explosion when charging li-ion cell, Universal Smart charger set on wrong voltage

LuxLuthor

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I have an extra battery pack from my BarnBurner that I carefully peeled off layers to confirm that these are using 4S-3P of 12 Samsung Unprotected 18650 cells. As far as I know, this pack has never been used, and I charged it one time about 2 months ago.

The pack voltage gives 16.55V and fortunately each of the cells gives a reading between 4.13 - 4.15V, but again an imbalance would only develop over repeated discharge and charging. There are no individual cell taps for balancing this pack.

Click on each thumbnail image for larger view.

 

Kevin Tan

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Lux, I cant be sure but this pack seems to have a single cell ( or 3 cell in parrellal ) monitering system. Its the systems used in all new notebook batt paks. Its got unbalanced cells protection in that it will shutdown if the block of 3.7v is 0.5v (depending on the setting ) off or different form the other blocks of cells. Notice that each 3p cells have a connection to the pcb. Try and trace the batt routing and see if you can get a reading for the 3p cells of 4.0 - 4.15v.
 

LuxLuthor

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Each block of 4 cells has 16.55V. Each cell has 4.13-4.15V. There are no "blocks" of 3.7V since that is the single cell average voltage.

It may have something that tries to balance one set of 4-S cells against the other two 4-S sets, but that is not reliable balancing...even if that is done.

Looking at the connections on both sides which you can see in my images, there is no independent connection to just a single cell for balancing. It would have to look like this type of configuration:

pack_wiring_taps_conv.jpg
 
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SilverFox

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Hello LuxLuthor,

Kevin was pointing out that notebook computer battery packs do not balance each cell within the pack. They check for a difference between strings.

This is not a bad way to go, if you limit the depth of discharge and charge a little sly of 4.2 volts. Individual cell balancing is ideal, but this isn't a bad compromise.

Tom
 

chasm22

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LuxLuthor said:
Andrew, I just don't think your assumption that charging Li-Ion cells in S4-P1 or S4-P2 will not result in a fire....because you have not heard of such an event is smart in the face of so many examples in the RC LiPo world. We know it has happened with free cells on airplanes. We know it happens with laptop packs that are not abused like the RC users. We know it happens with the non-rechargeable 123's. We know there are strict warnings given about maximum charging voltage cutoffs. We know chargers have cutoffs typically at 4.2V.

All of that suggests a stronger case for the real danger, than your speculative arguments that it is overstated and overblown.

I don't think you can be sure of your voltages coming closer into balance response to SilverFox unless it is specifically tested. The cells in a FM pack are touching the other cells on two sides. You honestly don't think there would be enough heat/damage from one cell exploding/catching fire to cascade the other three, while contained inside of a Maglite tube? I do.

Now, about my own failure to find out about the Lithium charging guidelines. Guilty as charged. I again remind you, that NOTHING was stated as a warning on AW's GB thread, nothing on Alin's charger GB, nor the plain box, nor in AW's DSD charger GB, nor the DSD's plain box, nor the Pila site where I chose the battery sizes I wanted, nor in the box with the Pila charger, nothing in any of FiveMega's GB threads that used Li-Ions, and linked Alin's charger, nor from you when I got the unprotected 4S Mag66, nor a warning of a danger of fire or explosions with my cell phone or laptop battery.

I heard about the Sony Laptop battery recall, but figured it was totally related to a mis-wired battery holder, or some bizarre manufacturing defect. It never occurred to me that there might be an inherant risk in the entire Lithium battery technology that was not present with Lead Acid, NiCad, or NiMH.

I also never thought that Maglite mods, Li-Ion batteries, and Lithium chargers would be sold here without a clear, obvious warning being stated in the GB threads that would have caught my attention. I guarantee I am not the only one who has missed this danger, and how to use Lithium batteries safely.


Lux,

I think you're being a little disengenous in your assertions about being unaware of the dangers. This is a direct quote from you in a thread you started almost a year ago to the day, "Yeah, after reading about the issues of Li-Ion/LiPo charging, storage, and care....I totally agree with you on needing to be very careful and more conservative when dealing with them." (Emphasis mine)

If you want to lead the charge now for safety issues as they pertain to li-ions, be my guest. It would seem that you are(and have been)quite well informed on the issues involved.


