How long does it take to fully charge the empty battery? Jenny Flor Jiang March 19, 2018 12:11 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? What are the cleaning modes? How long does the battery last? What are the Bluetooth features? Comments 0 comments Please sign in to leave a comment.