Series and Parallel Vape Batteries | Do I Need to Pair my Vape Batteries?

Unless you’re totally new to vaping, you’re probably familiar with dual battery vaping devices and 18650 vape batteries. But… do you know the difference between series and parallel vape battery configurations? More importantly, do you know why it’s important to know the difference?

Don’t worry if not!

In this post we’re looking at vape battery configurations, the difference between a series and parallel battery setup and why it’s important to pair or ‘marry’ the vape batteries you use!

So, where to begin…

We get literally dozens of questions regarding safe battery practices, especially in terms of dual battery mods and the safest way to use these devices. The most common questions we get relate to the issue of series and parallel configuration, battery pairing/marrying and battery stacking…

If you’re asking any of the following question, you’re in the right place!…

Can we use two smaller batteries? For example, two 18350 batteries in an 18650 mod?
What’s the difference between dual batteries in series and parallel configurations?

Can I use any battery in a dual or triple battery vape mod?

What is battery pairing and do I need to worry about it?

Before we delve in, take a look at our top tips for vape battery safety for (you guessed it…) tips to stop you losing a finger while using 18650 vape batteries!

Our awesome Vape Battery Guide – From Beginners to Advanced Vapers is also worth taking the time to read. We cover everything from battery chemistry to optimal battery charging!

So, let’s get stuck in and take a look at series and parallel vape battery configuration…

Dual battery vape mods (those that operate with two batteries) are designed to use in either series or parallel combinations.

We’ll cover both in just a minute, however most vaping devices are designed to run a parallel battery configuration.

To keep things simple, you’re not given the option of using your vape mod in either series or parallel configurations.

This is simply based on the design of the vape mod you’re using and isn’t optional. One less thing to worry about right?…

However, when you insert your batteries into your dual or triple battery mod, ALWAYS make sure you insert them into the correct orientation identified on that particular mod. Depending on the mod you have, you’ll either see a symbol/picture of the right way to insert the batteries, or a ‘+’ and ‘-‘ showing which way they need to be inserted.

So now that’s out the way, let’s take a look at series and parallel configurations in more detail…


Essentially this means your battery terminals connect positive to negative.

The combined voltage of the two vape batteries in this configuration is the sum of the individual batteries. This basically means you’re increasing the voltage of your battery supply when using batteries in series.

However, the current (mAh) and Continuous Discharge Rate (CDR) is that of the single battery.

The advantage of this setup is that it provides additional voltage and greater power to the coil,  increasing vapor production!


The opposite of batteries in series, your battery terminals connect positive to positive and negative to negative.

The combined voltage of the two batteries in this configuration is that of the single battery. The current (mAh) and Continuous Discharge Rate (CDR) is the sum of the two batteries.

The advantage of this configuration is to enable increased (twice the capacity) current. This will result in the combined battery current lasting twice as long as that of a single battery. In layman’s terms, your vape mod will run for double the time before you need to re-charge the batteries.

Furthermore, the CDR of each battery is doubled. This can have two possible advantages:

1.With two batteries, each having a CDR of 20 Amps, the overall CDR will be 40 amps. This will allow for a lower resistance coil build, enabling higher current to be drawn from the combined batteries.
2.If your coil build and battery voltage is such that the current drawn from the combined batteries is 20 Amps, you can use two 15 Amp batteries. This means you can use two lower spec batteries to achieve your required CDR value for your vape build.

Please take a look at our Ohms Law Calculator and/or Power/Resistance/Current Calculator to make sure the setup you’re using is safe.

Understanding the difference between series and parallel battery configurations is extremely important if you’re using a mechanical mod! Be sure to do your research and get a good understanding of battery safety before building on a mechanical mod!

Battery pairing or ‘marrying’ is essentially the act of using a set of batteries together exclusively.

Battery pairing or ‘marrying’ two or more batteries together for use in a dual/triple vape mod is really important in terms of getting the best out of your batteries, prolonging their life and avoiding any possible ‘stress’ being applied to them.

A paired battery is a happy battery…

Married batteries should be purchased brand new together, charged together and used together (discharged) in the same vaping device. They must also be the same type (the same chemical make-up and capacity). You can use them in other dual or triple vape mods but ALWAYS as a married couple.

If you do want to use the paired set in single battery mods you can BUT they should NOT be used again as a paired set.

Pairing or ‘marrying’ your set of batteries is for the life of the batteries…….for better or worse!

The reason behind this is simple…

Let’s say you’re using a dual battery powered vaping mod and you insert two random unpaired batteries. If one of your batteries is charged at a higher rate than the other, it will work harder trying to ‘cover the slack’ of the weaker battery. This places unnecessary stress on the batteries… not good.

One of the batteries could also fall below its safe operating voltage (batteries don’t last forever!) leaving the other to struggle with powering the mod… again this places stress on the batteries and could have unpleasant consequences!


Great question…

The easiest way to ‘marry’ your vape batteries is to keep them stored together in a battery case. By storing them together, it’s easy to remember to charge them and discharge them together!

Personally, I actually re-wrap the batteries with the same custom wrap. I recently bought a great set of superhero themed custom wraps of all different colors and styles. By re-wrapping the batteries with the same custom wrap, I can guarantee I won’t accidentally mix up my ‘married’ batteries!

I’ve written a step-by-step how to re-wrap a vape battery post that you can follow, be sure to check it out!

Please also keep in mind; every time you charge the batteries and re-insert them into your vape mod, alternate the orientation of the batteries. This will spread the working load of the batteries ensuring maximum longevity and safe discharge.


Using different battery types (with different chemistry) is a definite NO.

Mixing Lithium and Alkaline batteries together is another definite NO.

The ONLY exception to this rule is if we’re simply talking about using unpaired batteries (of the same type, chemistry etc) in a dual battery vaping device.

Although I don’t recommend it, if you have two unpaired batteries of the same chemistry, type and manufacturer, you can use them in an emergency. I would only do this in a real pinch or a ‘one-off’ though…

There’s one other thing we need to mention briefly…

Stacked (stacking) batteries is a term used to describe two or more batteries that are placed on top of each other (serial configuration). This means the positive end of battery ‘A’ is placed against the negative end of battery ‘B’.

An example of this would be to Stack two 18350 batteries in series into a vape mod designed to accept a single 18650 battery.

In a nutshell, unless the mod you’re using is designed to accept ‘stacked’ batteries, we don’t recommend it.

As mentioned previously, batteries placed in series (or ‘stacked’) will combine their respective voltage. For example, the overall voltage of two 4.2V batteries is 8.4V.
The combined mAh will remain that of the single battery. For example, two 2500mA batteries will still only provide 2500mA’s.

In a mechanical mod, this significantly affects the wattage you vape at for a given coil resistance. Potentially, this could be dangerous, both in terms of exceeding the safe wattage for your coil and demanding too high a current drain on your vape batteries!

Use a regulated mod and it’s not such an issue but you do need to be aware of its operating voltage. In some cases, apply 8.4v and your vape mod will shut down if its ‘cut off’ limit is below 8.4v. In other cases it could potentially damage the vape mod as it’s expecting a maximum supply voltage of around 4-5 volts.

If you have any doubts, it’s always best to err on the side of caution… Please don’t take any chances. Use the correct type and size of battery designed for the mod you’re using!

And there you have it folks! Hopefully you now understand the difference between series and parallel battery configuration and the importance of pairing your vape batteries!

Happy Vaping!