George, (Fresno, CA)
At the basic level, two 6-volt batteries are wired in “series” and two or more 12-volt batteries are wired in “parallel” in order to produce 12-volts final output. Take a look at the diagrams here; two, 6-volt batteries above and two, 12-volt batteries below. The final output that provides battery power to the components in the RV is still 12-volts DC. Therefore, both configurations can be charged by any 12-volt battery charger by simply connecting the charger’s red cable clamp to the “plus” 12-volt terminal lead and the black or ground cable clamp to the negative terminal as shown here.