Abstract: A battery charging device uses a primary battery source which is preferably a rechargeable lead acid battery, connected to a secondary battery source, which is preferably a pair of parallel battery circuits each using series-connected non-rechargeable batteries in series with a diode, the primary and secondary battery sources providing a charging voltage output. A switch has a first position in which the charging voltage output can be supplied to an external battery which is to be charged and a second position in which a recharging voltage can be supplied from an external source to recharge the primary battery source, and a third, or off, position in which charging and recharging operations cannot occur.