Should BATTERY CABLES connect
6 or 12 volt batteries

Battery cables can be used to wire RV batteries in series (positive terminal to negative) or in parallel (positive to positive).

You already know that 12 volt is the standard voltage used in recreational vehicles. We can make the equivalent of one 12 volt battery in connecting two 6 volt batteries in series, with battery cables.

Note that:

If batteries are connected in series:

- voltage adds together / amps are unchanged

This means:

  • two 6 volt batteries of 100 amps each, equal one 12 volt battery of 100 amps-hour.

If batteries are connected in parallel:

- voltage is unchanged / amps add together

This means:

  • two 12 volt batteries (or two sets of 6 volt batteries paired in series) of 100 amps each, would equal one 12 volt battery bank totaling 200 amps-hour.

Sets of 6 volt RV batteries interconnected in series as pairs or 12 volt battery units are all connected in parallel to increase the amperage (Ah) available, still maintaining the voltage at 12 volt.


DO NOT MIX 6 volt with 12 volt batteries, some new with some old.

It is recommended to have batteries of the same size, same age and even from the same manufacturer. If you are upgrading, you have to start fresh.

This is why it has to be very well planned the first time using the proper gauge of battery cables.


When you are going to figure out the size of your personal battery bank for your RV, you have to analyze your boondocking lifestyle first, taking in consideration every single task demanding electricity power from your batteries.

Also, be very much aware of all the phantom or dead loads in your electrical system. These parasite loads consume energy whether the device or appliance is on or off.

Some boondock RVers install in-line switches on each device to turn each off when not in use. You can simply plug an appliance when you need to use it and unplug it after use.

It is also very important to keep in mind that the amperage for each circuit breaker or fuse in your RV should not exceed the capacity of the wiring used in the electrical system.

You have to use the properly sized battery cables with adequate amperage capacity to sustain the electrical demand of whatever item you have installed in your RV.

To be safer, it is always better to have a wire with more capacity than less, if you can afford it.

Just as a reference, have a look at this table:

Copper wire gauge vs Amperage capacity

18/6 16/8 14/15 12/20 10/30 8/55 6/75 4/95 2/130 1/150 0/170

* you will have to take in consideration the length of the connection from point A to point B in selecting the wiring gauge to minimize the loss of current along the way and reduce heat.

Make sure that all batteries are in a specially designed vented compartment. Each battery is well secured with straps or brackets on trays so none move.

A battery falling against the RV frame or any metal may short out and starts a fire.

The compartment where the battery bank is located should be vented as mentioned before (even with AGM batteries ideally) and without any electrical device around.

Even a light could create a spark and ignite a fire where some potential explosive hydrogen gas built up.

OTHER TOPICS ( 5 total ) directly related to RV BATTERIES

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