Remaining time indication for a rechargeable implantable medical device

A method for preventing excessive power drainage and indicating the remaining discharge time of the power source of an implantable medical device for delivering a therapeutic output to a patient, which would result in damage to the power source and/or medical device and/or injury to the patient, the method comprising:

• implanting the medical device in the patient, the medical device comprising:
• a rechargeable electrical power source having a useful life;
• a therapeutic delivery device operatively coupled to the power source and adapted to deliver the therapeutic output to the patient;
• a power source recharge timing indicator operatively coupled to the power source, wherein the timing indicator includes means for determining and communicating when the remaining usage time before full drainage of the power source drops below a first predetermined level based on measurement of one or more physical characteristics of the power source and of the medical device;
• and safe mode means operatively coupled to the timing indicator, power source and therapeutic delivery device, wherein the safe mode means, upon activation, is capable of causing one or more actions to reduce the power consumption of the medical device;
• wherein the safe mode means is activated by receiving communications from the timing indicator that the remaining usage time before full drainage of the power source has dropped below one or more second predetermined levels, thereby preventing excessive power drainage from the power source;
• determining and communicating when the remaining usage time before full drainage of the power source drops below a first predetermined level based on measurement of one or more physical characteristics of the power source and of the medical device;
• and
• causing one or more actions to reduce the power consumption of the medical device;
• wherein the safe mode means is activated by receiving communications from the timing indicator that the remaining usage time before full drainage of the power source has dropped below one or more second predetermined levels, thereby preventing excessive power drainage from the power source.