Ultimate Deep Dive Into 6V vs 12V RV Battery

Ever wish you had more battery power from your RV? As an RVgoer, you know the importance of your electrical system. Whether plugged in at a state park or dry camping in the woods, a properly functioning electrical system is crucial to you enjoying your trip and keeping your travel trailer in top working order.

As you do a Deep Dive into Deep Cycle batteries (I know, it’s a corny joke), you will unravel the key factors involved in your RV battery selection. Here you will get a crash course in voltage, types of batteries, discharge cycles, and even learn about amp-hours. Don’t worry; you don’t need to be an electrical engineer to read on. The basic concept is all you should need to decide what is best for you and your travel trailer.

Table of Contents

RV Voltage

Before diving into the difference between 6v vs 12v batteries in an RV, let’s first understand the importance of voltage. Your RV will always run on 12v for electrical systems to work correctly. When using a 6v battery, you will wire it as a series connection, so the output is 12v (more on that to come)!

A good battery is essential even if you don’t dry camp (no electricity) because some electrical components only run on 12v. That’s right; even when plugged into the grid, you still need your battery to operate part of your electrical system. The RV water pump, slide, and lighting run on 12v (from the battery), even when plugged in for electricity (120v). The bottom line is that a fully functioning battery system is essential for every RVgoer.

Types of Batteries

Regardless of 6v or 12v, the types of batteries for your travel trailer remain the same. The two most common RV batteries on the market are lead acid batteries (flooded with sulfuric acid) and AGM (absorbent glass mat). Both types of batteries use lead plates, with the difference that flooded batteries have sulfuric acid while AGM uses a glass mat. AGM batteries generally have a longer life span because they are highly resistant to vibration. They are also totally sealed and are maintenance-free (sometimes you need to add distilled water to an acid battery).

Deep Cycle vs Starting Battery

A starting battery is the most common and known 12V battery. It is under the hood of every car or truck. Its purpose is to deliver a large burst of power for a short period to start the engine. These starting batteries are not meant to be drained down or used constantly. That is one of the reasons you have an alternator to keep that battery topped off as much as possible.

A deep cycle battery, sometimes noted as a marine battery, runs the 12V electrical components in your travel trailer. These batteries have thicker plates and are manufactured to withstand multiple discharges and recharge cycles. They are also intended to be discharged as much as 80% cycle after cycle.

Charging and Solar Panel

6v or 12v batteries are the same when it comes to charging. The charging requirements are the same since you will wire a 6v to become 12v (more on that ahead). Your RV charging system will still be able to charge these batteries with no issue.

When using solar panels to charge your battery, the voltage of the solar panel should exceed 20%-30% of the working voltage of the battery to ensure regular charging of the battery. That means a 12v battery will need a 15V to 18V solar panel to give it a charge.

Amp Hours

An important factor in battery selection is amp hours. An amp hour rating measures how long a battery can provide one amp of power per hour. When looking at a battery spec, it’s abbreviated as Ah. Most devices we use in our travel trailer or RV don’t draw just one amp of power per hour, so calculating can be a challenge. However, in general, knowing 100Ah is twice as much power as 50Ah is helpful in battery selection.

Trojan Battery
Image from Trojan Battery

The basic formula is Amp Hour = Current (I) x Discharge Time (T)

So if you are running a battery rated with 89Ah @ 20HR, you can rework the formula to see how long this battery will last with a given load. Let’s assume 2 amps in this example.

Amp Hour = Current (I) x Discharge Time (T)

89Ah = (2 amps) x T

T= 89Ah/2 amps

T= 44.5 Hours

This particular battery will run your electrical system of 2 amps for approximately 44 1/2 hours. This period is approximate as several factors are involved in the performance of a battery. Age, temperature, and the previous number of charging and discharging cycles play a role in the ultimate performance. Don’t know how many amps you need? The list below gives a ballpark on some of the typical required amps on electrical components.

