A battery backup system for use with vehicle telematics electronics includes a phone module configured for operation by the vehicle telematics electronics. The system further includes a battery module configured to provide power to the phone module and a circuit configured to determine that backup power is needed. The circuit causes the battery module to provide the backup power to the phone module for completing a transmission via the phone module. The battery module can provide the backup power to the phone module without providing operating power to the vehicle telematics electronics.