Now here's�a trick wording of batteries--

A "Marine" battery doesn't necessarily have to be a deep cycle
battery--it can be for marine use and just be an engine starter battery,
in which case no, it isn't deep cycle.
In general terms a "Marine" battery is the house battery, which is the
battery for the house, or cabin accessories, which usually is a deep
cycle unit.

A good example is an electric trolling moter battery which is drained
slowly for a long  time, which is a Marine deep cycle battery.
Most boater's , or guys with camper's have more than one battery in
their vehicles.
One for starting which has a short duration big cold cranking amps, and
a deep cycle for a slow, long drain, to run the house accessories.

The amp hours does not depend on what type of battery it is, it simply
depends on how the battery is rated--

And if it was possible to mount two big amp six volt batteries into a
Vanagon, the
duration of the crankig time would be increased--this is why Semi's use
4 six volt batteries in series, rather than two 12 volt--more cranking
duration----

Later,

Terry

E-mail message  From John�Brush

Well, just to split hairs, "Marine" batteries are not deep cycle
batteries. They tend to fall in between a car battery, and a true deep
cycle one. Of course its a lot of semantics, but manufacturers will try
and get away with what they can. Buy a true, deep cycle battery and be
safe. Decent sized deep cycle batteries tend to come in 6V packages
(size being amp-hours) so one usually ends of buying a pair of them,
especially when looking for a lot of amp-hours.
Its a roaring battle in a lot of other groups, but just be careful that
you get the right battery for the application.
John