Ultrafire 18650 3000mA exploded

ponts

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I'm sure happy I read this thread. I'm a newb and just bought a double Li-ion cell flash light with plans on using an unprotected Panasonic 18650 with a WF139 charger. YIKES! Going to make sure now to get a Voltmeter, AW protected cells and a decent charger like a PILA. My unprotected 18650's well run in My Klarus XT10 now. Thanks guys!!! :)
 

SHADE02

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the safest way to charge your battery is to put the charging set inside a big metal box (wall thickness >3mm ) with sufficient ventilation vane, and hook the supply through a high sensitivity MCB and ELCB or RCCD or even earth fault relay. you can then leave them unattended without problem, even if it vent or exploded the metal box will be able to quence the fireball and metal derbris propel by shockwave.

battery are very unlikely to explode during use even you drain it to very low voltage, you only need to be aware not to short the cell inside battery tube, for instant scratched packaging allow the battery to touch the wall inside, some poorly design spring, contact nipple, too short length of battery tube will simply crush the protection PCB and cause an effective short, but due to the force from spring the safety strip off contact in protected battery might not able to open circuit the current path. LED driver might has switching transistors, when they went bad they become shorted as well. the flashlight will take very less time to burst violently given that only very small room allow for vent gas expansion.

so always be alert, check frequently each time you recharge to see if there is any damage on plastic wrapping and both terminal, if then light output suddenly act funny or you hear hissing sound, immediately put the light on vertical standing position then run away.

THE BOTTOM LINE........
 

davec

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Re: Weak point in Protected Cells only

EVERY protected cell I've seen has a weak point that could lead to the cell exploding. Unprotected cells do not have this danger.

To feed the postive voltage to the control circuit at the negative end of the cell, a thin strip of metal runs from the + end of the cell to the - end. This strip carrying + is only separated from the negative case by a thin piece of insulating tape.

If this metal strip has a burr on it, or if there is any impact or pressure on the cell in this area, there will be a very direct short circuit across the cell that the PCB cannot control.

NEVER force the cell into a tight fit or drop the cell that could lead to this thin insulation being weakened.

Absolutely agree with the above statement, I was shocked when I first unwrapped some protected cells and the very poor design I saw in the ones I looked at. I prefer good unprotected cells, in a multi cell light as long as the light has a decent low voltage cutoff circuit, the cells being used are capable of a 4 amp discharge without any trouble, have low internal resistance and discharge at similar rates reaching similar voltages at the end.. In fact my latest crop of batteries are all unprotected. That said, you do need to do discharge/charge tests (with a proper charger) and use a multimeter to ascertain the characteristics of the cells your using, and determine whether they are best for series or parallel applications. After that a regular check could be enough.

Interestingly I recently bought some very cheap 3000 mah GTL unprotected flattops, tested them and as expected only 950-1000 mah capacity. I thought these are crap, but on further testing found them to have some quite interesting characteristics. Even though capacity is low, they will pretty much give of their full capacity at 1A or even up to 4A (I later tried 5A for a while, but only for 5 m). I seriously abused one with a 4A discharge and it gave almost the full 1000mah, quite amazing, there was a large voltage drop of course, but not enough to cause a problem. Didn't get warm, charged up fine again, very low internal resistance. Used a couple in my 3 XML-T6 Torch and it sucked 2.5 rising to 3+ amps out of them for a good 17 minutes before the torch protection circuit cut in (drawing more than 4A at the end). I was hugely impressed, all from cheap as chips batteries with a god awful capacity, but terrific current capability. If they could make the same cell characteristics with a 2400 capacity....I would happily buy nothing else, unfortunately I suspect high, capacity, current capability and low internal resistance don't go together (especially so in cheap batteries). The point of this is, these cells are great in torches for very bright light (not for very long though), but crap for usb battery boxes and that all cells however much they cost, need to be properly tested for the application. I find it amazing that many people rely on 1A discharge curves, especially when many high power flashlights suck out 2.5-3.5 amps.
 
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iron potato

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Re: Weak point in Protected Cells only

Guys, should I throw all my UltraFire cells to be recycled ? :sigh:

I read about WOW/Hi Max cells, the review seems not so bad about it & I have 4 of them, seems pretty good, maybe half year down, I'll order a couple of AW's 18650 then :thumbsup:

btw, after I joined this forum, only know where I can find AW cells lovecpf
 

bedazzLED

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Re: Weak point in Protected Cells only

Guys, should I throw all my UltraFire cells to be recycled ? :sigh:

I read about WOW/Hi Max cells, the review seems not so bad about it & I have 4 of them, seems pretty good, maybe half year down, I'll order a couple of AW's 18650 then :thumbsup:

btw, after I joined this forum, only know where I can find AW cells lovecpf

Hi iron potato.

You can head on over to the marketplace and get some.
http://www.cpfmarketplace.com/mp/sh...LiIon-Batteries-Sales-Thread-*Part-12*/page54
 

MDethCKR

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Aug 9, 2011
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So, you guys have taken a class in electronics and didn't pay a damn bit of attention huh?

IN A PERFECT WORLD, batteries in series will have the same current and draw. THIS IS NOT A PERFECT WORLD, let alone perfect cells. As people have said, cells have internal resistance and it is nearly impossible to have them be perfect.

STOP SPOUTING FALSE INFORMATION !
Sorry, I've been a lurker, and sick of people with 4/5 posts putting rubbish online.
 
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MorePower

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So, you guys have taken a class in electronics and didn't pay a damn bit of attention huh?

IN A PERFECT WORLD, batteries in series will have the same current and draw. THIS IS NOT A PERFECT WORLD, let alone perfect cells. As people have said, cells have internal resistance and it is nearly impossible to have them be perfect.

