Saturday, January 24, 2015

Box Mod Builds: Parallel vs Series

I received a question the other day by someone interested in the Hammer of God box mod.  The topic was, which is better (or safer) parallel or series circuit box mods.. and why.  So I thought this would make an interesting topic of conversation.

First, we have to understand each one and what it does.  So let's jump into a quick electronics lesson:

Parallel Circuit.  This type of circuit (specifically referencing a box mod) creates an electric current from each battery at the same time.  The total voltage remains that of a single battery, however the battery life of each is increased (and so is the overall amperage) since there is less draw on any one battery in the circuit.  When we discuss the harmful effects of vaping and they mention formaldehyde production, they are typically talking about voltage higher than what one 18650 battery can produce.  With a parallel build, the total current to your 510 connection will remain under 4.2v.  Regardless of how many batteries you use in parallel, the voltage will always remain that of (on average) the capacity of a single battery.

Series Circuit.  This type of circuit (again speaking in terms of a box mod) creates an electronic current through each battery consecutively (in a series).  By doing this, you effectively combine the voltage of each battery.  So if you have two 18650 batteries in a series, the voltage will be 4.2v PLUS 4.2v for a max total voltage of 8.4v.  The draw on each battery is combined with one another, similar to stacking batteries in a flashlight (or a mod).  This is where I feel safety comes into play.  Cloud-chasers want to blow bug plumes, so they will sometimes times choose a series build over parallel, so they can throw higher voltage/wattage through the coil and generate more heat/vapor production.

So the question now becomes safety, both in the quality of vaping and that of the battery itself.  If you're concerned with the recent studies showing that vaping over 5v produces significantly more cancer-causing formaldehyde than cigarettes, I think it's safe to say that parallel build box mods would be safer.  Unless you are a professional cloud-chaser and accept the risks that come with vaping at higher volts/wattage, my recommendation would be to use a regulated device or one that incorporates parallel builds.

But I am just scratching the surface here.  I know there are more opinions and sides to the story, so I'd love to hear your take.  Leave a comment in the section below to keep the conversation going.


  1. Where exactly is the formaldehyde coming from? Is it from the heat generated from the batteries? And are you speaking in terms of unregulated mods?

    1. Formaldehyde is a byproduct of the e-liquid breaking down at higher than usable temperatures. The heat is generated by a combination of the voltage and the coil ohm. Studies still need to happen so its somewhat of a gray area. Here is a press release I found regarding that topic.

  2. As a matter of fact, Suck My Mod, contacted the people who did this study and found out that they used a very old style clearo tank with a silica wick and pushed 5 volts. Between the high resistance and low airflow and the wicking speed if silica it turns out that the formaldehyde they found was actually coming from the fact that they were melting the silica wick. Not to mention that the clearo in question is unusable at 5 volts. Totally rigged skewed "study".

  3. Just to touch on the Hammer of god (I have the v3), that is a parallel series box mod, you get the best of both worlds in one. Higher ampage, higher mah but still 8.4v of power.