Battery Life On Mini Vari Tube Aka Young June

[twilightbloom]

I just purchased my first lavatube. I got a mini chrome vari tube aka as Young June. It came with two 18350 ICR (LiCoO₂) 900 mAh 3.7V Li-Ion Batteries. I charged them until the light on the charger turned green. I'm getting maybe 2 hours battery life out of this thing. I thought it was supposed to last most of the day. I'm vaping at 4.0 on 2.7ohms. Is it the batteries themselves? Or did it not charge enough. It was on the charger for around 3 hours? I am vaping with a vivi nova. I'm new to the lavatube world. Any help would help.