How to extend the life of an RV battery


By Mark Polk
The life of RV batteries varies. Factors include how they’re used, maintained, discharged and recharged, and how they’re stored. A battery cycle is one complete discharge from 100 percent down to about 50 percent and then recharged back to 100 percent.

One important factor to battery life is how deep the battery is cycled each time. If the battery is discharged to 50 percent every day it will last twice as long as if it’s cycled to 80 percent. Keep this in mind when you consider a battery’s amp-hour rating. The amp-hour rating is really cut in half because you don’t want to completely discharge the battery before recharging it. The life expectancy depends on how soon a discharged battery is recharged. The sooner the better.

How this affects you depends on how you use your RV. If you’re plugged into an electrical source most of the time then your main concern is to properly maintain your deep cycle batteries. But if you are dry camping you’ll want the most amp hours.

DEEP CYCLE BATTERIES come in different sizes. Some are designated by group size, like Group 24, 27 and 31. Basically the larger the battery the more amp hours. There are several options. You can use one 12-volt Group 24 deep cycle battery that provides 70 to 85 amp hours or you can use two or more 12-volt batteries wired in parallel. Parallel wiring increases amp hours but not voltage.

If you have the storage space you can switch from standard 12-volt batteries to two of the larger 6-volt golf cart batteries. These pairs of 6-volt batteries need to be wired in series to produce the required 12-volts. Series wiring increases voltage but not amp hours. If this still doesn’t satisfy your requirements you can build larger battery banks using four 6-volt batteries wired in series/parallel that will give you 12-volts and double your AH capacity.

Learn more with Mark Polk’s DVD Deep Cycle Batteries. Also check out RV Education 101.


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Richard Stegner

Question. We have our RV next to the house plugged into a dedicated 30 amp circuit as it is used when we have company. Should the batteries be disconnected (there is a switch to disconnect the batteries – Newmar coach) when plugged into outside power?

Gene Cheatham

Buy a battery tender — they are less than $15 and keep a trickle charge going to the battery to keep it up to snuff. They must be used on a fully charged battery as they are not a charger. Too, keep all the cells in your batteries at the proper level. This will greatly extend their life.

Tommy Molnar

I wish I had ROOM for a couple more 6 volters. I have two Trojan T-145’s, and those suckers are HEAVY!


The headline is about extending the life of batteries, but the article is about battery types. Copy editor, hello?


When batteries are wired in parallel, the weaker one will destroy the stronger one, or vis versa. The pair must be almost perfectly matched to prevent this from happening. Match down to being produced on the same line, same day, same batch.

Joe Bulger

Some things to remember with batteries is
1- when batteries are wired in series if one battery goes bad the whole string of them will appear to be bad.
2- when batteries are wired in parallel the stronger battery will take more charge than the weaker one.
3- clean connections are very important!