Battery Safety & Understanding

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This blog article is an adapted version of an article written by Timmothy Braun, an vapor enthusiast and battery expert. This is the first part of two parts. This is provided for those mod users who desire a more technical understanding of the batteries used in mods, and should provide a better understanding on the different battery chemistries and how to identify the proper battery for your intended application.

In a mechanical mod with a metal piston switch and no wiring, your weak link is the battery. This is not a link you want to break while it is in close proximity to your face. Over taxing a battery in a mech can create a little pipe bomb.

Thermal runaway

Too many people are jumping into mechanical mods without understanding what they are getting into and not realizing it is not a care-free device like an eGo or Vamo. It requires more attention to details and a better understanding of all the variables. Too often people on forums say, ” Mech mods are easy, just drop a battery in and go. I don’t understand why others say it is not for beginners.” Because if you don’t understand all the things you need to watch for there is a serious chance of something possibly going wrong down the road.

Mech mods are not learning devices. They need to be understood before you begin to experiment with them. So far people have been lucky. Some people don’t check the batteries they use, don’t know what resistance their coils are at etc, and nothing has happened, giving a false sense of security to others to try the same things, but all it will take is one bad coil or one bad battery to change someone’s face forever.

These batteries were not originally intended for what we are using them for. In fact, I have read that Panasonic, Sanyo, Sony, and Samsung, don’t even like the fact that we’re using these batteries because they were not intended for single cell, unprotected use in any device. The fact that they’re available can be attributed to modders of flashlights, pen lasers, and bicycle electronics. A demand formed around those markets and it was filled by various folks, and then e-cigs came along and the demand skyrocketed.

With some basic knowledge of battery and mod limitations, and always using safe battery practices, using these batteries for vaping can be considered reasonably safe. Just please always respect the power that are in them. – Baditude




Batteries are the most rudimentary part of any e-cigarette. It is the life force which drives the entire industry. With the initial e-cigarettes, the consumer didn’t have to worry about the type of battery their e-cigarette contained, only that it was safe and you screwed it into a charger when it was empty. With the explosion of the mod market, (no pun intended), and the rise of low resistance atomizers, the need for a more educated consumer has grown considerably.

This article covers what all the mystical numbers mean and how they affect your vaping experience. I will attempt to keep it as simple as possible without getting too technical and putting everyone to sleep…

What do all those numbers and letters really mean? The entire sequence can be broken down as such:
the first letter indicates the basic chemical makeup of the battery. The second, and most important letter indicates the material. “I” indicates the battery is a Lithium Ion class battery. “C” indicates the material as cobalt; “M” indicates manganese; “N” indicates nickel. “R” indicates it is rechargeable. Knowing this, “ICR” means Li-Ion/cobalt/rechargeable; “IMR” means Li-Ion/manganese/rechargeable. Using manganese or nickel makes the battery a “safer chemistry”.

Battery identification can be one of the most difficult aspects of battery purchasing. All batteries are not created equal and just because two batteries are labeled IMR18650, does not mean they have the same capabilities, characteristics and safety features.

The batteries we use in e-cigarettes generally follow an industry defined identification scheme consisting of 3 letters followed by 5 numbers, ie. IMR18650, ICR14500, NCR18650 etc. The first three letters indicate the battery basic construction and capabilities. The following series of numbers indicate the batteries approximate physical size and shape.

Battery duty cycle refers to the approximate number of recharges it can be “cycled” through before the battery will no longer hold a charge. Duty cycles can be 500 charges but will vary depending on the core battery composition.

It should be noted that while a lithium ion battery does not have “battery memory”, the capacity of the battery will diminish over time as you progress to the end of it’s life expectancy. This means you do not have to fully discharge the battery before charging it like you do with many other rechargeable battery types. You can also use it from the get go without first taking it home and throwing it on the charger, assuming it has a charge left when you receive it.

Stealthy Statistics

The battery identifier described above tells a basic story on what the battery can handle, but for
an ecigarette,and more notably modders, one of the most important ratings is the maximum discharge rate. The maximum discharge rate became more prevalent when vapors started designing their own coils. With the natural progression of things, our extreme inner drive to produce more vapor, and sub-ohm (< 1.0 ohm) resistance coils, we are dancing dangerously close to the physical limitations of lithium ion batteries.

