-> Pardon my ignorance (or stupidity) but what do you mean by Parallel? Is that
-> when I hook 2 x 12v batteries together, but still keep the voltage as 12v or
-> is that when I hook 2x 6v batteries together to increase the voltage to
-> 12v?
In electrical/electronic language, "parallel" means side by side, and
"series" means end to end. Your arrangement with two 12-volt batteries
is a parallel one, which can cause problems if the batteries are not
exactly identical. The alternative of putting two 6-volt batteries in
series so as to produce 12 volts is better.
dow