Parallel (++) VS. Series (+-) Devices And The Importance Of Battery Safety

Options are the spice of life. When it comes to vaping, this statement is beyond true and our devices options are virtually limitless. Today I want to look at a question I see over and over again. What is this difference between batteries running in series and batteries running in parallel? In this article I’m going to do just that.

Before I begin rambling a bunch of scientific and electrical engineering jargon at you, I want to discuss something very near and dear to my heart. If you’re an avid vaper, it should be near and dear to yours too, and this is battery safety.

In this discussion were only going to focus on batteries with a minimum of a 20 amp continuous rating. Examples of these would be Samsung 25r’s and LG HG2’s. These batteries are without a doubt the most common batteries used in vape devices and trusted among vapers across the globe.

These are top of line batteries from reputable companies with a history of safety and reliability. Never ever use a battery that has torn wrappings, if they are breaking down, rewrap them in approved heat-shrink wrap casings or dispose of them responsibly.

Same goes for fried insulation rings, bulging of the battery and any visible contusions or physical break down. Many new vapers reading this are probably wondering why this is such a big deal. Simply put, lithium ion batteries are volatile if mishandled.

A tear in the casing leaves the battery exposed to metal on metal contact, this could potentially cause a hard short resulting in the internals of the li-ion battery to heat to a staggering 500 degrees Celsius or 932 degrees Fahrenheit.

This heat could cause the other battery in your device to follow suit even if there is nothing wrong with it. This is called thermal runaway and can cause your batteries to vent. The gas released from vented batteries is super heated C02 and various other gases.

This high temperature could turn your device into a hand grenade and explode with ferocity and fury potentially causing fatal harm. When it comes to batteries, heat is your biggest enemy. Never ever gamble on battery safety.

If you happen to accidentally use a bad battery and your device over heats. Get outside and pull the batteries out of the mod to discourage further damage. The constant airflow from being outside will inhibit an explosion and in theory help bring the temperature of the batteries down.

Lay them on something fire retardant and away from where pets and children typically could be. I.e. Don’t leave them near a swing set or a dog house…don’t be a run-of-the-mill idiot is what I’m saying.

vape battery idiot

Now typically we don’t have this issue because most vapers as of late aren’t using devices that could potentially cause these issues. You’d know them as regulated mods or regulated devices. These devices are powered by a chip, whether it be an sx350j chip by Yihi or an Evolv brand DNA board, or any slew of other companies products like the Kanger Nebox or Joyetech Cuboid to name a few.

These devices are designed with safety embedded into the workings of the regulatory chip. For example, if you accidentally put in one of your batteries wrong in your Wismec RX200, it just straight up won’t turn on. But if you mess up the battery orientation in an unregulated series OR parallel mod, this could be disastrous.

Now that I have beat into your skull the importance of not messing around with Li-ion batteries. I want to shift gears into the types of devices you’ll need these batteries for. There are two types of devices that we will be focusing on.

Series mods, and parallel mods. What are they and why is their orientation important? We as vapers demand a lot from the devices we use. But one thing I think a lot of us forget about is that vaping, just like anything else in this world worth having, is all about give and take.

I personally like to think of it like the basis of an alchemic equation. If you want something, you must trade for it with something of equal value. As vapers we do this all the time. If you want to blow those “Clouds bro! Clouds!” You have to except the fact that you’re going to have terrible battery life and you need to carry extra batteries (in a proper plastic case I might add, you neanderthal) and or be near your external charger.

For those who want elongated battery life, you’re sacrificing that sweet sweet flavor producing power to have an operable mod to get you through that twelve hour shift at work. Before we get into the differences between series and parallel mods I would like to note that these devices are for vapers who are fluent in battery safety and know what they are doing. These are not like regulated mods and need specific care and need to be monitored at all times. Do not comment and say I didn’t warn you.

Series mods –

series mods

Unregulated series box mods are devices that effectively doubles the voltage that is being pushed to the coil. This type of circuit uses the current from each battery at the same time and combines the voltage from each battery.

Although the voltage is multiplied by the number of batteries, the amp draw and mAh (milli-amp hours) ratings remains at that of a single battery. When you place your batteries in the mod, one battery will have the positive connection pointed down, the other battery will be pointed up. Series mods technically stack the batteries in a small compartment.
An example of a mod like this is the ever popular Wismec Noisy Cricket

What this means –

say you’re using two Samsung 25r’s. Each battery has a nominal voltage of 4.2 volts with an amp rating of 20 amps. While the mod is wired in series this means that the voltage is being pulled from each battery for a total of 8.4 volts, utilizing the current from both batteries.

In turn you only have 20 amps at your disposal, two batteries may mean double the voltage but it doesn’t double the amperage. This is incredibly important because it means you CANNOT super sub ohm on a device like this.

For you vapers who like to see how low you can go, let me put something into perspective for you. Say you build a coil that reads .12 ohms (for the love of God and all that is holy don’t ever go below this on ANY kind of device, safety people, safety.)

With a simple bit of math using Ohms Law you’ll see that you’ll be pulling 70 amps for a whopping 588 watts. If your mod doesn’t nuke your living room, consider yourself lucky. Series mods NEED to be built at a higher resistance.

Personally I wouldn’t go below .6 or .7 ohms on a series device. Even a coil reading at 1.2 ohms will have an amp pull of 7 amps at 58.8 watts. That’s damn rowdy for a 1.2 ohm coil. With this being said, series mods are built for power in mind. But lack the battery longevity for all day enjoyment. Which brings us to our next topic.

Parallel mods –

parallel mods

While a series box is wired so the positive positions of the batteries are going the opposite directions. Parallel configurations have the batteries going the same direction. Both negatives are pointed down and both positives are pointed up.

