Inogen portable oxygen concentrators last between 2.25–13 hours before needing to be recharged, varying by the model, battery, and flow setting. For example, the Inogen One G4 can last up to 2.7 hours with a single battery on setting 1. With a double battery, it can last up to 5 hours on setting 1. The machine overall can last up to 4–6 years, depending on proper care and maintenance.