Battery Safety Guide

Posted by Mitch Clarke on 4th Nov 2016

In 2013, nearly 2.55 billion (that’s right, with a “b”) 18650 cells were manufactured worldwide, and as vaping becomes increasingly prevalent, the use of these types of batteries increases proportionally. As vapers, we know that there are important yet simple steps to be taken in order to get as safe as possible when using these high performance Li-ion batteries.

Choosing Your Cells

Batteries come in many different sizes and types with a variety of unique performance specifications, but as vapers, we only use a select number of a specific type of rechargeable battery. How can you be sure you’re getting the best battery for your vaping style? Well, just keep doing what you’re doing now (reading this awesome blog!) and you’ll find out!


Out of all of the many types of batteries on the planet, only a select few have the proper specifications and performance for vaping use. Vapers typically use large capacity batteries with high drain capabilities that can withstand the stresses modern devices place upon them. These types of batteries can be identified by their identifying number, the most common of which being the 18650 and 26650.

These numbers do more than identify the type of battery, they also give the specific dimensions of the cell right in the name: the first two numbers, “18-“, gives the diameter in millimeters, and the last three, “-650”, express the cell’s height in tenths of a millimeter. Similarly, these types of batteries often have a name that identifies the type of chemical composition the cell utilizes, though this can vary between manufacturers. The most common types of these Li-ion batteries are the IMR, ICR, and INR: the “I” identifies that this cell is a lithium-ion type, the second letter alludes to the type of ionic element is being used alongside the lithium, and the “R” expresses that this type of cell is cylindrical.

One more type of battery typically not available for individual purchase, instead usually coming pre-installed and irremovable from a device, is the Lithium Polymer (LiPo) battery. These batteries can come in a variety of sizes and shapes, but are most commonly found in a thin rectangular form, much like the one powering your cell phone. These cells can have very large capacities and discharge rates, rivalling even the best performing cylindrical cells, and can easily be connected together to form larger battery packs, leading to their use in an increasing number of APVs.


Every battery comes with a set of specifications that describe how the cell will perform under different situations, such as the nominal voltage (usually 3.7V for the batteries we use) and chemistry type – the main two we use as vapers are the continuous discharge rating (CDR) and the mAh.

The mAh is the number describing the amount of current the battery can continuously provide in one hour before being fully discharged – so a 2500mAh battery can provide a continuous 2.5A for a full hour. While it provides a good baseline for comparison across different types of batteries, a more accurate measurement for comparison would be the watt-hour (Wh): finding this is relatively easy – no more complicated than calculating Ohm’s law – simply convert the milliamps to amps (divide mAh by 1000), then multiply that quotient by the nominal voltage by the mAh measurement, then. For example, a 3000mAh battery would have a measure of 11.1Wh [(3000 / 1000) * 3.7].

The CDR is a number (somewhat arbitrarily) chosen by the manufacturer to convey the maximum amount of amps that can be continuously pulled from the battery until it’s fully discharged without absolutely any risk of failure. While battery makers tend to fudge this number due to inconsistencies in testing methods across manufacturers, the vaping community has its very own knight in shining armor, and he goes by the name of Mooch. A member of the vaping community since April 2015, this independent member of the community regularly tests batteries for their true CDR and publishes the results on his blog in the form of very helpful charts and graphs, providing a defined structure of testing methods and guidelines for an industry lacking the necessary standardization.

Take note of your cell’s rating and, if using an unregulated device, frequently ensure that your atomizer is of an adequate resistance by consulting, a free Ohm’s Law calculator that makes checking your amperage load as simple as entering numbers. Taking note of the CDR is also very important when choosing the perfect batteries for a regulated device, although you don’t use resistance to calculate the required amps (see Building Safely below).The CDR of a battery is typically expressed by a measurement in amperage, but in the case of some cells and battery packs, it can be expressed in terms of “C”; to translate a CDR in “C” to amperage, simply convert the mAh to Ah (divide by 1000) and multiply the resulting quotient by the CDR rating (in C). For example, a 2500mAh battery with a CDR of 20C has a maximum continuous discharge rating of 50A [(2500/1000) * 20].


