Patent attributes
A battery monitoring apparatus includes a battery ECU, satellite devices each of which measures the voltage at a battery cell in response to a command signal from the battery ECU, and a wireless module which achieves a wireless communication between the battery ECU and each of the satellite devices after a wireless connection between the battery ECU and each of the satellite devices is completed. When receiving a start signal outputted before a start switch for a drive power source of the vehicle is turned on, the wireless module is activated to start the wireless connection between the battery ECU and each of the satellite devices. This establishes and completes the wireless connections faster than when the wireless module is activated simultaneously with turning on of the start switch for the drive power source. This achieves quick monitoring of the state of the battery cells.