I feel there are too many variables from user to user in measuring a battery on how long you vape. Probably a lot less variance between users if you measure the juice you go through.
I get 17-18ml before having to swap batteries (using 40Ts). How is it for you?
I think that iJoy battery you're using is more geared towards mechs than regulated. You'd be waaaaay better off using a Sanyo 20700B.
Really, the only variable is the mAh rating of the battery, with regard to battery life. That is if you vape at the same wattage, with the same build, on the same mod.
I am comparing the same build on my mechanical Pulse mod with the same battery in the Pulse 80 and there is a very noticeable difference in battery life. That tells me that the Pulse 80 is less efficient. I expected that the Pulse 80 would be less efficient due to the board providing the exact same wattage for the entire life of the battery, just surprised by how quickly the battery dies. As it stands, I'm getting through 3/4 of the bottle before the battery dies - with a .25-ohm SS clapton using a 3000mAh battery at 33w.