Rechargeable batteries are used in a variety of devices. There are several
different types of batteries that use different technologies for different types
of devices. Three main types of
rechargeable batteries are 9
Volt, D, or AA and also AAA. But what to these letters mean and why are they
different?

A 9Volt battery is a rectangular battery used in small
consumer electronics. Rectangular is a shape used for most batteries which are 4
volt or higher, up to 12 volt. All batteries are made of cells, but the cells in
a 9 volt are connected in a series combination which makes the voltage rating of
the battery the sum of the voltage of the cells.

D is another type of available rechargeable battery. It is
cylindrical and 1.5Volt. D batteries are referred to as batteries, even though
they are really just a D cell. As opposed to the 9 volt which is several cells
connected, the D cell is simply one type of cell. D cells are used for a variety
of electronic devices.

AA or AAA batteries are typically composed of alkaline.
However, NiCd and NiMH are now available for rechargeable types and have higher
capacity than alkaline. AA and AAA are used in handheld devices like remotes,
digital cameras, model cars. AA and AAA hold the same amount of power, but AA
has more lifetime, which is why it is larger.

All rechargeable batteries are referred to as secondary
cells because they can be charged after they are drained. 9 volt, D, AA and AAA
are all dry cell type batteries because they do not contain the wet lead acid as
in the oldest type of rechargeable batteries. Buying quality batteries and
charging them properly is the best way to get the most out of your money.