Exploding batteries on sub-ohm builds

[anavidfan]

I had a battery vent last summer. I think Ive posted this before , so some might have heard it.

Long story short, resistance 1.1, AW IMR 18500 battery. No shorts, ELA telescopic. IT was in my car , real hot day, over a 102 , in the car ? I was lost and driving around with no air conditioning. Not really chain vaping. I put it down on a towel I keep to place it on. I picked it up and the whole device was loose and apart at the locking ring. I thought hmm. Next light tightened it up , took a few puff or two. Put it down. Again , picked it up and it was hot and all apart. THis time I left it alone , got home opened it up and saw that the battery was sweaty looking, and the neg end looked as if it had rust coming from the sides of the round end.
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I took the battery out and put it aside, wrote on here about it and the consensus was that with the heat in the car it vented. I dont remember smelling anything or seeing a toxic cloud. It being a IMR AW and the fact that my device did what it was designed to do in case of a "venting" all was well. There is a lot of confusion when buying batteries, we see some that are called "protected" and then we see high drain or IMR and wonder if these are safe. Both are safe and designed with safe chemistry. The AW IMR , like other high drains are made with a LOT less or no oxygen so they are not supposed to catch fire. I really dont know the details on why some are called protected and others are not called protected but still safe.

 

[ut1205]

If you wouldn't think of taking a piece of wire and shorting the positive and negative terminals of a battery (any battery) then you probably shouldn't think about sub ohm vaping.

 

[maxd]

sssshh that is already a reason to ban vapes on airplanes..... picture it: a airplane blown up with a sub ohm battery...

well, how about other batteries ? notebooks and cell phones....

sub-ohm vaping ... dont know ... it is different from the way you normally would vape,

some people like it and other - not

and it is not yet about battery and safety...

 

[MorpheusPA]

well, how about other batteries ? notebooks and cell phones....

Notebook batteries do occasionally fail very spectacularly and, for an item that can be sitting in your lap when it happens, that's a problem. Those batteries are on order 10-20 amps, but do tend to be in battery packs. It's unlikely for more than one cell to fail at a time.

I haven't heard too much about cell phone battery failures, but I'm sure it happens. Phones are a low-draw appliance but with micro-miniaturization the batteries keep getting smaller. Either they have to increase energy density in the batt or increase the drain in comparison to the capacity.

and it is not yet about battery and safety...

It always should be, particularly when pushing the envelope on your battery.

I design little electronics projects for home use and gifts and tend to include safety factors of 50% at minimum. That's on something that if it fails spectacularly it simply ceases to work and won't burst into flame, explode, and isn't near my face. NiMH batteries aren't known to fail spectacularly under any semi-reasonable circumstance. Safety factors in this case translate into durability and increased tolerance to harsh conditions.

For something near my face and having a high energy density, 100% safety factor would be my personal comfort point (I'm pretty conservative when it comes to losing teeth). And even then, I'd be happier if it were higher than that...

 

[Asmo6]

sub-ohm vaping ... dont know ... it is different from the way you normally would vape,

some people like it and other - not

This is not something I just 'wanted to do'. I'm not a lung dragger blowing huge clouds. I was chasing flavor in an Aqua. Math, and more importantly ohm's law put me at that particular resistance.

Here's why.

On a mech mod, the battery - and nothing else determines voltage. (aside from voltage drop from it's connection inside the mod) My mod drops < than .07v so. Let's just say 0.

Fresh off the charger the battery is spitting out about 4.15-4.17v. As it gets used, it will slowly drop down until I get to about 3.5-3.4v at which I pop it back on the charger. If you calculate voltage against resistance. (ohms) It will give you wattage. Wattage, is basically heat @ the coil. Obviously coil design, wicking, juice, and the atomizer design all effect performance. But if you look at the wattage as a descending power curve. (As the voltage drops under use) You will see a .8ohm coil start at about 22 watts. (4.2v) It's load is 5 amps at the battery. @ 3.5v, about 15 watts is still available at the coil. 4.4 amps load.

The point of the mech mod is that it is not constrained by chips, boards, and switches rated at a low amperage that you can burn out. It's a metal tube with an on / off switch. With that obviously comes some safety issues compared to a regulated mod. But also a ceiling as high as the battery can handle. (Let's take my Sony for example. Which is 30amps) On paper, that would require 4.2v at (point) .14 ohms. Pumping out 126 watts...

Ok back to square one. I did not start at .8 ohms. I started at 1.8ohms. And down, and down and down. What I was trying to do is set an appropriate power curve I would be satisfied with from start to finish. (4.2v-3.4v) Since I don't get the benefit of the voltage being regulated from start to finish like on a VV or VW mod. I have to set up a curve that is good from beginning to end.

Then came the size and type of coil. And diameter wick, to block flooding in the aqua's feed channels, and also resist drying out when vaping repeatedly. I found running a non-micro coil, but a tightly wound one, with increased wattage allowed me to get more flavor out, and run cotton wicks big enough to stop flooding but remain saturated with back to back vaping. (checking the wicks for tell tale singe marks near the coil edges.)

I didn't just go - oh yeah, watch me, billy bad ..... Here I go.

