Introduction to Batteries


This is by no means a comprehensive guide to batteries. This is to familiarize yourself with them and to serve as a warning. Batteries can explode if used incorrectly. If you know your batteries limits and use them within those limits, you will be fine.

Best 18650 Batteries to Buy

There are a large number of batteries available to vapers. Many have exaggerated ratings that make it difficult to know what is really going on and just what kind of battery you need. Here are a few reliable batteries to choose from. Each battery listed here has a current and power rating. Until you are comfortable with your mod, Ohm's Law, and battery safery and care, we recommend that you do not exceed these ratings.

  • Up to 10A or about 30W per battery

    • 3300mAh Panasonic/Sanyo NCR18650GA
    • 3500mAh LG MJ1
  • Up to 20A or about 60W per battery

    • 3000mAh LG HG2, Samsung 30Q, or Sony VTC6
    • 2600mAh Sony VTC5
    • 2500mAh Samsung 25R, LG HE4, or LG HE2
  • Up to 25A or about 75W per battery

    • 2500mAh Sony VTC5A
    • 2100mAh LG HD4, LG HD2C, Sony VTC4
    • 1500mAh Sony VTC3
  • Up to 30A or about 90W per battery

    • 1500mAh LG HB2, HB4, or HB6

Best Battery Chargers To Buy

It is within our best interest to purchase a quality charger. As different batteries have varying lengths so do chargers and their charging bays. With the growing popularity of 2x700 devices you need to make a good purchase the first time concerning your charger.

If you want to keep it simple, every Xtar charger will fit any of the batteries we use for vaping as all Xtar charger bays have 71mm length.

If you want to specifically buy a charger that gets your batteries charged in a quicker fashion though Xtar isn't always the best option. What you want in that case is a charger that charges all bays simultaneously of at least 1A. The Xtar VC2 Rocket, Liitokala Engineer Lii-500, Gyrfalcon All-44, Miboxer C4-12, Nitecore SC4, and Xtar VP4 Dragon all meet that criteria as well as have bay lengths of 71mm or more to fit all types of the batteries we use for vaping.

The Folomov A2 and Folomov A4 get an honorable mention as those chargers are very affordable, charge at least 1A across all bays simultaneously, and will fit up to 20700 batteries. As the Folomov charger bays only have 70mm bays though they may not allow 21700 batteries to fit.

Why is the continuous current rating (CDR) important?

Heat is the enemy of your batteries. The higher the temperature, the faster they age and the sooner you will be forced to buy new batteries. If the temperature gets high enough it can damage your batteries internally and even cause them to "vent" excess pressure that builds up when they get hot. If your battery vents it is no longer safe to use and should be recycled.

So how do you know whether the batteries you're using are going to get too hot?

The continuous current rating (CDR). This rating lets you know the maximum amount of current you can draw from the battery without it overheating or aging too fast.

How do I calculate if I am within the CDR or amp limit of my batteries?

Your maximum amount of current is represented on your battery by amps. For example, if we were to use /u/Mooch315 list of recommended batteries, which we always should as it is accurate information, we would see that the Samsung 30Q is in reality a 20A battery. For maximum safety and longevity of our batteries we should not use more than 20 amps of current with that battery.

The equations for regulated mods are pretty simple. The easiest way to go about calculating the average amount of watts your battery's amps can handle at the lowest voltage allowed by your mod before the mod cuts off is: Amps x Mod Voltage Cutoff = Power. 20(A) x 3.2(v) = 64W.

Rounding 64w down to 60w is in your best interest as the regulator within will have a certain degree of inefficiency. Also keep in mind your mod may or may not cut off when the battery reaches 3.2 volts. Most mods in fact do, but some others will be different. It's your responsibility to find that information.

For solving the current drawn from your batteries where the wattage is a potential changing variable: Amps = Watts / Mod Voltage Cutoff. 64W divided by 3.2v = 20A for a single battery. If you want to calculate 128W using a dual battery mod you can divide that number by two for the equation. The result would be your mod should under normal use produce no more than 128W to stay in line with your batteries maximum current of 20A (per battery). I sure hope you see the pattern.

