Beginners Guide To Ecig and Vape Batteries

Want To Know A Little More About Batteries Used For Vaping? Read on..


Vape Battery Introduction

So…from knowing clear zero about electronics, Ohms Law and the nature of Vegetable Glycerine, you’ve gotten to the point of building your own low resistance coils and crafting your own e-liquids to get the most out of your vape.

The logical next step in the process is to get to the point where you know what’s up when someone talks about milliamp hours and battery wraps, when you can go on line and make an educated decision on which battery brand and specs to buy for your new mech or regulated mod.

You need to know about your batteries for vaping, not just so that you can get the most out of your vape but also for your own safety and the safety of your device. It’s just another one of the reasons why we love vaping so much, there’s always just a little more to learn!

While there are a number of battery sizes available, 18650’s are one of the most popular batteries currently used in vape mods.

Replaceable batteries extend the life of our mods because in themselves they’re disposable.

When the batteries lifespan is over, we don’t have to throw away the whole vape mod like we would on, say, a built in 3000mAh mod. That said, how on earth do we choose an 18650 battery? What does the name mean and what on earth are those numbers and letters printed on the side? Well, you’re about to find out.

First Up, Mechanical Mods and Regulated Mods Require Different Battery Setups…Why?

Well, the basic difference between the mechanical and the regulated mod is this:

Mechanical/Unregulated Mods

  • The mechanical mod will draw power direct from your battery at a rate dependent on the resistance of your coils and the standard output that that specific battery is able to provide…the power will diminish with the charge of the battery.
  • It’s totally possible, with a low voltage battery, to have a build that your batteries are unable to fire. It’s also possible to have a battery with a voltage too high for your coil’s resistance, which will result in a catastrophic vent and possibly an explosive incident.
  • The mech is operated through direct contact being made between the tank’s 510 pin and the battery connection, via the users inward push of the battery through the mech mod. Mechanical mods require a thorough understanding of battery ins and outs, as well as Ohms Law, to operate. Not for beginners.
  • In the mechanical mod, the voltage translates directly into heat on your coils so…you’re going to need some kick ass batteries, the thing is though, there’s more to it than that. Provided you know the resistance of your coils and the voltage of your battery, you can make use of an Ohm’s Law Calculator to work out the average draw on your batteries.

    Image from

Regulated Mods

The regulated mod, on the other hand, will, via it’s onboard chip or regulator board, regulate and oversee the power draw on the battery, all dependent on how you set the watts/volts: keeping amperage (power draw) constant until the battery drains and so on.

In other words…a whole different story!

The gist of it is that mechanical mods require a far higher voltage battery to operate efficiently, while the regulating influence of your standard mod’s chip will do exactly as the name says and regulate your power through!!

Your Battery’s Amperage

When it comes to an 18650, only so much overall capacity can be squeezed in…thats why:

  • Batteries with higher Milliamp Hours (battery life) tend to have a lower discharge rate (lower Amperage, or how much power they can put out at once), making them more suitable for lower wattage devices.
  • While batteries with lower milliamp hours will tend to have a higher discharge rating (higher Amperage), making them more suitable for higher wattage devices.

Weird but true…although many of us might have thought it the other way around!! In other words, a higher mAh battery won’t necessarily mean the best battery for your high wattage device…what matters is the amperage rating or power/current capacity (at any given time) of your battery.

Discharge Rate / Continuous Discharge Rating / Current Rating

Think of the amperage (The discharge rate, which will be between 5 and 30 or so Amps) as how far the tap can open, how much current (or water…in the metaphor) it’s able to run at any given time. Amperage in vaping explainedYour Amp Rating and your mAh are two very different things!

Battery Capacity / mAh

The milliamp hours, on the other hand, dictate how long the batteries can run in one sitting, before they’re spent: 3000mAh can run 3 Amps for 1 Hour before dying. So, in the metaphor, the milliamp hours are the capacity of your water tank.

  • In a mechanical mod, the resistance of your coil will require or pull a certain number of amps from your battery. What you need to do is find out the voltage of your battery (this might be written on your battery, it might display on your external charger or you’ll need to use a multimeter).
  • Then You’ll divide your battery voltage by the resistance of your coils: the answer must not exceed the amperage rating of your battery, otherwise your battery won’t be sufficient to run your coils…a problem I struggled with for a few days when I bought my first mechanical mod!!
  • In a regulated mod the pull on your batteries will be regulated by the mod settings, based on the wattage or voltage you choose to use, you need to ensure that the wattage you choose isn’t demanding a higher discharge than your battery’s discharge rating can provide!

