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What Does a 12 Volt Battery Disconnect Switch On An RV Do?

by Dieter
(Lompoc, CA, USA)

What a battery disconnect switch does in an RV

What a battery disconnect switch does in an RV

How does the 12-volt battery disconnect work? I have lost 12-volt power on our 2006 Four Winds Hurricane.

ANSWER: Hi Dieter, a 12-volt battery disconnect switch is used to shut off all 12-volt power in the RV. When the switch is activated the batteries are disconnected/isolated and no longer supply 12-volt power to the house portion of the RV.

A Factory Installed Battery Disconnect Switch is usually a rocker switch that is located in the RV marked as "Battery" or "Battery Disconnect" or any abbreviation of those words. There are also Aftermarket Battery Disconnect Switches (like the one pictured at the top of this page) that can be installed directly on the house batteries.

For those of you that do not have a battery disconnect switch on your RV, you should watch the video below to see how easy it is to install an Aftermarket Battery Disconnect Switch on your RV.

To instantly download the RV Education 101 Videos available from RVing Expert Mark Polk featured in the video below, visit the RV Education 101 Video Download Store



If you find out that your problem is not caused by an activated Battery Disconnect Switch it could be that your house batteries are no longer holding a charge or no longer being charged or even a blown fuse. The problem could also be caused by low electrolytes in the batteries or loose connections on the batteries.

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I hope this helped.

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

Happy RVing

RVing Al

Comments for What Does a 12 Volt Battery Disconnect Switch On An RV Do?

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Rating
starstarstarstarstar 		battery disconnect
by: Dave

will the solar system still charge the batteries with the switch off?
Rating
starstarstarstarstar 		Need Batteries On
by: Ken


RV Solar Panels

Keep those batteries on when plugged in that's how they stay charged also I have two solar panels on the roof and when drydocking that's how I keep my batteries up. The RV can use a lot of power and the deep cycle 6 volts don't like being taken down low and back up again and again.
Rating
starstarstarstarstar 		Reply to.....
by: Sparky

...Battery disconnet switch
by: Anonymous

Know what battery disconnect switch DOES, but have conflicting views on whether or not it should be turned to off position when on shore power. Your answer? Thanks.

That's a good question, here's my opinion. When traveling your batteries should charge while connected to the tow vehicle, but if there's any problem with that charging circuit ( blown fuse, corrosion, etc...) you may not have fully charged batteries when you get to your destination connect to shore power. You wouldn't know what state your batteries are in unless you have reliable metering to show you (I never trust the idiot light on my display panel). I live in my RV for weeks at a time when working on job sites away from home and had the following situation happen to me, with the batteries switched to off. I was working 12 hr days, 2nd shift and it was colder out (in the low 40's at night) I got back to my RV at around 8 am one morning and noticed my LED awning lights were out. When I walked into the camper it was cold, like 45 degrees cold. The main breaker at the shore power box had tripped, and without my RV batteries my propane furnace had no way to run all night while I was at work. My propane refrigerator didn't switch over because there was no 12 volt power to ignite it. Had this happened to me during hot weather I would have lost all of the food in my refrigerator. My RV was cold, I wanted a hot shower and sleep but had to wait a few hrs for the RV to warm up and the water to be hot enough for a shower. Now I never turn my batteries off while on shore power and using the RV, just when I park it at home when not in use, unless we still have food in the refrigerator. When I get home from any trip I plug into shore power and leave my batteries on for a day or two to fully recharge them, then switch them off until the next trip.
Rating
starstarstarstarstar 		Check circuit breakers as well.
by: Anonymous

We had issues with very low power from our battery to the converter. We had just replaced the converter and everything had been working for a few days so we knew that was not the problem.

We had the battery tested, it was fine. We checked all the grounds. Everything was fine. However we were still getting almost no power to the 12 volt system when the shore power was disconnected. We ventrally tracked it down to two small circuit breakers mounted near the battery. (These are about an inch and half long and a half inch wide and have two posts with screws. You can find yours by tracing the positive battery connection back.

Both our circuit breakers were badly corroded and filthy and full of spider nests. When we disconnected them to try to clean them we found one had an internally broken post that was floating loose sometimes connecting sometimes not.

We replaced them using 30 amp circuit breakers from an auto body shop and the problem was solved. While we were at it, we also changed the open housing and made them much more weather, dirt and spider proof.
Rating
starstarstarstarstar 		RV battery
by: Darrell

I have had batteries that were continuously connected, to run dry and ruin.

That rotten egg smell is from overcharging. RV's before slideouts, used to have a switch at the battery, so you could turn off the charge from the converter.

This doesn't effect any thing else in the rv. 12v is then supplied by the converter. (correct if wrong,pls)
Rating
starstarstarstarstar 		YES, disconnect those batteries
by: Anonymous

My 5th wheel have 12v and 30amp 110v, I live in trailer and leave it plugged in all the time with little use for my battery. I have always left the battery hooked up with no problems except having to check the water level quite often. The only 2 things my battery operates besides lights and water pump when dry camping, are the slide in and front landing gear.

The other night I went to bed and a few hours later was awakened with an electrical smell, after searching inside, I finally tracked it down to my battery compartment, opened the door only to get a face full of smoke (no flames yet), I quickly unplugged the shoreline, grabbed a rag and pulled off the battery cover to find that the positive side terminal and wiring were at total melt down,

I reached down and ripped the wires off the battery which were fused together, this stopped the smoking, reconnected the shoreline, everything worked inside except the slide in and landing gear. Took me until early morning hours to get rid of the wire smell inside enough so I could sleep.

After I repair all the wiring I need to do, I plan on putting a quick disconnect in line to eliminate any 12v problems that might catch me by surprise. The burned wiring goes to the hydraulic pump of the slide out, haven't figured that problem out yet,
Rating
starstarstarstarstar 		Keep it on
by: Emilio of Niagara

Keep the switch in the on position all the time. It needs to be on when connected to shore power or gen is running so that the batteries could charge also some of the electronics use 12 volt. Only shut it down when storing of when fueling up gas or propane. This works for me Emilio
Rating
starstarstarstarstar 		Battery disconnet switch
by: Anonymous

Know what battery disconnect switch DOES, but have conflicting views on whether or not it should be turned to off position when on shore power. Your answer? Thanks.

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