The maximum discharge rate is generally measured in C and indicates how much current (Amps) you can draw from the battery without causing physical harm to the battery and yourself. Pull more than the maximum discharge rating and the battery becomes unstable, goes into a state of thermal runaway and can exhaust hot gasses, large flames or explode. Quite often, a mod’s features will include terms like “battery vent holes”. These holes are in place to safely guide hot gasses and flames away from your face in the case of most battery failures.

The C measurement unit can be a bit hard to understand. The C measurement indicates a current value relative to the batteries overall capacity. For instance, a 2,600 mAh battery with a maximum discharge rating of 1C can handle a maximum current draw of 2.6 amperes or 2,600 mAh; pretty simple. Change the rating to 2C and the maximum discharge rate is 5.2 amperes, 3C is 7.8 amperes, so on and so forth.

Battery Types:

AW 18650 IMR battery

IMR, or Manganese (Li-Mn) cathode batteries are modders’ preferred battery type. IMR batteries originally used a simple manganese cathode which provided for much higher discharge rates than its ICR counterpart. This was not without a loss though. With the manganese high drain cathode, IMR batteries had a much smaller duty cycle and overall battery capacity was nearly half of the ICR.

Over time, manufacturers started mixing manganese with nickel to improve the duty cycle and capacity of the battery with only a slight reduction to the maximum discharge rate. IMR batteries have a safer basic chemistry than ICR batteries as they can sustain higher internal temperatures before becoming unstable. The manganese cathode has a much lower internal resistance as well, which is the driving force behind the higher drain rating because resistance has a direct correlation to heat generation.

Most IMR batteries have maximum discharge rating of 10 amps, with some IMR or hybrid /IMR batteries having up to 30 amps. This is due to the balance of higher capacity and high drain of todays batteries. It is critical never to assume the maximum discharge rating though. If in doubt, Google can be used to find your battery’s data sheet which will state the continuous discharge rate in amps.

AW Protected ICR battery

ICR, or Cobalt electrode batteries were the original form of lithium ion batteries. These batteries can handle most atomizers we buy over the counter today. ICR batteries are known for their higher capacities and are suited for the average vapor’s device, but they are not at all well suited for use in advanced devices.

Using Ohm’s Law, running a device at 4.2v with a 1.8 ohm coil will draw 2.3 amps from the battery. This is safely below the 2.65 amp rating of the average 2600 mAh ICR 18650 battery. However, using a homemade 1.0 ohm coil at 4.2v on a RBA will draw 4.2 amps which is way over that battery’s rating and would not be safe to use.

Panasonic NCR18650PD hybrid battery

NCR batteries are a new type of “hybrid” battery manufactured by Panasonic and others. NCR batteries use a Cobalt cathode like ICR batteries but have the same hybrid makeup with nickel which IMR batteries have. This provides for higher drain capabilities while also having higher overall battery capacity.
Note that not all NCR batteries are considered “high drain”; Panasonic NCR18650B 3400 mAh and NCR18650A 3100 mAh are not high drain. – Baditude

The downfall of NCR batteries for e-cigarettes comes from how their capacity rating is calculated. NCR batteries are capable of a much lower minimum discharge voltage before causing physical damage to the battery. The battery is capable of being discharged to 2.5V whereas IMR/ICR batteries have a cutoff around 3.2V.

NCR batteries also have a feature called HRL or Heat Resistant Layer. HRL is an extra layer of material around the catode that prevents the battery from overheating even during internal short conditions. This makes it one of the safest batteries on the market but you lose 20 – 30% of the battery capacity due to general voltage range limitations mentioned previously.

Protected vs. Unprotected

There is a common misnomer in the vaping community that a protected battery is safer to use than an unprotected battery. There is a belief that a protected battery will prevent you from over-drawing your battery and prevent it to explode or vent gas. I’m not certain where this belief started, but it needs clarification. A battery labeled as “protected” does not always prevent you from applying a higher current draw than it is capable of handling.

The term “unprotected” is vague and often misunderstood. It can mean a “safe chemistry IMR or hybrid” that doesn’t use a protected circuit, or an “unprotected ICR battery”. Unprotected ICR batteries should NEVER be used in a mod; they are used in other applications such as flashlights or laptops. – Baditude

The protection circuits in batteries vary from manufacturer to manufacturer, but primarily prevent you from over-discharging (using the battery past its minimum charge rating) or over-charging the battery. The “protection” moniker is not all-inclusive either. Some will provide just over-discharge protection, others have over-charge protection, and in some batteries over-current protection.

