An Inogen One battery is normally charged by the concentrator. If you own more than one battery, this can make it difficult to have all your batteries fully charged at the same time. To solve this problem, the external battery charger was introduced. The external charger connects to the mains with its own power supply. Now just slide the charger over the battery, and it will start charging automatically. You never have to worry about depleted batteries again!

On top of that, the external battery charger charges the batteries quicker than the concentrator. These are the recharge times: