6 volt vs 12 volt RV Battery: Which is Best for You?

12v 600 amp-hour lithium battery bank for RV

With so many different types of RV batteries and potential configurations to choose from, it can be tough to decide what you need in your RV.

As full-time RVers, we eat, sleep, and breathe all things RVing.

Unsure about the differences between a 6v and 12v battery system? Or looking to learn more about the different types of RV batteries and their benefits and drawbacks?

We are helping you up your RV battery knowledge so that you can be confident in the core power supply of your RV and be free to spend less time worrying and more time exploring!

Types of Batteries

Assuming you have the same amount of watt-hours and they are true deep cycle batteries, the voltage of your batteries (6v vs 12v) is fairly negligible regarding performance. The biggest performance differences will be in the actual chemistry of the batteries.

Below are a few common types of RV batteries.

Lead acid batteries

As you might guess, lead-acid batteries are made of lead and sulfuric acid. They are called flooded batteries because they have open terminals on the top that must be kept full of distilled water to operate properly. Allowing these to dry out can drastically reduce the life of your batteries.

AGM batteries

AGM, or Absorbent Glass Mat) batteries are sealed lead-acid batteries. They do not require any maintenance with distilled water.

AGM batteries consist of lead plates, like traditional lead-acid batteries, but the electrolyte is absorbed by a fiberglass mat placed between the plates.

The maintenance-free construction and increased performance compared to lead-acid batteries does put them at a higher price point.

RVer's Pick
Qty 2: VMAX XTR6-235 6 Volt 235Ah Group GC2 AGM Deep Cycle Battery. Capacity: 235Ah; Energy: 1.62kWH Each; Reserve Capacity: 500min Each
$684.93

Set of 2 6V Deep Cycle Batteries with 235 Ah capacity

Buy Now
We earn a commission if you make a purchase, at no additional cost to you.
02/18/2024 04:22 pm GMT

Lithium batteries (LiFePO4)

Lithium RV batteries got their technology from lithium-ion batteries, which are the batteries in our phones and laptops. Lithium batteries are a game changer in terms of performance.

Some of the major performance benefits are:

  • Higher energy density than lead-acid and AGM
  • Significantly lighter batteries for the same capacity
    • Our 200AH 12v lithium batteries are 58 lbs each!
  • Much deeper discharge cycles compared to AGM and lead-acid. You can discharge lithium batteries to 20% or lower compared to the recommended 50% of lead-acid and AGM batteries
  • Lithium batteries have a vastly longer lifespan than lead-acid and AGM batteries

What’s the catch to all of these benefits of lithium batteries? Upfront cost.

Lithium batteries tend to cost far more up front, but given their long lifespan, is a wash in the long run. Given we full-time RV and spend a lot of time off-grid, we love our lithium batteries and wouldn’t go back to AGM or Lead-acid batteries any time soon.

RVer's Pick
Battle Born Batteries Lithium-Ion (LiFePO4) Deep Cycle 12V Battery 100Ah – Safe & Powerful Drop-In Replacement for RV, Van, Marine, Off-Grid – Cylindrical Cells, Internal BMS
$825.00

This 100Ah 12V lithium battery lasts 3,000 - 5,000 deep discharge cycles, providing up to 10-15 years of power.

Buy Now
We earn a commission if you make a purchase, at no additional cost to you.
02/18/2024 04:27 pm GMT

Trying to decide between 6-volt and 12-volt batteries for your RV and not sure which is better for you? We have been traveling full-time in our RV since 2021 and have learned the ins and outs of battery systems along the way. We’ve installed a large off-grid solar system on our fifth wheel and as a result, we have extensive knowledge about batteries and battery voltages. In this article, we’ll cover everything you’ll need to know to choose 12-volt or 6-volt batteries for your RV and help you choose the right system for your RV travels.  

READ MORE: Best Lithium Battery For RVs

RV Batteries: Fundamental Concepts

When looking to understand 6-volt, 12-volt, or even 24-volt batteries, voltage is just one piece of the puzzle. Understanding a few fundamental concepts will make the rest of this article a much quicker read. 

Amp-hours and watt-hours

You’ll often hear someone say something like they have “100 amp hours” of batteries. This can be misleading as the total power capacity of a battery bank depends on both volts and amps.

If they have 12v batteries, that would mean they could have a 100 amp draw at 12 volts (which would be 1,200 watts) on their batteries for 1 hour to bring them down to completely empty. Many batteries will cut off prior to being completely empty, but you get the idea.

To compare capacity apples to apples, watt-hours is the best metric to use. A 100 amp-hour 12v battery provides the same capacity as a 200 amp-hour 6v battery. Both give you 1,200 watt-hours of battery capacity. 

