As you start to enjoy your newly restored portable freedom with the ARYA Mini, whether that be catching up with friends or enjoying your daily dose of recommended exercise, you may start to consider purchasing an extra battery to have as a backup. That won't be a problem with the ARYA Mini, as you will want to consider the external battery charger. When using the AC power supply and the DC car charger, you will not have to wait for each individual battery to charge when you have the external battery charger for your ARYA Mini portable oxygen concentrator. The ARYA Mini external battery charger gives you the ability to charge one battery on the side with the use of any wall outlet with the included power supply. Now you can enjoy usage of your ARYA Mini with 1 battery in the unit, while your extra battery is simultaneously charging on the side. The external battery charger works with the single, double, and triple battery, meaning you won't need to sit around for hours waiting for your single battery to charge. Using the external battery charger, you won't be using the battery simultaneously, so you won't have to worry about prolonging your battery's charging cycle.