Just a explanatory note on "12 volt" batteries.
There is really no such thing as a 12 volt battery!
A battery is basically an electrochemical reaction between 2 different metals that form the + and - terminals and the electrolyte that flows between and separates them. In a car battery the electrolyte is a weak acid (no so weak if you spill it on your paint job). In a sense the electrolyte actually forms and contains the charge in the battery.
Is is a fact that the electrical reaction between the + and - terminals of ANY battery using the common materials used today is between 1.2 volts and 1.7 volts. This is true in nicads, lithium ion batteries, flashlight batteries and even the common garden car battery.
Voltages higher than 1.5 volts in a "battery" are attained by hooking up several batteries in series internally in the battery case to obtain the desired resulting voltage.
Remember the old 6 and 12 volt car batteries that were sealed in tar and had large straps running on top of the battery from cell to cell? And the separate filler caps on each cell? Each cell was an individual battery hooked in series giving a nominal total of 6 or 12 volts depending on how many cells were used.
What does all this have to do with the original question? IMO it doesn't matter if you use one large 12 volt "battery", 2 small ones in parallel or 2 large 6 volt batteries (if you can find them) in series. All you are doing is duplicating externally what the battery manufacturer has done internally inside a single battery.
Hybrid Mode
