Apparatus, comprising (1) a first controller comprising at least one first-controller antenna configured to transmit a first wireless power signal having a first signal power and a first-controller control unit configured to use battery power to drive the first-controller antenna (2) a second controller, comprising at least one second-controller antenna, configured to transmit a second wireless power signal having a second signal power and a second-controller control unit, configured to use mains electricity power to drive the second-controller antenna and (3) an implant, comprising one or more electrodes at least one implant antenna configured to receive 1-10 percent of the first signal power, and to receive 0.01-1 percent of the second signal power and circuitry configured to drive the one or more electrodes responsively to the received 1-10 percent of the first signal power, or the received 0.01-1 percent of the second signal power.