To get the maximum performance and lifespan out of your battery cells, you’ll want to treat them as delicately as you would a newborn child. Follow this quick list of don’t-do’s to keep your batteries performing like they were born yesterday.

  • Keep your babies away from sources of high temperatures, such as hot cars, campfires, microwaves, ovens, and soldering irons.
  • Don’t touch any leaking liquid coming from your babies.
  • Never put your babies in your mouth.
  • Don’t puncture your babies with sharp objects like nails or earrings.
  • Avoid subjecting your babies to impacts or drops.
  • Never directly connect your babies to any A/C or car plug.
  • Don’t attempt to disassemble your babies.
  • Recycle your babies at your local drop-off.

…I think that metaphor fell apart towards the end, but the tips still apply to batteries.


Storing your batteries properly is one of the easiest things you can do to make sure you’re handling your batteries properly and safely, yet remains the leading cause of accidental battery short circuits. Improper storage doesn’t take into account the possibility of cells making contact with other metal objects and greatly raising the risk for injury to you and those around you. For the simplest way to assure perfect health for you, your companions, and your belongings, follow these simple and easily incorporated tips.

At Home

If you have a charger from a respectable charger brand such as Nitecore, Xtar, or Efest at home, a great place to store your batteries while they’re not in use is in your charger. Most chargers available today are advanced enough to automatically cease charging when the cell reaches capacity, so as long as it’s within eyeshot, you can feel safe keeping charged cells where they are rather than ripping them out as soon as they’re done. Of course, if you own a charger made by a less-than-outstanding manufacturer – such as any brand with “-fire” in the name, or even worse, no name at all – you’ll want to make the switch to a higher quality charger as soon as possible, as these low-cost chargers more often than not fail to incorporate features that help keep you and your batteries safe, such as overcharging and overheating protections. However, when you go to sleep or leave the house, you should definitely keep your batteries somewhere more stable, just in case something catastrophically fails and you aren’t there to stop it. Plastic cases like the Large Plastic Carry Case For 18650 Batteries and Double 26650 Plastic Battery Case will work perfectly for those cells left behind.


While on the go, it’s important that you handle your batteries carefully. Most incidences of battery short circuits occur when batteries are being loosely carried in a pocket or purse and make contact with stray change or keys, creating a hard short which quickly results in venting and thermal runaway (and no one wants that). To help keep you and your cells safe while out and about, keep your batteries in a case that covers both poles of the battery. Soft cases such as the Single 18650 Silicone Battery Sleeve and Nylon Zipper Case work ideally, as they can be conveniently attached to key rings or placed in pockets without the discomfort associated with hard cases.

Say Buh-Bye

A battery cell’s optimal lifespan lasts for about a year of regular use; using a battery past this period gives diminishing returns as the battery holds less and less charge and performs more and more poorly. To make sure you catch the battery when its ideal lifespan reaches an end, write the purchase date on the wrap of the battery and at a year’s end, evaluate whether the cell is still performing well or if it’s time to dispose of it.


Charging is a major aspect of proper cell maintenance: when done properly, the result is batteries with a long overall lifespan and healthy performance, but when done improperly, can have disastrous consequences. Ensure you'll always be treating your batteries right with these simple tips.

External Charging

While modern regulated mods are becoming increasingly better at efficiently charging installed cells through an incorporated micro-USB port, past issues and events with the faulty charging boards of older devices have ruined the concept of USB charging for many vapers. Modern micro-USB charging ports have been designed and tested to perform exactly as expected, but for utmost safety as well as sheer time-efficiency, you’ll want a high quality external battery charger. This way, you can keep extra cells stocked and at the ready for you to swap with any dead ones at a moment’s notice. Plus, external chargers are designed to pamper your cells and treat them as ideally as you want; unfortunately, this isn’t always the case with on-board charging. When it comes to your batteries, it’s always best to err on the side of caution.

