From what I have read and understand - there is a risk with all batteries - including cell phones, laptops etc. I think sub ohm is slight riskier than 1 ohm and above...............
How is sub-ohm vaping dangerous?
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V=Voltage (V)
I= Current (A)
R= Resistance (ohm)
OHMS LAW for DC Applications
EQ1. V=IR
EQ2. Rtot=Rbattery+Rcoil+Rmechmod
Substitution
V=IRtot
V=I(Rbattery+Rcoil+Rmechmod)
Adjusting equation for current
I=V/Rtot
I=V/(Rbattery+Rcoil+Rmechmod)
Now lets use real numbers and a real world example. Let's say you make an amazing 0.3 ohm coil because you can and you use an AW IMR 18650 2000 mah battery on a decent mech mod. The engineering values for the equation would be:
Rbattery=0.05 ohms (assumed for AW batteries)
Rmechmod=0.05 ohms (assumed for mech mod)
Rcoil=0.3 ohms (lets use this for our example)
V=4.2 volts (freshly charged battery)
Solving for current
I=4.2/(0.3+0.05+0.05)
I=4.2/(0.4)
I=10.5Amps
AMP Limit is 10A for AW IMR18650 2000mah
So now your are running your system at 10.4 A which is above the rated limits of your battery keep it up for too long and this can cause catastrophic failure of your battery.
So the variables you can easily control as a user are the following:
Voltage= You can reduce your risk by using your battery slightly discharged
Resistance= You can increase the resistance (ohms) to ensure that you will never cross your batteries rated current limits based on the highest potential battery voltage. In most cases the highest actual voltage will be around 4.2 volts. So based on that you should really keep your coil resistance above 0.4 ohms.
Hopefully this helps out.
Please note that I have never ever built a single coil in my life and I have just gotten into the vaping world, but I do have an engineering background.
I take no credit for the resistance values and the link below actually goes into a really good discussion on coil voltages.
http://forums.aussievapers.com/e-ci...0-voltage-drop-under-load-explained-well.html
I= Current (A)
R= Resistance (ohm)
OHMS LAW for DC Applications
EQ1. V=IR
EQ2. Rtot=Rbattery+Rcoil+Rmechmod
Substitution
V=IRtot
V=I(Rbattery+Rcoil+Rmechmod)
Adjusting equation for current
I=V/Rtot
I=V/(Rbattery+Rcoil+Rmechmod)
Now lets use real numbers and a real world example. Let's say you make an amazing 0.3 ohm coil because you can and you use an AW IMR 18650 2000 mah battery on a decent mech mod. The engineering values for the equation would be:
Rbattery=0.05 ohms (assumed for AW batteries)
Rmechmod=0.05 ohms (assumed for mech mod)
Rcoil=0.3 ohms (lets use this for our example)
V=4.2 volts (freshly charged battery)
Solving for current
I=4.2/(0.3+0.05+0.05)
I=4.2/(0.4)
I=10.5Amps
AMP Limit is 10A for AW IMR18650 2000mah
So now your are running your system at 10.4 A which is above the rated limits of your battery keep it up for too long and this can cause catastrophic failure of your battery.
So the variables you can easily control as a user are the following:
Voltage= You can reduce your risk by using your battery slightly discharged
Resistance= You can increase the resistance (ohms) to ensure that you will never cross your batteries rated current limits based on the highest potential battery voltage. In most cases the highest actual voltage will be around 4.2 volts. So based on that you should really keep your coil resistance above 0.4 ohms.
Hopefully this helps out.
Please note that I have never ever built a single coil in my life and I have just gotten into the vaping world, but I do have an engineering background.
I take no credit for the resistance values and the link below actually goes into a really good discussion on coil voltages.
http://forums.aussievapers.com/e-ci...0-voltage-drop-under-load-explained-well.html
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Yes there are risks, but the problem with mech mods is there normally isn't a safety circuit to shut down a thermal runaway. A fuse is cheap safety precaution for mech users.
most batteries have a burst rating and a continuous rating. for example, mnke's are rated 20a continuous, 60a burst.
the problem is that everyone seems to have their own idea of how long a burst is. i don't know myself, but i wouldn't personally take a 10 second hit at a higher current than the battery's continuous rating.
also, general rule of thumb, if your battery is getting warm (not hot, just warm), you're probably stressing it and should either go higher resistance or better batteries.
