I use 1.5 Ohm atty's on my mini. I think a 1.8 is way too cool for a fresh 4.2V that may drop off sharply after a few squonks. You didn't say what juice you use, as that makes a difference too (tobacco/fruit/sweet, Pg/Vg, Mg). In my mini, I use 80/20 Ruby Red Grapefruit @18mg with a 1.5 Ohm...