Getting Started: Variable Voltage, Variable Wattage, what’s the difference?

In the post Getting Started: Electronic Cigarette Basics I touched on the benefits of moving beyond cigalikes (essentially better control of the vaping experience). There are basically two ways to go forward:

  • Regulated Advanced Personal Vaporizers (APVs)
  • Mechanical Advanced Personal Vaporizers

We’re going to ignore mechanical APVs for right now (I will be addressing it at a later date) and look at regulated APVs.

A regulated APV simply means that the device has an electronic circuit that controls (regulates) either the voltage (these are referred to as Variable Voltage or VV devices), or the wattage (these are referred to as Variable Wattage or VW devices), or both (these are commonly referred to as VV/VW devices) in the device you are using.

This allows us to use Ohm’s Law to determine what the proper setting for the desired voltage (in VV devices) or wattage (in VW devices), across the atomizer (resistance) is. Why? Some juices will taste better at specific wattages/voltages on some devices, and better at other settings on different devices. Some people like a given juice at a higher wattage than others.

Ohm’s Law is a very technical subject, and if you want to delve into it you can do so here. There are plenty of Ohm’s Law calculators available online, I like this one.

Vaping Power Chart - click to enlarge

Vaping Power Chart – click to enlarge

The point is control.

So, what’s the difference?

It’s hard to quantify, the best I can do is to offer some examples.

If I set my VW device to 8w (that’s 8 watts) on a protank with a 2.5 ohm head it will get 8w (at ~4.47v). If I then remove it and put say, an IGO-L with a 1.5 ohm coil on there, the device is still going to deliver 8w (at ~3.46v) to the atomizer (we’ll call this example 1).

If on the other hand I set my VV device to say 4.2v with the same two toppers, the protank will get 4.2v (at ~7.05w), and the IGO-L will get 4.2v (at ~11.76w).

How do I know this? Ohm’s Law.

Why is this important? Battery life and safety.

In example 1, the device is drawing ~1.78A (that’s amps) with the 2.5 ohm protank head, and ~2.31A with the 1.5 ohm IGO-L coil. If this example is using an APV that runs on an IMR 18650 battery that can sustain a 10A draw it’s fine, but if this is on an APV that is powered by an IMR 14500 battery that can only sustain a 2A draw, the only way it can function is what is referred to as voltage sag (a situation where the current draw is more than can be delivered by the battery, so the voltage delivered is actually less than what you have specified). This also means that my battery will not last as long with the IGO-L if I want the same vapor experience as I get from the protank atomizer (it’s kinda apples to oranges comparing a clearomizer and an RDA like that, but you see my point).

The safety part comes in when you are pulling much higher wattage than the atomizer should have (11.76w across a 1.5 ohm atomizer is too hot, and will result in premature coil burn out. It’ll also probably taste terrible).

Now that we know how VV and VW differ, why not just use one for all of vaping?

There are several reasons.

As it relates to vaping, we can equate wattage to heat (the more watts you draw, the hotter your atomizer gets). 8w is 8w regardless of device, but you can see from example 2 that 4.2 volts doesn’t produce the same power (wattage is a measurement of power) at 2.5 ohms as it does at 1.5 ohms.

Basically VW devices do some of the math for you and raise the voltage according to the resistance of the atomizer on them.

Another is cost. VW circuits are more complex than VV circuits, and will either raise the cost of the device, or lower the quality of the regulation circuit.

I like to think of the vaping experience I get with a given juice in terms of wattage. I find that using wattage to determine the sweet spot for a given prefer VW, but some of the best devices on the market only offer VV (the iTaste MVP and ProVari are two).

In the end it comes down to personal preference.



One thought on “Getting Started: Variable Voltage, Variable Wattage, what’s the difference?

  1. Oh my gosh, thank you! You have completely cleared this up for me. I cannot tell you how many explanations I have read that have only left me more confused. I’ve been so scared to start messing around with mods and ohms and things for fear of blowing up a battery.

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