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 DVDÂ Deep Cycle Batteries. Also check out RV Education 101.
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Brian touched on the issue of trickle chargers and I agree. That is only temporary. Batteries need to be exercised. I use a Battery Minder 12V maintenance charger with full-time desulfator (Model 12) when needed. If you leave it plugged in all the time, this would be better than a trickle charger (my opinion), and I leave this on my motorcycle that rarely gets ridden right now. Always make sure the battery type is compatible with your charger.
Does this battery life advice apply equally to Lithium batteries? We recently replaced AGMs with Battleborn lithiums and the associated hardware to monitor them properly. Love their performance and the ability to discharge further than AGMs without worry.
Can I install a 12 volt AGM battery in my Jayco travel trailer in place of a deep cycle battery? Will my inverter be ok charging the AGM?
First question: Are you using an INVERTER / CHARGER in your RV?
If so, you will need to confirm that the Device is capable of Charging an AGM Battery.
For instance, I have a MAGNUM Inverter / Charger in my RV, which has 2 setting for AGM Batteries. I had to call MAGNUM to ask which setting to use, based on my brand battery, (OPTIMA BLUE TOP) since it is NOT listed in the manual!
Hope this helps!
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?
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.
Yes, disconnect your house battery(s) from your RV’s converter/charger and hook up a battery tender as Gene C recommends. The only thing worse than letting a battery go flat from not charging it, is boiling out the electrolyte by leaving a trickle charger on it for months at a time.
On my sports car I left the dome light on and it drained the Interstate battery to where a battery charger wouldn’t charge it. Hooked up a Battery Tender and suprisely after a few days it charged up the battery. Got almost five more years out of the battery.
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?
Here’s part of the article: “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 its 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.” That sounds to me like a tip to “extend the life of an RV battery.” Thanks for writing, Laura. —Diane at RVtravel.com
I am a little confused by this. Is that cycled to 80 percent meaning down to 20 percent of the full charge?
Hi, Snayte. That’s what it sounds like to me — but I’m no expert on this subject. (My battery expertise is inserting batteries into a flashlight in the correct direction. 😀 ) —Diane at RVtravel.com
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.
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!
So, I leave my RV unattended with the solar hooked up all the time. Is this article saying I am doing it wrong because it doesn’t run down the batteries to 50% each night? I have two 6 volt Crown batteries that are now five years old and they perform as well now as the day I installed them.
No, he’s saying that when you use your batteries if you recharge after you have only depleted them by 50% they will last twice as long as if you recharge after depleting them to 80%.
The wording had me re-read it myself.
One little mentioned problem with leaving batteries on tenders or trickle chargers that do not periodically “load” the battery can lead to dendrite growth which can eventually short the plates. A lead acid battery under constant charge needs to be loaded periodically to break the dendrite growth off the plates where it will fall to the bottom of the container, below the plates.