BATTERY ALARM SYSTEM

A battery alarm system for generating an alarm on recognition of the reduction of an output voltage of a battery, wherein an analog output voltage value of a battery is converted to a digital value. The digitalized values are inputted into a controller for a plurality of times at predetermined intervals to obtain the average value, and when the average value is smaller than the predetermined threshold stored in the memory, an alarm is generated. By obtaining an average value of voltage values inputted for a plurality of times, an alarm can be produced stably with little influence of fluctuations of the output voltage of the battery.