A cochlear implant system has an implantable portion that includes a stimulator module for producing for the auditory system of a user an electrical stimulation signal representative of an acoustic signal. The implantable portion further includes a battery for supplying power to the stimulator module, a receiver module for receiving an electrical power signal across the skin of a user, and a recharge module that uses the electrical power signal to recharge the battery. The recharge module recharges the battery at less than the maximum recharge rate.