable) unprotected cells.

 

[kwak]

Redundancy is a critical issue in designing safety systems ... "Two is one, and one is none" :thumbsup:

We're glad that cars have both brakes and airbags, right?

Safety engineers look at situations from the perspective of "worst-case scenario" (what must fail for a hazard to occur), not the opposite (if everything works properly and as intended).

That's a pretty poor and inaccurate analogy.
A more accurate one in this case would be having the brake fail safe connected to hold the accelerator open 100%.

It is possible for the protection circuit to fail in a way that it would mean the cell is short circuit.
If that happens the protection circuit is more of a liability than a safety feature.


There is a LOT of scaremongering out there that is often exaggerated by people that have a little bit of info without understanding the whole picture.

The protection circuit will help prevent over and undercharge it will NOT prevent a cell from igniting in 100% of circumstances.

If you have a decent charger and monitor your cells well charging there over charge is not a problem.
Even if it is, the cell is not in the lights and you should be charging outside so worst case scenario is you have a nice fireworks display in your garden.

The Protection circuit also prevents pulling to much voltage out of the cell.
If the light has a low voltage cut-off though this like the charging is not needed.
Should also point out if the low voltage cut-off fails on the light this is not as dangerous as if the protection circuit failed on the cell, the light will just not switch on.

Also worth pointing out that taking the voltage too low is NOT dangerous.
Yes it will ruin the cell, but it's not likely to flare up in your hand.

The other failure point is if the cell has physical damage.
The protection circuit does absolutely NOTHING to protect for that.


So the protection circuit CAN help prevent a flare up in some circumstances.
BUT with the cell physically in the torch (i.e. cells not charging) there are more points of failure WITH a protection circuit than without.


I still use protected cells on my torches that don't have a low voltage cut-off, but i use non protected cells with absolute confidence in my other torches, 1 of which (my SC600) has been with me daily for over a year now.
It's been dropped, banged, dropped into a tub of oil (i use it when working on the car) dropped into our garage sized machines at work, used to retrieve a lost watch in the sea last week at about 5 meters depth etc etc.
All with unprotected cells.


So it really is worth doing some searching and reading on the matter before forming and expressing an opinion.

 

[sidecross]

That's a pretty poor and inaccurate analogy.
A more accurate one in this case would be having the brake fail safe connected to hold the accelerator open 100%.

It is possible for the protection circuit to fail in a way that it would mean the cell is short circuit.
If that happens the protection circuit is more of a liability than a safety feature.


There is a LOT of scaremongering out there that is often exaggerated by people that have a little bit of info without understanding the whole picture.

The protection circuit will help prevent over and undercharge it will NOT prevent a cell from igniting in 100% of circumstances.

If you have a decent charger and monitor your cells well charging there over charge is not a problem.
Even if it is, the cell is not in the lights and you should be charging outside so worst case scenario is you have a nice fireworks display in your garden.

The Protection circuit also prevents pulling to much voltage out of the cell.
If the light has a low voltage cut-off though this like the charging is not needed.
Should also point out if the low voltage cut-off fails on the light this is not as dangerous as if the protection circuit failed on the cell, the light will just not switch on.

Also worth pointing out that taking the voltage too low is NOT dangerous.
Yes it will ruin the cell, but it's not likely to flare up in your hand.

The other failure point is if the cell has physical damage.
The protection circuit does absolutely NOTHING to protect for that.


So the protection circuit CAN help prevent a flare up in some circumstances.
BUT with the cell physically in the torch (i.e. cells not charging) there are more points of failure WITH a protection circuit than without.


I still use protected cells on my torches that don't have a low voltage cut-off, but i use non protected cells with absolute confidence in my other torches, 1 of which (my SC600) has been with me daily for over a year now.
It's been dropped, banged, dropped into a tub of oil (i use it when working on the car) dropped into our garage sized machines at work, used to retrieve a lost watch in the sea last week at about 5 meters depth etc etc.
All with unprotected cells.


So it really is worth doing some searching and reading on the matter before forming and expressing an opinion.

Excellent point of view, I use unnprotected quality cells in most of my one cell lights and protected cells in my two and four cell lights, but even so as you have pointed out knowledge and understanding is the most important thing to have. :thumbsup:

 

[Joe Talmadge]

Too bad that protection PCB on a battery can't be compared to brakes nor airbrakes, because the way cells are protected increase changes of failure in single-cell lights.

