The method and 
system for managing power supplied from a charging circuit to a power source in an implantable 
medical device comprises the steps of and circuitry for: measuring the current drain of the 
medical device; measuring the elapsed time since the last full charge of a power source of the device; calculating the actual capacity of the power source (corrected for fade) based on the variable of current drain and the variable of elapsed time; calculating the 
operating time based on the variable of current drain and the variable of the actual capacity of the power source; measuring the 
voltage of the power source; signaling the 
medical device when the power source 
voltage has reached a certain low value which requires disconnection from the power source; disconnecting, during discharging, the power source from the medical device upon the power source reaching a certain 
low voltage in order to prevent deep discharging of the power source and subsequent damage; precisely limiting the charging 
voltage to the power source in order to prevent overcharging beyond safe limits; disconnecting, during charging, the power source from the charging circuit upon the power source reaching a certain 
high voltage in order to prevent overcharging of the power source and subsequent damage; sensing when the electromagnetic 
waves being transmitted by an RF 
transmitter / charger induce a voltage level above a certain value at an RF 
receiver of the implanted 
power management system; reconnecting power supply inputs of the medical device to the power source upon sensing this induced 
high voltage level; monitoring the temperature of the power source during charging and discharging; disconnecting the charging circuitry from the power source if the temperature of the power source raises above a certain level during charging; reconnecting the charging circuitry to the power source when the temperature of the power source drops below a certain low value during charging; disconnecting the implanted medical device from the power source if the temperature of the power source raises above a certain level during discharging; and, reconnecting the medical device to the power source when the temperature of the power source drops below a certain low value during discharging.