(12) Deeper Understanding of Mod Batteries - Part I
by, 10-24-2013 at 09:05 PM (30192 Views)
This blog article is an adapted version of an article written by Timmothy Braun, an vaper 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 hand or face. Over taxing a battery in a mech can create a little pipe bomb.
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 most novices have been lucky. However, some people don't check the batteries they use, don't know what resistance their coils are 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.
_______________________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?
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.
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 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.
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 continuous discharge rate. The maximum discharge rate became more prevalent when vapors started building 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.
Guide to Battery Specification Terms
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 18650 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 such as a regulated variable voltage mod or a mechanical mod with RBA attachment.
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.
End of Part I - click here for Part II