What if my battery dies during a session? Recharge the controller. Always try to recharge when you only have 33% power remaining. Related articles Abs Toning Belt Instruction Manual Where can I view my toning progress? How long does the battery take to charge? What do I need to work the Slendertone Abs Toning Belt? 60-day Money Back Guarantee Comments 0 comments Please sign in to leave a comment.