RV Advice

What You Need to Know About RV Batteries

May 7, 2023

Whether you are a new or experienced RVer, it is important to become familiar with the types of RV batteries you need. It’s also good to know about all kinds of batteries so you are familiar with the options. Learn about the pros and cons of different RV batteries and how to maximize your battery life.

What Types of RV Batteries Are There?
What is the Amp Hour Rating?
What Are Amp Hours on a Marine Battery?
What Are the Construction Types of Deep Cycle Batteries?
What Are the Disadvantages of Gel Cell Batteries?
What Are the Disadvantages of Lead Acid Batteries?
What is the Life Expectancy of RV Batteries?
How Can You Maintain the Life of Your RV Batteries?
What Kinds of Deep Cycle Batteries Are Available?
What Causes RV Battery Failure?

Types of RV Batteries

If you ever need a replacement battery for your RV and want to do the work yourself, it’s important to know the differences. In terms of specific battery types — like what size battery you need for a travel trailer — it depends on the specific components of your RV. If you can drive your RV and use home appliances, it will come with more than one kind of battery to perform both functions.

The types of batteries are:

1. The Chassis Battery

Also called the starter battery, this is the battery used to run your drivable RV’s engine. It starts the RV’s auto component using large currents over short periods. Your chassis battery has the following properties:

  • It has several thin plates to maximize the area exposed to the electrolyte.
  • It is rated in Cold Cranking Amps (CCA).
  • It is unable to perform deep cycle applications.

2. The 12-Volt Battery

The battery that supplies 12 volts to your RV is also called the house battery and you might have more than one. This is a type of deep cycle battery that powers the home appliances in your RV, like your microwave, refrigerator and TV. Your RV house battery has the following properties:

  • It is designed for deep cycles, with thick plates that are frequently discharged and recharged.
  • It is rated in Amp Hours (AH) or Reserve Capacity (RC) instead of CCA.
  • It provides a steady current over long durations.

If you have a towable RV, you only need to keep up with the 12-volt battery. It is important to make sure your battery is operating so your smoke and carbon monoxide detectors function.

What Is the Amp Hour Rating?

The amp hour rating determines how long your battery can run before it needs to be recharged. In technical terms, it measures how many amps your battery can deliver for a given number of hours until the battery has discharged. For example, if a battery can produce 5 amps for 20 hours before it discharges, the rating would be 100 amp hours. That’s a strong battery.

You might be asking this question because you want to learn what the best RV battery is, but the answer is that it depends on more than this single factor. The amp hour rating is important for deep cycle batteries, but you also want to have the correct amount of voltage. The battery itself needs to be safe to use inside an RV.

What Are Amp Hours on a Marine Battery?

Marine batteries are designed for boats instead of RVs. They have heavier plates than other types of batteries and are designed to withstand sudden, forceful movements and intense vibrations from a motor. The amp hours on this type of battery should be fairly high.

Construction Types of Deep Cycle Batteries

Three construction types of deep cycle battery include the:

1. Flooded Lead-Acid Battery

These are also called wet-celled batteries. These common deep cycle batteries come in two styles:

  1. Serviceable battery: This style has removable caps. This makes it easy for you to inspect the battery. Some serviceable batteries are low maintenance.
  2. Value regulated lead-acid (VRLA) battery: This style has an electrolyte suspended in a gel or a fiberglass mat. When gel acid is used, the battery is called a gel cell. This battery is leak-proof, making them ideal for use in a marine application.

2. Absorbed Glass Mat (AGM) Battery

With a fibrous mat wedged between this battery’s plates, it is a more expensive option than the average deep cycle battery. You can charge one like a lead-acid battery, but they are leak-proof, unable to freeze in cold temperatures and mostly maintenance-free.

3. Lithium-Ion Battery

This type of battery used to lack deep cycle applications, but now more are being produced for this purpose. Lithium-ion batteries have an internal management system for maximum safety. They provide more power than many other types of batteries and they are lighter and more compact than lead-acid batteries.

