RV Battery Issues – Understanding Your RV’s Electrical Systems

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When it comes to enjoying all your RV has to offer, you also need to be aware of problems that can occur.  And some of these can make for a terrible RVing day!  RV Battery issues are something that falls into this category.  With a little basic understanding, you will find that you can maintain the health of your RV’s 12-volt DC system and remain a happy camper!


In traveling the country in our RV, and speaking with many folks about their RV problems, we find a common theme. It appears to be a lack of understanding of how an RV’s electrical system works.  And, the RV battery is a big part of the electrical systems in an RV!

RV Battery Issues


How Many Electrical Systems Does an RV Have?


Your RV has three electrical systems!  First, you have a 120 volt AC (alternating current) electrical system known as your shore power.  This electrical system becomes active when you either plug your RV into a fifty, thirty, or a twenty amp power source.  This electrical system will control the power needs of your major appliances and allow for charging of one or more battery systems.  And, on some RV’s you can create this electrical power source from an external or onboard generator.  Please be aware of the amperage requirements of your RV when choosing a shore power source!


The second RV electrical system in an RV is the chassis 12-volt DC (direct current) system provided by an auto battery.  This system controls your tail lights, marker lights, brake lights, electric wheel brakes, engine starter motor and dash accessories.  It does not matter whether the RV is a towable or a motorized unit, it still has this electrical system.  It just may not be attached to the RV all the time!


The third and most important electrical system in the RV is the 12-volt DC RV house batteries.  They are located onboard the RV.  This system is powered by either a 6 or 12-volt DC deep cycle battery combination.  They are hooked together in either a parallel or series combination to create a strong 12-volt DC source.


Now here is where the confusion sometimes occurs!  Most things inside your RV will not work without a properly functioning 12-volt DC house battery system.  And this is where RV battery issues can occur because of a lack of understanding of how this system works, and its interaction with the 120-volt AC system.  Stick with me here!  I may be able to save you from a potential problem!


For your 12-volt DC house battery system to function, you need good batteries as well as a way to charge them.  That is where your RV’s power converter is used.  When plugged into shore power this device is converting 120-volt AC power into 12-volt DC power.  I think of the converter as the main 12-volt DC power system along with the house batteries, and that these batteries function as your backup, or the piggy bank if you will.  If the piggy bank is nearing empty, then the power converter will have a hard time keeping up with the demand when many 12-volt DC systems are being used. This situation may lead to systems not working properly!

RV Battery Issues


When disconnected from shore power you can run your 12-volt lights, your water pump, your gas furnace, and even some electrical devices if you have an inverter.  This device takes your 12-volt DC power and converts it to 120-volts of AC power.  But during use, the piggy bank will empty quickly without being recharged by the power converter.


You need both a properly functioning set of batteries and a working power converter!  Do you know where your power converter is?  Do you need to to be sure it is doing its job?  Not necessarily!


Do you need to know where the house batteries are located?  Yes! One of the main causes of RV battery issues is the lack of a proper maintenance schedule for them.  They may require water to be occasionally added for the chemical reaction to continue to occur in creating DC voltage.  If water is not checked and added on a regular basis, the RV’s house batteries will deteriorate and not allow many of the needed systems to function in the RV!


Have you ever been inside your RV when the 120-volt AC power went out?  Perhaps you had your 12-volt lights on and noticed just as the 120-volt power went out the lights also dimmed.  This could be an indication of either a power converter problem or weakened batteries due to age or neglect.

RV Battery Issues


Without a properly working 12 volt DC house battery power source the RV interior lights will not work, the water pump will not function, the appliance control boards will not have the power they need to allow the gas/electric refrigerator to work, the air conditioning units will not function, the furnace will not provide heat, and the slide outs and leveling systems will not function. Even if the RV is plugged into a 120-volt AC source, those items will not work if there is a problem with the RV’s 12-volt DC house battery system.  Do you know where all your 12-volt fuses are located?


