A vehicle includes first and second battery packs having respective first and second banks of contactors. The packs are wired in electrical parallel. A propulsion system is driven using electrical power from the packs. A controller determines which pack has the highest state of charge (SOC), and balances the SOC of the packs by controlling an open/closed state of the contactors. Contactors open to disconnect the pack having the highest SOC, and close again when a voltage difference between the packs is approximately zero. A system for use in the vehicle includes the packs, contactors, and controller. A method for controlling power flow in the vehicle includes determining which pack has the highest SOC, opening designated contactors during a near zero current event to disconnect the battery pack having the highest SOC, and closing the designated contactors when a voltage difference between the packs is approximately zero.