I got the same kit and depending on the coil and watt I am vaping at, the battery lasts around:
12-24 hours @25 - 35w,
6 - 8 hours @36 - 44w,
2 - 4 hours @ 45 - 58w
And less at even higher wattage. It seems to be normal with that mod or well the tfv8 tanks that come with it. When chain vaping I use lower watt, but even then, it won't last longer then half a day, most of the times and I actually use the great Samsung batteries. As others suggested keep a spare on the charger and take it with you, I you're planning on leaving the house.