(12) Deeper Understanding of Mod Batteries - Part I
Deeper Understanding of Mod Batteries (part I)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, -- IMR18650, ICR14500, NCR18650 etc. The first three letters indicate the battery's 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. "I" indicates the battery is a Lithium Ion class battery.
- The second, and most important letter, indicates the material. "C" indicates the material as cobalt; "M" indicates manganese; "N" indicates nickel.
- "R" indicates it is a round shape.
- Knowing this, "ICR" means Li-Ion/cobalt/round; "IMR" means Li-Ion/manganese/round. "INR" means Li-Ion/nickle/round. 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.
It should be noted that you will get longer life expectancy from a battery if you don't drain them down each time you use them. "Topping them off" once they reach about 3.5 volts is better than using them until they stop working and causes no harm. Charging after "half" of a duty cycle of use will prolong the overall life expectancy of the battery. Consistantly draining a battery to 3.4 volts or lower before re-charging will decrease battery life expectancy.
Long term storage of batteries: Lithium batteries should be stored at 40% capacity at room temperature (69 degrees F).
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, or amp limit rating. 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. This is because the lower the coil resistance, the more current (amps) it will draw from the battery. Attempting to draw more current than the battery has to offer can cause the battery to vent or explode.
The maximum continuous 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. If they were not present, then a battery venting hot gas with it having nowhere to go could turn it into a pipe bomb.
There Was a Vape Blast at Vape Blast
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 - what defines capacity, amps, and discharge rates with battery specs?
BATTERY (Lithium) TYPES:
Understanding the Types of Battery Chemistry
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 18650 IMR batteries have maximum discharge rating of 10 amps, with some IMR/Hybrid 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. Or, you can trust the amp ratings posted in my Battery Basics for Mods blog.
Sony VTC4 IMR/hybrid battery
Hybrid batteries (also called IMR/hybrid; also known as INR and NCR) are a newer type of "mixed chemistry" battery manufactured by AW, LG, Panasonic, Samsung, and Sony. Hybid batteries use a Cobalt cathode like ICR batteries but have the same manganese and nickle makeup which IMR batteries have. This provides for higher drain capabilities while also having higher overall battery capacity (mAh) than the first generation of IMR batteries. This sub-class of IMR batteries are the most popular for today's mods due to their combination of having maximum current output (amps) along with good capacity (mah).
Panasonic calls their hybrid batteries NCR, and Samsung calls theirs INR.
Note that not all Panasonic NCR batteries are considered "high drain". The Panasonic NCR18650B 3400 mAh and NCR18650A 3100 mAh are low drain and are designed and best suited for applications like a flashlight, and not mods.
Hybrid 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.
AW 18650 Protected ICR battery
ICR (Li-ion), or Cobalt electrode batteries were the original form of lithium ion batteries. These batteries could handle most factory-made atomizers found in earlier clearomizers or cartomizers. ICR batteries were known for their higher capacities and were suited for the early "entry level" vaping devices, 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.
Due to ICR batteries not being safe chemistry and having an unacceptable amp rating for today's APV's, they are no longer recommended for vaping and are considered to be obsolete.
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.
LiPo battery pack
LiPo batteries have been used in advanced remote control toys for a number of years. They are used in the vaping industry in eGo batteries as well as in regulated box mods which use an internal, non-replaceable battery. They generally use onboard USB charging. Like ICR, they are not a safe chemistry and depend upon the protection circuitry of the processor to be considered to be relatively safe for vaping purposes. In thermal runaway the reactions are extremely violent and usually accompanied by flames. Their higher reaction temperature creates a lot more gas a lot faster. This can lead to very violent bursting of the battery case.
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