I keep hearing people saying to be careful on sub ohm builds because your battery may explode. Does this mean burst into flames? Or actually explode in your hands?
Exploding batteries on sub-ohm builds
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Honestly, I wouldn't go so far as to going into subohm without the proper knowledge, for that reason especially. I don't wanna find out what happens. I've seen pictures, I just rather take the precautions so that i don't have to worry about anything bursting into flames or blowing up in my hands... near my face... Which i like too much
It can properly explode. Battery safety is something to seriously educate yourself about when building sub-ohm coils.
they can do both if the battery is mistreated, used improperly, charged with wrong charger, shorted out ( low sub ohm apps).
The road to vaping nirvana is filled with many potholes. Proper education when it comes to batteries and sub ohm builds is a must and not to be undertaken unless you are totally competent. Even then you still have risks. I've seen and heard enough stories to be able to confidently deem myself too much of a novice to venture into those waters. And being satisfied with my current set up leads me to believe my novice status won't be changing anytime soon. 
Could be either. Could also just be a lot of gas venting and some heat - no real way of controlling the extent of the fail.
What happens, generally, is called "thermal runaway". Good name for a band, crappy thing to have happen in your hand... next to your face. As the term implies, it's nigh unstoppable once it occurs, and it usually happens when a battery is either fired at too low a voltage (it's overdrained), too high an amperage (which is a real possibility with some coil build resistances), or overcharged in a charger.
What happens, generally, is called "thermal runaway". Good name for a band, crappy thing to have happen in your hand... next to your face. As the term implies, it's nigh unstoppable once it occurs, and it usually happens when a battery is either fired at too low a voltage (it's overdrained), too high an amperage (which is a real possibility with some coil build resistances), or overcharged in a charger.
How long do you have once it starts and what are the indicators its fuse is lit?
I'm guessing heat?
If your batteries are charged on a good charger, never depleted below say 3.5-3.3v. Your coils are clear of any shorts and balanced evenly. And you are well below the amp limit of the battery. And also using IMR batteries.
How probable is something like this to occur?
I found the wattage-band (powerband) of say a .8ohm dual coil setup to be preferable to a 1.2 or 1ohm setup throughout the voltage range of the battery's life.
You start out at about 22watts and taper down to about 15watts as the battery drains. The whole time it maintains a fairly powerful, but not incendiary vape. I think this barely crests 5 amps at it's peak. Am I really walking the razor's edge with 30 and 35 amp rated batteries? I check ALL my coils on a VW mod before firing on the mech. (it also reads ohms) And then periodically as its used or any time it's being rewicked and something might get knocked around.
I check my legs to keep them even and check warm up from cold to ensure I don't have a hotter coil too.
I'm guessing heat?
If your batteries are charged on a good charger, never depleted below say 3.5-3.3v. Your coils are clear of any shorts and balanced evenly. And you are well below the amp limit of the battery. And also using IMR batteries.
How probable is something like this to occur?
I found the wattage-band (powerband) of say a .8ohm dual coil setup to be preferable to a 1.2 or 1ohm setup throughout the voltage range of the battery's life.
You start out at about 22watts and taper down to about 15watts as the battery drains. The whole time it maintains a fairly powerful, but not incendiary vape. I think this barely crests 5 amps at it's peak. Am I really walking the razor's edge with 30 and 35 amp rated batteries? I check ALL my coils on a VW mod before firing on the mech. (it also reads ohms) And then periodically as its used or any time it's being rewicked and something might get knocked around.
I check my legs to keep them even and check warm up from cold to ensure I don't have a hotter coil too.
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Less than a tenth of a second and the usual first indicator is the jet ejecting from the vent holes of the mech. Hopefully your mech has a vent hole...
Yes, but gentle warming is fairly normal under even high-resistance circumstances. After a heavy vaping session at 2.2 ohms, even my battery gets a little warm.
Thermal runaway usually happens when the battery fails. Things go from warm to hot to stinking hot very quickly. In this case, the hotter it gets, the larger the volume of the battery that starts to break down, further increasing the heat.
If you always stay below the amp limit of your batteries, use reasonably fresh, undamaged batteries, and take great care to monitor for any faintly unusual behavior and discard the batteries when that happens, your risk is reasonably small. There's still a risk, however.
Lithium batteries pack a lot of stored energy in a small container. That's why they are chosen for use in advanced personal vaporizers. However, all that energy packed in a small space has its disadvantages, too. These batteries don't like heat or to be overworked past their capacity. They react very angrily and self destruct in a chain reaction called thermal runaway, much like a small thermonuclear explosion.