Sometimes it's hard to determine if the battery is actually warming or it the atomizer is warm/hot and transferring that heat, via conduction, to the battery case/ mod. Also just because a battery warms in general, doesn't necessarily mean one is in danger. Think of cellphone batteries.
This all comes down to staying within the limits of your knowledge. Start doing things outside that area and you may increase the risk of danger.
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all you need to know is the C-rating of your battery and two simple equations.
Kemsobabe - I am using an SVD with Panasonic CGR18650CH Rechargeable 2250mAh 3.7V 18650 Lithium Batteries and a Kanger protank - it appears this has a C rating of 10. So using ur formula - I get 10 x 2250/1000 = 22.5 draw...plugging that into Ohms law at 4.2 Volts = 0.18667. So looks like I should be ok with 1.4-1.8 oh coils?
Also - I keep getting conflicting info on ICRs - (ICR18350 3.7V "900mAh" Rechargeable Lithium Battery) are they safe or not to use with a Vamo V2 and SVD? I dont intend to stack em.
Thanks for your assistance.
Kemsobabe - I am using an SVD with Panasonic CGR18650CH Rechargeable 2250mAh 3.7V 18650 Lithium Batteries and a Kanger protank - it appears this has a C rating of 10. So using ur formula - I get 10 x 2250/1000 = 22.5 draw...plugging that into Ohms law at 4.2 Volts = 0.18667. So looks like I should be ok with 1.4-1.8 oh coils?
Also - I keep getting conflicting info on ICRs - (ICR18350 3.7V "900mAh" Rechargeable Lithium Battery) are they safe or not to use with a Vamo V2 and SVD? I dont intend to stack em.
Thanks for your assistance.
ICR batteries are not considered "safe chemistry". They will explode. (in a runaway situation)
This is why they are available in "protected" versions. They need protection.
This is why they are available in "protected" versions. They need protection.
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I'm sure that there are lots of ways in which stupid or unfortunate disasters can occur in relation to vaping and handling vape gear. There seem to be two categories, however, which figure prominently. One is a hard short of the battery. This is where (by whatever means, a bad switch or atomizer, the change compartment in your car, or the misapplication of a bent spork) the two ends of your battery are allowed to form a complete and substantially uninhibited circuit. Here, your battery is discharging in an uncontrolled fashion, faster than it can handle; and it either gets very hot (250degF) and/or vents gasses and/or explodes. The resistance of your build is irrelevant here, and having a 3Ω coil in your topper is no safer than 0.3Ω. With this situation, one can try to be safe by using "safe chemistry" batteries. IMR batteries are considered safe chemistry because the Manganese (IMR) is less volatile than the Cobalt (ICR). The one will get very hot, the other will explode. Take your pick. (protected batteries have a little "circuit breaker" that shuts the battery down if too many amps are flowing . . . if it works)
The other thing that could happen (and this is where resistance matters) is that your battery is drained, not at a freefall rate, but at a rate that it isn't designed to do without going apesh_it. Meaning that, if you draw more than the limit, you are risking internally triggering the same reaction as is caused by a hard short. However, here, your are doing it "intentionally". Surprisingly, there are batteries (18650s) on the market, that can't do more than a 2 or 3 Amp draw safely. People complain that their protected batteries keep shutting down and they can't vape their setup. That could be on a 1.3Ω coil. My batteries can comfortably handle a 24 Amp continuous draw. That means I can stand there, holding the button down, on a 0.2Ω coil and stay within the product's specs. I like 0.5Ω. Lately, I've been tipping into the 0.4Ω region.
This is the kind of information one should have a decent grasp of before using a mechanical mod, more so before vaping superlow resistance. That doesn't mean you just read this . . . . that means you could explain it to someone else.