Proper Charging Amps

Just like cells can only handle a certain number of amps being drawn, most devices can only handle a certain number of amps while being recharged through USB (another reason to use external chargers). Consult your mod’s owner’s manual to get an idea of the limits – usually, it’ll be around 0.5A for pen-style devices, 1A for older regulated devices and 2A for modern mods – and choose a wall adapter that has an output within that range. The exception for this rule would be older eGo-style devices – these devices can only be recharged with the provided eGo-USB charger. Some external battery chargers such as the Nitecore SC2 and Efest LUC V6 allow users to pick the charging current being provided to installed cells. This output can be as high as 3A, but this rate can do damage to your cell’s lifespan over time and should be reserved for necessity; for a happy time all the time, stick around 1A-2A.

Marry Your Batteries

Don’t draft up that prenup just yet – we mean marry your batteries to each other. This is an important aspect of using batteries in mods that take multiple cells – by ensuring these cells are only used in the same manner as the others, you’ll give each cell an equal amount of wear. Only marry cells of the exact same make and model – it’s no good if you have one 3000mAh cell and one 2500mAh, because they’ll be discharged at different rates and you may end up discharging one too far. If you think you’ll have a hard time keeping track of which cells are married to each other, you can write the set number on the wrap (right next to the purchase date).

Proper Use

First Impressions

Each and every time you handle your batteries, whether installing them in your charger or replacing them in your mod, you should be checking them for imperfections.

Carefully check the:

  • Wrap
  • Body
  • Poles
  • Scent (give it a good whiff!)

Don’t use the cell if:

  • It has any sort of rust or corrosion
  • The wrap has started peeling, cracking, or has otherwise been damaged (even if it’s a just small nick)
  • It is bulging or deformed at any part
  • It is giving off an odor
  • It feels extremely hot to the touch (a little warmth after use is to be expected, but if it’s too hot to touch, it’s a goner)
  • The insulator in the positive pole is damaged
  • Any irregular charging/discharging behavior (unusually quick or slow)
  • Anything doesn’t look, smell, or seem right (trust your instincts)

Tricks to Fix Nicks

If you should find that your battery has a nick in the wrap, the fix can be relatively hassle-free. There are replacement wraps (with sick designs like $100 bills and AA batteries) available for purchase – installing these wraps takes little more than 5 minutes and a hair dryer. But if you “really, really need it right now”, a temporary fix would be to cover any small nicks with electrical tape, but this is only a (literal) band-aid fix that shouldn’t be relied on for more than a few hours or be used on large tears in the wrap.

Calculating Amperage Draw

When building coils for an unregulated mod, it’s very easy to calculate the maximum amperage load being drawn from your batteries just by using the resistance and maximum voltage (even easier when using a calculator). Calculating the maximum amperage draw for batteries in a high-wattage regulated device, however, is slightly more complicated, but no more difficult: simply divide the maximum wattage of your device by a number slightly lower than the minimum input voltage for your device – your owner’s manual will probably help to clear this up, but for a dual 18650 device with a minimum voltage of 6.4V (3.2V per cell), 6.0-5.0V (3.0V - 2.5V per cell) is a good guess that accounts for voltage sag under load – then multiply the resulting quotient by the difference between 200 and the efficiency percentage of your device’s regulating chip.

That last bit sounds a little complicated, but some examples show it’s simpler than it seems: for the Evolv DNA200 chip with an efficiency of 97%, multiply by 103% (200 – 97), and for Hohm Tech’s FSK chip efficiency of ~99%, use 101% (10% is a good estimate if you don’t know your device’s efficiency). So, for example, for a DNA200 device with three 18650’s wired in series, the maximum amperage draw your device will ever pull from each battery will be about 27.5A [200 / (2.5 * 3) * 1.03].

