"Capt. Neal®" wrote in message
...
I'm talking about two 12v batteries in a series circuit meaning one
positive pole connected
to the negative pole of the other battery. The left over positive and
negative poles must be
connected to some sort of circuit and load such as a light bulb or
electronic gadget that will
cause current to flow through the entire circuit.

In such a circuit, neither battery will charge the other, they will only be
discharged together through the load.
The same current will flow through both batteries, and in both batteries you
can regard the current as "flowing out" of the positive pole.

To charge a battery, current must be flowing "into" the positive pole, which
can only happen if you connect two batteries in parallel, where one is more
discharged than the other.

Meindert