Again, account for regular inefficiency. Round down from the above examples to 60w and 120w respectively. You can also change the formula for solving amps to A = W / MVC / 0.9 (accounts for regulator inefficiency).

You might be curious if this has anything to do with battery life, and the answer is yes and no. More reading?! Yes this requires an explanation too. If you use a 3000mah 20A battery at the same wattage, for example 120W, as a 2500mah 25A battery the first listed battery will last longer under use as the, mah, represents battery capacity. The only exception would be if you were to use Battery A at a wattage which exceeds its max current in the same way you would use the Battery B. If for example you were trying to vape Battery A at 150W it is entirely plausible it could damage that battery's life. However Battery B would just chug along like nothing is wrong, he thinks he can, he thinks he can, and will.

  • What is venting and thermal runaway?

If you've ever seen a news story about someone's vape "exploding", this is what they're talking about. Battery venting can occur when batteries are pushed beyond their amperage limits for too long or if a torn battery wrap, misplaced insulator ring or improper metal contact causes a short. Vents are characterized by a "hissing" sound paired with a release of gasses from inside of the battery. Thermal runaway is much more commonly caused by battery shorts rather than amperage over-pull, however they are far more dangerous than venting. Thermal runaway is characterized by loud explosion-like sounds and a spewing of red-hot battery internals. -/u/conceptcutthroat

  • What to do if your mod autofires or your battery vents.

If you notice your mod auto-firing, remove the battery(s) immediately and check on them. If they feel extremely hot to the touch, you are risking the possibility of a vent, and as such you should immediately discontinue all use of the effected battery(s). If you believe your batteries are venting, you'll notice a distinct hissing sound. Immediately remove the battery(s) from your mod onto a non-flammable surface and wait for them to finish venting. Once you are absolutely sure that they are done venting, dispose of the batteries immediately. Do NOT attempt to use the batteries again! Once a battery has vented, it is automatically dead and should be replaced. If only one battery out of a set vents, replace all batteries from that set. If you experience thermal runaway, do not even attempt to remove the batteries from your mod. Immediately throw your mod onto a non-flammable surface away from yourself and other individuals until they have fully stopped reacting. Once you are sure the thermal runaway has finished, wait until you are sure the batteries are cool enough to touch and dispose of them entirely. There's a very good chance you'll also need to scrap your mod as well, as it has most likely been damaged because of the explosion. -/u/ConceptCutthroat

  • What are "rewrapped" batteries?

"Re-wrapped" batteries refer to batteries "produced" by companies other than the big four (Sony, Samsung, LG & Panasonic). Producing batteries is a very expensive process, something that most companies cannot afford. Because of this, many companies such as Efest, MXJO, CoolFire and others instead purchase batteries from the above-mentioned manufacturers and place their own wraps on them in order to pass them off as their own. While this may not seem like a big deal as the batteries themselves are still coming from reputable manufacturers, there are two issues that you need to be aware of. Firstly, many re-wrapping companies tend to exaggerate the amperage and mAh capacities of these batteries, leading users into a false sense of security that they can push much more power through these cells than actually possible. One important piece of information to remember is that their is no such thing as an 18650 with a rating higher than 30A! Any battery that states otherwise is lying and should be used with extreme caution. The second issue presented is that many of the cells purchased by these re-wrapping companies are often sold to them because they have been rejected by the original manufacturer. This is usually because of manufacturing defects that give them a lesser amperage or mAh rating compared to correctly crafted cells of the same model. Because of these unknowns, it is heavily advised that you look into independent tests done on these cells by testers such as Mooch. Mooch is heavily endorsed throughout the vaping community and has done numerous tests on both authentic and re-wrapped batteries. You can find a list of Mooch's battery tests here. -/u/ConceptCutthroat

  • Not all non-Samsung/Sony/LG batteries are rewraps

  • Where can authentic batteries be purchased?

