What about
Raining +dry skin 1/8 hp
leftovers 1/16 hp
aqua ring 1/16 hp
in a double battle get another Pokemon to use surf (with dry skin it will restore 1/4 hp to you)
use recover (or have another Pokemon use heal pulse on you)
have sturdy as a second ability
you recover 100% of your hp per turn and you have sturdy, unless 2 opposing Pokemon attack you (and do enough to kill you) you are practically invinsible (well... until your Pokemon using surf or heal pulse faint)
you can also add rain dish