Patent ID: 8855832

Claim:
A power management device for connecting a power consuming device to a power source, the power source providing electrical power at a cost determined by a power rate, the power rate varying over time, and the power rate being available via a power rate signal, the power management device comprising: (a) a power output adapted to electrically connect to the power consuming device; (b) a power input adapted to electrically connect to the power source; (c) a current relay switchably connecting the power input to the power output, the relay comprising a power flow switch having on and off states, wherein power flows from the power source to the power consuming device when the power flow switch is in the on state, and no power flows from the power source to the power consuming device when the power flow switch is in the off state; and (d) a controller adapted to receive the power rate via the power rate signal, the controller being electrically connected to the power flow switch and programmed to switch the power flow switch between the on and off states in accordance with a power usage specification provided by a user, wherein the power usage specification comprises a maximum power rate, and the controller maintains the power flow switch in the off state when the power rate exceeds the maximum power rate, and provides a control interface to accept an external control signal specifying whether to turn the power on or off when the power rate is less than or equal to the maximum power rate, wherein the controller maintains the power flow switch in the on state when the power rate is less than or equal to the maximum power rate and the external signal specifies turning the power on, and maintains the power flow switch in the off state when the power rate is less than or equal to the maximum power rate and the external signal specifies turning the power off.