Open the seal on the USB port, insert the supplied USB cable, and connect to any USB power source, for example a laptop computer. A green indicator light shows that See.Sense. is charging. When it is fully charged, indicator light goes out. A full charge takes around 2.5 hours. When you have finished charging See.Sense. remove the USB cable and make sure the seal is securely closed. To maintain the battery’s performance, charge See.Sense. fully at least once a month.