Go here and obtain a lot of good information. But to answer
your questions there are deep cycle batteries for RV rigs
and there are deep cycle batteries for Marine and RVs and
then there are starting batteries. All just a little
different. The size has some to do with it also.
I might note here that the converter/charger in your rig
might not have what is called a three stage smart charger in
it, it also is not noted to be much of a charger at all just
maintain the battery while you are plugged in to shore power.
http://www.uuhome.de/william.darden/

No Laurie, it doesn't take a car battery. Car batteries are designed to be
continually charged as the vehicle runs. You want a deep cycle battery that
will take frequent discharge/charge cycles. If you discharge a car battery
only a few times you will most likely damage it.

Locally GanderMountain sells Trojan deep cycle batteries that are considered
a pretty good battery.

By the way, most refrigerators today do not run on 12 volts. Generally they
either run on either house current which is 110 volts or propane. When I
owned a Starcraft popup tent camper, my 12v battery would last all weekend
running a few lights.

1st thing to do is check with the person/company you bought it from
and ask why there is no battery. There has to be a reason, like
something burned out or worse.
Why did you buy it without making sure all the parts were there and
working?
RVs use deep cycle batteries. Marine batteries are not true deep cycle
batteries.

Tom J

Hi,
Was the battery left out for a reason?  You should ask the previous
owner if there is a problem using the battery. Like is the converter
charger broken or not working?  A problem with the wiring?   If you
bought off of a dealer ask the same question along with why a battery
wasn't included in the deal.  It may be that the previous owner only
used the RV while in campgrounds so he didn't need a battery or took it
out while the RV wasn't being used and forgot to put it back.

First, don't use a car battery.  They are not designed for the type of
continuous loads seen in RV's.   The number and size of the batteries
you use for RV'ing depend upon what type of RV'ing you are planning on
doing.  If you are going to be spending most of your time in campgrounds
with electrical hookups then a Marine type battery will serve you well.
While not a true deep discharge battery for that type of camping it
would not be used much anyway and would last a long time.

If you plan on camping with no hookups some of the time then the
batteries become much more important.  In that case you might want to
consider getting one or two true deep cycle 12V batteries or two 6V golf
cart batteries, (they are deep cycle) and wiring them in series.  At the
least for that type of camping two Marine 12V type batteries.

Your fridge probably runs off of 120V and propane.   There are some 3
way refrigerators that run on 12V, 120V and propane but they aren't that
common.   The fridge however even while running on propane may need 12V
for the circuit board found on newer RV refrigerators so a battery or
working converter is required just for it to work.  The bigger the
battery (amp wise) and the more batteries you have the longer you can go
without having to charge them.

What is a converter?  Glad you asked :)  A converter takes 120V AC
shore power and converts it to 12V DC power to run the DC things in your
RV when plugged in at a campground (shore power).  Most converters also
have a built in charger used to charge your batteries.

Hope this helps.  Take care and Happy Campin...

Laurie here is 2 articles on batteries that will help you decide what type
of battery you need and why.
http://bart.ccis.com/home/mnemeth/12volt/12volt.htm

part two:

http://bart.ccis.com/home/mnemeth/12volt/12volta.htm

good luck

Burt

If you have the space, put two 6v. batteries in there.  They won't cost much
more than a good 12v., and they will last lots longer for boondocking than
one or even two 12v. batteries.

Be sure to hook them up right.

Steve

They have 2 types of marine batteries at Wal-Mart.
He wants the Deep Cycle battery.