An in-vehicle system is described that initiates a telematics service call via a touch-based user interface. The in-vehicle system includes a telematics unit that supports communications relating to telematics services, an infotainment center, and a touchscreen interface configured to present user-selectable controls for invoking services provided by the infotainment center and the telematics unit. The system further comprises a backup battery configured to supply power, during a disruption of power supply from a primary power supply, to: the touchscreen interface, the telematics unit, and a microphone/speaker providing bi-directional audio communications with providers of telematics services. The system furthermore includes a backup battery mode control configured to sense a disruption of power provided by the primary power supply. In response to the disruption, the mode control activates a low-power operating mode for the touchscreen interface.