[Glenn and Lorraine]

Copied from the Optima Battery website.

quote:Question: Are 6V batteries superior to 12V batteries for deep cycle applications?


It's popularly believed that 6 volt batteries are better for deep cycle power applications than 12 volt batteries, but it isn't true. This myth likely developed from the fact that golf carts use 6 volt systems. Because golf cart batteries were the only deep cycle batteries widely available for many years, the best way to obtain good 12 volt deep cycle power was to connect two 6 volt golf cart batteries in series (or more batteries could be connected in a combination series and parallel configuration for higher voltages like 24 volts or 36 volts.) The effectiveness of that approach owed entirely to the design characteristics and quality of the batteries used, not to the fact that the batteries used produced 6 volts.

In reality both 6 volt batteries and 12 volt batteries are simply built from 2 volt cells; if a battery is built with three such cells, it's a 6 volt battery. If a battery is built with six such cells, then it's a 12 volt battery. To make a 12 volt system by connecting two 6 volt batteries in series is to do nothing more than to build a 12 volt battery with two cases and external interconnection. In fact, every cable end connection results in some efficiency loss, so the two 6 volt batteries, because they must be connected by a cable, will be slightly less efficient than the 12 volt unit.