I've had a protected ICR battery explode in a mechanical mod when the fire button got stuck, allowing the battery to over-discharge too quickly. ICR batteries are a volatile chemistry, so the battery expelled hot gas and flames, burning the pants pocket the mod was in. (Luckily I wasn't wearing the pants at the time!)
IMR batteries are a safer chemistry, and although they can still vent during battery failure with hot gases, they won't likely vent with flames. I've had an IMR battery vent in a pocket that I wasn't aware had a couple of coins in it, and it got so hot I could barely touch it. It popped its cap and vented, ruined because of my stupidity and carelessness.
Sub-ohm coils are dangerously close to being a dead short, the most dreaded event in vaping. Use extreme caution at all times.
Here's some graphic photos of Lithium batteries which have vented into thermal runaway:
I've had a protected ICR battery explode in a mechanical mod when the fire button got stuck, allowing the battery to over-discharge too quickly. ICR batteries are a volatile chemistry, so the battery expelled hot gas and flames, burning the pants pocket the mod was in. (Luckily I wasn't wearing the pants at the time!)
IMR batteries are a safer chemistry, and although they can still vent during battery failure with hot gases, they won't likely vent with flames. I've had an IMR battery vent in a pocket that I wasn't aware had a couple of coins in it, and it got so hot I could barely touch it. It popped its cap and vented, ruined because of my stupidity and carelessness.
Sub-ohm coils are dangerously close to being a dead short, the most dreaded event in vaping. Use extreme caution at all times.
Here's some graphic photos of Lithium batteries which have vented into thermal runaway:
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I rotate my batteries each use. They are also dated and stored in a safe, dry place. I never deplete them below 3.4-3.5v typically.
My mech is a nemesis. It has quite a few vent holes.
The 'jet' you refer to is a flame? Or just hot expanding gasses? Like what am I dealing with here? A torch of flame? An enormous volume of noxious gas capable of pressurizing and bursting a metal tube? This happens in one second? 3 minutes? 5 minutes? 15 seconds?
My batteries don't even get warm at this load. The atomizer / steel drip tip gets VERY warm. But I've even popped the battery to make sure. I'm using Sony 18650 VTC4's. And the new Efest 18650 rated at 35amps. Again the max load on the battery with this setup pulls 5 amps. The little 18350 Efest's I have are rated beyond that. (And why I chose this particular ohm / setup. Because it was safe on all batteries in the lineup just in case I wasn't thinking and switched to the smaller battery.)
What I want to know is what is the immediate reaction when it gets past the tipping point. A jet of flame into my pocket? Or just hot gases bubbling out of the vent holes, gradually increasing in intensity until the battery melts down like a mini reactor core? Is the vent an instant dump of extreme volume, or gradual?
This may seem like an odd question. But I want to know the consequences so that I can react appropriately if it does happen. What if I'm in my car, at work, in my house. I need to know ahead of time WHAT I need to do if it does happen. Since there is no way to stop it, I'd like to know how to handle such a situation as safely as possible given the worst happens.
If it just instantly blows up like a bomb. Then whatever. You don't prepare how to react for that. You painstakingly monitor the things that could cause such a situation and focus on prevention. But if say you have 5 seconds before things get to the point where you simply cannot handle them. Then that's 5 seconds that can be used to move the mod to a steel sink. Pull over and exit the vehicle. etc.
What's my window?
My mech is a nemesis. It has quite a few vent holes.
The 'jet' you refer to is a flame? Or just hot expanding gasses? Like what am I dealing with here? A torch of flame? An enormous volume of noxious gas capable of pressurizing and bursting a metal tube? This happens in one second? 3 minutes? 5 minutes? 15 seconds?
My batteries don't even get warm at this load. The atomizer / steel drip tip gets VERY warm. But I've even popped the battery to make sure. I'm using Sony 18650 VTC4's. And the new Efest 18650 rated at 35amps. Again the max load on the battery with this setup pulls 5 amps. The little 18350 Efest's I have are rated beyond that. (And why I chose this particular ohm / setup. Because it was safe on all batteries in the lineup just in case I wasn't thinking and switched to the smaller battery.)
What I want to know is what is the immediate reaction when it gets past the tipping point. A jet of flame into my pocket? Or just hot gases bubbling out of the vent holes, gradually increasing in intensity until the battery melts down like a mini reactor core? Is the vent an instant dump of extreme volume, or gradual?
This may seem like an odd question. But I want to know the consequences so that I can react appropriately if it does happen. What if I'm in my car, at work, in my house. I need to know ahead of time WHAT I need to do if it does happen. Since there is no way to stop it, I'd like to know how to handle such a situation as safely as possible given the worst happens.
If it just instantly blows up like a bomb. Then whatever. You don't prepare how to react for that. You painstakingly monitor the things that could cause such a situation and focus on prevention. But if say you have 5 seconds before things get to the point where you simply cannot handle them. Then that's 5 seconds that can be used to move the mod to a steel sink. Pull over and exit the vehicle. etc.
