Hi there! My name is***** am a computer professional with over 15 years of experience with both Mac and Windows computers, phones, tablets, and printers. It would be my pleasure to assist you with this.
This problem and many others are often the result of a "glitch" in the software. Luckily, it is easily fixed.
Please do the following:
To get a full factory reset and will make the device, as new out of the box:
That should resolve the issue so your Vivofit can accurately read battery life again. If it does not, please reply back and let me know the exact model of your Vivofit. For instance, is it the Vivofit HR, Vivofit 1, 2, or 3?