The battery in the Quick Keys, once fully charged, will last 52 hours.
When charging the Quick Keys, it is recommended that you connect it to your computer or USB hub that is connected to your computer. Using a USB charger that is connected to the wall socket is not recommended due to possible damage due to an incorrect voltage being sent to the Quick Keys and causing damage to the unit.
Once you are done using the Quick Keys for the day, plug it in via the USB cable, and it will charge overnight and be ready to go the next day. You can also use the Quick Keys while it is plugged in and charging.
You do not want the Quick Keys to stay in a drained state, once the battery life is 10% or less, it is recommended that you charge the Quick Keys to keep the battery properly conditioned.