Pam and I have been traveling the country in an RV for fifteen years and have enjoyed full time RV living for eight of those years.  We have learned a lot of things the hard way, and some things by the mistakes of others.  As we travel and talk to other RVers, we find this topic is quite difficult sometimes to grasp.  It is even difficult to thoroughly cover it here in about one thousand words!  I will have more on this topic in future articles.


Avoiding RV Battery Issues!


What can you do now to keep your 12-volt lights on and appliances operating?  Please, check your batteries regularly!  Be sure they are at the proper water level.  Some of these batteries are hard to get at but take the time to check them and fill them as needed with distilled water.  Also, clean any corrosion you see developing on the battery terminals.  This will add extra resistance to the system that you do not want to have!


If you know how to use a voltage meter you can check the house battery voltage with your RV disconnected from the AC electrical source.  Compare that to a battery voltage reading with the power back on and the power converter operating.  This test can reveal a lot of information about the health of your RV’s 12-volt DC house battery system!  I will discuss this topic further in a future article.


In summary, to avoid RV battery issues, be sure to check them on a regular basis!  If you use your RV all the time, make it part of a regular maintenance program.  Check them once a month.  If you notice maintenance is needed more frequently, do so.  If you only use your RV occasionally then you must be sure your RV batteries remain charged, the battery water levels are adequate, and that they free of corrosion. That way, when you are ready to hit the road, so is your RV!


Do you want to know more about how your RV works?  Do you want to be able to fix eighty percent of the problems in an RV that are easy to access and easy to fix?

Please click here for more information.  You can learn most of the things you need to know at your own pace in the comfort of your RV Home. 


Thank you!!


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    • Norm on August 14, 2022 at 12:19 PM
    • Reply

    We just purchased a used 2000 Damon 3670 ultra and are having battery issue.
    I just replaced all four 6 volt batteries, i cleaned the converter/charger terminals. i am plugged in to
    220 shoreline and things are running accept the batteries will not stay charged, I have to start the diesel engine
    to charge the batteries in order for the brand new Refridg to stop beeping and the Slide out wont work sometimes


    1. Hi Norm! It sounds like your converter, the battery charger, is not working. I would check that.

    • Wally on July 30, 2022 at 5:07 PM
    • Reply

    I removed my house batteries to charge, had some spark’s issues disconnecting, and everything went dark. I found and reset two inline protection breakers, one under the battery tray and one behind the converter. Most everything powered back up except for a battery monitor, in house radio, and the cab radio which has a backup camera. Any thoughts about what I’m missing, checked al fuses and replaced two in the panel under the bed. This is a 2017 Thor 29fe. Thanks.

    1. Hi Wally!

      I am wondering why you did not use the converter to charge the house batteries. That’s its job.

      At this point you probably still have a chassis fuse that may have blown for the cab radio and backup camera.

      As far as the battery monitor, if you can, disconnect it’s power cable and reinstall and see if that helps.

    • David Everson on May 15, 2022 at 7:34 PM
    • Reply

    We lost shore power while we were gone for a couple of days. When we got back, shore power had been restored but the converter fan was running and wouldn’t shut off. The RV battery was hot to the touch. I unplugged the 30 amp inline fuse in the battery box and the converter fan stopped running. Is my RV battery dead? Thanks

    1. Hi David!

      I would have the battery load tested at a battery store to see if a replacement is needed.

    • JJ on October 27, 2021 at 3:33 PM
    • Reply

    I have a 2017 Thor citation 24SS RV will not run off the house batteries house batteries have been checked tested good why will nothing work off the house batteries all works when plugged into shore line

    1. Did you trip the battery disconnect switch?

    • Julana on April 22, 2021 at 11:08 AM
    • Reply

    Hello! We have a 2021 toy hauler. We have four 6-volt batteries and for some reason the panel in the trailer is saying dead batteries but when tested we are getting full voltage. Our furnace would not come on last night and we froze! Once we started the generator the furnace worked perfectly. Any idea why batteries would show full and the trailer is showing dead?

    1. Hi Julana!

      What is the voltage of the batteries with the RV plugged into shore power or with generator power. Then what is the voltage of the batteries with no generator or shore power?

