Abstract: A power control system arranged for use in a power-over-Ethernet system comprises a battery (38), a battery charging unit (40) connected to, and for charging, the battery (38) and a processor (34) arranged to monitor the charge level of the battery (38) and, in response, to direct current to, or away from, the battery (38). A power-over-Ethernet (PoE) system for delivering power to a load comprises a powered device (14) and an Ethernet power sourcing device (20) configured to supply DC power to the powered device (14). The powered device (14) has a battery (38), a battery charge unit (40), and a processor (34). The processor (34) is arranged to monitor the current requirement of the load (16), and to control the charging of the battery (38) and the supply of current from the battery (38) to the load (16) in response to said monitoring.