Abstract: A module and method incorporated thereby is provided for maintaining the float voltage of a battery cell at an optimum fully charged condition while being continuously charged by a float current. The module preferably includes a mechanism for measuring the actual float voltage of the cell, and a circuit is established for variably bypassing the float current directed to the cell. A device is provided for calculating and establishing a predetermined relationship between a desired cell float voltage and a bypass current required to maintain the desired cell voltage. A mechanism then determines a desired bypass current by comparing the measured actual float voltage of the cell with the predetermined relationship. A system compares the actual bypass current with the desired bypass current, and then a mechanism adjusts the actual bypass current to equal the desired bypass current.

Abstract: A microwave communications system enhances microwave wave propagation in tunnels, mines and the like by transmitting and receiving communications signals at frequencies ranging from 5 GHz to 15 GHz. Duplex transmissions and call signal alarm functionality provide enhanced safety features for workers.