Chuck
 

VidPro

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LuxLuthor said:

looks like a "proper" 6 cell protection curcuit. is the extra connector for a charger? the pack looks like its parellel series.
so each parellel set is protected? (well that is what it looks like)

like said above, is the protection tapping off each of the sets of cells?
 
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andrewwynn

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SilverFox said:
Hello Andrew,

I am sorry if you don't understand how Li-Ion cells work. The example I gave is exactly how it works. Li-Ion cells have no ability to withstand an overcharge and can not be balanced through peak charging.

When Li-Ion cells are completely discharged the cell to cell imbalance will be greater, but if you look at the example you will see that some of the cells were nearly fully charged. These cells have nowhere to go but up to a higher voltage.

The RC people do push the limits, but there is a lot of them that work within the limits too. When these people report their packs catching on fire, I take notice. When they report that their packs have gone out of balance and the packs puff and blow while charging, it is enough evidence for me.

Your theory is wrong. There are a whole bunch of people with burned up trailers, shops, cars, and houses to prove that it is wrong.

If you tell others that Li-Ion cells will self balance, you are wrong and this is a very dangerous thing to do. People listening to your theory will end up having problems, which may include fire damage.

If you want to play with fire, please do so by yourself. Please don't bring unsafe and unsound charging methods forward and encourage others to follow them.

Tom

never said they will self balance.. i also said it's important to make sure cells are relatively balanced, what i did say.. was there is no 'high risk' in the one example shown and enumerated above... there just isn't.. the 'high risk' packs which people are showing examples of are 50 to 100WH+ and almost exclusively LIPO packs.. *i* am talking about a <1C charge of a 9WH pack.

I'm not saying that it is by any means an ideal way to charge a pack and have said also quite specifically that the 14500cell is pushed beyond design limits running the 1166 lamp, which is a good likely cause of the misbalance in the first place. In my M66 thread i posted this:

awr said:
Maybe i should call it the 'middle-class' M6 :-D (the prototype maybe cost $130-150 including all the various parts).. i'm hoping if i get it to a turnkey that i can sell them for at about 1/2 the price of the M6, just starting to explore cost-saving options.. the light doesn't have the shock isolation of the M6, but the beam is much whiter and brighter. I just upgraded the battery pack to use 14650s (i think i mentioned that).. but it's a huge deal because it means the cells are only pushed to 2C not 2.6C which i would not recommend anybody copy.

I am 'on record' many times saying do not push LION over 2C. When people choose to do things not recommended ... it's their dime on the research.. it's bad juju to push a LION cell over 2C.

I am saying that comparing the list of 'extra bad things' to a 4S 14500 pack charged at 1/2A is ludicrous. I would have no problem having my mother charge that pack. I would tell her to charge it not near combustible materials and i would consider that darn near risk-free.

Icebreak.. it's well documented that the FET on a 100W hotdriver goes through enough punishment that it can be damaged... the light will not shut off should this happen and you will have to remove the tailcap to shut it off. This is a documented issue and is part of life on the cutting edge.. it poses no considerable risk to a user.. it is most certainly not in any way shape or form similar to the concept of charging LION batteries.. properly or otherwise.

-awr
 

VidPro

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LuxLuthor said:
No. Almost all the packs that are being made for these flashlights and spotlights are using Li-Ion cells such as the ones being sold here. RC Lithium Polymer LiPo packs such as the one cell seen here use a number of an even less safe, more fragile type of cell like this one that are soft and lacking the hard metal case of a Li-Ion cell.

i dont think one as being "safer" than the other
the canned cell has a projectile, or rocket, and the bagged cell can be damaged easier.
a GOOD canned cell built to U.S. (overly protective) specs should be safer, because it has the facility to have a anode disconnect. but when there are incidents CLAIMED to be due to extra lithium metals, its CAN structure can move further when ignited.
Protection for bagged cells doesnt run the opposing pole of the battery right next to the other pole.

its a tossup, if there was a most critical factor its the HUMAN :) and how the human uses it, and pushes it.
take 50,000 toy playing humans trying to get to play with thier toys faster, and some human is going to fall off thier skateboard.
 
