Exemplary embodiments are provided of a telematics system for a vehicle with a main power supply. The telematics system includes a secondary power supply and a telematics unit that provides vehicle information. The telematics unit includes a communication device that selectively provides two-way communication between the telematics unit and an external device. The telematics system further includes a power management system that selectively causes the telematics unit to be powered by at least one of the main power supply and the secondary power supply. Further, the system includes a controller that controls the power management system such that the telematics unit is powered by the secondary power supply for communication between the telematics unit and the external device when the telematics unit is electrically disconnected from the main power supply.