The External Battery for Resmed Mobi Portable Oxygen Concentrator is an optional external battery that can be paired with the Mobi's internal battery to provide extended battery life and run time. The External battery provides approximately the following run times:
 
Setting 1: 4.5 Hours
Setting 2: 3 Hours
Setting 3: 1.9 Hours
Setting 4: 1.6 Hours
Run times will vary based on several factors including elevation.