This paper proposes the power management technology for stand-alone PV system to extend installation environment and coverage. The proposed power management technology in this paper can protect battery safeness from overcharge/discharge with keeping the proper SOC(State of Charge) and extend using time of system through estimation of operating power. The proposed power management technology in this paper is applied to Infra-free Variable Message Sign. And performance of power management technology in this paper was verified using simulation scenario.