Is there anything to back up that claim? I realize there's probably nothing in the way of formal studies, but there is a wealth of anecdotal stories of Li Ion battery events, and exactly zero I've read seem to have the protection circuit as a root cause -- granted, that could be my limited reading. And I do acknowledge the point about protection circuits introducing a thin insulator as the difference between a short and not. That said, you made a strong claim about protection increasing the chances of failure in batteries, and it feels like you just made that up -- there's no real reason to think that's the case. Intuitively, it feels easier for the manufacturer to get the insulating layer on the protection right, than it does for the user to get everything else right.

 

[archimedes]

But airbags only deploy when there's actual crash, that is, when they're meant to deploy....

Not true....

That's a pretty poor and inaccurate analogy....

It was not intended as a perfect and literal analogy, as you probably know.

:sigh:

These safety threads always seem to devolve into a majority trying to convince others (and/or themselves) that added safety features are somehow useless, expensive, and/or increase (?!?) the risks of using Li-Ion batteries, with a minority of others suggesting that protection circuits (as admittedly imperfect as they may be) do overall improve safety and provide a net benefit.

:shrug:

I agree that people should educate themselves, and will obviously make their own choices....

 

[kwak]

Is there anything to back up that claim? I realize there's probably nothing in the way of formal studies, but there is a wealth of anecdotal stories of Li Ion battery events, and exactly zero I've read seem to have the protection circuit as a root cause -- granted, that could be my limited reading. And I do acknowledge the point about protection circuits introducing a thin insulator as the difference between a short and not. That said, you made a strong claim about protection increasing the chances of failure in batteries, and it feels like you just made that up -- there's no real reason to think that's the case. Intuitively, it feels easier for the manufacturer to get the insulating layer on the protection right, than it does for the user to get everything else right.

Just did a quick search here and found this
http://www.candlepowerforums.com/vb/showthread.php?280909-Ultrafire-18650-3000mA-exploded

No doubt more would be found with more searching, but my point was that a protected cell does NOT mean it's 100% safe.
The protection is mainly for the battery not for you.

Not true....



It was not intended as a perfect and literal analogy, as you probably know.

:sigh:

These safety threads always seem to devolve into a majority trying to convince others (and/or themselves) that added safety features are somehow useless, expensive, and/or increase (?!?) the risks of using Li-Ion batteries, with a minority of others suggesting that protection circuits (as admittedly imperfect as they may be) do overall improve safety and provide a net benefit.

:shrug:

I agree that people should educate themselves, and will obviously make their own choices....

I don't agree it has devolved.
IMO this thread is a great platform for someone to read the +'s and -'s of protected and non protected cells and as long as they are a responsible adult make their own mind up.

A protected cell does NOT mean your torch has the luxury of redundancy from a safety viewpoint as you stated.
IF the torch your using has a low voltage cut-off then a protected cell simply has redundancy for under voltage, which is not really a saftey concern till charging time anyways.

 

[Norm]

But airbags only deploy when there's actual crash, that is, when they're meant to deploy. While protection PCB can short cell out without the need to do so.

Search of the web for Inadvertent airbag Deployment.

Norm

 

[HKJ]

The protection is mainly for the battery not for you.

That is closely related, mistreat the battery and you might be damaged when it goes bang.

There is a reason that LiIon cell manufactures always specifies that a protection circuit must be used with their batteries. The cell manufacturer does not make the protection circuit and they sell less batteries when the batteries are protected, but demands protection anyway.

 

[archimedes]

Just did a quick search here and found this
http://www.candlepowerforums.com/vb/showthread.php?280909-Ultrafire-18650-3000mA-exploded

No doubt more would be found with more searching, but my point was that a protected cell does NOT mean it's 100% safe.
The protection is mainly for the battery not for you.

I don't agree it has devolved.
IMO this thread is a great platform for someone to read the +'s and -'s of protected and non protected cells and as long as they are a responsible adult make their own mind up.

A protected cell does NOT mean your torch has the luxury of redundancy from a safety viewpoint as you stated.
IF the torch your using has a low voltage cut-off then a protected cell simply has redundancy for under voltage, which is not really a saftey concern till charging time anyways.

Yes, thank you for that link ... I would like to highlight Post#69 ( down a couple of pages from the OP) -

http://www.candlepowerforums.com/vb...mA-exploded&p=3456132&viewfull=1#post3456132

There were some translation difficulties (from the original German, from another forum), but it was later clarified that this was an unprotected cell.

