Abstract: An energy management system comprising a method and an apparatus for controlling thermal runaway in a telecommunications switching station backup battery recharging system receiving current from a power supply and delivering current through a rectifier to a battery and a load, the system having a low voltage disconnect switch capable of interrupting current to the battery. A current shunt is provided for generating a first signal having a first value representative of the current flowing through the rectifier. A current shunt is provided for generating a second signal having a second value representative of the current flowing through the load. A microprocessor is provided for calculating a third value, the third value being equal to the second value subtracted from the first value. A microprocessor is also provided for generating a third signal indicative of thermal runaway when the third value exceeds a predetermined value.