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Author Topic: RV 12 volt system.  (Read 460 times)


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RV 12 volt system.
« on: September 13, 2017, 05:25:46 PM »
I am a little confused as to how the electrical system works in my 2000 Tiffin Allegro that I just bought. Our slide out was having problems. It wouldn't initially go out then it did. The next day, we couldn't bring it back in. The motor just made a tapping noise. I called a mobile rv repair guy and I did explain the 2 6 volt golf cart batteries seemed older and were corroded. He said most likely the problem is not enough amps. I ran the engine like he told me and was able to bring the slide out in.  To make a long story short, I went and bought two brand new 6 volt golf cart batteries. Installed them just as they old ones were ( I took pics) and then tried to open the slide out. It didn't work.  I ran the engine for 20 minutes and it worked.  I guess it's possible these new batteries sat for a while and were not fully charged.  So my question after this long narrative is this.  When I'm plugged in to the campground electrical, does it, or does it not charge these batteries?  I'm hoping at some point these new batteries will be fully charged and I will not have to go through this every time. 
Thanks to anyone who can help me with this issue.


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Re: RV 12 volt system.
« Reply #1 on: September 13, 2017, 05:56:56 PM »
If everything is working as it should, then yes, the "house" batteries get charged when you're plugged into shorepower.
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John From Detroit

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Re: RV 12 volt system.
« Reply #2 on: September 13, 2017, 06:12:06 PM »
New batteries always say "Charge before using" Always.  Unless you specifically ask the store to pre-charge them for you. (Some stores do that).

And yes corrosion on the connections will limit current and make it not work.. Wish my fix was that simple but we have not even LOCATED the blasted failed part.. Not a problem. I'll make my own
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Larry N.

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Re: RV 12 volt system.
« Reply #3 on: September 13, 2017, 06:17:06 PM »
You don't mention what your rig is, but many RV manufacturers recommend that you have the engine running when deploying the slides, just to handle the electrical load (of course plugged in should work). So even with fresh batteries, especially if they're not fully charged, a little corrosion on the contacts, perhaps other dirty connections somewhere, could easily rob you of enough power to operate the slides fully.

From a practical standpoint if everything is right, then you should be able to operate the slides when plugged in to shore power, and you shouldn't have to run the engine for 20 minutes before you're able to operate the slides. So you'll need to troubleshoot the system to find what's not right.

So, assuming you have a voltmeter, check the voltage on the battery terminals when plugged in -- I'd expect at least 13.4 volts, perhaps a bit more, if it's charging. If you get much less than that, then there's no charging taking place.
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Re: RV 12 volt system.
« Reply #4 on: September 13, 2017, 09:41:13 PM »
I had a bad ground connection on my fifth wheel that caused a similar problem. Low current items like lights and the fridge were fine, but the heavy current draw of the slide motor was too much and it would frequently fail until I found and fixed the problem.
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Re: RV 12 volt system.
« Reply #5 on: September 14, 2017, 08:01:17 AM »
Chances are your slide is powered from the chassis battery instead of the house. This is the case in most all later years, and for some 2000's as well. If the slide works fine with the engine running but just clicks or tap-tap-tap without it running, then the chassis battery is probably the issue. Could be the battery itself, or the slide wiring to it.
Gary Brinck
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Re: RV 12 volt system.
« Reply #6 on: September 14, 2017, 08:13:24 AM »
Gary is right, Tiffin products usually power the slides from the chassis batteries. And no, being plugged in will not automatically charge the chassis batteries. Plugging in to shore power will charge the house batteries, but older units may or may not have a charging circuit that will trickle power over to the chassis batteries while the rig is parked.  You can add a simple trickle charger off of your house batteries that will charge your chassis batteries when parked.

You can also call Tiffin customer service at 256-356-0261 and ask to speak to a customer service tech. They can tell you if your year coach has a battery trickle charger for the chassis batteries or not. 
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Re: RV 12 volt system.
« Reply #7 on: September 14, 2017, 10:36:22 AM »
Ours is a Winnebago, and as others have said, our slides are connected to our chassis batteries. Our owners manual specifically says not to operate the slides unless the engine is idling. We've got two fairly strong chassis batteries, but even so, they aren't powerful enough to move our two larger slides in or out on their own. My suggestion is, if your slides operate correctly while the engine is idling, idle whenever you operate them.

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