This invention provides an actively controlled battery with a programmed-timing actuation capability. As a preferred embodiment, the battery comprises (a) a first metal-air cell assembly and at least a second metal-air cell assembly electronically connected in parallel and (b) electronic control devices. The first cell assembly comprises at least a first metal-air cell comprising an active anode enclosed in an anode compartment, an air cathode, a first air access vent, a separator separating the anode from the cathode, an electrolyte fluid reservoir, and a first controllable fluid valve being in flow communication with the electrolyte fluid reservoir on one side and in control relation to the anode compartment on another side. The first air access vent and the first fluid valve are closed during a battery storage period and are opened, at the first use of the battery, to admit outside air into the cathode and to allow an electrolyte fluid to enter the anode compartment to come in contact with the anode therein for activating an operation of the first metal-air cell assembly. The second cell assembly is similarly configured with its corresponding air vent and fluid valve being closed during a battery storage period and being opened in response to programmed signals to admit outside air into the second cathode and to allow an electrolyte fluid to enter the anode compartment to come in contact with the anode therein for activating an operation of the second metal-air cell assembly. The control devices, preferably including a sampling unit, a power control unit and a logic control unit, are capable of sensing the battery output voltage, current, or power and sending programmed signals to open the electrolyte fluid valves and to open up or close down the air vents at the same time or at different moments of time in a programmed fashion. The battery has an exceptionally long operating life and is particularly useful for powering microelectronic or communication devices such as mobile phones, laptop computers, and palm computers.