The amperage draw will only reach its maximum when the installed batteries are nearing their minimum voltage, but it’s wise to prepare for your device’s full range of performance.


Unlike college, orientation is important. Your device only functions correctly if electricity is flowing in a certain direction, so ensure that your batteries are facing the designated direction before installing them in your mod or charger. While most regulated devices will have protections against reverse polarity, mechanical mods typically won't nor will they have the proper orientation displayed in the chamber; however, most, if not all, will accept batteries with the positive pole facing the atomizer and the negative facing the switch.

Hybrid Connections

In some mechanical mods, something called a hybrid connection comes standard or included in the package; this special type of 510 connection does away with the mod’s traditional 510 positive pin, instead directly contacting the positive pin of the atomizer to the battery’s positive pole. While this method of connection is fantastic for eliminating unnecessary voltage drop, it presents an additional source of risk: what if the positive pole doesn’t touch the atomizer’s positive pin, but instead makes contact with the threads of the atomizer’s 510 connector? Well, because the threads are part of the atomizer’s negative pole, electricity is directed from the threads straight back into the positive pole of the cell, and we all know what that means. To avoid this unfortunate short circuit situation, always ensure that the positive pin of your atomizer extends far enough (≥1.25mm past the edge of the threads) and cannot be pushed back into the threading. This is a good idea to do with all types of 510 connections, just to be safe, but it’s absolutely crucial with hybrid connections.

Building Safely (No Engineering Degree Required)

While building your own coils, it’s important to keep the amperage limit of your batteries at the forefront of your mind and have a solid idea of what kind of coil you’ll need to build in order to stay within the safe range of your batteries. It’s also just as important to utilize proper rebuilding safety (ensuring your coils aren’t short circuiting by touching the positive post, your coils are of an adequate resistance, etc.) in order to avoid accidentally putting excessive strain on your batteries.

Now, I’ll be honest with you: despite the well-meant intentions of some naysayers, if your build pushes slightly past your battery’s CDR, you don’t need to kiss your limbs and good looks goodbye (otherwise, cloud competitions would look like a leper colony). Batteries are able to “pulse” slightly past the CDR (+1A-9A) for very limited amounts of time, but because this functionality is extremely time-sensitive, it should never (never) be relied on as a daily-use device – if you should ever accidentally leave it firing in a pocket or purse, the result may very well be catastrophic venting and thermal runaway – so keep the atomizer, battery, and mod disassembled when not in use, reserve use to hour-long sessions, rest the mod for a full minute between hits, and don’t build stupidly.

Dying Battery

So, apparently, your batteries are dying. At least, that’s what your regulated mod says. If that’s the case, simply replace them with fresh ones and install the dead cells in your charger, or wait for USB charging to do its job. Easy peasy. But what if your unregulated mod, such as a mechanical mod, doesn’t explicitly say when the batteries are dead? Well, dying batteries go not with a bang, but with a sizzle. If your mech starts to perform noticeably poorly, it’s probably time to change out your battery. Keep close attention to this decrease in power, as not doing so can cause your battery to over-discharge: once a battery’s resting charge falls to 3.0V, you risk damaging the cell; if it should fall below 2.5V, it can prove difficult to revive it without a specialized charger, and damage to the cell’s overall lifespan is almost certain.

What To Do When Venting

So, let’s say you’re going about your business one day, whether you’re chilling at home, working in the office, driving around town, or trying new juices at the local vape shop, when suddenly, you smell something…funky. You look around for any nearby hobos, but none seem to be the source of the scent. You think back to a few seconds previous and contemplate if you really let a little gas pass and just didn’t notice. Then, you notice a light 'hiss'-ing and a thin wisp of smoke passes through your line of sight. You look down and find the offender: the substance pouring out of your mod isn’t the usual pleasantly aromatic vapor, but instead, stinky smoke. Your worst fears have come to pass: your battery is venting. What do you do to make sure you and those around you stay safe? Take a look at some info below, but please be advised that we are not responsible for any damage or injury that may occur when following these steps. 

