A system for inductive power transfer that may selectively transmit power in a plurality of modes based on characteristics of a power receiver and determine which transmitter coils to drive based on received signal strength information. The inductive power transfer transmitter may detect characteristics of the power receiver in order to control the mode of the power transfer and selectively control which transmitter coils are driven based on signal strength information received from a power receiver. The power transmitter may have slugs formed of a magnetically permeable material within common coil winding openings and the transmitter coils may consists of a plurality of parallel windings.