Understanding how an E Cigs works –

It’s more than simply the volts of your battery.

It’s about oHms, Watts, Amps and Volts, plus how they react to your device.
The math may be confusing to some, but it’s important to understand the basics. Although we can cheat a little by using charts.

ALL Delivery System Devices are assigned oHm ratings

The Formula is:
Watts = Volts X Volts / Ohms
Amps = Volts / Ohms

Here’s some in-depth information already written-

There are reasons one should understand the basics

  • To know the correct resistance for your Delivery System purchase
  • To help find your sweet spot of vaping
  • To ensure you don’t overpower and burn out the device

A Video explanation on oHms Law from VapePowered YouTube

Some general guidelines


  • Power (watts) is the intensity of the vape. 6-8 watts is the “sweet spot” for most vapers
  • Current (amps) is what can burn out atomizers. 1.5 – 2.0 amps is fine. 2.0+ amps is risky
  • The lower the resistance of your device, the faster it will drain the battery
  • The lower the resistance – The lower the volts
  • The higher the resistance – The higher the volts
  • For a 3.7 volt device use 1.8 oHm resistance



  • Will run hotter producing warmer vapor
  • Will create more vapor
  • Will produce more throat hit
  • Will affect the flavor produced, either by producing more or diminishing it.
  • Will drain your battery faster
  • Will go through e-liquid faster, which increases the likelihood of a dry hit, if  your e-cig can’t keep up with the rate of use



  • Will run a bit cooler, producing a cooler vapor
  • Will create less vapor
  • Will produce a smoother vape with less throat hit
  • Will affect the flavor produced, either amplifying or diminishing it, depending on the individual flavor.
  • Will allow your battery to last longer between charges
  • Will use less e-liquid

Everyone has different tastes and expectations. Some may look for a warmer vape or greater throat hit. Some may want a mild, all round experience. At times, we want the ability for both, so it’s nice to have a few variations for any given device/s.

When ordering a new Delivery System – it’s best to get 2 variations.

If you’re ordering a Cartomiser or Clearomiser, you wish to try a 1.6 or 1.8 oHm and a 2.0 oHm.
See which one performs best for you. 
You only get to know your preferences by experimenting.

Here is an easy to follow Chart for those that don’t wish to use math- Click to enlarge

3.7 Volt setting examples

Let’s look at an example from the chart above. Follow the 3.75-volt column listed on top.
We can see that the safe resistance range is from 1.8 up to 3.5 oHms.
This may be true yet on all 3.7-volt devices I’ve used, I find anything over 2 oHms produces insufficient levels of vapor and little satisfaction.

For my Silver Bullet an older  3.7 volt Tube Mod, I always use 1.8 oHm.
In some respects, a 3.7 volt device is simpler to work with.
You are given a voltage limit. Therefore, your only means of adjusting performance comes down to the oHms of your Atomiser or Coil.

Everyone has different tastes, so it’s impossible to give a single set of numbers to abide by.
e liquid viscosity is a factor too, as Flavor/Taste alters at different outputs.
Some e liquids taste better at 4.5 or 5 volts.
One important point regarding 3.7 Volt devices.

Lower oHms generally provide a better vape but lower oHms reduce your battery life
This is one of the primary reasons for owning a larger style e Cig Mod.
They take much larger batteries and allow for all day vaping without the need to recharge.

I understand that some may find this too much. Perhaps confusing and even frustrating.
Whilst I feel it’s important to grasp the theory of oHms Law, using one of today’s Mods, along with a Clearomiser or Cartomiser, is certainly a safe practice. Vaping at around 4 volts on any device will be fine with Atomisers or Coils rated at 1.6 to 3 oHm.

I hope this has been helpful

From the table,

Share This