    • Frank on August 9, 2020 at 11:57 AM
    • Reply

    Hi I have 2 brand new 12v batteries both coach and chassis battery lights are on showing they are good but when I turn the key to start engine absolutely nothing and the chassis light turns off?

    1. Hi Frank!

      What chassis is your RV on?

    • Ron Heimer on May 6, 2020 at 2:47 PM
    • Reply

    I had checked my house batteries a few days before a trip. I did not plug into shore power until the day before the trip. We drove about 6 hours to our summer base and was storing the RV. After three days I went to put out a slide and nothing. I don’t have shore power available here. I checked the battery levels from the inside panel and it said less the 2 volts. I went out to look at the batteries and found them to be low on water, just barely over the plates. Any thoughts?

    1. Hi Ron!

      Thanks for stopping by our website!

      You could try filling the batteries with distilled water after removing them from the RV, hook them to a charger, and then once they are charged have them load tested by a place like Batteries Plus to see if they are still good.

      Let us know how it turns out!

    • Hiram Schoonover on March 8, 2019 at 7:58 PM
    • Reply

    I converted a hi low trailer into a reptile trailer. I came in and found the trailer ripe with the smell of rotten eggs. I search thirty minutes in the fumes, sniffing cages, checking the gas lines. Then i did an external inspection with two other folks. We found the issue. Our battery at the front of the trailer was smoking, kicking off noxious fumes. We have it connected to the trailer still but also have the trailer drawing power from the house. Not sure what happened. Got any clues?

    1. Hi Hiram!

      Diagnosing the fumes from the battery would depend on what was going on with the trailer at the time: what was it hooked up to, what was in use, etc.

    • laura galvez on November 21, 2017 at 2:13 PM
    • Reply

    I have a 2007 keystone that i just bought to live in within 3 days of using tbe gas furnace it quit working..di you have a idea why? And 2nd i then bought a space heater( regular 1 from Wal-Mart.. but it keeps tripping the breakers. Im plugged in to a full time rv park and the ac is electric and so is the water heater.but the furnace is gas..what do i need to do to solve this problem.? Thank you for any ideas..i had a idea that even though the ac was not actually running it was on automatic so i thought maybe i should turn it completely off and that would give me more power for the space heater..yes or no..? Thank you so much for any info..

    1. Hi Laura!

      Sorry to hear about your issues! You have so many things going on here that I think an onsite RV technician would be in order. You need to have the furnace looked at first. If you are tripping the main breaker you either are exceeding the allowable watts that the electrical service can handle of the breaker is failing. Try turning off most of the electrical demand and try the heater. If it still trips, maybe it’s the heater that’s the problem.

      As far as the furnace, check to be sure you have enough propane in the tank and check the fuse that controls the 12-volt power. If you don’t have 12 volts, nor propane, the furnace will not function. As I said, too many issues possibly for you to handle by yourself.

  1. RV power management device controlling the Microwave and fireplace … can you tell me where it is on an forest river ultralite and who makes one that I can replace mine with? Microwave works but no power to the fireplace on the outlet.

    1. Sorry Art! I am not familiar with that RV and the RV power management device you are referring to. That being said, I am sure that the information you need is available through Forest River. Give them a call and see if they can help you out.

    • Beverly on September 3, 2017 at 1:00 AM
    • Reply

    My 12 volt works when the engine is running and i have the dual switch on. As soon as i turn the engine off no more 12 volt lights or panel that shows levels and there is not enough dc power to run the fridge off of propane. I am going crazy trying to figure it out. Batteries are fully charged when i turn the notor on. It is a 1989 super chief class a chevy chassis. Thank you in advance for helping me

    1. Hi, Beverly!

      Can you tell me the voltage of the coach batteries with the engine off and the RV unplugged from the shore power? The batteries may be reading a full charge with the alternator charging them, but depending on the battery age, the actual storage capacity of them may be depleted. If voltage without charging is significantly less than 12.6 volts after ten minutes of the engine being turned off, it may be time for new batteries.

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