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LuxLuthor

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chasm22 said:
Lux,

I think you're being a little disengenous in your assertions about being unaware of the dangers. This is a direct quote from you in a thread you started almost a year ago to the day, "Yeah, after reading about the issues of Li-Ion/LiPo charging, storage, and care....I totally agree with you on needing to be very careful and more conservative when dealing with them." (Emphasis mine)

If you want to lead the charge now for safety issues as they pertain to li-ions, be my guest. It would seem that you are(and have been)quite well informed on the issues involved.

Chuck

I think I must have early Alzheimers, because honestly, I have no memory of making that post, nor what I had read that made me post it. It may also have been more of a case of jumping on the bandwagon of something I saw in a general glancing on the subject, and dismissed or forgot right afterwards. I might have been trying to sound more educated on the subject than I really was, so as to not look stupid. I'm really not sure about that...but I am sure I was not well informed on the subject.

I assure you if I had really been clear about the fires and explosions, I would not have been using unprotected cells in series, and would never have been charging packs in series on my wooden dining room table. I have recently moved my charging into the garage, looked all around for anything potentially flammable, and totally changed everything related to using Lithium cells, testing them, storing them, etc. etc. I never knew anything about cells getting out of balance in a pack, and only ever charged the Mag66 I got from AWR with the Alin universal charger...with cells being left in the light ever since I got it from him.

The thing that really made this danger sink in was buying the Hyerpion 1210i charger, and going to find out how to use it for Li-Ion charging, and having no idea what "balance charging" meant. In the process, I watched a number of video clips showing the explosions and fires which I never saw before, and seeing pictures like Norm just showed.

But if it is important for you to spend an unknown amount of time searching through my past posts, and throw out some accusation that I must be disingenuous, and not trying to help the community, be my guest...but you are wrong in your assumptions regarding my motivations.

Edit: Just out of curiosity, I did a search to see what was the source of my Alzheimers...and to see how out of context your accusations were...and LOL! sure enough, you pulled that brief comment out of 3 pages of posts from this thread where I was exclusively trying to figure out if my crappy $20 HiTech NiMH charger could be used to charge a 9 pack of NiMH cells....and had spend enless hours mainly reading about NiMH. I was agreeing with wtpski, but actually knew nothing about Lithium battery dangers since my entire focus was on NiMH's. In fact reading my stupid comments in that thread, it was obvious that I didn't know squat about NiMH before that thread.

You should be proud of yourself, chasm22, you did a real public service today
!!! :barf:

Now back to the relevant discussions.
 
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LuxLuthor

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VidPro said:
i dont think one as being "safer" than the other
the canned cell has a projectile, or rocket, and the bagged cell can be damaged easier.
a GOOD canned cell built to U.S. (overly protective) specs should be safer, because it has the facility to have a anode disconnect. but when there are incidents CLAIMED to be due to extra lithium metals, its CAN structure can move further when ignited.
Protection for bagged cells doesnt run the opposing pole of the battery right next to the other pole.

its a tossup, if there was a most critical factor its the HUMAN :) and how the human uses it, and pushes it.
take 50,000 toy playing humans trying to get to play with thier toys faster, and some human is going to fall off thier skateboard.

I have never used LiPo or done RC'ing, so I really don't know that much about them...but I'm more going by what was listed in this long string of documented incidents....and like AWR says, how many Li-Ion cell fires and exploding cells (like Norms) do we know of. My guess in part is the RC groups have tons more battery hours logged than we CPF'ers do, so we have not been pushing our cells as hard, and as long as them. Our chargers also tend to be the low current DSD, Ultrafire, Pila, Universal Alin charger which may help protect us.

The idea of the LiPo cells being soft and easily damaged seems more prone to problems, and remember reading that on some RC sites.
 