What's my window?
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Yeah, I wouldn't go there yet. There's been several articles about people having their batteries blow up on them. A man in Florida had that happen to him about a year or two ago and it knocked out most of his front teeth. My mom showed it to me as a "You should stop using e-cigarettes now" lecture, but if you go with the batteries at a supplier you should never have that problem... so long as you charge it on the proper charger and don't do anything really stupid with them. See the guys above who are smarter than me.
I'm using an intellicharger and the measured voltage of the batteries at full charge is never more than 4.17-4.18. I do not leave them on the charger for long periods either and ALSO monitor the temperature while charging to get an idea of the condition of the charger and batteries.
I also check the batteries periodically with a voltmeter. I have a thread in 510 meter for quick checks, but also use standard VM when at home. In fact, I think I've approached this with extreme caution and care.
So what happens exactly when the battery goes? What's the time line?
I also check the batteries periodically with a voltmeter. I have a thread in 510 meter for quick checks, but also use standard VM when at home. In fact, I think I've approached this with extreme caution and care.
So what happens exactly when the battery goes? What's the time line?
Above a certain temperature, the difference becomes academic. Suffice to say that tissue or fabric will burn when exposed to it. The actual material being ejected probably isn't itself aflame, just super-heated gas. I'd still call it a flame-out due to the temperature and ability to light other things on fire.
But like I said, the difference is mostly academic.
Seconds. Semi-controlled failures may not be terribly noticeable, except that your mod gets hot and the battery stops working (that's fairly normal with an IMR failure). ICR failures are very fast--a second or three, although I've heard it feels like about ten years--and eject a good volume of gas.
The gas itself isn't toxic, just really, really hot. I'd advise against breathing it, but incidental exposure doesn't require a call to Poison Control or anything.
Warm attys are normal, mine gets warm at 2.2 ohms and if I'm chain vaping, warms the entire tank.
Shattering themonuclear reactions won't happen, but there's no good way to determine how a given battery will fail.
Best case, they get very hot and stop working and you don't notice any other effects than that. While IMR batteries can fail spectacularly, they tend to fail best case on average--but there are no guarantees. There's essentially no warning that this is going to happen.
Worst case, they jet four inches of extremely hot gas from their vent holes. If in your pocket, you'll be removing your pants very, very fast. There's essentially no warning that this is going to happen.
When lithium batteries fail, it's generally reasonably graceful and nobody has to change pants. Spectacular failures are rare and usually related to a dead short circuit, but sub-ohm vaping can push the limits and cause a less than graceful failure.
Regardless of the failure, there's generally little to no warning. If you're extremely lucky, thermal breakdown is slow enough that you hear a hiss for half a second. You're generally not going to be that lucky; breakdown takes place faster than human perception can notice.
Lithium batteries are a lot of energy in a very small package. When it goes, it goes fast--and goes all at once. A theoretical seven watts in a tenth of a second can generate one heck of a heat event.
I usually just listen to what Baditude says, but great to see you're being cautious before jumping in
This is why I avoid sub-ohm builds. If you know exactly what you're doing and understand the risks, more power to you.
In my case, I understand the risks and choose not to take them. My extremely expensive teeth are very close to that battery, not to mention my extremely pretty face.
MorpheusPA:12131769 said:
Just for clarity, as I'm not sure how it was taken.
I am not downplaying the need for safety precautions or awareness. I was simply stating that a lot of what I have learned about battery safety has come from reading Bads posts.
Ok so we are talking a full dump even in the best case scenario.
The video I saw on YT I just looked up showed about 185* at the battery. I also found a few of them shorting 18650's under water. One where the battery was trapped into a secondary container to measure the amount of gas expelled by the failing battery.
It appears to be a rapid, semi-violent dump. I can see where, if confined, super heated gas could instill a whole new level of fear of god into you when it does it's thing. It does not vent a large quantity however. IE: It's not a gallon of volume. It's not even half a cup.
I was just wondering how much warm up there was before the pitch, so to speak. Still undetermined I guess, depends on the method of failure.
The video I saw on YT I just looked up showed about 185* at the battery. I also found a few of them shorting 18650's under water. One where the battery was trapped into a secondary container to measure the amount of gas expelled by the failing battery.
It appears to be a rapid, semi-violent dump. I can see where, if confined, super heated gas could instill a whole new level of fear of god into you when it does it's thing. It does not vent a large quantity however. IE: It's not a gallon of volume. It's not even half a cup.
I was just wondering how much warm up there was before the pitch, so to speak. Still undetermined I guess, depends on the method of failure.
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