RV Battery System Setup: Series vs. Parallel

Wiring batteries in series vs. parallel is extremely important. The main thing to remember is wiring two batteries in series will increase the voltage while keeping amps the same. Wiring two batteries in parallel will increase the amps while keeping voltage the same.

Wiring in Series vs. Wiring in Parallel: An Overview

Assume we have (2) 200 amp hour 6 volt batteries. By wiring them in series, you will end up with a total of 200 amp hours at 12v. That is a higher voltage than each 6v battery alone. Remember, wiring in series keeps amps the same and increases voltage. In this scenario, you’ll have (2) 6- volt batteries wired up to produce 12 volts, which will power all of your 12v appliances in your RV.

Now assume you have two 100 amp hour 12 volt batteries. Wiring them in parallel will create 200 amp hours of batteries at 12 volts. That is a higher amp hour rating than each individual battery. When wiring in parallel, the amps increase and voltage stay the same.

In both scenarios above, you end up in the same place: 200 amp hours at 12 volts. The biggest differences in the two battery setups above are the weight and size of each individual battery.

Example of Series-Parallel

You’ll also hear folks mention wiring in “series-parallel.” Wiring in series-parallel is a mix of both series and parallel.

Assume you have (4) 100 amp hour 6 volt batteries. If you have two sets of two batteries wired in series, that would give you two sets of 100 amp hours at 12 volts. Now wire those two sets in parallel and you get a final outcome of 200 amp hours at 12 volts, which is the same as the other two scenarios above.

Wiring Differences

There are important differences when wiring batteries in series compared to wiring in parallel. The main differences are:

  • Series: Connect the negative terminal of one battery to the positive terminal of the other battery. If you have more than two batteries, repeat this pattern and the voltage will continue to increase while amps stay the same.
  • Parallel: Connect the negative terminal of one battery to the negative terminal of the other battery. You’ll connect the positive terminals together as well. Repeating this pattern will increase the amps while keeping voltage the same.

Wiring batteries in series doesn’t provide any tangible increase in amp hour capacity.

If you are a visual learner, this graphic should add some clarity.

12-volt RV batteries

12-volt RV batteries are a portable energy bank specifically made for your RV. It has a voltage of 12 volts, which is the measure of the electrical pressure it can provide. 12-volt batteries for your RV store electrical energy and release energy when you need to power things like lights, appliances, and fans while you’re on the road or camping.

6-volt RV batteries

A 6-volt battery for an RV is another type of power source that gives electricity to various parts of your RV. It’s similar to the 12-volt battery but designed in a slightly different way.

Imagine it as a compact energy storage unit tailored for your RV. It operates at a voltage of 6 volts, which is a lesser electrical strength than 12 volts. 

6-volt batteries are commonly known as “6-volt golf cart batteries” because they can be found in almost all golf carts! Newer electric golf carts typically operate at a voltage higher than 6-volts, so they will have multiple 6-volt batteries wired in series to provide the appropriate voltage. A 36-volt golf cart will likely have six 6-volt batteries wired in series to get to the 36 volts. 

RV manufacturers often use 12v systems from the factory when manufacturing a new RV. Providing 12-volt electricity can be accomplished with a 12-volt option or a 6-volt option (wired in series).

Comparing 12-volt and 6-volt RV batteries

​There are many differences between 12 volt and 6 volt batteries for your specific RV. I’ll go through both practical considerations and technical considerations.

After RVing full-time for over two years and installing an upgraded battery and solar system, I think size, weight, and cost are the most important factors.

Let’s go through all the considerations and then I’ll give my personal opinions below.

Fifth wheel camping for free at a remote boondocking spot in Wyoming next to lush green vegetation and a deep blue river
12v or 6v batteries will get you where you want to go. Battery chemistry should be a big focus.

Cell Configuration

There is more than one big “hunk of battery” within a 12-volt or 6-volt battery. Both battery voltages are made up of smaller batteries, or “cells”.

  • 6-Volt Batteries: A 6-volt battery typically consists of three cells, each providing about 2 volts. These cells are connected in series inside the battery casing, resulting in a total voltage of 6 volts.
  • 12-Volt Batteries: A 12-volt battery, on the other hand, consists of six cells, with each cell providing around 2 volts. These cells are also connected in series within the battery housing, resulting in a total voltage of 12 volts.

Plate Configuration

  • 6-Volt Batteries: In a 6-volt battery, the plates (positive and negative) inside each cell tend to be larger, thicker, and have more surface area compared to plates in a 12-volt battery. 6-volt batteries are often used in applications that require more sustained energy output over time, such as deep-cycle applications like golf carts and RVs. Thicker plates can support higher capacity and a slower discharge rate, making them suitable for these applications.
  • 12-Volt Batteries: In a 12-volt battery, the plates are usually smaller due to the limited space inside each cell. 12-volt batteries are often used as starting batteries in vehicles where they provide a burst of energy to start the engine but are not subjected to as deep cycling as deep-cycle batteries.