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Art Vandelay

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Car batteries will explode if they are jumped incorrectly. When car batteries explode it's more powerful than a little flashlight battery. I don't plan on eliminating car batteries from my life. I will even jump a car battery. Following the directions it's not too dangerous. If you don't follow the directions, you are like a rat in your own little experiment.

Personally, I will continue to use and maintain my car and flashlight batteries as directed.:)
 

chasm22

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"I think I must have early Alzheimers, because honestly, I have no memory of making that post, nor what I had read that made me post it. It may also have been more of a case of jumping on the bandwagon of something I saw in a general glancing on the subject, and dismissed or forgot right afterwards. I might have been trying to sound more educated on the subject than I really was, so as to not look stupid. I'm really not sure about that...but I am sure I was not well informed on the subject."

"You should be proud of yourself, chasm22, you did a real public service today !!!"

Lux,

So we're having some memory problems. You say you might have stretched the truth?? Is that the same as a lie? Or maybe you're stretching it a little bit now when you say that you don't remember?? Hmm. Funny how you don't remember the post, but you remember being uninformed. Double hmmm. Have you ever practiced law?

You see I'm only concerned because of you're attitude. It seems you're very concerned that some of the best builders,modders and sellers didn't forewarn you about the risks of li-ions and that you were put at risk of life and limb. Pretty dramatic stuff. Videos and everything. Yet it seems you were just posting about setting paper on fire in less than a second with one of your lights. Also very dramatic stuff. With one difference. You did it on purpose, with no reason except to be dramatic. Pretty smart stuff. Oh, but I forgot. After doing it you warned everybody not to be stupid. Is that like warning everybody not to use fireworks after you just did? Hmmm, another public service message by LL I guess.

So what's it going to be today Lux? Drama queen or daredevil? Fire or water? Heaven or hell? How about a good dose of personal responsibility??


Chuck
 

Bimmerboy

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LuxLuthor said:
I did a search to see what was the source of my Alzheimers...and to see how out of context your accusations were...and LOL! sure enough, you pulled that brief comment out of 3 pages of posts from this thread

Sure enough what? How does "pulled that brief comment out of 3 pages of posts" diminish the point chasm22 makes? How is it out of context? Did you not specifically say "Yeah, after reading about the issues of Li-Ion/LiPo charging, storage, and care....I totally agree with you on needing to be very careful and more conservative when dealing with them."?

LuxLuthor said:

You should be proud of yourself, chasm22, you did a real public service today
!!! :barf:

Actually, that comment makes me want to :barf: How self-righteous.

In my estimation, both Chasm22's posts, in effect, are more of a public service than this sudden crusade you're on.
 

LuxLuthor

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I really don't give a rat's patootie what both of you assume I understood from pulling that line out of 3 pages where I was just starting to learn about NiMH battery charging with a $20 cheap Chinese pack charger from a year ago...because there is nothing the two of you are contributing to the safety of using Lithum cells.

You wanna rag on a sentence I wrote a year ago to try and say that Lithium cells are not dangerous, and we should not be warning people now? That's up to you...but I don't see the point.

My entire focus during that 3 page post was to find out about NiMH cell charging, and if I brushed over some unknown reference about needing to be more careful with Lithium batteries, that does not mean that I understood the specific dangers. I'm 100% sure that I had no understanding of Li-Ion fires, explosion, balance charging, and have never seen a video of the enormous power and danger of Lithium cells, until last week.

For you num-nuts to now be so certain that I was informed and aware of the specific dangers of Lithium batteries based on that one sentence is showing your ignorance in making your assumptions. I'm glad you have nothing better to do than go back and research my many posts.

Now you bring up the Torch starting a fire as somehow challenging the unrelated general concern for explosive, significant fire and smoke from Lithium cells, is irrelevant and more of your vindictive ignorance. The Torch light fire test was done with full awareness, and in a controlled fireplace after seeing the YouTube video.

The Lithium cell explosions and fire dangers, and issues of cell balancing are not something I had any awareness about, nor had I seen any videos making it clear....and it is why I have been charging all my Lithiums in the garage on a cement floor since last week.

What else you two little female dogs wanna bring up?
 
