You can charge the receiver two ways: 1.) First, you can use the Dexcom AC outlet charger, which will fully charge the receiver in three (3) hours 2.) Second, you can use the Dexcom USB charger, which will fully charge the receiver in five (5) hours. To use the USB charger, a Windows-compatible computer is needed and the Dexcom Studio Software must be downloaded in order to charge your receiver from a computer. After downloading the software, a.) Plug the included USB cable into your computer. b.) Plug other end of the USB cable into the receiver. c.) The battery charging screen will appear on the receiver. Note: If your receiver does not show the charging icon when plugged into the charger make sure that both ends of the USB cable are fully inserted into the receiver port and wall charger.