How long does it take to fully charge the empty battery? Jenny Flor Jiang July 12, 2018 09:53 Updated Follow If your Amabrush battery is completely empty, a full charge takes about one hour. Related articles Can I leave the Amabrush constantly sitting on the charging station? How do I charge the Amabrush? How long does the battery last? What are the Bluetooth features? Tell me more about the UV-station Comments 0 comments Please sign in to leave a comment.