Weight

So, if an RV uses 12v power, why would someone use a 6v battery? One big reason is weight.

If you aren’t using lithium batteries, which tend to be much lighter than sealed or lead-acid batteries, hauling around 12v batteries can be a pain. A single 200 amp hour 12v battery can weigh 100 pounds or more.

It’s much easier to carry (2) six volt batteries with the same amp hours and then wire them in series. From the research I’ve done, A 100 amp hour 6v battery will weigh less than a 100 amp hour 12v battery. Due to the larger cells and plates in 6v batteries, the 6v battery won’t be half the weight of the 12v battery, but generally it’ll be lighter.

Larger battery banks will only emphasize the concerns about weight. Keep in mind what makes the most sense for you and your RV!

Size

The shape and size of your battery box is another consideration you should keep in mind. There can be large differences in overall storage pace and compartment sizes between vans, travel trailers, fifth wheels, and motorhomes.

Depending on the exact battery you get, the dimensions of your batteries can vary. I’ve noticed that 6 volt batteries tend to be taller and narrower while 12 volt batteries of the same capacity (amp hours) tend to be shorter and wider.

The size of your battery bank and the dimensions of your battery box may dictate what your battery dimensions must be. Save yourself an extra headache and make sure your batteries will fit properly in your RV before you purchase them.

Cost

To compare costs fairly closely, let’s look at the same brand of battery and build out a close to equal system. This VMAX 200 amp-hour 12 volt battery costs around $460. This set of 6v VMAX batteries will produce 235 amp-hours at 12 volts and costs roughly $680.

Above we see that for the same voltage and capacity, the pair of 6-volt batteries is almost 50% more expensive. This may be because 6 volt batteries tend to last a little longer than a 12-volt of the same chemistry.

Lifespan

Because of the thicker plates mentioned above, 6 volt batteries tend to have a longer lifespan than 12 volt batteries.

A flooded 6 volt battery can last anywhere from 4-7 years on average. A flooded 12 volt battery will likely last between 3-6 years. The difference in battery life isn’t massive, but it is a factor nonetheless.

Load Capacity

Given the thicker plate construction in 6 volt batteries, they can perform slightly better when under load. Wiring the batteries in series also helps with this.

However, you’d also see benefits from wiring 12v batteries in parallel, so don’t put too much weight in this.

Where you’ll see major differences in performance is different chemistries (i.e. lithium compared to flooded batteries).

6v vs. 12v Charging & Discharging

Just like your phone’s battery, RV batteries eventually need to be recharged. You can charge the RV battery by connecting it to a power source, like when you plug your RV into a campground’s electrical hookup. You can also recharge batteries using a generator or solar power.

Charging

There is a common misconception that batteries with the same chemistry will charge faster or slower based on voltage. In general, 6-volt batteries do not inherently charge faster than 12-volt batteries and vice versa. 

The recharge rate of a battery is determined by several factors, including capacity, state of charge, battery charger specifications, and the battery’s internal chemistry (flooded, gel, lithium, etc).

The rate of charge is fairly negligible between 6v and 12v batteries given you have comparable battery voltage and capacity. Both 6v batteries in series and a 12v battery of the same capacity will get back to a full charge in about the same time.

Discharging

Some may say that there is a lower discharge rate between 6 volt batteries in series compared to a 12v battery.

One “cycle” is drawing a battery down to it’s recommended discharge percentage and then recharging back to full capacity. I haven’t noticed much of a difference in the cycle life of one vs. another from my experience.

As mentioned above, there will be a measurable difference in the number of cycles (lifespan). 6 volt batteries will be able to endure more cycles than 12 volt due to the thicker plates.

There may be a difference in discharge rate in a lab, but you likely won’t notice a big difference in your real-life use.

Types of Batteries

Assuming you have the same amount of watt-hours and they are true deep cycle batteries, the voltage of your batteries (6v vs 12v) is fairly negligible regarding performance. The biggest performance differences will be in the actual chemistry of the batteries.

Below are a few common types of RV batteries.

Lead acid batteries

As you might guess, lead-acid batteries are made of lead and sulfuric acid. They are called flooded batteries because they have open terminals on the top that must be kept full of distilled water to operate properly. Allowing these to dry out can drastically reduce the life of your batteries.

AGM batteries

AGM, or Absorbent Glass Mat) batteries are sealed lead-acid batteries. They do not require any maintenance with distilled water.

AGM batteries consist of lead plates, like traditional lead-acid batteries, but the electrolyte is absorbed by a fiberglass mat placed between the plates.

The maintenance-free construction and increased performance compared to lead-acid batteries does put them at a higher price point.

