An external battery charger comes in very handy if you need to use your POC for many hours during the day. It's very simple to use – you just plug it into an AC outlet, and place the battery into the port with the terminal side down to charge it. It will take some time to charge, just like it would if it was charging inside the oxygen concentrator.
It will only work with AC power, and cannot be charged in the car. The external battery charger was made to allow you to charge up more than one battery at a time, so you won't need to worry about running out of battery power while you're out and about.
You just charge up the battery in the external charger the night before, and charge the other in your oxygen concentrator while you sleep. You can then put the spare, fully-charged battery(s) in your accessory bag or backpack and be on your way. When the one in your unit runs out and you still need to use it just replace it with the extra battery.
The external battery charger itself only weighs a few pounds, so it will be no problem taking it along with you on trips. It's perfect for going on vacation, because it allows you to stay out all day to see the sights and have fun, without worrying that you will run out of battery power. The power cord is long enough so that you can comfortably plug it in and set it on a surface to charge your battery.
To use the external charger, you will need to plug it into a wall outlet. Be sure the battery terminal (the inside of the battery with the metal components) is facing down and lines up with the inside of the charger port.
It works the same way as a cell phone charger, and you'll need to make sure the battery slides all the way down inside the charger for it to charge. You'll see an indicator light, and that's how you'll know that the battery is charging. When the light changes color, the battery is charged to 100%, and you can take it out of the charger. Remove it by pulling upward on the top of the battery.
A tip for transporting extra batteries: Do not allow the battery terminals to touch anything corrosive, or allow two battery terminals to touch each other. Pack them in their own separate bags (plastic sealable bags will do) before packing them in your accessory bag or backpack.