If you’re an avid RVer and you plan to spend a lot of time camping in remote locations without any facilities or hookups, then chances are you are going to want to upgrade the batteries in your RV. By upgrading I am referring to installing additional batteries as well as better quality batteries. The batteries in your RV are the lifeline that all your 12 Volt accessories rely on. Most travel trailers and 5th wheels sold today come with the absolute minimum; usually one standard, Group 24, deep cycle flooded lead acid battery to meet all of your 12 Volt needs. If you are lucky, then maybe you have two batteries. Either way, as most new RVers will quickly find out on their first trip into the woods, one or even two 12 Volt batteries may not be sufficient to meet all their needs on an extended camping trip. 

After one full day and night of camping and using your RV’s standard amenities such as the lights, radio, refrigerator, etc it is entirely possible to drain one or even two batteries completely. Nothing is worse than waking up in the morning and realizing that your batteries are dead. In addition to not being able to get any water or flush the toilet, you suddenly realize that your refrigerator, lights, radio, water heater and CO2 detector are no longer working either. At this point you will quickly realize how important having sufficient battery power is. What most RVers don’t realize is that in addition to the items they were utilizing such as the lights and radio, there were several “phantom loads” draining power from their batteries also. Phantom loads are the items in your RV that are using 12 Volt power that many RVers are not aware of such as the carbon monoxide detector, radio memory, and refrigerator electronics. When “boondocking” (camping in remote locations with no hookups), RV enthusiasts rely heavily on their RV batteries. Therefore, it is important to make sure that you have enough power to get through the night without draining the batteries to a point that they become damaged. Similarly, it is important to have a plan for recharging the batteries quickly in order to maintain their longevity.

Choosing the right battery and understanding how to take care of your batteries is critically important. Often the batteries in an RV are the least understood component. When I bought my first RV I would routinely run my batteries until they were completely drained before recharging them. At the time, I did not realize what a critical mistake this was because I did not know anything about batteries or how they worked. Most people are only concerned with the amenities of an RV; however, they never really consider how these amenities are going to be powered until they have a problem. If you plan on staying at camp grounds and plugging in most of the time, then batteries are not going to be your main concern since you will not rely on them much. However, if you plan to boondock, then batteries become your lifeblood, unless you want to continually run a loud and obnoxious (not to mention noxious) generator. How you use or misuse your batteries will surely determine their longevity and usefulness.

Types of Batteries:

Although the batteries in your RV may look like a standard car battery, there are some key differences. RV and boat batteries are usually deep cycle batteries while car batteries are not. Car batteries are built to supply a quick surge of energy to start your car and then they are immediately recharged. A deep cycle battery, on the other hand, is built to supply power over a long period of time. Although a deep cycle battery is similar to a car battery in design, it is built with internally thicker lead plates meant to withstand repeated deep discharges, meaning that they are built to be discharged or drained heavily and then recharged many times. The average deep cycle battery is built to be discharged and recharged hundreds of times before it will reach the end of its useful life. A car battery, if treated in the same manner as a deep cycle battery, would withstand this type of abuse 20 times or less before it was completely worthless.

Deep cycle batteries come in many sizes and capacities and even in different voltages (12V and 6V for example).  Some of the common sizes that you will see referred to for RV use are Group 24, Group 27, 8D truck batteries and golf cart batteries. All of these types of batteries can be used in an RV (Take note, however, of the battery voltage. Many golf cart batteries are 6 Volts and need to be wired in series to create 12 Volts for your RV. Refer to the section 6 Volt vs. 12 Volt batteries). The main differences between these batteries are the dimensions, internal construction, and the amount of charge or current that they can store. Similarly, there are different technologies that batteries are built upon with some being better than others, especially for RV use. 

There are three main types of lead acid batteries. Flooded acid or wet cells, gelled acid (gel cells) and AGM (absorbed glass mat). Almost all batteries that are supplied with new RVs are flooded acid batteries unless you are lucky enough to be able to purchase an extremely high end RV. Flooded acid batteries are the most common lead acid battery because they are the cheapest. Let’s take a little time to discuss the difference between the 3 main types of batteries. 

Flooded acid batteries consist of lead plates that are separated and surrounded by a liquid electrolyte (sulphuric acid and water). This is the same kind of battery that you find in most cars. Usually these batteries are not sealed and require a lot of maintenance. A flooded acid battery loses some of its electrolytes each time it is recharged through a process that is referred to as “gassing”. Because of gassing, flooded acid batteries’ fluid levels have to be checked occasionally and distilled water added to maintain them. Care also needs to be taken when maintaining a flooded acid battery to assure that none of the liquid spills out or splashes, which can cause burns from the sulphuric acid inside the battery. Similarly, flooded acid batteries require additional maintenance in the form of occasional equalization. Equalization is a process used to bring each of the batteries cells to an equal charge. Since this is a major pain and I have never done it, nor do I plan to ever have to do it, I am going to leave this topic alone. For those of you who are using or plan to use flooded acid batteries, there is plenty of information on the web regarding the process of equalization.

