You appear to understand that a dual coil carto rated at 1.5 ohm overall has two coils, each individually rated at 3.0 ohms. Therefore a dual coil will require additional voltage to fire the two coils, draining your battery faster than if you were using a single coil carto.
What do you hope to gain from using dual coil cartos? I started out using them and was disappointed in their performance. I tried single coils and have never gone back to dual coils.
My disappointment stemmed from them developing a burnt taste soon after using them. I'm certain that they were properly primed initially. However, once you've taken a few puffs the juice not only gets pulled from the tank, but also gets pulled from the upper half of the cartomizer. The tank will never keep the entire filler material soaked with juice, just in the lower half where the punched holes are.
For a single coil carto, that works out great. The lone coil sits down in the bottom area of the carto where the filler stays wet with juice from the tank. A dual coil will have the second coil located in the upper half of the carto, above where the punched holes are, and the filler around this coil may not continue to stay as wet as it needs to to keep from burning the filler. Once the filler becomes burnt or scorched, you'll never get that taste removed from the carto.
