The vehicle-use battery monitor apparatus includes a first function of
receiving a power generation rate indicative of an operating state of a
vehicle alternator from a power generation control device, a second
function of detecting a charge/discharge current of a vehicle battery, a
third function of transmitting the power generation rate to an electronic
control unit for controlling an output power of a vehicle engine in order
that an idle-up control is performed depending on a value of the power
generation rate, a fourth function of increasing the value of the power
generation rate when it is determined that the vehicle battery is in a
discharge state on the basis of a detection result by the second
function, and a fifth function of generating a notification signal in
accordance with which an indicator light makes an indication of the power
generation rate being increased by the forth function.