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How to Replace RV “House” Batteries (& Chassis Batteries, Too)

How to Replace RV “House” Batteries (& Chassis Batteries, Too)

While the “chassis” batteries start your RV’s engine, it’s the “house” batteries that power the interior lights, vent fans, water pump and other 12-volt equipment. Through the use of an inverter, which converts 12-volts DC into 110-volts AC, they also power the coffee maker, TVs, microwave oven and other household appliances.

Like the rest of our equipment, we take good care of our batteries. But after 6 years of service, we were ready for a new set. We decided to replace the house and chassis batteries at the same time and thoroughly clean and paint the battery tray, too.

We chose to splurge on a set of Lifeline AGM (Absorbed Glass Mat) batteries. They’re direct replacements for our old 6-volt lead-acid deep cycle batteries, with a bank of four, wired in series-parallel. But they’re completely sealed, accept a charge faster and perform better in every way. They’re just extremely expensive!

Since we completed the job in the Phoenix area (where golf carts are everywhere) and there was still some life left in all of our old batteries, we posted them for sale on Craigslist. They were gone in under an hour. The $100 we received from that sale helped to offset a little bit of the cost of new batteries, plus it saved us from having to lug them to a recycling center.

Since it was four years ago, before we started making how-to RV videos, we’ll be demonstrating the process without actually doing the work. But you’ll clearly see how to do this job, which isn’t too challenging for a handy DIY RVer.

If you’re interested in splurging for an awesome (but very expensive) set of AGM batteries like the ones we bought, you can find them on Amazon by clicking the following link. Just be sure you’re sitting down before you look at the prices! ;-)


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CHUCK RAGUSA

Tuesday 7th of June 2022

I REPLACED STARTER RELAY ON MY 1996 FLEETWOOD TIOGA MONTARO. IMUST HAVE GOT WIRES MIXED UP. COULD YOU HELP ME GET MY SANITY BACK? DO YOU KNOW WHICH WIRES GO WHERE? THIS RELAY IS ON RADIATOR WALL BY HEADLIGHT. THIS IS ON A FORD E350 CHASSIS

TheRVgeeks

Tuesday 7th of June 2022

Hi Chuck. Sorry, we don't have any experience with that specific issue/repair, and don't want to steer you in the wrong direction. Our suggestion would be to post your question over on the forums at iRV2.com. There's one specifically for Fleetwood owners, so you can search the forum to see if someone else has already posted a solution... or you can sign up (it's free) and post your question. Here's a link right to the Fleetwood Owners forum: https://www.irv2.com/forums/f107/

Hope you get an answer!

ozeas silva

Sunday 27th of March 2022

Hi everybody! I got a 1990 fleetwood southwind RV but with any kind of batteries, and looks like the place under hood is for 3 batteries. I have no idea if the batteries is 6 or 12 volts, and what kind battery for starting and for house battery. the engine is Chevrolet P30. Any help? thanks ozeas Silva

TheRVgeeks

Sunday 27th of March 2022

Hi Ozeas! Do we understand correctly that your Southwind motorhome has no batteries in it at all? Or does it not have HOUSE batteries? The chassis battery for starting the engine will always be 12 V. If you have a starting battery in place already, and have a spot for three house batteries in addition, that almost certainly is set up for 12 V batteries. That’s because 6 V batteries can only be used in pairs, since they need to be wired together to create the 12 V. For example we have four house batteries wired in series-parallel to create the equivalent of two large 12 V batteries. Any other information you can provide would be helpful.

Barbara Rediker

Sunday 3rd of October 2021

I have the house battery under the hood but I also have a small outside compartment with a battery in it. What is it for? I have a1995 jayco. Class c

TheRVgeeks

Sunday 3rd of October 2021

Hey Barbara. That battery under the hood is you engine (also called “chassis”) battery. It’s what’s needed to start the engine and to run the headlights, wipers, and other “automotive” electrical loads.

The other battery you found should be your “house” battery. That’s what powers the RV electrical loads. So the interior lights, water pump, vent fan(s), etc.

Habib

Monday 30th of November 2020

Hi guys, thanks for all the information and advice you are providing. I own a 2015 Thor Palazzo 33.2 and it's been sitting for a long time (9 months) up to few weeks ago I could started just fine. but since last week I plugged in the outlet to get it charge, but it seems like instead of charging it drain it completely. I looked all over (places I could check) but nothing I could find that shows it's a problem. What can I do to fix this so I can start the rig and take to a shope. Thank you for any advice you can give me.

TheRVgeeks

Monday 30th of November 2020

Hi Habib! Sorry to hear that you're having trouble with your Palazzo. We're not that familiar with your particular RVs wiring (and, unfortunately, every manufacturer does things a little different), but we did look on the Thor Palazzo Owner's Forum over on iRV2.com (https://www.irv2.com/forums/f281/) to see if we could confirm if your RV has a similar system to ours =(it's called a Bi-Directional Relay Delay... or "BiRD" for short) for charging the chassis battery when you're plugged into shore power... and it seems like it should. So... it sounds like yours isn't working the way it's supposed to.

That said... you have 2 options for getting things working so you can get the RV into the shop:

Check on your dash (probably to the left of the driver's seat) for a switch that says something like "Batt Boost" or "Aux Boost". That switch should trigger a relay that connects your house and chassis batteries together... and is designed to let you use your house batteries to start the engine in an emergency (like when the chassis battery has gone dead). So if your house batteries are charged, that should work to allow you to start up the coach so you can get it into the shop. You could put a standard battery charger on the chassis batteries to see if you can get them charged up enough that you can start the engine.

Hopefully one of those two options will get you going so you can get this problem fixed!

[email protected]

Saturday 9th of May 2020

Hi! How do I know what type of battery to use for chassis starting battery? My 30ft RV has a 1986 Ford E350 chassis, do I need a 29group deep cycle marine/RV batt to start it? Or what?? I have been driving it for 5yrs and parked it a year ago and need a new battery now

TheRVgeeks

Saturday 9th of May 2020

Hi Mama Moonlit. No, your RV's starting battery does not need to be a deep cycle battery. Quite the opposite, you want one with the correct "Cold Cranking Amps" (CCA) rating to ensure it has enough amp output for the sudden boost needed to crank an engine (while deep cycle batteries are designed to provide lower power outlet over a longer period of time). You'll want to check the battery currently in the engine bay and look for the label to determine the Group Size and CCA rating... then get a replacement to match. If you can't find/see the label, any major auto parts store or auto battery supplier should be able to look it up. Or you could try calling a local Ford dealer to see if they can tell you what specs your battery is.

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