The Caliburn A2 has a 520mAh battery which would last the average user a full day of regular usage. It can be charged from 0-100% in around 30 minutes and the LED light at the bottom of the device indicates your battery level. Red means 30% or less, blue means between 30% and 70% and green is 70-100%. The light will flash red when completely dead and when charging, the green light will stay solid when fully charged.