Unregulated Parallel box mods are devices that split the current between two or more batteries at the same time. While the total voltage remains that of a single battery (4.2v), the total battery life (or mAh rating) is increased as well as the overall amperage since there is less draw on any one battery in the circuit.

Basically it’s the EXACT OPPOSITE of what a series box is built for. An example mod that uses this configuration would be the Tugboat #TUGLYFE mechanical box mod.

What this means –

We’re going to use those Samsung 25r’s as an example again. You pop two of those awesome batteries into your parallel mod and your ready to rock at some high voltage!

No, just kidding. Even though you have two batteries in there that run at 4.2 volts apiece, the mod can only utilize said 4.2 volts as a whole. But the trade off is that instead of 20 amps and 2500 mAh at your disposal, you now have 40 amps and 5000 mAh for all day use.

Remember that dangerous .12 ohm build I was taking about before? In series you’d pull a dangerous 70 amps at 588 watts. But in parallel you’ll be pulling at 35 amps at 147 watts, which is obviously more reasonable. In terms of safety, parallel mods are the way too go, especially if you’re just starting to get into unregulated devices.

With all this being said, even though a parallel box is technically safer than a series box. It is up to the user to ALWAYS make sure that the device they use is safe for the builds they want to put into it. Series and parallel devices are both extremely powerful and caution CANNOT be thrown to the wind when working with them.

Always check your resistance on a regulated device, ohm meter, or multi-meter and double check your calculations with a vape calculator like Steam Engine, that’s what I used for my calculations in this article. Always make sure your batteries are in tip top shape and never use batteries with less than a 20 amp rating. I just have a few more points to go over

-Always make sure your series and parallel boxes are cleaned regularly. Gunked up contacts will cause current resistance and make one of your batteries drain faster than the other. This is potentially dangerous and cause all the things I mentioned above.

-Series and parallel boxes DO NOT have battery meters on them. It’s important that you don’t drain your batteries completely dead, if you do your batteries will be useless and need to be properly disposed of.

Don’t discharge your batteries passed 3.6 volts as a safety measure. How do you know when your batteries are getting low? Pay attention to your hits. If you’ve been chain vaping for the last hour and your hits are getting weaker and weaker, it means your batteries are getting weaker and weaker. Time to charge them.

– Although this article was meant to tell you the difference between parallel and series mods. The main point that needs to be driven home is that it doesn’t matter which devices you have, battery safety is more important than either. These devices aren’t meant for the casual vapor, do your research to make sure a device like these are right for you.

– Most series and parallel boxes have hybrid 510 connectors. this means it has a direct atomizer to battery connection. Do not, I repeat, DO NOT USE SUB OHM TANKS WITH THIS TYPE OF CONNECTION.

Sub ohm tanks don’t have an adjustable 510 pin. If you over tighten the atomizer, the 510 threads (Negative connection) on the tank will make contact with the positive pole of the battery, this is super dangerous and your literally asking for an explosion to happen, I’m sure your parents and room mates don’t want there living room to look like an average game of “Boom Beach.”

Only use RDA’s and RTA’s that use an adjustable 510 pin. This boys and girls is non-negotiable. I don’t mean to beat this dead horse into submission but I can’t stress to you enough how important this concept is. You have been warned.


Suprisingly enough there is hybrid box in existence that utilizes this. Remember that Wismec Noisy Cricket I mentioned earlier?

Well it has a bad ass baby brother known as the Noisy Cricket II-25 (the 25 stands for 25 millimeter, and can use up to 25 millimeter atomizers without overhang) and the circuit board is reversible. On one side you can use the box in series connection, and if you flip the circuit over you can use it in parallel.

The box also has a potentiometer that is easily accessible on the side and you can adjust voltage with your thumb while vaping. This is super cool people! It’s also stupidly dangerous if you don’t know what you’re doing. Always pay attention to your battery orientation and which circuit you’re utilizing. Battery safety guys and gals!

Mod battery idea

In a world where regulated devices rule the roost. Series and parallel boxes are making a come back, especially with the hobbyists and DIY-ers, I believe that we are going to be seeing a huge resurgence of series and parallel mods in the near future along with hybrid connections like the NC II-25.

Please be careful and do your research before committing to devices that don’t have built in battery protection. With that being said, have fun on this new excursion.

Okay my final, FINAL thought. The FDA is trying to take away our rights to vape and protect our health. Battery safety is one of their main points and they believe we aren’t capable of safely using these devices which is partially why they are trying to take them away from us.

Practice battery safety, people. Please also visit and sign the petition to save our rights. The only way we can survive is if we ban together and fight as one. Stay safe and vape on brothers and sisters!

– Christov J. McCauley


One thought on “Parallel (++) VS. Series (+-) Devices And The Importance Of Battery Safety

  1. David Rector says:

    I am 50, and I have been vaping for a year now. I have educated myself thoroughly regarding ohms law and battery safety and I have been switching between regulated series box mods and mech mods. I find that when I am at home I vape mainly mech mods and in the car or out and about, I vape a regulated series box mods. I just now purchased a NC2-25. After watching many reviews regarding $399 mods, or $40 mods, whether unregulated mech or regulated box, the NC2-25 seems to be the one device that makes total sense to me. This device has the best of both worlds, simplified to the experienced vaper, no oled, nor computer chip which allows me remain stupid and enables me to disregard ohms law, but the device allows me to decide for myself how I want to vape today. Long battery life while away from home, or clouds bro clouds and switching batteries out when desired. For $30 I get total satisfaction. I found your article to be on point, and I will share it for the layperson to become that much more educated. Thank you

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