The Inogen external battery charger is your ticket to no longer having to wait for your Inogen batteries to recharge to use your oxygen concentrator. This is because the external battery charger allows for patients to run a battery in the G5, while having an additional battery on the side charging. Setting the external battery charger up is simple, just plug the included power cord into the back of the charger and plug the wall adapter into any of your homes power outlets. Recharging your batteries have never been faster, a fully drained battery depending on the size will take anywhere between 3 – 6 hours.Planning on traveling? Well you’re going to need another way to charge your additional batteries apart from the AC/DC power supplies, so if you plan on traveling you will want to include the external battery charger on your necessities list.