What Are the Disadvantages of Gel Cell Batteries?

Gel cell batteries are great options, but the application and your planned use for them are both important factors. Some of the most common disadvantages that gel cell batteries have are:

  • You must charge them slowly and use a lower voltage than you would for a flooded cell battery.
  • Overcharging a gel cell battery can cause lasting damage.

What Are the Disadvantages of Lead-Acid Batteries?

Lead-acid batteries are a very common type to find in an RV and are highly universal, working well in many different applications. Common disadvantages for this type of battery are:

  • They might have a shorter lifespan than other types of deep cycle batteries.
  • They are heavy.
  • They require maintenance checks.

What Is the Life Expectancy of RV Batteries?

The overall life expectancy of your RV batteries depends on these factors:

  • What kind of batteries you have. Some last longer than others.
  • Your usage habits and how frequently you go RVing.
  • How well you maintain your batteries if maintenance is required.
  • How you discharge and recharge the batteries.
  • How you store your RV.

How to Maintain the Life of Your RV Batteries

Most battery types require proper care to function properly. Batteries with a lead-acid component might be connected in a series, where an important factor in the battery life is how deeply it cycles during each use.

A battery cycle is one complete discharge from 100 percent down to about 50 percent and then re-charged back to 100 percent.

To maintain your RV batteries, do the following:

  • Recharge the batteries after use to prevent damage.
  • Use the built-in battery charger to charge the batteries when your RV is plugged in.
  • Avoid forcing the battery to power more amperage than the battery is supposed to supply in an hour.
  • If you have deep cycle lead-acid batteries, make sure you get routine inspections and maintenance.
  • If you use lithium-ion batteries, make sure you have the appropriate charger.

What Kinds of Deep Cycle Batteries Are Available?

Deep cycle batteries come in all different sizes. Some are designated by Group size, like group 24, 27 and 31. Basically, the larger the battery the more amp hours you get. Depending on your needs and the amount of space you have available, there are several options when it comes to batteries, including:

  • One 12-volt 24 group deep cycle battery: You can enjoy about 70 to 85 AH from one battery.
  • Two 12-volt 24 group batteries: When the batteries are wired together, they provide around 140 to 170 AH. Parallel wiring increases your amp hours, but it leaves the voltage unchanged.
  • Two large 6-volt golf cart batteries: These should be wired in a series so they can produce the full 12 volts needed for an RV. Series wiring will increase their voltage while leaving the amp hours unchanged.
  • Four large 6-volt batteries: Wiring multiple batteries in a series is a complex process but can produce the required 12 volts while doubling your AH capacity.

What Causes RV Battery Failure?

When your RV battery fails, it might be because of undercharging and overcharging, two very common reasons for this issue.

1. Undercharging

Although other issues might be the cause, failure is often the result of frequently discharging the batteries without fully recharging them between cycles. If the battery is left discharged for long periods, it is also at risk. Many types of batteries are unable to tolerate this treatment and will eventually stop working properly.

The sulfate in the battery will harden and crystalize without fully recharging. This is called sulfation. The crystallized sulfate in your battery is eventually fixed in place, unable to convert back into an active plate material.

2. Overcharging

When batteries are charged for too long or at too high of power, numerous issues can result. Batteries lose water when overcharged, and severe enough water loss can make them unable to operate. The plates can also become corroded if the battery is overcharged. Corrosion will make your battery unreliable.

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MarkheadshotKOAKOA’s resident RV expert, Mark Polk, and his wife Dawn started RV Education 101 in 1999. Since that time RV Education 101 has helped educate millions of RV owners and RV enthusiasts on how to properly and safely use and maintain their RV. Mark’s favorite past times are RVing in their 35-foot Type A motorhome, and restoring vintage RVs, classic cars and trucks. For more information on how to learn about RVs the easy way, visit RV Education 101. Be sure to check out their RV Online Training Course too!


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