Abstract: An apparatus for detecting a reduction of a level of electrolyte in a wet cell battery includes an electrically conductive sensing rod in contact with an electrolyte in a battery cell, a voltage comparator connected to the rod for generating a first output signal when an input voltage is greater than a reference voltage and generating a second output signal when an input voltage is less than the reference voltage, and an indicator responsive to the output signals for generating a green visual signal when the rod is immersed in the electrolyte and generating a red visual signal when the rod is not immersed in the electrolyte. The apparatus also include an audio alarm device sounding an audio indication when the red visual signal is generated. A sensing circuit can be connected between the voltage comparator and a pair of battery voltage input terminals to selectively connect the terminals to the comparator when a voltage of a battery connected to the terminals exceeds a predetermined voltage level.