Slower Charging and Higher Temperature Rise after Wireless Charging Coil Potting? Check Coil Offset and Magnetic Sheet Clearance First before Changing Adhesives

When reduced charging speed, lower efficiency or abnormal local temperature rise occurs after wireless charging coil potting, priority should be given to checking the relative position of transmitter and receiver coils, magnetic sheet assembly condition, post-potting coil height and resonant parameters, instead of directly concluding that potting adhesive blocks wireless energy transmission. For inductive wireless charging systems, potting materials not only provide waterproofing, insulation and fixation, but may also indirectly affect magnetic coupling and charging performance by altering coil assembly status. Electric shavers, electric toothbrushes, smart wearable devices and some industrial wireless power supply modules usually realise non-contact energy transfer via electromagnetic induction. There is a defined structural relationship among internal receiver coils, magnetic materials, rectifier circuits and charging control modules. Any shift in assembly position may affect the final system performance. Some products charge normally in bare-board state, yet show longer charging duration, abnormal input power or increased temperature rise after potting, curing and housing assembly. At this stage, it is necessary to confirm whether the fault originates from electromagnetic coupling, power conversion or thermal management. Why Wireless Charging Efficiency May Drop after Potting despite Normal Performance before Potting Energy transfer efficiency of wireless charging is related to the coupling degree between transmitter and receiver coils. For inductive systems, coil clearance, lateral offset, tilt angle and magnetic material condition can all change magnetic flux coupling and the system operating point. Before potting, the receiver coil may be fixed by plastic positioning posts, brackets or adhesive tapes. After potting, the coil may shift due to adhesive flow, assembly pressure or mechanical stress generated during curing. Even if no obvious coil displacement occurs, the added thickness of the potting layer may change the distance between the receiver coil and the housing surface. If the total gap between the charging base and…