A Super PWRgate is a 12 volt backup power system that can supply up to 40 amperes continuously from either a Power Supply or a Battery, and can also charge the battery with its high performance charger. Connected equipment will instantly switch to battery during a power blackout or power supply failure. No glitches. The circuit uses two 80 ampere Schottky diodes as an OR-Gate to isolate the battery and power supply from each other. Forward voltage drop of less than 0.3 volts at 20 A. To keep the battery fully charged and ready for use, the Super PWRgate has a built-in four-stage battery charger with selectable current rates of 1, 4, 7 or 10 amperes. The circuit is optimized for use with GELLED & AGM type batteries, but will keep flooded lead acid and marine type batteries near full charge as well. The Super PWRgate and the power supply may also be used to charge a battery that is powering the radio, as described in December 2003 QST Page 41 titled "Emergency Power at W1ZR".