Hope it's OK to quote that post here (in part)

I now read the complete thread on "messerforum.de" and these UF batteries turned out to have no protection PCB.
His wife already noticed "the light was very dim" so the batteries will have been severely over-discharged.
The cells had been charged a few dozen times, and were 1 year old, who knows how many times the cells had been overdischarged by now??
Then, he charged two of the three batteries overnight(!) in a WF-139 charger (version still unknown) and one cell he charged later, this one was "not hot" when it came out. Hmmmm, it should have been COLD, even the slightest warm-up of a Li-cobalt cell NOT caused by the charger itself should ring all alarm bells :oops:

Coincidence or not, I have two of these cells also.
I noticed from the beginning, that after charging one of them had a slightly higher voltage, and they just could not hold voltage very well under heavy loads (think of incans drawing in excess of 2 Amps).
You could actually SEE it with your bare eyes, my Surefire M6 didn't have as much output as with 2 AW cells...
Not until recently, I knew why this happened... one of the cells is just pure junk! It reaches a capacity of just over 800mAh, while the other one seems sound @ 2400mAh.
I'll ditch the bad one as soon as possible...

Timmo.

The photos in that thread certainly point out the power of these cells, if things go :poof:

 

[Joe Talmadge]

Just did a quick search here and found this
http://www.candlepowerforums.com/vb/showthread.php?280909-Ultrafire-18650-3000mA-exploded

As already pointed out above, the thread you reference turned out to be about unprotected cells. Ironic, right? Although buried in the thread, there was talk of another incident that may have been due to the protection. Still, the point is: I am less concerned about being right in this case, than I am about lowering my risk profile. Someone made a glib claim about the protection circuit increasing risk, and it should be possible to find some evidence on that -- instead, anecdotally, the evidence shows exactly the opposite... so it seems fairer for the claimer to just admit they made that up, or that it's a hypothesis pending a search for some proof. There should be more incidendents that seem to be caused by the protection circuit, than not.

The protection is mainly for the battery not for you.

As it turns out, if the battery is protected from catastrophic failure, that protects me, too. There are multiple ways in which the protection circuit does that, and -- and this point in time, to my knowledge -- it appears the protection circuit is a big win despite a design flaw which appears to be exceedingly low risk (much lower than running an unrprotected cell) in practice

 

[kwak]

Yes, thank you for that link ... I would like to highlight Post#69 ( down a couple of pages from the OP) -

http://www.candlepowerforums.com/vb/showthread.php?280909-Ultrafire-18650-3000mA-exploded&p=3456132&viewfull=1#post3456132

There were some translation difficulties (from the original German, from another forum), but it was later clarified that this was an unprotected cell.

Hope it's OK to quote that post here (in part)



The photos in that thread certainly point out the power of these cells, if things go :poof:

As i say it was just a quick search.
Here's another failed protected cell.
http://www.e-cigarette-forum.com/fo...ures-serious-battery-failure-imr-18650-a.html

Again just the first result from a google search.

As already pointed out above, the thread you reference turned out to be about unprotected cells. Ironic, right? Although buried in the thread, there was talk of another incident that may have been due to the protection. Still, the point is: I am less concerned about being right in this case, than I am about lowering my risk profile. Someone made a glib claim about the protection circuit increasing risk, and it should be possible to find some evidence on that -- instead, anecdotally, the evidence shows exactly the opposite... so it seems fairer for the claimer to just admit they made that up, or that it's a hypothesis pending a search for some proof. There should be more incidendents that seem to be caused by the protection circuit, than not.

:laughing: :laughing: :laughing: :laughing: :laughing:

Please see my above response.

I have absolutely no loyalty to any manufacturer or assembler of anything, certainly not batteries.
If you are an adult then it's completely up to you to read up and carry out your own risk assessment, i'm not here to hold anyones hand, i'm just speaking my opinion from my experiences.

You can choose to use them or disregard them and you will, i'll sleep well tonigh either way :thumbsup:

As it turns out, if the battery is protected from catastrophic failure, that protects me, too. There are multiple ways in which the protection circuit does that, and -- and this point in time, to my knowledge -- it appears the protection circuit is a big win despite a design flaw which appears to be exceedingly low risk (much lower than running an unrprotected cell) in practice

NO battery has protection from catastrophic failure.
In fact i'd go so far to say that nothing in the entire universe has protection from catastrophic failure.
I've seen LiPo's burn down cars and NiMh's literally explode.

The are batteries like LiFe chemistry cells that are inert, but these cells tend to be a lot more bulky and heavier that LiPo cells so only tend to be used in things that live a very hard life like power tools etc.
Even though they are inert i still i wouldn't like to overcharge one just for the kicks.

