What follows is an easy way to calculate what your voltage should be depending on the ohms of your atomizer: Here's what you do: Take the Ohms level and simply add 2 to it, and that will get you very close to the voltage level you should be at. Let's take a couple of examples using the equation "Ohms * Watts = Voltage squared." 1.8 ohms, 8 watts = 3.79volts (rule of thumb = 3.8 volts) 2.4 ohms, 8 watts = 4.38 volts (rule of thumb = 4.4 volts) 3.0 ohms, 8 watts = 4.89 volts (rule of thumb = 5.0 volts) The "Add 2" rule, while not perfect, is a good place to start, and will get you to a place where you can add/subtract a tenth of volt here or there to get you to that perfect vape.