    Stay Calm 
    • Panic causes mistakes. Don’t blame yourself (just yet) or get too embarrassed to function. Just focus on what needs to be done.
    • If there’s no sparks, only heating and hissing, you lucked out and pushed the cell only slightly past its limits, as the cell is only venting and not undergoing thermal runaway, so negating this risk will be relatively easy. The gases being expelled aren’t necessarily extremely toxic, as it’s mostly CO2, but it will be extremely hot and have vaporized/liquid electrolytes leaking out as well, so avoid directly handling the mod whenever possible.
    • If the cell is sparking and giving off flames, you’ve probably pushed the cell way past its limit by allowing it to hard short and begin thermal runaway. You’ll still be fine if you don’t insist on handling the battery unnecessarily, but you’ll need to take additional precautions to keep yourself and your surroundings safe as you negate the risk as quickly as possible. 
    • You’ve probably dropped the mod by now. Good idea. If not, it just hasn’t gotten hot enough yet – decide whether you can continue with the following steps before the mod becomes too hot to touch or the gases become a problem. When in doubt, even for a second, save your hands and drop it or toss it in a safe area away from flammable objects, people, or pets. 

    Take Note of Environment 

    • Identify any nearby exits, bystanders, fire-safe water sources such as metal or porcelain sinks, and any fire extinguishers. Keep these things in mind as you follow the next steps.
    • We've heard of some folks that fill a small metal trashcan(with a metal lid) with sand for the off chance that they have a venting battery. This gives them a fairly safe receptacle to throw a battery or device into. 


    Assess Current Risk

    • Is the battery really venting? Failing CPUs and circuit boards can give off smoke and a nasty smell, so be sure it’s your battery venting before you take steps that will disable the cell.
    • Are any bystanders at risk from where the venting battery currently is? If so, promptly let them know and persuade them to quickly move to an area of lower risk.

    Decide Best Low-Risk Action

    • Is it best to make a dash for the door and try to get the venting cell outside? Consider whether there’s a closer isolating area, such as a bathroom with porcelain sinks or a tile floor.

    Separate Assets From Risk

    • Tell all bystanders to step back or out of the way as you attempt to move the venting cell.
    • If necessary, ask bystanders to clear a straight path free of any obstacles or flammable materials from yourself to your chosen destination.
    • Keep the venting cell away from your face and limbs whenever possible.

    Isolate Risk Damage

    • If the cell is already on a fireproof surface, such as a tile floor, and away from any flammable materials, there’s no need to risk personal harm by moving the cell before it finishes venting. If you must move it to a better ventilated area, try covering it with a fireproof bowl and carefully moving it while covered.
    • If the cell is at risk of starting a fire with nearby flammable materials, you’ll need to move it quickly before you end up liable for property damage on top of a new mod. 
    • Get the cell to a fire-safe location. The ideal location would be an outside sidewalk where the cell can finish venting in a ventilated area, to a stainless steel or ceramic bowl that can be left momentarily while you get a fire extinguisher, or to a bathroom’s (fireproof) sink where the cell can be extinguished with water (do this last one only with Li-Ion batteries, not plain lithium batteries).

    Eliminate Risk

    • Now that you’ve waited until well after the battery has visually ceased the venting process (~20min), cover the poles of the cell with tape (preferably of an electrically resistant variety).
    • Look up how your local county handles disposal of lithium ion batteries – it might be illegal to simply toss it in the trash. You may have to take it to a government-approved disposal facility, but you can probably take it to your local vape shop and have them handle all that for you.


By following these extensive yet easily implemented guidelines for proper battery maintenance, care, and precautions, you’ll be well on your way to using our high-powered rechargeable batteries in a perfectly safe manner. Feel free to show this guide to as many vapers as you can; the more vapers you show, the more safe we can making vaping as a whole.