Abstract: A method of estimating power dissipated by a foreign metallic object in a transcutaneous energy transfer system (TETS) includes estimating power loss between an external coil of the TETS and an implanted coil of the TETS using a transfer function, the transfer function including inputs, the inputs including: a power supplied to the external coil, a power received by the implanted coil, a measured current within the external coil, and a carrier frequency between the external coil and the implanted coil and generating an alert if the estimated power loss between the external coil and the implanted coil exceeds a predetermined threshold.