Batteries in Series and Parallel: What’s The Difference? (all examples are as for 2 x 18650’s)

Okay, first just a word of advice, always use the same brand and model batteries in any 1+ battery device, it will ensure correct device functioning, ease calculations and it’s just the sensible thing to do!

Plus, make sure they are fully and equally charged when you insert them into any device. Best practice, if your mod uses more than one battery, is to buy new batteries together for your mod.

You may have heard it said that batteries either run in series or parallel…now you’ll find out what that means!

  • In a dual 18650 series configuration the voltage is doubled, while the milliamp hours and amperage remain the same as if for one battery. (3 x 18650 setup in series will triple the voltage and so on, you get the point!)
  • In a parallel configuration both the milliamp hours and the amperage are doubled (for dual 18650s) while the voltage remains the same as if for one battery.
  • Parallel boxes tend to have the positive terminals facing in the same direction and vice versa. Inserting batteries the wrong way around in an unregulated device or a regulated device without the correct safety features can lead to an explosion!

What this means for your vape is that series accommodates more power with less battery life and parallel accommodates less power with more battery life. Parallel unregulated mods are essentially safer than series unregulated mods, especially if you’re delving into low resistance builds.

Ohms Law Calculator

Once you’ve worked out how much power your coil setup and mod settings will be demanding from your batteries using an ohms law calculator (the calculator only requires a 2 value input, so you could enter your coil resistance in Ohms and your expected power in Watts, which will depend on your mod and coil setup), you can use a battery life calculator like this one to work out the battery life you can expect from the device, based on your battery’s mAh as well as your inhalation time.

Keep in mind that because all of these calculators are based on Ohms Law principle equations, the best thing you can do for your vaping self is learn Ohms Law by heart, so that you don’t need a special calculation app and just a normal calculator.

You also need to know the difference between series and parallel battery format and when calculating for series, for example, you’ll need to adjust your voltage accordingly.

So…I opened the Ohms Law Calculator To Work Out Power Demand / Discharge Requirements for 2 x Samsung IMR 2500mAh /3.7 volt /20 A batteries in series on the Smok Alien 220W…running a 0.5 Ohm coil at 80W.

  • Resistance = 0.5 Ohm
  • Wattage = 80 Watts
  • Power Draw in Amps (Obtained From Calculator) =12.64 A
  • Required Voltage (Also From Calculator) = 6.32 V

Now…you can also see that if I divide my voltage by my resistance: I’ll end up with my Amps figure. That is an Ohms Law equation in action.

You might note that the necessary voltage exceeds the voltage for one of my batteries (3.7V) but luckily the SMOK Alien Mod operates batteries in series…effectively doubling my voltage, because there are two batteries.

I can also see that the Amp draw is well inside the 20A  Continuous Discharge Rating or CDR limit of my Samsung IMR batteries so I know I’m good to go.

Knowing this, that 2 batteries in series doubles only the battery voltage…I move on to this calculator, being careful to enter a doubled voltage (for two batteries n series) as well as a 6 second draw time.

I get an answer of a 97 inhale battery life at 80W on these batteries, which is to be expected and seems pretty close to the truth for me. You’ll notice that the variable mod calculator doesn’t require a resistance setting…that’s because the mod is regulating the resistance based on my wattage setting.

This is the equation and it forms an integral part of Ohms Law, a must-know for all sub-ohm and mechanical mod vapers:

Voltage / Resistance = Amps


Battery Voltage / Coil Resistance = Amps pulled from battery

Once again, the Amps pulled may by no means exceed the Amp rating of your battery if you want any joy!

Here’s a super handy calculator that provides a few different entry options.

Recommended 18650 Batteries

  • I like to stick with well known brands, with products that are heavily regulated and manufactured to an extremely high standard.
  • Remember, when it comes to choosing batteries for your mechanical mod, you need to use a calculator to work out your desired power draw and then purchase your batteries according to their amperage rating…once again, use only the recommended brands.

LG HB2 /HB4/HB6 = 30A 1500 mAh :

High amp ratings with lower battery life, great on high wattage devices.LG h2 h4 h6 vape battery

Buy LG HB6 Batteries

Samsung 20R=22A 2000mAh / Samsung 25R5=20A 2500mAh /Sony VTC 5A=25A 2500 mAh:

Slightly lower amp ratings with a slightly higher battery life, medium to high wattage devices.Samsung 25R Vape Batteries

Buy Genuine Samsung 25R Batteries:

Buy Genuine Samsung 20R Batteries

Buy Genuine SONY VTC5 Batteries

Panasonic/Sanyo NCR18650GA=10A 3300mAh /Samsung 30Q=15A 3000mAh / Sony VTC 6=15A 3000mAh :

Lowest amps with an extended battery life, great for low wattage devices.Sanyo NCR18650GA

Buy Genuine Samsung 30Q Batteries

Buy Genuine Sony VTC6 Batteries

Buy Sanyo/Panasonic

(Check out Mooch’s full list of recommended batteries, he’s a battery expert who does extensive testing on every aspect of battery performance in vaping and we highly recommend his blog.)

