@ajaxfraser 

Hi,
Thank you for the case report and please help confirm the following information about the reported issue for further analysis.

1. Do you have an issue after inserting the battery into the camera soon after fully charging it?

2. Do you have another battery Tapo A100?

If yes, insert a different fully charged battery into the camera to confirm the issue is related to the battery or camera.
 

3. Remove the battery from the camera, use a dry cloth or paper towel to clean the battery and camera, reinsert the battery, and tighten the camera's back cover. 
Check if the battery value is displayed correctly on the Tapo app.

4. Ensure the Tapo Hub, Tapo camera, and the Tapo app are up-to-date.

Best Regards