A method for efficient fuel consumption comprises recharging batteries or operating a device carrying out a task, with an engine through an electrical connection. The method also includes monitoring at least one of (i) current in the electrical connection, (ii) voltage of the batteries, and (iii) length of time of the recharging or task, to determine if the recharging has reach a preselected endpoint or the task has been completed. The method further includes generating a signal through a communication link to cause the engine to stop operating by: (a) preventing operation of a spark plug, (b) preventing delivery of fuel to the engine, or (c) preventing delivery of oxygen to the engine.