I would love to have the time to search and post the results of protected cell failures, i'd love to have the time to be able to read through the new posts on this forum, as it is though i'm only able to have quick scans in-between getting the kids their milk ready and getting them off to bed.

As i say i'm not on here to hold anyones hand or badmouth anyones products, i have and use both protected and unprotected cells so have absolutely no axe to grind.

If you are interested and have the time i would strongly recommend you search and read up and make your own mind up.

That fact is though unprotected cells have and will continue to fail to use your term catastrophically.
Protected cells have and will fail catastrophically.
The protection circuit is there to avoid overcharging and under voltage simple as that.

Use a good charger and physically monitor it while charging overcharging is a very very small risk.
Under voltage over absolutely NO risk to the user.
Physically damage the cell and the protection circuit does absolutely NOTHING to stop the cell flaring up.

Make your own call :thumbsup:

 

[Shadowww]

Physically damage the cell and the protection circuit does absolutely NOTHING to stop the cell flaring up.

+1 on that, in fact, certain types of physical damage can make a protected battery :poof: while a unprotected one wouldn't - due to positive and negative being separated by 0.1mm thick tape, which is very easy to get worn through.

 

[archimedes]

As i say it was just a quick search.
Here's another failed protected cell.
http://www.e-cigarette-forum.com/fo...ures-serious-battery-failure-imr-18650-a.html

Again just the first result from a google search....

I hope we can agree to disagree, without being disagreeable ;) ... but you have again linked to a failed unprotected cell, an IMR in this case (which are generally not even available with a protection circuit).

Although I too don't have time to read through every post in that 17-page thread, or attempt endless web searches to find a counter-example, that particular case appears to have been a short across the leads by a metal eyeglass case ... a short that the PCB on a protected cell might have prevented :thinking:

 

[FlashLion]

The driver boards on some flashlights are also not very safe. I like my batteries to have short circuit protection and overheat protection.

 

[kwak]

+1 on that, in fact, certain types of physical damage can make a protected battery :poof: while a unprotected one wouldn't - due to positive and negative being separated by 0.1mm thick tape, which is very easy to get worn through.

Hopefully you'll have better luck putting the point across as it seems that my attempts have fallen on deaf ears so to speak :D

I hope we can agree to disagree, without being disagreeable ;) ... but you have again linked to a failed unprotected cell, an IMR in this case (which are generally not even available with a protection circuit). Although I too don't have time to read through every post in that 17-page thread, or attempt endless web searches to find a counter-example, that particular case appears to have been a short across the leads by a metal eyeglass case ... a short that the PCB on a protected cell might have prevented :thinking:

Absolutely as i said i'm not here to hold any ones hand.
People should make their own risk assessment (after searching and reading up) and whatever they feel will get the job done.
On my TK35 the battery tube is generously sized so i se protected cells.
On my SC600 it's one from the pre-ordered batch so the battery tube is VERY tight on ALL protected cells, so i use unprotected and have been doing since i bough the SC600, so daily use/carry for well over a year without blowing myself up :naughty:

So i'm not saying one is better than the other, they both have their good and bad points.
The only point i'm trying to put across is that protected cells when used together with a quality charger and a quality torch with a low voltage cut-off are no safer than unprotected cells.

I'm not recommending people sell all their protected cells and move over the unprotected, i'm not saying one is better than the other.
I'm just pointing out that the risks are STILL there no matter protected or unprotected and IF parts of a protected cell fail it has the potential to destroy the cell.

To sum up

Protected

+
No voltage cut off needed on the torch
A noggin safer when charging on lower quality chargers

-
Bigger diameter
Longer
More expensive
If certain components fail in could lead to catastrophic failure of the cell


Unprotected

+
Cheaper
Smaller diameter
Shorter
Lighter
Bit of a cheat as it's really as a result of all 3 above, but in my case more mAh yet still fits (1st gen SC600)
No circuitry to go wrong

-
Requires a torch with low voltage cut-off
Require a quality charger


Both Protected and Unprotected

NEEDS to be treated like you would an egg when out of the torch in case of physical damage
NEEDS monitoring when on charge at all times
NEEDS charging outside or in a well ventilated area with nothing flammable anywhere near it
NEEDS storing safely (i keep my cells in a small petty cash tin, in the fireplace when not in use)
WILL dramatically fail if overcharged
WILL dramatically fail if physically damaged

That about clear up my thoughts and advice on the subject.

