There is disclosed apparatus and methods for providing a reserve power source for a ventricular assist device. In an embodiment, the apparatus includes a primary power source for powering the device, and a controller housing having a reserve battery for powering the device when the primary power source provides inadequate power, and the controller housing configured for use externally of the patient with a percutaneous cable to the device. In another embodiment, a method includes powering the device with a primary power source, monitoring power provided to the device, powering the device when the power is monitored as inadequate to the device with a reserve power source disposed within a controller housing, the device disposed subcutaneously within a patient, the controller housing disposed externally of the patient, and the device and the controller housing connected by a percutaneous cable. Other embodiments are also disclosed.