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cy

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Lux, don't know about anyone else, but I appreciate you sticking your neck out and taking a stand.

and no not all hotwire folks are aware dangers of using li-ion packs. to RC folks who have been discharging rechargeable lithium cell hard for some time. along with fires, special balance features of packs, etc... this is old hat.

but hotwires supported by mult-cell li-ion pack is a relatively new trend. for example, look at the garbage AWR is spouting in this thread if you want to see someone that doesn't understand how li-ion cells work.

li-ion cells have no peak and will accept a charge for long as you deliver current, that is until thermal runaway occurs at aprox. 4.6v or so.

charging a li-ion pack slowly or otherwise will never bring voltage closer like AWR would like for you to belief. instead individual cells will keep on climbing until thermal runaway and/or explosion occurs.

further if you discharge a rechargeable lithium cell beyond it's ratings. plating will occur on anode. when metal is deposited it forms as dendrites. sharp peaks forms and could pierce insulating barriers causing a dead short. this will not cause problems during discharge, it's what happens afterwards when cell is fully charged.

there's a solid possibility this is one of the reasons lipo packs and of course the infamous laptop packs have caught on fire all by itself. here's a little more info: http://candlepowerforums.com/vb/showpost.php?p=1923305&postcount=118

So if Lux is being obnoxious warning folks about dangers of hotwires supported by multicells li-ions. I say .... great better obnoxious and get the message out, than to keep it to yourself. or worst yet make like this is no big deal like AWR's garbage.

here's an innovation by Lux, a modded multi sized battery holder design with provisions to balance li-ion cells. Perfect for new C li-ion cells or other li-ion cells could be placed in this cradle and safely charged.

http://candlepowerforums.com/vb/showthread.php?t=158121&page=1&pp=20

note: one would never charge different size cells at same time in finished balanced charger mod. cells are shown for different sizes only.

li-ion cradle.JPG
 
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LED61

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LuxLuthor said:
I have an extra battery pack from my BarnBurner that I carefully peeled off layers to confirm that these are using 4S-3P of 12 Samsung Unprotected 18650 cells. As far as I know, this pack has never been used, and I charged it one time about 2 months ago.

The pack voltage gives 16.55V and fortunately each of the cells gives a reading between 4.13 - 4.15V, but again an imbalance would only develop over repeated discharge and charging. There are no individual cell taps for balancing this pack.

Click on each thumbnail image for larger view.



Thanks for taking the time to do this Lux, this is one of the most constructive posts I've seen from you.
 

LuxLuthor

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Thanks LED & Cy !

SilverFox said:
Hello LuxLuthor,

Kevin was pointing out that notebook computer battery packs do not balance each cell within the pack. They check for a difference between strings.

This is not a bad way to go, if you limit the depth of discharge and charge a little sly of 4.2 volts. Individual cell balancing is ideal, but this isn't a bad compromise.

Tom

Tom, I can see that there is the 3 parallel sets of 4 cells, and the PCB on the pack that I'm not really sure what it is doing. The AC adapter says the output is 19V & 2.3A which with 12 x 18650 (@ 2200 mAh) is at best a 0.1C charging rate....and has an auto termination, which I imagine is likely set at 4.2 So, unless someone sees a concern, I'm feeling ok about this setup.
 

LED61

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I´m feeling pretty much at ease also Lux, after seeing the 4s3p setup and the PCB board, only I think the charge rate is more like .3C give the three parallel sets.

I went back and did some research to better explain the .3C charge rate above given I am not an expert in the matter but this is what I´ve more or less found, someone correct me if I´m wrong please.

The BB has three strings of 4 in series 18650 2200 ma cells

Voltage= 4.2V x 4 cells = 16.8 Volts and Current= 2.2 amps (cells in series do not add current but voltage

Ok, so now we have three of these strings and so the charger does see an individual voltage of 16.8 V, but now we add the currents of the three strings

2.2 A x 3 = 6.6A

And hence the charge rate is more or less 0.3 C

And so that configuration allows the BB to hold a voltage for the ballast and increase the runtime. If the protection circuit built in the pack is good, it should monitor each cell connected in series and each of the three strings as well.
 
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