A wirelessly rechargeable device (20) is positioned on an underlying charging surface (S) for charging a battery of the wirelessly rechargeable device. While the wirelessly rechargeable device is charging, it is detected whether the wirelessly rechargeable device is being displaced (A), or is likely to be displaced, relative to the charging surface. Additionally, it is detected whether the displacement, or the potential displacement, is unintentional. In response to detecting that the wirelessly rechargeable device has been displaced, or is likely to be displaced, a magnetic field between the charging surface and the wirelessly rechargeable device is controlled to inhibit the unintentional displacement of the wirelessly rechargeable device.