A total battery plant system consisting of rectifier/chargers and a voltage control and distribution bay is discussed. The rectifier/chargers each have built-in provisions for testing and adjusting their high and low voltage alarms and their high voltage shutdowns without removing them from service or affecting their outputs during the testing sequence. Likewise, the voltage control and distribution bay discussed, contains provisions for cycling its voltage related alarms and end cell controls without disturbing the plant operation. Instrumentation is totally digital to assure accuracy in adjustments and ease in reading.