If you plan on using flooded acid batteries in your RV, it is important to be careful when choosing the location you plan to mount them. Since flooded acid batteries are prone to gassing, it is imperative that you find a storage location with proper ventilation and away from any ignition sources. The gasses that are given off during recharging are not only dangerous to people but are explosive as well. Therefore, you should NEVER mount a flooded acid battery inside of your RV cabin. The biggest drawback to a flooded acid battery is the required maintenance and the biggest advantage is that they are the cheapest (relative to gel and AGM) type of battery that you can use. Although you can use flooded acid batteries in your RV, in my opinion, it is not an optimal or desired solution due to the maintenance requirements.

Gel cell batteries use a gel around the internal lead plates instead of liquid. Therefore, if the battery case is cracked or broken, no liquid will leak out and the battery will continue to function.  Gel cell batteries are a better option than flooded acid batteries since they are sealed and don’t require any maintenance. However, one of the biggest disadvantages of gel cell batteries is that they have very specific charging requirements (slightly different than flooded acid) and can be damaged quickly if overcharged. Additionally, gel cells are very finicky and less forgiving if any mistakes are made while charging or discharging them and are sensitive to any abuse. Gel cell batteries are more expensive than flooded acid batteries and are a good choice for your RV, however, they are still not the optimal solution. I suggest that if you are going to spend the money on gel cell batteries, then you might as well go all the way and do it right and use AGM batteries. After all, gel cells are roughly equivalent in price to AGMs and AGM batteries have some distinct advantages. It is because of these advantages that AGMs tend to outsell gel cells by a margin of 4 to 1.

AGM batteries use a fiberglass like mat to hold the electrolyte in place. Like a gel cell battery, if the case is broken, the battery will not leak. AGM batteries are sealed batteries and therefore, there is no maintenance required and there is no gassing under normal operating conditions. This means that they can be put in locations with limited ventilation. Even if overcharged (which you will not allow to happen to your expensive AGMs), AGM batteries are less prone to gassing than gel cells. Therefore, if you need to mount your batteries inside of your RV cabin due to space limitations or lack of a better location, AGM batteries are the best choice. Note however, that best practice dictates that even though you can mount an AGM battery inside the cabin of an RV near people, it is still highly recommend that you find an external location to mount your batteries with proper or at least decent ventilation.

So which type of battery should you use for your RV? For an RV application, I would highly recommend using an AGM battery. There are a few reasons for this. AGM batteries are made for rugged applications and are much better suited toward environments with high vibrations (such as the constant bouncing of your RV while driving). This is especially important if you don’t have an exterior storage space to mount your batteries and you need to put them inside the RV cabin in a cabinet or other location near people. AGM batteries are less prone to gassing if overcharged. Again, this is important if you need to store them inside the RV cabin. AGM batteries can also be stored in any position including upside down if needed. Additionally, AGM batteries have a higher charge efficiency, which means that you can recharge them with less energy. If you plan to use solar panels to recharge your batteries like I do, then this is an important factor since AGM batteries will lose less energy to heat. A standard flooded acid battery can lose up to 15-20% of the energy used to recharge them to heat. A gel cell will lose 10-16%. An AGM battery will only lose approximately 2-4%. Lastly, AGM batteries will hold their charge longer than a gel or flooded acid battery while in storage.

What brand battery should you buy? There are many reputable battery brands out there such as Lifeline, Trojan, Exide, Interstate, Sonnenschien, Optima, etc so do your homework first and look for recommendations from other RVers. The batteries that I chose after researching the best brands available were 6 Volt Lifeline AGM (model GPL-4CT) batteries, which are manufactured by Concorde Battery Corporation. Based on my research, Lifeline batteries had a solid reputation as being the best in the industry and seemed to be in use by many hard core RV enthusiasts.

Understanding Battery Capacity:

Each deep cycle battery has its own capacity rating, usually rated in Amp Hours (AH). An Amp Hour is a unit of battery energy capacity. In very rough terms, a battery that is rated at 50 amp hours could supply 1 amp of power for 50 hours. If a light is running that consumes 10 amps in one hour, then it is said to consume 10 AH. If it runs for 5 hours, then it will consume 50 AH (5 hours x 10 AH per hour = 50AH). However, the AH rating of any battery needs to be taken with a grain of salt. It is only an approximation and in reality a 50AH battery may not supply 50AH of battery capacity. As in most industries there can be a lot of hype regarding the advertised rating vs. real life application. Similarly, there are many factors that can affect a batteries actual performance such as temperature. A good general rule to follow when planning for your battery upgrade is that a battery will only supply about 80% of its actual rated capacity. Choosing the right battery is important and will depend completely on your needs, space, and weight considerations.

Next: Charging, Recharging & Monitoring Your RV Batteries  |  Home