Vehicles can employ onboard telematic monitoring devices to collect vehicle and operation data, such as for improved vehicle fleet management. Such telematic monitoring devices are dependent on power from a vehicle, such that data collection and communication can be interrupted if a telematic monitoring device is disconnected or has a poor connection. The present disclosure relates to battery devices, which provide power to telematic monitoring devices as needed in order to maintain data collection and communication, or other more limited functionality. The present disclosure also relates to systems including battery devices, and methods for operating battery devices. The present disclosure also relates to detecting temperature of batteries, as well as emergency input and messages for telematic monitoring systems.