What you need to know about RV batteries?


What you need to know about RV batteries?
By understanding the basic knowledge of your RV battery and how it works, you can properly maintain and extend the life of your RV battery.

Lead-acid batteries for RVs

Lead-acid batteries for RVs

In order to properly maintain and extend the service life of the RV battery, you need to have a basic understanding of the meaning of the battery and its working principle. The batteries used in RVs are lead-acid batteries, which mean they have several batteries connected in series. Each battery cell generates approximately 2.1 volts, so a 12-volt battery with six battery cells in series produces an output voltage of 12.6 volts.
Lead-acid batteries are made of plates made of 36% sulfuric acid and 64% water electrolyte, made of lead and lead oxide. Lead-acid batteries do not generate electricity, they store electricity. The size of the lead plate and the amount of electrolyte determine the amount of charge that the battery can store.

To choose correct RV batteries

choose correct RV batteries

Now, it is very important to use the correct battery for the type of application. The battery used to start and run the engine is called the chassis battery or starting battery. The vehicle starter requires a large starting current for a short time. The starting cell has a large number of thin plates to maximize the area of the plates exposed to the electrolyte. This is why a large amount of current is provided in a short pulse. The starting battery is rated in cold start amperes (CCA). CCA is the amperage that a battery can provide at 0 degrees Fahrenheit for 30 seconds and no less than 7.2 volts. Starter batteries should not be used in deep cycle applications.
Generally, one or more batteries used to provide 12 volts to the RV itself are called house batteries. Household batteries must be deep-cycle batteries designed to provide a stable current for a long time. Starter batteries and marine batteries should not be used in this application. A true deep-cycle battery has much thicker plates and is designed to be deeply discharged and recharged repeatedly. These batteries are rated in ampere-hours (Ah) and have a recent reserve capacity (RC).

The rated ampere-hours basically refers to how many amperes of current the battery can provide and last for several hours before the battery is discharged ampere per hour. In other words, a battery that can provide 5 amperes of current within 20 hours before discharging will have a 100 ampere hour rating, that is, 5 amperes×20 hours = 100 ampere hours. The same battery can provide 20 amp current for 5 hours 20 Amps×5 Hours = 100 Amp Hours. The reserve capacity rating (RC) is the number of minutes that the battery can deliver 25 amps at 80 degrees Fahrenheit until it drops below 10.5 volts. To calculate the ampere hour rating, multiply the RC rating by 60%.

The two main structural types of deep-cycle batteries are overflow lead-acid and valve-regulated lead-acid. Full-liquid lead-acid batteries are the most common type, and there are two styles. The removable cover can be used for maintenance, so you can check and perform maintenance or maintenance-free type. In VRLA batteries, the electrolyte is suspended in a gel or glass fiber mat. Gel batteries use battery acid in the form of a gel. They are leak-proof, so they perform well in marine applications.

Gel batteries used in RV applications have several disadvantages. Most importantly, they must be charged at a lower rate and lower voltage than fully charged batteries. Any overcharging will cause permanent damage to the battery. Absorption glass mat, or AGM Technology, uses a fiber mat between the plates, which is soaked in 90% electrolyte. They are more expensive than standard deep-cycle batteries, but have some advantages. They are charged in the same way as standard lead-acid batteries, do not disperse water, do not leak, require almost no maintenance, and are almost impossible to freeze.

How to maintain the RV batteries

How to maintain the RV batteries

The life expectancy of the RV battery depends on you. The way they are used, maintained, discharged, charged, and stored all help to extend battery life. The battery cycle is a complete discharge, reducing from 100% to about 50%, and then recharging back to 100%. An important factor in extending battery life is the depth of the battery in each cycle. If the battery is discharged to 50% every day, its life will be twice as long as it is cycled to 80%. Keep this in mind when considering the ampere-hour rating of the battery. The actual ampere hour rating is actually reduced by half because you don’t want to fully discharge the battery before charging it. The life expectancy of the battery depends on the charging time of the discharged battery. The sooner you charge, the better.

What does all this mean to you? It depends on how you use the motor home. If most camping is done where the power source is plugged in, then your main concern is to properly maintain the deep cycle battery. However, if you really want to get rid of all this and do some serious camping, then you will want the largest ampere hour capacity to fit your RV.

Deep cycle batteries come in various sizes. Some are specified by group size, such as groups 24, 27, and 31. Basically, the bigger the battery, the more ampere time you get. Depending on your needs and the amount of available space, there are many options for batteries.

You can use a 12-volt 24 deep-cycle battery that can provide 70 to 85 AH of power.

You can use two 12V 24 cells connected in parallel, which can provide 140 to 170 AH of power. Parallel wiring will increase ampere hours, but will not increase voltage.

If you have a room, you can perform many of the operations of RVer and switch the standard 12-volt battery to two larger 6-volt golf cart batteries. These pairs of 6 volt batteries need to be connected in series to produce the required 12 volts, and they will provide 180 to 220 AH of power. Wiring in series increases the voltage, but does not increase the ampere-hours.
If you still can’t meet your requirements, you can use four 6-volt batteries in series/parallel to build a larger battery pack, which will provide you with 12 volts and double the AH capacity.

The two most common causes of RV battery failure are undercharge and overcharge. The undercharge is due to the battery being repeatedly discharged between cycles without being fully charged. If the battery is not charged, the sulfate material adhering to the discharged part of the plate begins to harden into crystals. Over time, this sulfate could not be converted back to the active plate material, and the battery was damaged. This can also happen when the battery remains discharged for a long time. Sulfate corrosion is the number one cause of battery failure. The second major cause of battery failure is overcharging. Overcharging of the battery can cause severe moisture loss and plate corrosion. The good news is that both of these problems can be avoided.


Batteries are essential to any RV power system and the batteries you choose and the way you maintain the batteries can make all the difference when it comes to enjoying your RV lifestyle.

Share now

Leave a Reply

Your email address will not be published.