The other thing that could happen (and this is where resistance matters) is that your battery is drained, not at a freefall rate, but at a rate that it isn't designed to do without going apesh_it. Meaning that, if you draw more than the limit, you are risking internally triggering the same reaction as is caused by a hard short. However, here, your are doing it "intentionally". Surprisingly, there are batteries (18650s) on the market, that can't do more than a 2 or 3 Amp draw safely. People complain that their protected batteries keep shutting down and they can't vape their setup. That could be on a 1.3Ω coil. My batteries can comfortably handle a 24 Amp continuous draw. That means I can stand there, holding the button down, on a 0.2Ω coil and stay within the product's specs. I like 0.5Ω. Lately, I've been tipping into the 0.4Ω region.
This is the kind of information one should have a decent grasp of before using a mechanical mod, more so before vaping superlow resistance. That doesn't mean you just read this . . . . that means you could explain it to someone else.
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pdib is right, a lot of the criteria is limited by your battery characteristics. If your battery is capable of the higher current load then you can go down lower in resistance.
What is important for people is if you are going that low in resistance you should have a solid grasp of current, voltage, resistance, and how they relate to each other and your system. Again exactly what pdib said.
What is important for people is if you are going that low in resistance you should have a solid grasp of current, voltage, resistance, and how they relate to each other and your system. Again exactly what pdib said.
Thanks Pdib - looks like it would be prudent for me to chuck the ICRs.....thanks.....
I don't have a engineering degree. I don't have a ton of vaping experience. That said, I do have some common sense. All hobbies or habits (whatever you clasify vaping as) have those who like to push the limits. Vaping is not entirely safe. Think about it - when you vape, you are using an electrical device close to your face. Risk and reward; it is tons of fun to go fast in a car, even more fun to go verey fast. But, (yes here comes the but) the faster you go, the more you can get hurt if you crash. Same logic here - some try to reach the outermost limits of vaping (.1 ohm coil) which can produce extreme clouds of vapor, but the more one risks, the higher potential for harm - if something fails. I do beleive that ecigs are still farely new (correct me if I am wrong - invented in 2005). Best thing about this free country - you can take the risks you want. IMHO if you want to try the ub-ohm world - go for it; just please remember, pushing the highest limits will always have the highest risk. I personnally don't see the need - I vape for the benifits of no analogs and the taste -don't need sub-ohm for either.
I think the issue we are looking at here is analogous more to someone souping up a go cart and letting the neighbor's kid borrow it. Meaning, the power inherent in this technology can be pushed to its limits intelligently with given risks; but we want to see some experience and knowledge (even some skill) accompanying that. We prefer to avoid people pushing the envelope in ignorance. Furthermore, the technology available can be used to produce some ba_dass results in a relatively safe setup if a person is willing to take a few minutes to learn how this stuff works.
A couple of years back, many of us here were trying to be rid of single-battery, unregulated mods like the plague. A smaller group were stacking batteries for high-voltage vaping.. Now, we are at single-battery sub-ohm vaping in large numbers.
Personally, I don't understand the draw towards this trend. I was under the impression most of us were vaping as a healthier substitute for smoking tobacco. (emphasis on substitute) I've read more posts than I care to count recently involving folks walking out of vape shops with pre-made sub-ohm coil devices, and batteries right on the edge or below of being able to safely handle them. What makes it worse is the purchaser's lack of knowledge of their device, and potential limitations of the batteries they're using at that resistance.
In almost 30 years of smoking (before I totally quit 3 years ago), I can't recall ever hanging out with my friends, and seeing how much smoke we could bellow out of a single drag.. Now with vaping, cloud-chasing is turning into a sport. I have to wonder how many younger folks who never touched a cig before are being drawn into this because they watched it on YouTube, or have a group of friends doing it.
