An exemplary cochlear implant system for a patient includes a cochlear implant, a sound processor, and an implantable battery configured to be implanted within the patient. The cochlear implant is configured to 1) determine that a signal is not being provided to the cochlear implant by a device external to the patient, 2) determine, in response to the determination that the signal is not being provided to the cochlear implant, that an amount of power remaining in the implantable battery is above a predetermined threshold amount, and 3) initiate, in response to the determination that the amount of power remaining in the implantable battery is above the predetermined threshold, an idle mode in which the cochlear implant remains powered on while waiting for one or more signals to be provided to the cochlear implant by the device external to the patient.