6volt vs. 9volt batteries..........?

Question

Why is a 6 volt battery much larger than the 9 volt battery?

Answer 1

Battery voltage is a function of the chemicals used.  That's why AA, AAA, and D cells all operate at 1.5v, but the different sizes allow the larger ones to supply current for a longer period of time.  Simply stated, that means the longer it can last under a given job.

And that's why 6v lantern batteries are so huge.  They have to power energy-hogging devices like large flashlights.  A 9v battery COULD do the same thing, and the light would be even brighter due to the higher voltage, but the battery would go dead in about 1/20th of the time.

Answer 2

It isn't necessarily.  Certain types are, but size has nothing to do with voltage.  A watch bettary, and sizes AAA (used in mp3 players etc) AA (used in many toys and remote controls) right up to size C and D (used in large ghetto-blasters/portable sound systems) are all 1.5 volts!  The small square batteries are 9 volt, but an enormous car battery is only 12 volts.

A larger size means that the device the battery is attached to can draw a larger current (measures in amperes, or amps, denoted by I), or that for a given current, a larger battery will last longer.

Answer 3

As percival says, it's the chemistry not the size.  Each single cell of an alkaline battery is 1.5 volts no matter how big it is.  If you open a 9 volt battery you'll find 6 small battery cells.  If you open a 6 volt battery you'll find 4 larger battery cells.  Just like a car battery.  That chemistry creates a 2 volt cell so a 12 volt car battery has 6 cells connected together.