This Is Why Your RV Battery Is Overheating? (Read This First)


Recreational vehicles, or RVs, come in all shapes and sizes. Whether you buy yours from an RV manufacturer or convert one from a used bus or van, it is a must to have a battery charging system. Overheating of RV batteries can occur.

Why is my RV battery overheating? RV batteries overheat for three main reasons:

  • For lead-acid batteries, the older and more sulfated the battery becomes, the more heating will occur when charged.
  • For lithium batteries, having them encased in an area without ventilation can cause overheating while charging.
  • The third reason, regardless of battery type, can be caused by a malfunction in the charging system itself. These malfunctions can cause an overcharge to your battery and cause heat buildup.

Overheated batteries in your RV are not only a hassle when you need power. Depending on the circumstances, an overheated battery can be dangerous.

Fire and battery explosions have occurred for this reason. Continue reading to find more about overheating RV batteries and how to avoid it from happening.

What Causes an RVs Charging System to Overcharge?

1.) Convertor Malfunction:

A convertor transforms AC power into DC power and allows for battery charging in an RV. This is important when using an AC power source plugged into your RV to charge batteries.

If the converter is damaged and does not shut off when the battery is fully charged, it will continue to feed power to the battery.

This overcharging will make the RV battery overheat.

2.) Alternator failure

With a damaged alternator, we may only think about not charging a battery with enough power. The opposite can also be true.

If an alternator is running above a specific voltage (usually more the 14.5 Volts), batteries can overheat.

How Can You Prevent Batteries from Overheating in Your RV?


  • Have your alternator checked as part of your RVs scheduled maintenance. Either have a mechanic, or yourself use a meter to check for proper voltage regularly. Catching the issue before it becomes a major problem can save you an incident when in the wilderness. Remember, if your batteries fail from overheating while off of the grid, you will not have power.
  • Many converters have a voltage control that shuts off charging when your batteries are full. Make sure to check this system at least monthly to make sure it is working correctly.
  • If your lead-acid cell batteries use water, make sure they do not run out of distilled water. This can exasperate a battery cooling ability when it begins to overheat.

Proper Ventilation

Most modern lithium battery systems in an RV are created to shut off power with a warning if the battery overheats.

This is a good idea as a safety feature but can leave you without power until the battery cools.

Most manufactured RVs allow for proper ventilation to help keep batteries cool; however, aftermarket and do it yourself, battery containers can sometimes not allow for adequate ventilation.

Make sure any battery storage in your RV has proper ventilation by checking temperature readings until you are sure.

What Type of Batteries Are Best for RVs?

When it comes to RVs, there are two types of batteries that provide adequate power and lifespan to the house part of the vehicle.

Both can be charged solar, AC power converted, and by the vehicle’s alternator system.

There are some pros and cons of each battery type. Let’s take a look at both types and learn about each one.

AGM Deep Cycle Battery

The AGM deep cycle battery is a type of lead-acid battery used for RVs and boats.

It is different from your average starter battery as it is mainly used for powering lights, fans, and other needed components.

Lithium Batteries

These are another type of rechargeable battery used in recreational vehicles.

They are lithium-based as the name implies and have become popular in recent years by owners of RV’s, especially those who want to be off-grid for extended periods.

Pros and Cons of a Deep Cycle Battery


  • AGM Deep Cycle batteries have a high-power output that allows for a large load to be run on them.
  • These batteries are sealed and will not spill or leak.
  • Allow for faster charging times than any other flooded battery.
  • Long lifespan These batteries will last up to 10 years in the best of conditions.
  • These batteries are less expensive than lithium batteries, which means something when you require two to four batteries to maintain an RV’s power.


  • There are limitations on what can run on them, especially at one time.
  • Known for losing their charging capacity over time
  • They are easy to damage from overcharging.

Pros and Cons of Lithium Batteries


  • The amp hours on lithium batteries allow them to run multiple appliances in an RV over a long period of time.
  • By being able to carry several times the energy of conventional batteries a lithium battery can be produced smaller
  • Lithium batteries do not lose their charging efficiency over time as deep cycle batteries.
  • The cost per kWh is less with lithium due to being able to discharge them much further than a deep cycle before charging.


  • There is more upfront cost to a lithium battery
  • 100% discharge of the batteries could damage them
  • Are sensitive to level charging across all batteries. A charging management system is a must-have with lithium batteries.
  • Require proper ventilation and cooling to prevent overheating

You can probably find as just as many people who swear by these two types of systems.

It will probably come down to your needs and budget. If visiting parks with electric power available for backup, a deep cycle may be a better choice.

If living in the mountains off the grid with just solar and battery backup, Lithium is probably the way to go.

How Do You Know When to Replace an RV Battery?

Whether using a deep cycle battery or a lithium battery, how do you know when to replace them? 

  1. Both batteries are expected to last a certain amount of years. To avoid being caught without battery power while in the woods, change your batteries before the assumed expiration dates.
  2. A check with a meter will tell you if your RV battery is running out of life. If fully charged and only showing around 12.5 volts or less, it is time to change the battery.
  3. If the battery cannot reach a full charge, its life is probably close to its life’s end and time to replace.
  4. When you fully charge your battery and its power is drained faster than in the past, you will need to start thinking of a new battery. This can be deceptive over several years, as we can forget how long the batteries lasted when new. Make a note in your service log of how long your batteries are holding a charge during the first two years.
  5. Obvious damage to the case of the battery is a sure requirement for a change. This is common in conversion RVs when the batteries are not sufficiently secured and allowed to move around while driving.


Realizing how to prevent battery overheating can not only save your RV from a fire hazard but save your life as well.

Understanding why your battery is overheating and maintaining it properly will keep your system running smoothly.

As we learned about the different batteries available for your RV, you should have a better understanding of what type of battery is best for you and your charging system.

For more helpful articles about RVs please check out our articles below:

What is an Inverter in an RV and Why Do You Need it?

This Is Why Your RV Inverter Is Beeping [Facts You Should Know]

Do RV Thermostats Go Bad? How To Check It?

How Many Watts Do I Need to Run a Camper AC? Facts You Need To Know

What Does Solar Ready or Prep on A Camper Mean?

5 Practical Ways To Unfreeze Water Lines In RVs (That Actually Work)


AGM VS Lithium

How to Know a Bad Battery

Mike Gilmour

Hi, I'm Mike, co-founder, and editor of RV and Playa. My passion is traveling (with my RV) and enjoying the day at the beach (Playa)! Well, I originally created this blog as a way to share what I've learned by experimenting with the RV lifestyle, and I want to help others develop in life through new skills and opportunities.

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