Multiple RV Batteries
Connecting Multiple RV Batteries
When installing more than one battery for use with the 12 volt RV system, it is
recommended to purchase the batteries at the same time. The batteries should be
matched with regard to capacity, brand, and age. This will give you the best
possible life from your RV battery bank.
RV Battery Voltages
RV Batteries are constructed to supply 12 volts or 6 volts (for the purpose of
this article). In most cases two six volt batteries will have about 20% more
capacity than two similar sized 12 volt batteries. This is due to the larger plates
that are built into a six volt battery.
RV Battery Circuits
Two 12 volt batteries are connected in a parallel
configuration with the two positive terminals connected together and to the
positive trailer lead. The negative terminals are connected together with the
trailer negative lead.
Two six volt batteries need to be connected in a
series circuit in order to get the 12 volt needed to run the coach system. In
this case the trailer positive lead is connected to the positive terminal of
the first battery. The negative terminal of that battery is connected to the
positive terminal of the second battery. Finally, the negative terminal of the
second battery is connected to the trailer negative lead. The size of the
jumper wire should match or exceed the size of the trailer leads.
RV Battery Polarity
It should be noted that the positive lead from the trailer is normally the black
colored wire(s) while the negative lead is the white colored wire(s). This is
sometimes confusing, as most automotive applications use red as the positive and
black as the negative. Polarity is very important to the electronics and the
various motors in the RV and must not be reversed.
Note: battery terminals (or posts) are marked with a plus sign for the positive
terminal and a minus sign for the negative terminal.
To make it even more confusing, makers of after market items, such as solar
panels will have the red wire as positive and black as the negative.
Before disconnecting your RV battery for any reason, it is suggested that you
tape the wires together near the terminal that they are attached to and then mark
them with respect to what terminal they go to. This will avoid confusion and
reversed leads when re-connecting the terminals.
Hard to reach your batteries?
Qwik-Fill™ 12-Volt Battery Watering System with Filler
Remote battery watering systems lets you fill all batteries to proper electrolyte
levels from a single fill tube, using a simple hand pump. Safer and more accurate than conventional filling.