Wireless charger and method of charging an electronic device

A method for charging an electronic device and a wireless charger having a set of transmitter coils and a plurality of magnetic field sensors are disclosed. The method may comprise measuring magnetic fields in a predetermined charging region, detecting a change in the magnetic fields, and selecting the subset of the transmitter coils associated with the one of the magnetic field sensors. The method may further comprise energising each transmitter coil in the subset of the transmitter coils to transmit a predetermined maximum power output, selecting one transmitter coil from the subset of the transmitter coils, determining a first power output of said one transmitter coil, and energising said one transmitter coil to transmit at the first power output.