Dual Battery Load Sharing with Automatic Switchover to a Wall Adapter

An application circuit for dual battery load sharing with automatic switchover of load from batteries to a wall adapter is shown in this circuit. When the wall adapter is not present, whichever battery that has the higher voltage provides the load current until it has discharged to the voltage of the other battery. The load is then shared between the two batteries according to the capacity of each battery. The higher capacity battery provides proportionally higher current to the load.