Monday, December 4, 2023


RV batteries more important than anything else in the rig? Yup

Steve Savage submitted this article to when he was a Master Certified RV Technician with Mobility RV Service.

Question: I have heard the batteries in my RV are more important than almost everything else in the RV. Why?

Answer: What you have been told is spot on. There is no way I can over-emphasize how important the batteries in your RV are.

The house systems in every RV depend on 12-volt power, and some systems will not work without a good battery (for example some slide-outs), even when plugged into the shoreline. I have found many RVers have a difficult time understanding what components require battery power and which require the RV to be plugged in. It is perhaps easier to say the systems that do not require batteries.

As a rule, anything – other than the entertainment system and the microwave, including any air conditioner with a thermostat on the wall – needs the batteries. That is because the controls all work on 12 volts. When plugged in, the converter can handle most of the 12-volt loads; however, when loads peak the battery comes off the bench and provides the additional power.

Simply put: When things don’t work, check the batteries and fuses first!


Emily Woodbury
Emily Woodbury
Emily Woodbury is the editor here at She was lucky enough to grow up alongside two traveling parents, one domestically by RV (yep, Chuck Woodbury) and the other for international adventures, and has been lucky to see a great deal of our world (and counting!). She lives near Seattle with her dog and chickens. When she's not cranking out 700+ newsletters for she's hiking, cooking or, well, probably traveling.



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Don Corrigan (@guest_88155)
3 years ago

I don’t know if this has been asked in the past or not. If so, sorry for the repeat. I have been full time RV living for the past two years but felt forced to purchase a sticks and bricks because of this virus. Anyway, my question is i have a fifth wheel that has 2 batteries. My brother in law recommended that i purchase a 30 amp adapter and another adapter to connect to my house plug just to keep the batteries charged. Is this safe? Will this method actually charge my batteries??? I also have a 50 amp surge protector. Thanks for your input!

Bob P (@guest_110850)
2 years ago
Reply to  Don Corrigan

Your batteries will discharge over time, it the RV is going to be parked for extended periods it would be advisable to keep it plugged in. If you’re only going to be parked a short time you can turn the master disconnect off, but it does disconnect everything that is powered by 12 volts including presets in your entertainment system.

Dennis Noon (@guest_69546)
3 years ago

My motorhome will charge the 6 Volt batteries but not the 12 volt batteries. Does anyone have any ideas what could be wrong?

Cinerama (@guest_71237)
3 years ago
Reply to  Dennis Noon

Are you talking about the MH alternator or shore power?

Tom Malia (@guest_68416)
3 years ago

I have a question about batteries! I have two sealed 12 volt batteries that in the off season(Maine Don’t Cha Know!) I keep on a charger and alternate between them! They have only been used one season and it seems that they lose their charge after about a week! Have I or am I doing something wrong? Will they be ok for this coming season?

Joe Sesto (@guest_68417)
3 years ago
Reply to  Tom Malia

In a related low mileage use situation I put a Battery Minder (not a battery charger) on my Corvette that got 13,000 miles in 12 years. The factory battery lasted 9 years. I have 2 AGM batteries on my camper and the solar panels have kept their Battery Minder on top of their status for 5 1/2 years. Battery Minders cost about $50 and keep a constant voltage they also have a feature that helps desulphate conventional battery cell plates.

PS I’m in California…plenty of sun year round. The Vette was garaged so it was plugged in 24/7/365.

Cinerama (@guest_71234)
3 years ago
Reply to  Tom Malia

Totally agree with the BatteryMinder. The new ones have a “pulse” technology instead of high voltage to desulfate a battery. My pickup battery would also go dead within a week if I didn’t drive it. I purchased the largest BatteryMinder (4/6/8 amp model) @ $160, put it on the pickup battery for a week. The battery stays charged for at least a month now. I have since used it on ALL of my batteries (MH, two cars, and even my wife’s scooter AGM batteries).

Michael Weaver (@guest_68388)
3 years ago

I am a RVIA master certified tech 26 years in the industry yes batteries are the most important and yet the most neglected item bar none

Dick and Sandy at the NHRA Gator Nationals (@guest_68380)
3 years ago

On some Class A DP coaches, the 12 volt House batteries operate some of the dash controls. This may include but not limited to the AC, Heater and Defroster, the Power Windshield Shades, Windshield Wipers and others. These and other controls are all installed by the manufacture of the Motor Home on their Chassis of choice that uses the Chassis batteries that do not come from the Chassis Manufacturer with any dash installed. The maintenance of both the House and Chassis batteries as well as proper tire inflation is foremost in operating any motor home.

Robert Love (@guest_68368)
3 years ago

Forgot the brakes! If the trailer is disconnected while driving, the battery is necessary to put on the brakes to stop a run-away trailer.

Herb Goff (@guest_68421)
3 years ago
Reply to  Robert Love

exactly – that is the most important function of the battery – of course you won’t need it until you need it….

Dan D (@guest_68361)
3 years ago

I agree. Batteries are very important and they do require some maintenance. I just wish the clever “designers” that put our RV together would have found a better place for the house batteries. All I’ve got is a small door to barely access the battery posts. It’s a real pain to assure that the cables are tight, plus they are always covered with rock and dirt. No protection from the elements.. Worst of all, I have to use a motorcycle jack to change the batteries from below. Even worse is access to some of the plumbing and that noisy, green boat anchor that says Onan on it. Live and learn. Our next one will have to meet every point on a checklist.

Bob P (@guest_110854)
2 years ago
Reply to  Dan D

Totally agree on the placement of various parts on a RV, our first class A Bounder the house batteries was behind a small door behind the left front tire requiring several parts of the opening be removed to remove and install replacement batteries. And the placement of the generator under the head of the bed ??? There is one manufacturer that requires their engineers to live with their designs before it goes into production but I can’t remember which one it is.

JBC Cripps (@guest_68344)
3 years ago

Hmm, should there be something here that references the GFCI outlet and resetting it if there is an outage? This was the problem when a toaster inadvertently was turned on overloading the system. It was not a fuse as first thought – just had to reset the GFCI and all was back up and working. Fortunately the GFCI was working. In this case should this be the first thing to check and then the fuses and battery? Thanks

Drew (@guest_68357)
3 years ago
Reply to  JBC Cripps

Good reminder, but since this article was dealing with batteries it wasn’t covered. GFCI’s are part of the 120v system.

Bill T. (@guest_68318)
3 years ago

Hi Steve. When you said “As a rule, anything – other than the entertainment system and the microwave, including any air conditioner with a thermostat on the wall” I just wanted to ask for clarification on this since my air conditioner needs 12V to run the thermostat on the wall. The on/off controls for the A/C unit are DC operated. Without it, my A/C unit won’t turn on. Thanks.

David Cloer (@guest_68413)
3 years ago
Reply to  Bill T.

Just camp fire talk but research using 2 or more 6 v batts ..just thought? Longer reserve deeper cycle…lighter and cheaper

Wayne (@guest_83435)
3 years ago
Reply to  David Cloer

Or 12 volt lifepo4 (lithium iron phosphate) batteries if your budget allows.

Bob P (@guest_110857)
2 years ago
Reply to  Wayne

Before you make that decision you need to determine if your converter is rated for these type or you will experience more costs than you thought.

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