An information handling system may have multiple batteries and be powered by any one or combination of those batteries. The multiple batteries may be in different detachable portions of the system. When the portions are attached, a battery in one unit connects through multiple input paths to provide power to the other unit. Under a heavy loading condition, power may be drawn from a first battery while power from a second battery is routed to an external power input of the information handling system to supplement power drawn from the first battery.