Systems and devices for improving wireless power transmission are disclosed herein. The system can include an implantable medical device that can include an energy storage component and a secondary coil electrically coupled to the energy storage component. The system can include a charging device. The charging device can include a flexible housing defining an internal volume, a resonant circuit, a plurality of sensors coupled to the primary coil, and processor. The resonant circuit can include a deformable primary coil located within the internal volume of the housing. The processor can determine a deformation of the primary coil based on at least one signal received from at least one of the plurality of sensors.
