A system and method for managing battery energy usage by a mobile wireless network which detects threshold conditions for network signal found and lost; records historical events of signal found and lost with operational criteria associated with operational conditions of the events such as time, day, date, tower number, and geographic location; upon each detection of network signal loss, determines from the recorded event records a nap termination condition upon which network signal has been historically reliable; and enters a battery-saving nap mode until the nap termination condition is met.