Inogen One G3 Double Battery

Q: how long will the battery orperate in hours

The sixteen cell (double vs the eight cell single) is stated to last 8 hours on 2 liters of oxygen, going down to 6 hours at 3 and 4 hours at 4 liters. My wife's experience has been that it actually lasts a bit longer, a little over 9 hours on 2.This is usually plenty, especially since it can be charged in the car while driving. We've also added a backup battery (which can easily be swapped in) and a second power supply, so it can be plugged in and charging when my wife is stationary (in bed at night, at her ofice, in the kitchen). This combination seems to take care of all or her needs.