6-Volt vs. 12-Volt RV Batteries: What’s the Difference?

If you want to make your RV trip a thousand times better then you need to have a reliable source of electricity. RVs need to have AC electricity for household appliances like microwaves, air conditioners, and television sets. This kind of system is the same as the one that you have in your home.

6-volt vs. 12-volt RV Batteries: What's the Difference

However, to have this kind of powered electrical system, you will either need a generator, an inverter plugged into a household circuit, or use a 12-volt battery system. You can use a combination of different kinds of batteries to achieve true 12-volts. However, if you have to choose, you may have to ask yourself about 6-volt vs. 12 volt RV batteries: what’s the difference?

Different Types of Batteries

There are three main types of batteries that you can use in your RV: Lead-acid, AGM, and Gel. Lead batteries are the most inexpensive of the bunch, which is also the reason why they are the most popular. This type of battery needs a bit of maintenance, particularly the battery’s water levels.

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You will need to top up the battery with distilled water every couple of weeks or every month depending on how much you use the b attery. If you will be intensively using the batteries, like for the water heater and environment controls, then you will need to top up the batteries every month.

In case you have to store the lead batteries like if you will not be using the RV for a while, it is important to store them vertically. Lead-acid batteries also need to be installed outside of the trailer because they tend to produce hydrogen gas, which is very flammable in large concentrations.

AGM and Gel batteries, on the other hand, are maintenance-free, which is a great benefit. Furthermore, these batteries do not need to be stored in any particular way. You can store them vertically or horizontally. You can even store them upside-down if you want to. This means that these batteries are more versatile, especially if you want to try different configurations.

The biggest downside to using these batteries is that they are more expensive and they are not that common. This can be a problem when you are out camping in the backwoods and the nearest small town will most likely not have any AGM or Gel batteries available.

Differences Between 6V and 12V Batteries

Apart from the obvious, which is the difference in voltage, other things make 6V batteries different from 12V batteries. They are:

Uses

When high power is needed and the weight and cost are not big factors, you should go with the 12V batteries instead of the 6V. This is especially true if the weight and cost of the batteries are non-issues.

Voltage

What kinds of appliances a battery can power and how long it will last depend on the amount of voltage it can push out and how many ampere-hours it has. The voltage is a measure of the battery’s strength while the amp-hours is the measure of stored energy.  Usually, 6V batteries have lower ampere-hours compared to 12V batteries.

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Charging

You can connect two 6V batteries in series so that they can pump out 12V of power. However, when you charge batteries that are hooked up in series, it will only charge up to the capacity of the battery with the lowest ampere-hour capacity.

When two 6V batteries are connected in parallel, their combined voltage will still be 6V but their ampere-hour capacity will be equivalent to the sum of the capacity of the batteries. Also, when you charge batteries connected in parallel, they will all be completely charged to full capacity.

Longevity

Because 6V batteries use heavier plates in each cell, they have comparatively longer lifespans compared to 12V batteries, especially when used in deep charge/discharge cycles. When used in deep-cycles, a 6V battery can last anywhere from four to eight years.

Weight

A 6-volt battery weighs significantly less than 12-volt batteries, so much so that a single person will have no problem handling it. Because it is important to shave weight wherever possible so you can improve the fuel efficiency of your RV, having lighter batteries is always a good idea.

12-volt or 6-volt Batteries: Which One to Choose?

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12V batteries in parallel

This is the most common type of battery configuration used in most RVs. With this type of configuration, you will only need 2 small jumper cables to create this configuration – positive to positive, negative to negative, and the main RV wires attached to each end.

This is usually the way that most dealerships install their batteries and this is most likely the way your batteries are currently wired. Most 12V have an amp-hour rating of 70Ah, so when you connect them in parallel, you essentially end up with around 140Ah while still maintaining the 12V battery rating.

Advantages of Using 12-Volt Batteries in Parallel:

  • Voltage stays at 12V – There is no voltage drop even when the charge dips below 50% of the batteries’ capacity.
  • Amp Hours essentially doubled – You are getting twice the charge capacity when you connect batteries in series. You can use your smaller appliances, like radios, televisions, and the like much longer than when you connect them in series.
  • Much cheaper than 6V batteries – Even though they have lower voltages because they are more durable and can last longer, 6V batteries are a lot more expensive than 12V batteries. This is one of the reasons why more RVers use 12V batteries.
  • Can be found in most auto parts stores and garages – You can find 12V batteries in all auto supply stores. This makes it easy to find replacements even when you are out camping. You will most likely find a 12V battery even in small towns.

Disadvantages:

  • The amp hour rating is much less – 12V batteries do not carry as much charge as 6V in series.
  • The batteries cannot recover  quite as well as 6V batteries when they are discharged completely

6V Batteries Connected in Series

Many experienced RV owners would often upgrade their batteries to 2 x 6V batteries that are connected in series. This configuration will still provide you with 12V of voltage, which is the requirement for running appliances in an RV.

Advantages of Using 6V Batteries

  • They have larger Ah capacities – When fully charged, 6V batteries have bigger capacities compared to 12V batteries.
  • They have a bigger discharge and recharge capacity – This means that you can discharge and recharge the batteries more often than 12V batteries. These batteries are also less prone to charge memory.
  • With proper maintenance, 6V batteries can last much longer – You can expect 6V batteries to last anywhere between 4 to 8 years depending on how you take care of them.

Disadvantages

  • 6V batteries are more expensive – If you are on a tight budget then you might as well get 12V batteries as you might not have enough room for 6V cells.
  • 6V batteries are much taller and may require you to install different battery boxes – Most battery boxes in RVs are designed to accommodate 12V batteries. If you will be using 6V batteries, you will see that they stick out quite a bit from the battery box.
  • They are quite uncommon and can be hard to find in case you need emergency replacements – There are not that many brands of 6V batteries, and you usually only find them in specialty stores or large automotive supply stores.

The Bottom Line

It is highly recommended that you switch to using 6V batteries as soon as the 12V batteries that came with the RV conk out. Although there are some disadvantages to using 6V batteries in series rather than 12V batteries in parallel, the benefits that you can get far outweigh them.

Regardless of the type of battery configuration you choose for your RV, it is vastly important that you never allow them to discharge below 50% of their total capacity. The more often you let them get below 50% before you recharge, the less amount of charge they will be able to store the next time.

Conclusion

Although most RVs come with 12V batteries by default, that does not mean that those are the only type of batteries that can be used to power your onboard appliances. It is not uncommon for experienced RVers to replace the old batteries that came with the camper with new, more efficient 6V batteries.

To achieve the 12V needed for your onboard appliances to run, the 6V batteries need to be connected in series. The great thing about these new batteries is that they are relatively maintenance-free and can last much longer than their 12V counterparts.

Yes, there are a couple of disadvantages, like their expensive prices and them being quite rare and hard to come by but you will find that their advantages far outweigh their disadvantages. So, to answer the question, “6-volt vs. 12-volt RV batteries: what’s the difference?” the answer will be that the 6V batteries are vastly superior in almost every way.

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