action activates the zinc air battery 306 39 and causes the generation of electrical power the electrical power is applied first to the voltage regulation circuitry 308 39 then to the charging control circuitry 309 39 the voltage regulation circuitry 308 39 acts to provide the correct voltage for charging the energy source by increasing or decreasing and regulating the output voltage of the zinc air battery 306 39 the regulation of the charging voltage can be performed by a linear or switch mode regulation circuit these regulation circuits are available in integrated circuit form an are well known to those skilled in the art after the output voltage of the zinc air battery 306 39 has been regulated by the voltage regulation circuitry 308 39 it is applied to the charging control circuitry 309 39 the charging control circuitry 309 39 senses the amount of charge required by the energy source or battery by monitoring the battery and controlling the amount of power delivered to the energy source or battery the output of the charging control circuitry 309 39 is coupled to the energy source via charging contacts 303 39 if the energy source is fully charged the charging control circuitry 309 39 adjusts the output power accordingly to prevent overcharging and or damage to the energy source the charging control.