I can see vaping as harm-reduction from tobacco, and a way to get our nic-fix responsibly. I can't see turning it into a potentially dangerous sport. I watched a few vids of sub-ohm vapers with hoarse voices, and going into coughing fits. How can that possibly be good? Pushing batteries to the edge of their rated amp-limit over and over is not good either. The more that non-smokers see this trend in public, and battery-related injuries / incidents are nationally reported, the greater the chance is of the FDA having all the ammo it needs to shut the door on vaping as we know it entirely..
Just My
Personally, I don't understand the draw towards this trend. I was under the impression most of us were vaping as a healthier substitute for smoking tobacco. (emphasis on substitute) I've read more posts than I care to count recently involving folks walking out of vape shops with pre-made sub-ohm coil devices, and batteries right on the edge or below of being able to safely handle them. What makes it worse is the purchaser's lack of knowledge of their device, and potential limitations of the batteries they're using at that resistance.
In almost 30 years of smoking (before I totally quit 3 years ago), I can't recall ever hanging out with my friends, and seeing how much smoke we could bellow out of a single drag.. Now with vaping, cloud-chasing is turning into a sport. I have to wonder how many younger folks who never touched a cig before are being drawn into this because they watched it on YouTube, or have a group of friends doing it.
I can see vaping as harm-reduction from tobacco, and a way to get our nic-fix responsibly. I can't see turning it into a potentially dangerous sport. I watched a few vids of sub-ohm vapers with hoarse voices, and going into coughing fits. How can that possibly be good? Pushing batteries to the edge of their rated amp-limit over and over is not good either. The more that non-smokers see this trend in public, and battery-related injuries / incidents are nationally reported, the greater the chance is of the FDA having all the ammo it needs to shut the door on vaping as we know it entirely..
Just My
Awsome post Technonut - my thoughts exactly. I love LOVE vaping, it has greatly helped me kick a 30 year smoke habit. Greatest fear for vaping - some poor fool will blow his face off - end up on the 5'oclock news and vape is outlawed. I fear the day I have to go through quitting cold-turkey again. 
You also have to Trust that the "C" Value actually is the Rating of the Battery that you are Holding in your Hand. And not a Number that was Derived Statistically from a Sampling of Batteries done by the OEM.
Or an Over Inflated Value meant to Entice people to Buy a Battery.
And of course, that the Silk Screened Info on the Battery in your Hand is Real and that you are Not just holding a Re-Wrapped Trustfire Flunky.
good point, zoiDman. This is one of many reasons why I go with the Maximum Continuous Discharge rating and not the Pulse/Burst figure. I know its not an accurate means; but it allows for discrepancies and leaves a large margin for my own error or the manufacturer/distributor's "error". Another reason to go with the Continuous Discharge rating is to account for accidental/unforseen continuous firing of the device.
There are not many local vape stores here, but the only person i trust to make a decent coil for my devices is me. If anyone is going to mess about with sub Ω coils then they had better tool themselves up. At the very least you need to be able to use a multimeter and take the batteries seriously.
Some people are able to achieve wizardry with coils ^^ for example! I am just happy to keep off the ciggies and get a satisfying vape with the minimum effort and risk.
T
Some people are able to achieve wizardry with coils ^^ for example! I am just happy to keep off the ciggies and get a satisfying vape with the minimum effort and risk.
T
Thank you pdid.
I've worked in the Manufacturing Sector and seen the "Trust in Numbers" Phenomenon too many times.
If the Amps are given by (C * mAh)/1000, and a Person wants to Crawl up to the Bleeding Edge of what a Battery can handle, then you had better be Sure that the "C" they use is Correct. But Also that the mAH is Correct Also.
If the "C" value is Statistically High and the mAh is Over Rated for the Physical Battery, how much is Error is there going to be on the Amp Value?
The Couple that with a Person using a $11 DMM with a +/- .2 ohm range for there Homemade Coils. Is this starting to Spiral Out of Control Number Wise?
Good Design Engineers, or Anyone Else for that Matter, take into Account what the Worse Case Scenarios.
And to me, the Worse Case Scenario is that a Person is Holding a Battery in their hand that Doesn't Physically have Either the "C" or the mAh that some e-Cig web site Description says it does.
Hence, all the Math is Meaningless.
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