It depends on the transformer(s) being used in your mod. The resistance of those coils+resistance of your cartridge and maybe the addition of the minute resistance on the battery itself will be the Resistance factor. You'll also need to know the discharge rate of your battery..which is more than likely 70%. With my 18650 2600mAh battery, with only the input of my cartridges resistance(2Ohm) to get the current, I will get .91 hours of consecutive operation. The addition of the resistance of the transformer(s) coil will increase the duration of length. This is being able to hold the button down continuously. Obviously one would have to respirate oxygen at least on a few occasions in that hour, but it does sound about right for your battery to last only a few hours with constant use.
I=V/R
If you want to stick with that battery style, you can always try to find a higher capacitance or mAh..which is mili-Ampere hour.