The inventive subject matter provides a circuit and a method for efficiently charging a battery. In one aspect of the invention, the circuit includes a constant current circuit configured to provide a direct current through the battery. The circuit also includes a pulsing current circuit that works with the constant current circuit and configured to simultaneously provide a series of pulsed current to the battery. In some embodiments, the series of current pulses includes constructive resonant ringing that is constructive with respect to the charging of the battery.