You will have to hunt down the data sheet from the battery manufacturer to find exactly which protections are provided, or hope that your merchant has this listed online. Protected batteries are quite often longer in length than their unprotected counterpart. This is due to the additional circuitry that is embedded in the battery. Confirm measurements before you commit to purchasing.

Now, this said, lithium ion batteries have what’s called a PTC or Positive Temperature Coefficient circuit. This is built into the battery just above the positive terminal and is present regardless of any “protected” labels. The PTC is designed to raise the resistance of the battery as the temperature of the battery rises.

The theory behind PTC is that as the resistance goes up, the current draw from the battery goes down – Ohm’s Law. This helps prevent most accidents from becoming catastrophic, but it should not be relied on. The PTC is designed to be unobtrusive and you can still over-draw the battery if you aren’t paying attention. The PTC circuits can also fail if exposed to static electricity or from a faulty charger. When a PTC fails, it often fails in a position which allows you to continue using the battery without fault.

Ohm’s Law 101

Ohm’s Law defines the relationship between Voltage, Resistance, and Current, or: I = E / R

E = voltage (volts)
I = current (amps)
R = resistance (ohm

If you are building your own coils, you should make yourself familiar with Ohm’s Law. This will allow you to calculate the draw on your battery before you fire it up for the first time and potentially push the battery past its limits.

Ohm’s Law Calculator

Basically, if I build a coil that has a resistance of 1.5ohms, and I apply 4.0v across it:
4.0v / 1.5ohm = 2.6 amps:

This means you will have a 2.6 amp current draw on your battery. If I was using an ICR18350, I would be pushing the limits of the battery while an IMR18350 would accept it with ease.

What exactly is an AW anyway?

Anybody who owns a Provari knows about AW from Provapes’s nice little warning about voiding the warranty if a non AW battery is used. AW are the initials of a man Andrew Wan, who owns a China-based company which purchases batteries from the big boys (Panasonic, Samsung, etc) and performs quality tests. Once the battery passes the quality tests, they slap on a sexy shiny red wrapper and add their AW label to it.

The reality is that internally, a battery labeled AW and a battery labeled Panasonic, Samsung, etc are the exact same thing. Aw has just run it through a foray of tests. Does it make their battery safer? Not really. Does it help ease the mind? Absolutely.

Inline fuses are becoming more popular as more people venture into the market of rebuildable atomizers. Inline fuses are small, disk-shaped components which you place inside your mod below the negative terminal on your battery. An inline fuse, commonly rated at 7 amps, will prevent you from accidentally pulling too much current from your battey either from device failure or low atomizer resistance. Inline fuses are fairly inexpensive, but do add have small space requirements to fit into the battery compartment of the mod. If you are using a mechanical mod and you can fit one with your battery, I would suggest you add one or two to your setup. If you are using a regulated mod like a Vamo, ZMax, Provari, etc, an inline fuse is probably overkill as this protection is already built into their processor circuitry. Both Smok and Vape Safe offer inexpensive inline fuses which are specifically designed for e-cigarettes..

Vape Safe Mod Fuse

Stacked or Unstacked?

In some mods, you can fit two 18350′s when the mod is configured for an 18650. This boosts the voltage output from 3.6V to 7.2V which means more vapor. Yay. BUT, you should NEVER do this. Unless you are familiar with matching batteries, you are only endangering yourself and others. Sometimes, just because you “can” doesn’t mean you “should”.

You may think, “Well, shucks, laptops have multiple batteries in them, why can’t my e-cig?” Laptop batteries are specifically designed for stacking and are paired for use at the factory. When using un-matched batteries, they will discharge and provide current at different rates. This means one battery will continuously take more of the stress than the other.

You may not notice any trouble at the start, but as the batteries age with use the problem will become more severe. Push the batteries a bit further and now you’ve entered the realm of thermal runaway (see pics at beginning of this blog). Downside being that one battery entering thermal runaway will push the other battery into thermal runaway. Now you have two small, flaming explosives only inches from your face. Save your teeth and home, don’t stack batteries .


Choose your batteries wisely. If in question, go with AW IMR high drain batteries. If you are building your own coils, make sure you test first before firing for the first time. If using sub ohm, make sure you are using the appropriate battery that can easily handle the amp draw of your coil. Never assume that since your configuration worked once, then it is safe to use continuously and repeatedly – coils can drastically change in resistance.


The above information was adapted and condensed from an article written by Timothy Braun, a vapor enthusiast and battery expert. – Batteries Explained and Safety – » The Original Electronic Cigarette Social Media Network


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