Why is my Infratonic not holding a charge?

The battery last for about 300 charges. After that, it stops holding a full charge.  In most cases, simply replacing the battery resolves the problem. 

For longest life:  

1. Allow the battery to discharge until the red low battery light (read “BAT”) starts to flash.  
2. Charge it for 1.5 hours until the battery light turns green.  
3. Also, leaving it on the charger tends to shorten battery life. 

Charging after each use tends to use up the 300 charges faster.