Can't take any credit for myself, found this on a Facebook group wall, so thanks go to Mitzi Faught Miller for posting it.
It's a chart, separated into three sections, one for each resistance of carto, 1.5, 2.5, and 3.0. It does NOT take into account the fact that dual coils draw more amperage, so keep in mind these results are for single coil ONLY.
The general consensus of the vaping community is that the "sweet spot" is between 7-10watts [please correct me if I'm wrong on those numbers]. So, for example, take a 1.5ohm single coil carto, you want to try it at 7w, if you look at the chart, you see that at 3.4v, you'll get 7.7watts and it's drawing 2.7 amps, so you're within the safe zone there.
Keep in mind, the 2.5ohm cartos are like WOWs, and the 3.0 cartos are like Cool Carts, give or take a couple tenths. I hope this helps, and if my post needs to be reworded or corrected or anything, please feel free to Morandir
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