how long should a battery last in months ? Im a heavy vaper and my battery is always going dead after 3-4 hours.One is 2 months old the other 2 are 9 months old.Also if you want a heavier pull what is the number of coil to get? I got 2.4 now and sometime when the battery is fresh i can vape good.Is it the battery or the coil? I'm sorry if this has been asked but there is a lot of info on here to go through.Thanks MO