Detecting heating of implanted coil hermetic package when misaligned

A method of monitoring heating of a hermetic package of an implanted transcutaneous energy transfer system (TETS) coil, comprising:

• monitoring a power transfer between the implanted TETS coil and an external TETS coil;
• detecting an amount of power lost during the power transfer that is above a first predetermined threshold;
• generating an alert and initiating a first predetermined period of time in response to detecting that the amount of power lost is above the first predetermined threshold;
• monitoring the power transfer during the first predetermined period of time,
• determining that the power transfer has not improved during the first predetermined period of time;
• reducing a charging rate of a battery of an internal controller of an implanted blood pump in communication with the implanted TETS coil and initiating a second predetermined period of time in response to determining that the power transfer has not improved during the first predetermined period of time;
• monitoring the power transfer during the second predetermined period of time;
• determining that the power transfer has not improved during the second predetermined period of time;
• and
• suspending the power transfer between the external TETS coil and the implanted TETS coil based on determining that the power transfer has not improved during the second predetermined period of time.