A large bypass path allows substantial utility-supplied loads to pass through while grid power is available, so the battery does not have to carry the same demand through the inverter stage. This can preserve stored energy for outages or scheduled energy management. In a solar hybrid inverter system, bypass current is not additional converted inverter power; it is a separate path from the accepted AC source. Upstream service capacity, breakers, conductors and downstream equipment still have to be sized for the current that may pass through.