RVer's Pick
Qty 2: VMAX XTR6-235 6 Volt 235Ah Group GC2 AGM Deep Cycle Battery. Capacity: 235Ah; Energy: 1.62kWH Each; Reserve Capacity: 500min Each
$684.93

Set of 2 6V Deep Cycle Batteries with 235 Ah capacity

Buy Now
We earn a commission if you make a purchase, at no additional cost to you.
02/18/2024 04:22 pm GMT

Lithium batteries (LiFePO4)

Lithium RV batteries got their technology from lithium-ion batteries, which are the batteries in our phones and laptops. Lithium batteries are a game changer in terms of performance.

Some of the major performance benefits are:

  • Higher energy density than lead-acid and AGM
  • Significantly lighter batteries for the same capacity
    • Our 200AH 12v lithium batteries are 58 lbs each!
  • Much deeper discharge cycles compared to AGM and lead-acid. You can discharge lithium batteries to 20% or lower compared to the recommended 50% of lead-acid and AGM batteries
  • Lithium batteries have a vastly longer lifespan than lead-acid and AGM batteries

What’s the catch to all of these benefits of lithium batteries? Upfront cost.

Lithium batteries tend to cost far more up front, but given their long lifespan, is a wash in the long run. Given we full-time RV and spend a lot of time off-grid, we love our lithium batteries and wouldn’t go back to AGM or Lead-acid batteries any time soon.

RVer's Pick
Battle Born Batteries Lithium-Ion (LiFePO4) Deep Cycle 12V Battery 100Ah – Safe & Powerful Drop-In Replacement for RV, Van, Marine, Off-Grid – Cylindrical Cells, Internal BMS
$825.00

This 100Ah 12V lithium battery lasts 3,000 - 5,000 deep discharge cycles, providing up to 10-15 years of power.

Buy Now
We earn a commission if you make a purchase, at no additional cost to you.
02/18/2024 04:27 pm GMT

6v vs. 12v Battery for Boondocking

If you take your RV from campground to campground and always have access to shore power, your batteries are of minimal importance.

Your batteries will keep things like your fridge and smoke alarms on while you are towing, but you’ll charge right back up once you plug in to shore power.

Once you boondock or dry camp, your batteries become much more important!

READ MORE: RV Boondocking Guide For Beginners

DRV Fifth wheel boondocking with solar array in Gros Morne National Park, NL. The picture shows large mountains as a gorgeous backdrop
Our 12v 200 amp hour Lithium batteries have taken us to incredible places!

Which is better for solar?

This is probably an unpopular opinion. 6v vs 12 volt batteries don’t make much of a difference even for off-grid usage. Sure, your 6v batteries in series may handle a slightly higher load and they may last slightly longer, but the differences are minimal. Both will run DC appliances like your water pump without issue.

I’ve said it before and I’ll say it again. The big differences in performance come from battery chemistry.

Having a high performance battery such as lithium batteries will require fewer solar panels given their faster recharge rates and deeper discharge rates. Lithium batteries will excel when powering power hog appliances like your RV air conditioner.

READ MORE: Can You Run Your RV AC On Solar Power?

Bottom Line: What should you really care about?

That was a lot of information. When it comes down to it, what is the right battery for you?

In my opinion, the main differences between 12v and 6v batteries that you should care about are size, weight, and price. There is no single best option for everybody.

A pair of 6v batteries tends to be a little more expensive than a single 12 volt battery with the same capacity. If you aren’t using your RV all that often, the cheaper 12v battery is the better option. It’ll serve you just fine and you’ll have a little beer money left over!

If you have specific size requirements, shop around between both 6v and 12v batteries to find the battery that will fit in your space. Just remember you’ll need two 6v batteries to get to the 12v.

If you don’t want to lug around heavy batteries, getting more 6v batteries compared to less 12v batteries may be a good idea. It will allow you to carry more lighter batteries. You shouldn’t have to lift your batteries all too often.

If you are trying to get the biggest boost in battery performance, the main difference will be battery chemistry. Upgrading your batteries to lithium is a great idea if you boondock or dry camp often. They are also great if you want a maintenance-free light weight battery.

I hope this guide provides useful information for you as you decide on which RV batteries will work best for you! If you have additional questions, please leave them in the comments or contact us and we’ll get back to you as soon as possible. Safe travels!

Interested in learning more about RV power or off-grid camping? Check out these resources:

Our Favorite RV Resources

Our favorite resources for finding great campgrounds and campsites include :

  • Harvest Host: For finding unique and convenient overnight stays at breweries, vineyards, farms, and more! Perfect for a fun weekend getaway or stopover during a long travel stretch.
  • Campspot: For finding and booking great campgrounds and RV parks conveniently and easily all in one place!
  • RV Life: RV safe GPS, RV Trip Wizard route planning, maintenance tracker, campground reviews and more. Everything any RVer needs, all in one place!
  • CampendiumiOverlander: For finding free camping spots
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