12 Volt DC Amp Ratings
Appliance or AccessoryEstimated Amps
Aisle Light1 Amp
CO Detector1 Amp
Fluorescent Light1-2 Amps
Furnace10-12 Amps
LP Gas Leak Detector1 Amp
Overhead lights (Per Bulb)1 Amp
Porch Light1 Amp
Power Roof Vent1.5 Amps
Radio/Stereo4 Amps
Range Hood (Fan & Light)2-3 Amps
Refrigerator (LP Gas Mode)1.5- 2 Amps
Security System1 Amp
Television (12 volt)4-5 Amps
TV Antenna Booster<1 Amp
TV Antenna Booster 12 Volt outletUp to 8 Amps
Variable Speed Ceiling / Vent Fan4 Amps
VCR Recorder / Player2 Amps
Water Pump4 Amp
typical list of RV 12v amp draw components

Now let’s take a look and compare 6V vs 12V battery amp hours. A 6V golf cart battery (this is how these batteries are typically sold) is rated around 200 to 225 Ah. That is much more than the typical 85 to 100 Ah you will see on a 12V deep cycle marine battery. However, this can be misleading because this is at 6V, not the 12V that your RV needs. That means you will get half of the amp hours to power 12V electrical components. That makes the 6V to 12V batteries comparable in how much power or current flow they provide for RV use.

Series Connections

Above, you learned that your travel trailer will always need 12V to run the electrical components properly. So how do you get 6V batteries to become 12V? Simple, by running two batteries in series. This setup is no different from putting a couple of house batteries into a flash flight. Let me explain.

All household batteries are single cells and are 1.5V ea. They also have a positive (+) and negative (-) end terminal. When you put those batteries into a flashlight, you sometimes put them end to end, right? Technically, you install those batteries in series (the positive + connected to the negative -). By doing this, you are increasing the voltage of the battery’s output. You add 1.5V + 1.5V, giving a 3V light bulb the proper power.

We can also do this with a 6V battery for your travel trailer. A 6V battery is no different in theory than a household battery. There are positive and negative ends (terminals) that you will wire in series.

Instead of connecting the batteries directly from end to end in your battery box, you will use a proper gauge wire (usually, 10 to 12 gauge wire is acceptable). You are using one wire to connect one battery’s positive (+) terminal to the negative terminal (-) terminal of the other battery.

Once that wire connects the positive and negative terminal, you can join the trailer red (positive) to the open positive side of one battery and the trailer black wire to the negative open side of the other battery. This setup will give you the 12V power supply your RV needs to function.

Remember, you are increasing to a higher voltage here and not the current or amp hours. If your 6V batteries are both rated at 225Ah each, your current power output is still 225Ah.

Parallel Connections

The example we just went through was how to increase the voltage (while keeping amp hours the same). What if we keep our voltage the same but increase our amp hours? We can do that by connecting two 12V batteries in parallel.

Unlike a 6V battery, you do not need two 12V batteries to run your RV correctly. However, it does come in handy to compare amp hours between the two batteries to see if you prefer two 6V or a two 12V setup.

The parallel connection with 12V batteries is different than the 6V series connection. In this case, you will be connecting positive terminal to positive terminal and negative terminal to negative terminal.

Your voltage will remain the same with this parallel setup, but your amp hours will double. For example, if your 12V batteries are 100 amp hours ea, your output will not be 200 amp hours at 12V. Slightly less than the wiring of the two 6V batteries above.

Discharge Cycle

You read a bit about discharge cycles above when comparing Deep Cycle to Starting batteries. Now let’s review the difference between 6V and 12V discharge cycles. This cycle is an essential factor because discharge cycles directly relate to battery life.

If you recall the household battery example, we looked at how each battery is 1.5V. And each battery is a cell. Well, your RV battery is no different. Each Deep Cycle battery has 1.5V cells (or battery banks) inside that make up the ability to have 6V or 12V. For example, a 6V battery has four cells (4×1.5V cell), and 12V battery has eight cells.

Image from wired.com

Battery Life

Given that a 6V battery needs fewer cells in a limited space, the plates used to make up the cells are thicker plates than with a 12V battery. These thicker plates allow for deeper discharge cycles and a longer lifespan. Generally, a well-maintained 6V battery has a life span of 6 years. At the same time, a 12V battery has around a 4-year life span. 6V is the winner in this category.

Battery Failure

It may seem that the long life span of the 6V battery is the clear winner and that there is no disadvantage. Well, there are a couple of things to consider. 6V batteries are not as readily available as 12V batteries (available at any Walmart or Sam Club off the shelf). Also, if one 6V battery fails, your travel trailer will not operate as you are only getting 6V vs the 12V that the camper needs. Whereas if you have two 12V batteries in parallel, if one fails, your RV will still operate properly, just will fewer amp hours.

Final Thoughts

A two 6V set up for your RV is a great option. You learned that you could connect two 6V batteries into a long-life and stable power source for your travel trailer by a single wire. Although it does offer many advantages over a single 12V battery, it does have some drawbacks and things to consider while you are on the road or dry camping somewhere. Enjoy your travels, and good luck!