description the present invention will now be described more fully hereinafter with reference to the accompanying drawings in which preferred embodiments of the invention are shown this invention may however be embodied in many different forms and should not be construed as limited to the embodiments set forth herein rather these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art prime notation is used to indicate similar elements in alternate embodiments with reference to fig1 and 3 the solid state switching elements scr 1 and scr 2 are shown as controlled by two circuits shown in a block diagram form the first being a voltage sense circuit connected to the load and the second being a switch control circuit responsive to the voltage sense circuit to generate control or gate signals for the components scr 1 and scr 2 the voltage sense circuit derives its input from a voltage input connected to the battery positive terminal and a ground connected to the battery negative terminal internally the voltage between these terminals is compared to a reference to determine if a battery voltage is above or below the desired level and.