Ultrafire 18650 3000mA exploded

[PapaLumen]

Hmm makes me think about drilling a big hole somewhere in my mag 4d with 4x18650 in it

 

[aurum]

It appears you have a typo; In the picture you have it spelled Schutzschlatung, not schutzschaltung.

... you are right never noticed that for the past few month :ironic:

 

[TooManyGizmos]

~

I think they may be pushing the envelope of safety trying to put 3000mA capacity in there where other brands limit it to 2400 or 2600mA.

Maybe they make the inner wrapping layers too thin , unstable and easily damaged .

You can only get so much water in a gallon bucket before your cup runeth over.

Those unrealistic hi capacity cells worry me .

I hope we get more details on this event.

~

 

[Quension]

Here's the thread run through Google's translator for those who want to read it in almost-english.

What an ugly event.

 

[jasonck08]

~

I think they may be pushing the envelope of safety trying to put 3000mA capacity in there where other brands limit it to 2400 or 2600mA.

Nope. It's just a marketing lie. These batteries don't come close to 3000mA. They are about 2500-2600 tops.

The only companies currently capable of producing cells higher capacity then 2600mAH are Sanyo, Panasonic, Sony, LG, Samsung etc.

My guess is that the guy had unbalanced cells and mixed a junk cell with two fresh ones or something. Then there was too much stress on the junk cell and it exploded.

Also keep in mind that these cells may have not been protected, or protected very well. I find that most cells from DX and stuff that are listed as protected hardly due anything to protect the cell from overcharging or over discharging. Even several AW's that I've tested fail to protect the cell from being over discharged. I've taken an AW purposely down to 2.3v without the low voltage protection kicking in.

Lastly, if you review several of these Li-ion explosions on CPF you will find that most of them have a few things in common.

1) Multiple cells in one light
2) High current draw

If your cells are used in either of these applications please make sure you test each cell indivdually to make sure all cells can deliver the same current and capacity.

 

[old4570]

Possibly the worst 18650 to chose for a multi battery set up Im sorry to say .
The internal resistance on these is possibly the highest of any 18650 on the market .

And an important warning for anyone running a multi Li-ion set up is to check the charge state of the batteries , as often one battery discharges faster than the other . So it might be an idea to number the batteries so you can periodically swap them from front to back , to give them more even discharge .

So I guess with ever increasing numbers of 2x18650 lights on the market , we may see the 18650 doing the CR123A

The 18650 was inherently safer as it replaced the dual battery set up , with a single battery set up , so remember , any multi li-ion set up needs to be carefully monitored for voltage parity in the batteries or you may very well run the risk of turning your flashlight into a hand grenade .

 

[kramer5150]

Oh wow... Thank goodness he is OK.

 

[jirik_cz]

There has been many reports about leaking of these batteries so I'm not so surprised, that they can even explode...

 

[VidPro]

~
Protected cells are NOT supposed to do this thermal runaway thing !
NOW I'm Really wondering what caused this incident !
Someone please explain how this can happen with protected cells ?

~

What jirik_cz said, the battery is capable of becomming unsealed, when unsealed the anode disconnect would not function as it requires pressure to function. is ONE possibility.
other possibility with the ultrafires i own are the protection itself Shorting out, which can happen on any protected battery, but as we have seen many times the UF is not very carefull about its assembly of the whole battery package, and parts used to do so, so shorting of the protection connections is slightly more likly.

again it could happen to any of them, it was just more likly to happen with this than anything, because of its obvious flaws.

 

[alpg88]

~


Why do folks put UN-protected cells in a MULTI-cell light ?

~

why not??? i do it all the time, i got 4 lights that take 3 to 6 unprotected 18650.
use caution and you'll be fine.

btw it was protected cell that blew up

 

[malow]

yay! new 3000mah cell at DX!! :sick2:

http://www.dealextreme.com/details.dx/sku.42153

 

[VidPro]

just what they needed a new "Batch" i would bet that a new batch would be different.

 

[bobstay]

So it might be an idea to number the batteries so you can periodically swap them from front to back , to give them more even discharge.

Sorry to say this, but swapping the order of series-connected cells won't help in the slightest. With cells (or any other component) in series, they all experience the same current flow, so they will discharge at the same rate regardless of the order. The lowest capacity cell will always end up empty first.

 

[TranceAddict]

Do not buy *fire brand product (surefire excluded) and you will be fine

if you are non-sophisticated user just stick to protected cell like AW
if you are sophisticated enough to use unprotected cell then opt for panasonic, sanyo, sony, samsung and LG


basically all li-ion 2 bay chargers in the markets are crap, it will be much much more safer to modify those chargers that come with electronic gadget like camera or mobile phone than using crappy china made chargers.

if you can afford, go for hobby grade charger like schulze

for headlamp DO NOT use any lithium cell at all, use nimh cell instead

 

[Mjolnir]

Do not buy *fire brand product (surefire excluded) and you will be fine

if you are non-sophisticated user just stick to protected cell like AW
if you are sophisticated enough to use unprotected cell then opt for panasonic, sanyo, sony, samsung and LG


basically all li-ion 2 bay chargers in the markets are crap, it will be much much more safer to modify those chargers that come with electronic gadget like camera or mobile phone than using crappy china made chargers.

if you can afford, go for hobby grade charger like schulze

for headlamp DO NOT use any lithium cell at all, use nimh cell instead

You shouldn't generalize. The PILA IBC is most definitely not "crap," and it is a 2 bay charger. How can you possibly say that it is safer to modify a charger yourself and use it for what it is not designed than to use a charger designed specifically for that purpose? I realize that most of the cheaper Chinese made bay chargers don't use the CC/CV charging method (only CC), but there are a few that do.
It is NOT advisable to modify mobile phone or camera chargers... Buying a hobby charger or an IBC would be much safer.

