Solid State version of John Bedini's "Telsa Switch".
Circuit was created by Mr. Ronald Brandt who claimed he had a car that used the circuit to drive a DC motor that never needed recharging.  John Bedini made a small version of it that ran off 5v NiCad batteries and demonstrated it at a 1984 convention. His circuit powered some small lights and he claimed the batteries never lost charge.
The circuit sends power from a 24v battery bank to a 12v battery bank and a load is connected between the bank negatives. The banks then switch the other direction. Conventional measurements show only 50% of the power is recovered in the lower 12v bank, plus whatever power the load sees, and accordingly the unit should not be spectacular. However, many experimenters have tested it and claimed loads can be powered well beyond their standard capacities. This is my solid state version of the circuit.
Unfortunately, I did not see any efficiencies beyond or even close to 100%. Batteries do not perform well when they charge/discharge in rapid succession. The circuit may work better if it pulsed power from the 24V to the 12V bank for several minutes and then reversed course.