To anyone that doesn't know me or have read my previous posts i have been using lithium batteries several times a week for around 10 years now in radio controlled craft.
I've bought everything from cheap Chinese cells, expensive American brands, from 1S to 10S (42v charged) configurations, i would guess over the years i have bought easily over 200 batteries in all formats and chemistries that are all commercially available.
I certainly would not say i'm anywhere near an expert or even a well informed amateur compared to many of the various RC forums, but i would say i have a interest in batteries and enjoy reading and experimenting.

 

[Joe Talmadge]

As i say it was just a quick search.
Here's another failed protected cell.

Well, maybe the problem is we're arguing different points. Based on this on your arguments below, you seem to be arguing that protected cells can still fail. I agree -- and no one has made any assertion to the contrary, so I think we're all aligned on this point. Hurray! :) No need to point to examples of protected cells failing, they can.

The point I was arguing is, Shadoww stated outright that the protection circuit increases the chance of failure -- not "doesn't decrease it", not "sometimes there are failures that the protection circuit can't protect against", but that the protection circuit increases the chances of failure, which obviously was just something made up, since no one can find any actual evidence of it. If you agree with that also, then we're all in agreement.

Protected cells can still fail. They seem to fail less often than unprotected, and it definitely seems to be the case that the protection circuit itself isn't a usual cause of failure.

 

[sidecross]

I might point out that in 1905 Albert Einstein in The Special Theory of Relativity showed that time was not an absolute.

Everything has a relativity; even in the field of the 'Sub-Particle' what Einstein called 'spookiness at a distance' or better known as Entaglement has been proven using 'Bell's Theorem' to show that sub-particles can communicate instaniously that is faster than the speed of light.

To paraphrase J. B. S Haldane 'Things are not stranger than you imagine, they are stranger than you can imagine'.

I do not think we can say with 100% certanity that 'protected vs. non-producted has a definitive certainty. ;)

 

[lwknight]

Well put Sidecross!
I still think that people that do not want to be technical will be generally better off with protected cells on average.

There are only a few things left in the world where we can make our own informed decisions about. There are laws to make me wear my seat belt even if I'm not to exceed 5 mph and I hate that but have to live with it or the consequences.

 

[march.brown]

Perhaps people just "feel" safer using protected cells.

None of my torches/drop-ins have any protection built in ... I have used both protected and unprotected cells (Ultrafire) and no longer use Li-Ion cells in multi-cell torches ... The old cells are gradually being replaced by Panasonic 3100mAh protected cells as required ... I have four protected Ultrafire cells left and will be replacing them fairly soon (probably this year) as after charging , the (rested) Voltage sinks from 4.2V to about 4.1V ... I have had the cells a few years now so I don't mind buying another couple of new Panasonics ... I have no objection to using non-protected cells as I am pretty careful about charging/topping up when they get down to about 3.8V ('ish) ... All my torches will accept the additional increase in length of the protection circuit , so this is the reason why I will be standardising on the Panasonic 3100mAh protected cells from now on ... None of the torches are a "tight-fit" for the diameter of protected batteries.

The only device in the house that now uses multi-cell Li-Ions is my Wifes laptop and that is usually kept in the lounge ... When my Wife charges it up , it is always on the wooden kitchen table.

I always charge my batteries on the wooden desk in my study ... My AA & AAA NiMh cells are charged in a C9000 ... My 18650's are charged using my "cheap charger-boards" and I monitor the charging voltage and the cell temperature regularly ... So far , there has been barely any increase in cell temperature when checked on my infra-red thermometer ... During charging , the cells are checked regularly at about 15 minute intervals ... Usually it is more often than this , as I am at the desk using my computer ... I only ever charge one or two cells at a time ... Theoretically , the protection circuits on the Panasonic cells should reduce the risk of charging problems and also reduce the risk of discharge problems when in the torch.

My reason for going with the Panasonic cells is that I feel that they have a better quality control than the far cheaper ****fire (and other) cells available on Ebay ... I can only hope that the protection circuits that are added onto the Panasonics are of the same quality ... Maybe it might be better to go for the unprotected Panasonics since I only use single cell torches ... But maybe the advantages (?) of the protection circuits outweigh the possible disadvantages ... I think that this debate will go on for ever !

In the meantime , I will carry on as usual ... I won't be charging my Li-Ions outside or in a concrete bunker or in a "blow-bag" ... Does anyone charge their phones , camera batteries or laptops this way ? ... If I was really worried about Li-Ions , I wouldn't have a laptop , camera or mobile phone ... After all , we hold our mobiles to our ears and hold our cameras to our eyes ... Our lap-tops are on our laps and therefore very close to our reproductive organs.

Still , it does make you wonder if we are not taking the safety aspects very seriously !
.