Mooch Recommended Batteries For Mech Mods

mech mod batteries recommended by mooch

Mooch Recommended Batteries For Regulated Mods

vape batteries recommended by moochAs a rule of thumb, aim for brands you can trust like Sony, Samsung and LG. Just be sure you are buying from a genuine stockist. Sony VTC5’s are notorious for fakes knocking around online.

Also, if you’ll be drawing no more than 12A, for example,  save yourself a penny by not insisting on a 30A battery because 20A will serve you well and will likely come with an extended mAh reading.

The important thing is that you work out your expected draw and choose your batteries accordingly so…battery voltage (multiplied for series set ups) divided by coil resistance to attain your required amperage draw!

After that, find a battery with a high enough amperage rating, combined with as high a mAh as you can find in your budget! It’ll start coming naturally once you’ve let it sink in!

Other Vape Batteries like the 20700, 18500 and 26650:

Well, first up…let me try to simplify things further for you. That number name for your vape battery does in fact refer to the actual dimensions of the battery.

So, if your battery says nothing on the wrapper but it measures in at 26mm width and 65mm length, well then you’re vaping with a 26650 battery!

iJoy has been making waves with the release of a 20700 battery that takes the set up to the next level, with a high mAh of 3000, combined with very impressive amperage at 40A…kinda going against the general flow that we see with 18650s, where higher mAh means lower amperage!

With just a slight increase in size and an effective doubling of amperage for the same milliamp hour rating…I can see why iJoy is hailing the 20700 as the way of the future for vaping.

Indeed their Captain PD270 regulated dual 20700 mod is going to be a high powered beast with an impressive battery life.

As for 26650’s well, those have been around for about as long as 18650s but my guess is that there larger dimensions made them a little less popular in the vaping world, which is always aiming for fist friendly ergonomics and a vape that doesn’t feel like a ton of bricks.

Battery Wraps?

When you see that your 18650s wrap has become damaged in any way, this should send off alarm bells, it can lead to unequal heat distribution, battery short, battery venting (releasing of gases) and explosion.

But a damaged wrapper doesn’t mean you have to buy an expensive new 18650…provided the actual battery isn’t damaged, all you need to to do is rewrap it.

You can order wraps in the UK through the following links or just check out your regular vape shop or online store for 18650 wraps, most decent shops will stock them!

Otherwise, ebay has some more affordable options, including whole rolls of shrink wrap that you can cut yourself.

How To Apply Battery Wraps

  • You can apply the wraps using a heat gun, mini blow torch or simply a hairdryer as the shrink is heat activated!
  • If using a roll, cut your wraps to 69mm, the length of an 18650.
  • Remove the damaged wrap from your 18650, being careful to preserve the insulator around the positive terminal.
  • Insert the 18650 into the shrink wrap tube…there needs to be an overhang of about 1mm on either side of the tube because it shrinks around the edges.
  • If using a blow torch, make sure the setting is low and the blow torch a good 8 cm away.
  • Rotate the battery in your had, moving the blow torch/heat gun/hair dryer steadily around the edge of the battery where the wrap overhangs, you want it to shrink at the edge and grip onto the battery.
  • Once the first edge is gripped, time to apply heat to the creases running down the length of the battery on either side. Be sure to distribute heat lightly by moving the gun quickly from side to side, you don’t want to apply constant heat anywhere! Do this until both creases have vanished.
  • Once the creases are down you can apply heat to the other edge.
  • Once both edges as well as the the creases. Rotate the battery in hand and move the gun steadily to apply heat lightly to all the rest of the battery.
    Your done!

If you found these instructions hard to follow…check out this re-wrap tutorial by The Devil Vaper on YouTube.

Battery Safety Notes:

Invest In A Silicon Battery Holder: Your batteries need to be kept away from metal objects and magnets while out of device, the safest bet is a silicon battery holder. Not only can the wrap be damaged but your battery could leak or even explode if you’re not careful how you transport them.

Under no circumstances should you carry loose batteries around in a bag or pocket.

Silicon Cases Are Available Here. Plastic cases are also widely available.Silicon Battery Case

Buy An External Charger: This is the safest way to charge your 18650s (or other vape batteries) and there is simply no two ways about it, not only will charging with an external charger prolong the life of your batteries, it will also prolong the life of your mod.