    • List of known, reliable vendors.

For North American buyers: BatteryBro, Illumn, IMRBatteries, LiIonWholesale, OrbTronic, RTDVapor

For European Buyers: Akkuteile, EcoLuxShopDirect, NKON -/u/ConceptCutthroat

  • Avoid eBay and Amazon when buying batteries, there are far too many fake batteries in regards to either or and it is absolutely imperative you use authentic batteries.

  • What is marrying your batteries?

Battery "marrying" refers to the process of always charging and discharging sets of batteries together over the entire course of their lifetimes. Married batteries should be the exact same make and model of battery and purchased at the same time. As soon as they are purchased, it can be useful to mark the battery wraps with a permanent marker in order to signify that certain batteries are married to one another. Contrary to popular belief, batteries do not need to be married to a specific mod - only to each other. This means that if you have two dual battery mods, you can use a set of two married batteries in either mod at any time without any issues. -/u/ConceptCutthroat

  • When would you need to marry batteries?

Marrying batteries is very important for any mod that utilizes more than one battery at a time. Over repeated charges and discharges, the internal resistance of batteries can change. Using cells that have high fluctuations in these internal resistances can lead to poor battery health and errors while trying to fire your mod. -/u/ConceptCutthroat

  • Can I marry a set of used batteries?

Because of the fluctuations of internal battery resistance mentioned above, attempting to marry heavily used batteries is not recommended. New batteries are relatively cheap and should be bought new when attempting to marry them. -/u/ConceptCutthroat

  • Is it safe to use married batteries separate from each other?

Married batteries can be "divorced* at any time in order to be used in a single-battery mod, however after extended time away from each other they cannot be re-married do to an eventual fluctuation in internal resistance. Before considering divorcing your batteries, make sure that you have absolutely no intention of ever using them together again. -/u/ConceptCutthroat

  • Safe battery charging

    • Temperature, during charging and letting battery cool to room temp before using
    • Recommended charge rates

For optimal health of your batteries and longevity it is recommended to charge at 1A or below that value. Charging at 2A for example will reduce the life of your batteries, but it is not however dangerous.

  • List of reliable charger brands

Efest, Nitecore are reputable charger brands at an affordable price. It is not recommended to buy or use dirt cheap off brand chargers which may compromise your and others safety.

  • When to replace a battery? How long do they last?

    • What ages a battery?
      • Time
      • Cycles, define this
      • Too high volt
      • Too low volt
      • Temp, hi or low
      • Starts getting significantly warmer than normal during vaping.
      • Battery is dented
      • Battery was hot enough to melt the wrap
  • Battery wraps, why are they important?

    • What is a wrap?

Battery wraps are not just there for aesthetics. The heat shrink wrap used on batteries are there to prevent the negative and positive portions of a battery from completing a circuit where they shouldn't which causes shorts. -/u/ConceptCutthroat

  • Insulating ring

The insulator ring is the small circular disk around the positive end of the battery that works with the battery wrap to prevent completed circuits that cause battery shorts. It's important to remember that the positive pin surrounded by the insulator ring is the only positive portion of the entire battery, with the rest being the negative portion. The idea of the battery wrap and insulating ring is to assure that a completed circuit is only made using the positive and negative ends of the cell and not any part of the side of the battery. -/u/ConceptCutthroat

  • Can short out

Improper care of battery wraps and insulator rings can lead to battery shorts, which can cause venting and thermal runaway, both of which can be extremely dangerous to the device and the user. -/u/ConceptCutthroat

  • Can be replaced

Always be sure to check your battery wraps and insulator rings to make sure they are in perfect order. If you notice a tear in your battery wrap or an insulating ring that is not properly covering the negative portion around the positive pin of the battery, replace them immediately! Battery wraps are dirt cheap and easy to reapply with a hair dryer. -/u/ConceptCutthroat

  • Battery storage
    • Temperature
    • Time
    • Topping off
    • Storage voltage

revision by LostRonin— view source