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Ultrafire 18650 exploded..

SHIN

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Ultrafire protected 18650 exploded....

I saw this at:

Ultrafire 18650 3000mA exploded - CandlePowerForums

In these days, especially after the appearance of high power laser, the usage of bigger battery, rapid exhaustion and mismatch of battery because of host design, is usual.

I think laser owner or Li battery owner should keep in mind that this could happen any time.
No matter how careful you are and no matter how low the probability is, you can't escape from this perfectly.

SHIN
 
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LarryDFW

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Re: Utrafire 18650 exploded..

Shin;

Minimize the potential for problems.

Use quality "brand name" UL listed cells.

Larry
 
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Re: Utrafire 18650 exploded..

Shin;

Minimize the potential for problems.

Use quality "brand name" UL listed cells.

Larry
I agree, the only ones I consider worthy of using are the Trustfire "flames", and AW. But I think the real lesson to learn here is to NEVER CHARGE CELLS OVERNIGHT! No matter how good you think they are, that's never a good idea. Sorry but, what does "UL" mean?
 
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Re: Utrafire 18650 exploded..

Who the hell charge 18650 overnight? that sounds kind of irresponsible. I usually unplug chargers whenever i leave the room and alway check with a MMU (each 20-30min) and touch them to know if they are hot. (THATS WHY IT TAKE 3 DAMN DAY to charge a pair )
 
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I leave the room, but I check back at least once an hour. I also have a habit of charging them every night, so it doesn't take long unless I used them for a long time that night.
 

Morgan

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It's also advisable to charge batteries individually. As the chargers go through up to three charging cycles; constant current; constant voltage; and one I can't remember just now, (trickle charge I think); if the batteries are mismatched or differently charged the charger doesn't know which cycle to use and could put one of the batteries at risk of overcharging. It may not be convenient but is it safer. Mostly though I suspect our builds only use one battery at a time and that is likely how they will be charged also but it's something to bear in mind.

M
:)
 
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It's also advisable to charge batteries individually. As the chargers go through up to three charging cycles; constant current; constant voltage; and one I can't remember just now, (trickle charge I think); if the batteries are mismatched or differently charged the charger doesn't know which cycle to use and could put one of the batteries at risk of overcharging. It may not be convenient but is it safer. Mostly though I suspect our builds only use one battery at a time and that is likely how they will be charged also but it's something to bear in mind.

Thanks, I didn't know that. Good thing I only use a single charger. What are your thoughts on those chargers that do more than one type of battery?
 

BShanahan14rulz

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I have one charger that I use for my 18650's and my 17670's, but a seperate charger for my 10440's and 14500's (AAA and AA's). This smaller charger takes much longer, but it's safer to charge smaller capacity Li-Ion's with a lower current.

I've noticed a few of my cells getting hot when I charge them, they are probably at their EOL.

I'd say push for LiMn like A123 did, but we don't really have a use for those in the laser hobby yet, nothing we use draws that much current, but LiMn is supposed to be a muc safer chemistry.

I only have one ____fire cell, and it's my 17670's. The rest are namebrand, some older sanyos and some newer panasonics. All LiCo.


Chargers. DSD charger is single-channel paralleled over two slots, and looks to be basically a battery protection chip retasked to drive a transistor to charge the batteries. WF-139 has 2 independent charging channels and is a much more complicated circuit than the cheap DSD charger. Includes 220/110 to dc converter internally and many other components.
 

Cyparagon

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You only need to worry about charging one at a time if the charge states are mismatched. Since both anodes and both cathodes are common, one could short into the other one if one of them has higher charge. But if they are close in charge, it's of little concern.
 

millirad

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Pull the batteries from the charger immediately when they are charged. Keep the batteries cool. Don't leave them in direct sunlight. Make sure they are a reliable name brand. Dispose of any batteries that have ever become hot.
 

Benm

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Re: Utrafire 18650 exploded..

Holy crap, that seems like a serious bang!

Glad it ended up hurting his arms and didnt explode right in his face or something like that!

Who the hell charge 18650 overnight? that sounds kind of irresponsible. I usually unplug chargers whenever i leave the room and alway check with a MMU (each 20-30min) and touch them to know if they are hot. (THATS WHY IT TAKE 3 DAMN DAY to charge a pair )
Well, i often charge my laptop overnight or when i'm absent. Obviously there is some protective circuitry in there, but its still basically the same deal. On the other hand it wouldn't hurt me if a cell exploded, unless it would set my appartment on fire or something like that.
 
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It's also advisable to charge batteries individually. As the chargers go through up to three charging cycles; constant current; constant voltage; and one I can't remember just now, (trickle charge I think); if the batteries are mismatched or differently charged the charger doesn't know which cycle to use and could put one of the batteries at risk of overcharging. It may not be convenient but is it safer. Mostly though I suspect our builds only use one battery at a time and that is likely how they will be charged also but it's something to bear in mind.

M
:)
Good double battery chargers have seperate circuits for each charging panel. so no matter what voltaage they are on the charger will start its cycle. the charger doesnt do the same thing to 2 batteries it does them individually. well atleast the charger i have does that.
cheers
 

jbtm

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Scary indeed. What is considered an 'over-charged' voltage? My charger from rayfoss stops at 4.47V, and I have batteries that have over 6 protection features on it, and over-voltage is one of them, the battery over-voltage is actually set to 4.2V, but I could be wrong, It's been months since I last had to do a charge. But the battery was never warm or anything when it came out of the charger, So seeing it was protected I didnt take much of it...It's a single cell configuration anyways

I also always have my laptop pluged into a charger all day because (i have actually tested the circuits with a meter) Once the battery is fully charged, a relay by-passes the battery, and the laptop runs on the power supply, NOT the battery. And the battery isnt in constant charge. I had it for over 2 years now, and the battery life is still over 6 hours, just like the day I got it.
 
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