A welding-type power system that includes an engine configured to drive an electric generator to provide a first power output. In addition to the electric generator, the system includes an energy storage system to provide a second power output. The system includes energy storage devices and charging devices that are used to charge the energy storage devices. A controller is configured to control the charging devices to provide charging power output to the energy storage devices based on the parameters related to the charge level of the energy storage devices. The controller, using data received from sensors and charge measurement devices, determines the respective charge level for each energy storage device; compares the respective charge levels to one or more threshold charge levels; and controls the charging devices to provide a charging power output to the energy storage devices with a charge level that is below a threshold charge level.