Harold, I also have to think about which way it is rigged every time I talk about it.
Series.
Amperage is constant and Voltage is additive in a series circuit. You have a 25A, 12V rectifier. You pull about 25 amps @ 3volts for a 3 gallon cell, using about 0.4 sq.ft. of anode area, standard solution composition, and 4.5" anode/cathode spacing. At 100% efficiency, using these parameters, one cell produces about 3.2 tr.oz. of silver/hour. With 4 identical cells of this size, you would apply 25 amps (Amperage is constant) in EACH cell @ 3 volts, for a total silver output of 12.8 tr.oz./hour. You would have a total of 12 volts (4 cells x 3 volts, Voltage is additive) in the system. If the 4 cells weren't identical (actually, in practice, they will never be exactly the same), each cell would have a different amount of resistance and their individual outputs would be somewhat different, although the total output of 12.8 tr.oz./hour should be the same, as long as you applied 25 amps and a total of 12 volts to the whole system.
I have assumed 100% efficiency in these calculations. In practice, this will never hold true, especially when running silver anodes of less than about 98-99% purity.
In parallel, the total 25 amps would be divided among the 4 cells and you would only produce 1/4 as much silver as you would had they been in series.
