POWER SUPPLY FOR BATTERY POWERED DEVICES

An apparatus (150) for supplying electrical energy to a battery powered device (100) including a first, rechargeable battery (104) and first electrical circuitry (102), wherein the first electrical circuitry (102) receives electrical energy from the first battery (104) and presents a time varying electrical load current during operation of the device, the apparatus comprising: a first housing which defines a battery receiving region; first and second battery contacts for making electrical contact with a second battery (152) received in the battery receiving region; a first electrical connector (108a) in mechanical communication with the first housing and disposed electrically between the second battery (152) and the first electrical circuitry (102); second electrical circuitry, wherein the second electrical circuitry (154) receives energy from the second battery (152), generates an output for supplying electrical energy to the first electrical circuitry (102) and for recharging the first battery (104), and adjusts the output as a function of the state of charge of the first battery (104) and a signal indicative of the time varying electrical load current.