It took some trial and error with a goal in mind.

And for the record, when I say very warm on that drip tip. 22 watts on the third drag in a row - you TAKE your mouth off. It's hot. Like uncomfortable. So I genuinely can't see me pushing much further in this device. But again, the point was achieving a specific power / flavor level without the benefit of a chip regulating output voltage.

That's why sub-ohm. That was how it was getting there. Not just because.

 

[ZeroOhms]

Lots of great post here.
One thing I would add is, if you want to use mech mod, you can always use safety fuse or kick for added protection.
These will cut the power if the battery is pushed too hard.
These aren't absolute solution but will provide added safety of VV on your mech mod.

 

[Asmo6]

Lots of great post here.
One thing I would add is, if you want to use mech mod, you can always use safety fuse or kick for added protection.
These will cut the power if the battery is pushed too hard.
These aren't absolute solution but will provide added safety of VV on your mech mod.

There are also fuses. (2 cent safety fuse) That will help protect against a hard short on the battery.

The underlying problem of the kick in a mech mod is it cuts the fun off at a similar point any of the newer VW mods do. 12-15W. You get the regulated bit, where it will keep and hold that specific wattage as long as it can. (until supplied voltage drops to a certain point.) So it will be consistent.

But you cannot bring the hammer down on a rebuildable atomizer in a mech like you can without it.

There is an insane difference between 20W and 12W.

Also, as some chips regulate voltage over a span of time, instead of the actual output voltage. IE: to get 2.5v it fires 5v 50% of the time it's being fired. So you get a pulsed current. You get none of that with the mech. (And some VW devices not using a chip that cycles voltage as a duty cycle.)

Kicking a mech mod caps the power. The great part though is, it comes right out.

 

[Burnie]

Well another 1 post and 3 pages of reply's, and the OP is nowhere to be found.

Time for some more

Vape On
Burnie

 

[caz345]

Ive had the batteries in my Surefire flashlight explode on me, first it hissed and vented hot gas for a good 15 seconds then it went bang like a M80, I tossed it on the tile floor as soon as it started to hiss then took cover, lol. Luckly this light was built like a brick @#$@ house and the explosion was contained so I got lucky.

 

[ZeroOhms]

Ive had the batteries in my Surefire flashlight explode on me, first it hissed and vented hot gas for a good 15 seconds then it went bang like a M80, I tossed it on the tile floor as soon as it started to hiss then took cover, lol. Luckly this light was built like a brick @#$@ house and the explosion was contained so I got lucky.

Imagine that happening a few inches from your face with burning coil. Yikes!

 

[G8GTJav]

Good info. Sounds like you have a lot of good or may be bad, lol, battery experience under your belt. I carry my batteries in a case but your example of what can go wrong when you carry batteries in the pocket is a good one.

 

[Baditude]

The vast majority of vapers have never had a battery/charger incident. Maybe they've been lucky, the law of averages have been in their favor. The vast majority of battery incidents have been due to user error or using poor common sense judgement. Things like leaving bare batteries exposed to metalic objects (change or keys in a pocket or purse, completing the electrical circuit and over-discharging the battery). Or using an unknown faulty battery or charger and leaving them unattended.

Having experienced a battery go into thermal runaway in a mechanical mod, I have consciously chosen to not do sub-ohm builds. It's just too close to being a dead short, and it has been my decision to not put myself into a higher risk category. I use safer-chemistry high-drain IMR batteries in all of my mods, whether they are regulated or mechanical. I no longer use protected ICR Li-ion batteries and never recommend them for use in any mod; in this day of modern battery technology there is no reason to use them.

I choose to use my regulated mods more than my mechanicals; first because I prefer the options a regulated mod provides me, but second because of their added built-in protections that a mechanical mod simply does not have. Protections such as timed auto-cutoff of the fire switch, short circuit protection, processor shutdown if a short circuit exists, thermal protection, reverse battery protection, built-in ohm and voltage meters for easier coil and battery checking, etc.

Even a safe-chemistry IMR battery can explode. AW IMR batteries have long been considered the safest battery that you can use in a mod. Rechargeable Batteries The below AW 18490 IMR battery was a spare battery being stored in a bookbag. It apparently made contact with some metal in the bag and vented dramatically. What you see is what is left of the bare metal casing, with the contents of the "guts" of the battery which shot out of the casing. The heat from the hot gas expelled scorched the bookbag and melted off the plastic shrink wrap of the battery. Imagine this happening in a mechanical mod with inadequate vent holes or none at all. Batteries going into thermal runaway can swell and increase in size, potentially blocking off the vent holes of the mod (see pic), effectively turning a metal tube mod into a pipe bomb.

Using common sense and practicing safe battery habits will lower the chances of this happening to almost being negligable. However, shorts can still happen in our mods despite practicing battery safety. No battery can be considered 100% totally safe (even those 30 amp batteries). Only you can decide if using sub-ohm coils is worth the added risk.

AW IMR battery

 

[FourWinds]

Those little automatic cig-a-like batteries can be an issue. I've read a couple of reports of peeps taking a hit and throwing the little thing into a pocket, only to find that the auto switch decided not to disconnect! You could end up with a hot pocket real quick.