STOP SPOUTING FALSE INFORMATION !
Sorry, I've been a lurker, and sick of people with 4/5 posts putting rubbish online.

Calm down there, Hoss.

It doesn't matter if cells have internal resistance. If they are in series, the same amount of current will flow through all of them. Internal resistance will cause different amounts of voltage drop in different cells under discharge, but the current flowing through each of them will be exactly the same.

Current flow = electrons moving. Picture 3 cells in series. You are saying that cell 1 could have 500 electrons flow through it into cell 2, which could have 400 electrons flow through it into cell 3, which could have 300 electrons flow through it. Where would the disappearing electrons go?

I hope my number of posts meets with your approval.
 

davec

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The important question is.....does the torch still work? :naughty:
 

spiros

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Sep 8, 2010
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im not an expert,im using ultra fire and fireworm 18650 3000ma both say re/discharging protection circuit my 123's are spyder fire my chargers say travel charger on them for both batteries,from what im reading here i thing i need to change my set up to something safer,please reccomend chargers , 18650 and 123 batteries.
thanks spiro
 

Monocrom

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Best 18650 cells = AW brand protected cells.

Best rechargeable RCR123 cells = AW brand.

Best charger = PILA IBC model (And I mean by a very wide margin.)

Best primary CR123 cells = Any Made in the USA cells (SureFire, Panasonic, Streamlight, Duracell, Energizer, Rayovac.)

Best way to save money on CR123 primaries = Buy online (from a respected dealer), buy in bulk, buy Made in America cells. The first two in order to save money. The last, in order to make sure you are getting quality cells that are not cheap & dangerous junk that might explode.

Hope this helps.
 

Bajades

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A friend of mine had a single battery 18650 protected cell flashlight running a single P7 LED (Aurora AK-P7) explode/catch fire while in his flashlight holster. When it blew there was a loud pop, the tailcap blew out and caused a small second degree burn to the inside of his forearm. I don't know the brand of the battery (came with the flashlight-marked ICR 18650 2400 mah), but disecting another identical battery showed it did have a protection circuit at the base of the battery. The battery was charged with an inexpensive single cell Li-Ion charger that came with the flashlight. What would have caused a single cell protected battery to explode? Seems to me the protection circuit must have failed in this case? Still, what would be the explosion mechanism?
 

SilverFox

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Hello Bajades,

Welcome to CPF.

It is possible for the wiring that connects the protection circuit to the cell to short out. This doesn't happen very often. This could cause the cell to heat up and pop.

The most common cause of this is rough service or rough handling. This results in physical damage to the cell.

Tom
 

DavidMB

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Very interesting thread. I've seen some new lights on the market that take 4 18650.. That's like holding a bomb. But,, I think not so much if one buys a good charger and good quality batteries.

If someone did buy a unprotected Li-ion battery's and has a light without a low voltage cut off, what would keep the batteries from discharging too low and ruining the cells? Do you just have to guess when to recharge?
 

aimxplode

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Very interesting thread. I've seen some new lights on the market that take 4 18650.. That's like holding a bomb. But,, I think not so much if one buys a good charger and good quality batteries.

If someone did buy a unprotected Li-ion battery's and has a light without a low voltage cut off, what would keep the batteries from discharging too low and ruining the cells? Do you just have to guess when to recharge?

Use a multimeter or voltmeter to see what the charge status is at. I use the voltmeter that is sold in the CPF Marketplace by "cottenpickers", its extremely easy and convenient. Here is a pic of it:

fQjQD.jpg



4.2V = 100%
4.1V = about 90%
4.0V = about 80%
3.9V = about 60%
3.8V = about 40%
3.7V = about 20%
3.6V = empty
<3.5V = over-discharged
 

DavidMB

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Nice volt meter! So that's the only way? to carry around a portable voltmeter, or just guess?
 

Monocrom

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Never guess with these types of cells. You don't have to carry a voltmeter with you. You should test the cells often. Not so often that you need to EDC a voltmeter. But if you feel that guessing will become a real possibility . . . Don't use 18650s or similar types of cells.

Some flashaholics rely only on AA or AAA rechargeables for their uses. Or, they rely on older rechargeable models; such as a SureFire 9AN for example.
 

andrewnewman

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General rule(s) of thumb:

1. NEVER just guess.
2. NEVER use unprotected 18650 cells in a multi-cell flashlight.
3. If you use unprotected cells in a single cell light with low-voltage circuit, I would make absolutely sure I knew what the low voltage indicator was. Some cells ramp down to a lower level, some flash or beacon periodically, some go suddenly dead (like a protection circuit was triggered) and some do combinations of these.

One further observation is that even with a single cell light, it's particularly risky to use an unprotected cell (IMO) with lights that have a wide voltage range such as 0.9V - 4.2V. These are popular because they can use different chemistries but can really do damage to a LiIon cell trying to get that last electron out before the user notices. By contrast, my Malkoff M61 drops out of regulation around 3.4V under load. There is a nice slow and visible dimming between 3.4 and 3.1V. After 10 minutes the unloaded voltage will bounce back up to 3.5-3.6V. You really have to be paying no attention to manage to trigger the protection circuit. Having said that, however, I still use protected batteries in my Malkoff. Who knows when I might doze off with the flashlight on :)
 

DavidMB

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Jan 5, 2005
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I use 14500 in my light. I'm trying to figure out what daily or weekly procedure people use keep the voltage from dropping too low (because testing often seems like a chore) using unprotected cells, (any type).

Do you have to get out the voltmeter every so often and test it or maybe do some people get a feel when to pull the battery recharge it before it drops too low..

Seems like one slip up could ruin an expensive cell.
 
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