6-9 depending on the liquid and your drags
honestly I don't think people should be so fast to recommend the ego to kr808 users, it is not the same experience...yes you should like dripping but unless you get an LR atomizer it will not be the same warm vapor you are use to. That being said as a person with both an inferno (big battery style 510 like the ego) and a kr808 I have gravitated to using the inferno more just because of the battery life and the fact that I live with someone who uses a normal sized 510...so it is easier to share atty's and cartridges and the like.
Honestly I don't think half the people who recommend ego batts to kr808 users have ever tried a kr808. That being said...try a LR atomizer on it...or a lower than 3.0 anyway if you want the warm vapor the kr808 was making...or get use to the cooler vapor..there is plenty of it with an ego after all