Well, even at .6 if you average the run time out continuously that gives you about 24 minutes continuous and and you would in reality run it down for half of that so you're looking at an average of 8-13 minutes of actual vape time divided by how long your take a drag. If you're wondering where I get my math I do the ohms law calculation at 3.8 volts for a fresh battery after average voltage drop on my mechs and that gives me about 6.1 amps and that is only going to drop with every drag....6.1 amps divided by a 2.5 Ah runtime for the battery is .41 .... .41 hours is about 21 minutes,,,,not take into account continuing voltage loss from a dying battery and you're looking at about 13 minutes of decent, not total, but decent vape time off a good and healthy battery at best...now if you're taking 10 second drags which is super long for even higher sub ohm vaping like .6 you can hope for at best 78 good drags...but we all know in reality from feel and experience it's more like 50 on a good day....so unless your battery is dying in like 10 drags or less it should be ok.
if you're battery is dying in 10 drags or less than either your battery or your charger is faulty or there is a short somewhere sucking the life out of your battery,,,either way something is not right and if you have another battery I would use that one...maybe your charger is faulty, they can stop working properly in time, especially cheap ones, or there is a short somewhere in your atty or your mod...if not from a loose or pinched coil than an insulator is bad somewhere if it's not your charger or your battery