How long should I charge the battery when I first get my toothbrush handle? March 07, 2019 19:12 Updated Follow Before you use your Shyn sonic toothbrush handle for the first time, be sure to charge it for a full 16 hours. Related articles How do I know when it’s time to charge the battery? How do I charge my Shyn toothbrush handle? What should I do if my charger stops working? How long does the battery life last for?