And FYI, the PILA IBC is made in China.

 

[senecaripple]

thanks for the warning!

 

[TranceAddict]

if you analyze the waveform on oscilloscope at the gadget charger terminal, for example mobile phone itself, you will notice the charging algorithm is not simple as CC/CV only.

at first some pulse at varied time interval would be fed into cell for probing cell voltage and remaining capacity, then only CPU/MPU/MCU would select the proper charging current in terms of pulse width of PWM to begin the charge.

during charging process the circuit continues to monitor the feedback at each PWM off period to determine current charge state and adjust the pulse width accordingly all over the time, resulting in variable output voltage and current.

when the feedback cell voltage raises up to around 4.15v output current will drop exponentially and continue to charge and monitor until it reaches perfectly at 4.20v (+- 0.01v)


for any other NON-OEM 2 bay chargers, the best algorithm seem to be charge - probe - charge - probe at fixed time interval, on the other hand the output voltage being fed into cell is fixed until cell reaches 4.2v, and only Pila IBC manage to terminate perfectly.

advance algorithm are applied on high end hobby charger, laptop and almost all mobile phones, even on the cheapest $25 Nokia.

only OEM design from reputable brands offer the best quality of cell and charger, they are well researched and developed to avoid costly lawsuit and massive product recall (billions compared to less than few thousand units sold in flashaholic market), due to the fact li-ion cells are not meant for direct application for consumer, i am dare to say all 2 bay chargers in the market don't meet international standard of testing and regulation, prove me wrong if you can find one with real UL, CE, TÜV, FCC certification.

imagine if you burnt down your house, whom are you going to sue ? you probably won't even be able to find out who is the real manufacturer, even if you found out do you think they have the money or insurance to compensate your loss ? all community product in this market are maybe just higher than hobby grade, but it will never meet the OEM standard.

i am not advising anyone to modify gadget chargers unless you know exactly what you are doing.

for plug-n-play Pila IBC as 2 bay charger, Schulze as hobby charger and AW as protected cell are the best you can get in market, but when a cell is slowly venting inside a flashlight, no matter how many safety features it has, which including thermal, over current, self strip-off contact due to cell pressure, safely release valve on cell..etc, the light will still blow up violently because the air tight chamber really does not have much room for the vented gas, unless flashlight also implement a safety release valve or burst disc.

conclusion, use the best components and products available to keep the potential risk at the minimal level.

 

[mfm]

imagine if you burnt down your house, whom are you going to sue ? you probably won't even be able to find out who is the real manufacturer, even if you found out do you think they have the money or insurance to compensate your loss ? all community product in this market are maybe just higher than hobby grade, but it will never meet the OEM standard.

Do you think the above (ex) house owner could sue the manufacturer of his expensive hobby charger because it burned his house down? He couldn't.

If you keep it secure and simple you will be safer than with expensive gear that you have too much trust in, for example

1) ALWAYS monitor the charge, never charge overnight. This leaves out slow chargers.

2) Check the voltage before and after charging of all cells with a qualiy DMM (one that has a low battery warning at least).

3) Don't use multi-cell lights and assume that the protection circuit doesn't work! (Or if you use multi-cell lights, do careful voltage measurements).

If you do this then you are reasonably safe with a cheap chinese charger and *fire cells (but don't get known crap like the UF 3000 mAh cells or the older WF-139).

 

[ToNIX]

Is it possible that the cells were not at the same voltage?

I always check mine before and after charging. My red/black Trustfire always come out at 4.19v with the sku.6105 DX charger.

This is why I only want single cell lights, less problems IMHO.

 

[old4570]

Sorry to say this, but swapping the order of series-connected cells won't help in the slightest. With cells (or any other component) in series, they all experience the same current flow, so they will discharge at the same rate regardless of the order. The lowest capacity cell will always end up empty first.

Really ? Funny that ..

If you do a little re-search here on CPF you will find many experience variable discharge in multi batt set ups .. [ One cell discharges faster than the other ]

Many theories have been proposed for this , personally I think it has to do with the individual cell and internal resistance , and the fact that they simply do not discharge at the same rate . Some say it has to do with the heat [ MC-E SSC P7 ] and that the forward batt runs warmer and there fore discharges faster , and this could be true , as I have noticed that from cold my SSC P7 may do 2.7A and once it warms up it may do 3.1A ..
In a dual battery set up , the forward battery may indeed run warmer and there fore discharge at a higher rate simple because of a temperature variation between the batteries . So if you were to swap the batteries - front to back - you may find they discharge more evenly over time .

Or if simply a matter of resistance and the variation is from the batteries themselves then it wont help ...

Many other theories abound ,