Recommended Brands

Pay Heed To Battery Amperage: Work out the draw via Ohms equation…Amps = Voltage / Resistance and make sure those Amps don’t exceed your battery’s rating! Exceeding the limit can lead to a noxious chemical release by your batteries and a possible explosion. This is even more important on a mechanical mod where there are no inbuilt protections.

Image from

Always Check Your Battery Wraps & Carry Spares: See the section above on battery wrapping and always carry spares, especially if you swap out batteries a lot or use a mechanical device that causes wear on your wraps.

A Few Notes About In Device Charging

Check Your Manual: While some devices feature balance charge, overcharge and over current protection, some devices do not. That’s why it’s essential for you to ensure the following.

Use The Device’s Native Charge Cable: Because every power cable has it’s own output reading and every mod has a max input reading, using the incorrect cable can result in overheating, which can be catastrophic for your batteries and your devices board. Use the cable that came with your device, for the sake and longevity of your mod and your batteries. If the charger you’re using has a higher voltage output than your batteries, the batteries could overheat and seriously damage you and your device.

Avoid Overcharging: Most devices have overcharge protection but not all of them. Try not to do onboard charge overnight, unplug your device once those batteries are showing 100%.

Passthrough Charge: I totally broke my first cigalike pen back in the day by trying to vape on it whilst it was charging, that’s when I found out what passthrough charge means. Only devices that support passthrough charge can be vaped whilst charging so watch out for that.

E Cig Battery FAQ’s

Can I Use Any Battery for Sub Ohm Vaping?

No, please don’t.

Why Can't I Use Any Battery for Sub Ohm Vaping?

A battery is an energy store; different batteries are designed to release that energy in different ways. A sub-ohm coil places a demand on the battery to discharge itself quickly – using the wrong battery can cause it to damage itself.

How Can I Tell If My Battery Isn’t Coping?

First sign is that it gets excessively hot – then expands before (finally) venting gases. Any battery that has done any of these requires recycling.If you have heard about or read a story of an e cig exploding then it will be because the battery vented only the gas had nowhere to escape the mod. If you have heard about ‘e cigs exploding in pockets and bags’ then these are likely the batteries, not the e cig.

If you are carrying spare batteries then carry them in a protective case. They cost next to nothing. If you don’t and they come into contact with keys, coins or other metals they can short, which in turn can be dangerous.

Will My E Cig Battery Explode?

It’s unlikely as long as you follow, and stick to following, battery safety. Find out How & Why E Cigarette Batteries Explode Here

What Do I Want To Avoid?

Anything cheap: it makes no sense to save pennies when it comes to batteries. The branding actually does mean that the battery will do what the company claim it will do.Anything fake: Might sound obvious but the term ‘too good to be true’ generally rules here. Not only does cheap definitely mean fake but some brands can only be bought through certain suppliers. Some vendors are unaware of what to look for so it pays to only buy from strongly recommended battery dealers.

Inadequate venting holes on mods: Some mods have the atomizer directly contacting the battery. This isn’t a bad thing, but a number of them have been associated with problems in the past. Batteries vent from the positive end – mods with holes for the gases to escape at this end are better.

Any Final Things I Need To Remember?

  • I know we have said this before! It’s important – Prevent spare batteries from shorting in your bag or pocket by storing them in a small plastic battery case.
  • Keep batteries dry at all times.
  • Do not use a battery if the wrapper is damaged, if it is a tight squeeze to insert it or if it has become very hot previously.
  • Use a quality charger and do not overcharge them.
  • Do not ‘run a battery to empty’ as over-discharging batteries damages them.
  • Always remain near a charging battery. Do not leave them on charge overnight and unplug the charger if leaving the room.
  • Recycle old or damaged batteries at your local tip in the appropriate container. They can poison the ground if placed into landfill.
  • For more info take a look at our Beginners Guide to Sub Ohm Vaping
Greetings Vapers! I’m a 34 year old writer, editor and massive vaping enthusiast (since 2015) based in the beautiful Helderberg region in South Africa. My passion for vaping has steadily grown since I started vaping in earnest (as has my scorn for smoking). See, I tried vaping years before that but returned to cancer sticks after a bad experience (PG sensitivity). When I finally got back on the vaping train I decided to make it my business to educate beginners and vapers in general, so that they don’t jump to the conclusions that I did. I visualise a world without cigarettes…not just for health reasons: I’m tired of picking thousands of cigarette butts up off my lawn every morning, tossed over the wall by passers by. I can’t believe I used to be one of those people!



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