# 5th wheel killing batteries



## Chris (Oct 12, 2012)

So my 5th wheel has been eating batteries. I have it plugged in at all times and just put two new batteries in it a couple weeks ago. I unplugged it last night and by this evening both batteries are toast. Something is drawing power, what is the best way to figure out what?

It is a 2005 Thor Wanderer 325.


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## havasu (Oct 12, 2012)

I would just install a Perko Battery switch and not worry about it. 

View attachment perko.jpg


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## Otahyoni (Oct 12, 2012)

Is it boiling them out? Since you have it plugged in all the time i wouldn't think the load is the problem. It might be the charger/converter.... Check the output voltage at the batteries.

If it's too high or that's not it, I suggest signing up over at RV.net and asking there.


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## Chris (Oct 12, 2012)

havasu said:


> I would just install a Perko Battery switch and not worry about it.




I would but they die while we are using it throughout the day



Otahyoni said:


> Is it boiling them out? Since you have it plugged in all the time i wouldn't think the load is the problem. It might be the charger/converter.... Check the output voltage at the batteries.
> 
> If it's too high or that's not it, I suggest signing up over at RV.net and asking there.



I'll check that today.


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## havasu (Oct 12, 2012)

Just remember, one dead cell will kill a battery, and one dead battery will kill a fresh battery. 

My son just gave me a report from Lake Havasu. I need 3 deep cycle marine batteries, one quad battery, and 6 six volt golf cart batteries. I should own stock in a battery company!


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## Chris (Oct 12, 2012)

These batteries are brand new and so where the ones before it and they have all been tested. I too should own stock in batteries.


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## havasu (Oct 12, 2012)

The biggest draw in a motorhome/fifth wheel as Otah mentioned is a bad inverter, a direct short, a fridge not shutting off, or a tv cable box or satellite box drawing juice. Since I hate electrical problems, maybe a quick trip to an auto-electric shop who can trace the amp draw for a few bucks?


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## Chris (Oct 12, 2012)

Yeah I have everything turned off or unplugged, there is not to many 12v things on the coach so it shouldn't be to hard to trace. My bathroom vent fan switch went out a year or two ago so I am going to start there and hope but whatever it is it is drawing juice pretty quickly. Once I get this meat off the smoker I will have a chance to get out there and work on it.


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## havasu (Oct 12, 2012)

Did you do any drilling, screwing or modifying to better trace a possible short? Maybe something underneath the coach that is pinching?


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## Chris (Oct 12, 2012)

No, it started this when I left it at someone ranch for about a month, they called me on day two and said the batteries were dead which I thought was odd but they did not plug it in at all for the month it was there after I had thought they did so those batteries were toast and wouldn't hold a charge so that is when I got new ones. I guess I can crawl around under it to see if anything was chewed.


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## Chris (Oct 12, 2012)

So stressed about work today I never made it to the trailer to look things over, maybe tomorrow.


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## havasu (Oct 13, 2012)

I can relate. I went "home" and got into another fight with the money-hungry ex. Not fun.


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## Ecam (Oct 15, 2012)

I'll ask, are you sure the batteries are getting fully charged?  Wonder if the charge circuit is shutting down early.


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## Chris (Oct 15, 2012)

Haven't checked but I would think so, the gauge inside the coach says they are full when I first disconnect it.


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## Ecam (Oct 15, 2012)

Depending on supplier, you might take them back and have them load checked.  Like it was said earlier, one cell can cause problems with a brace of batteries.  A good store should check 'em for free and replace one if bad.


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## Chris (Oct 16, 2012)

Wal Mart was my supplier.

I don't have time to think about them until after my trip, glad I have full hook ups.


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## Gsport (Nov 8, 2012)

i had the same problem on my 2010 cougar... my bet is it's the converter.  easy test. mine was located behind the fuse panel. pull the fuse panel away from the wall and the convertor was there.  unplug the convertor, undo the two wires (maybe 4) take it out and plug it in, check the voltage where you disconnected the two wires, it should be up around 12 volts if i remember correctly.. i took mine out and took it into the RV dealer, they quickly checked it for free, it was only putting out about 3 volts.  they were happy to sell me another.  works fine now
  good luck


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## Chris (Nov 8, 2012)

I will definitely check that out. Thanks.


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## Chris (Nov 26, 2012)

So while camping this last week, no problems with the batteries at all except killing them from running the heater for ever without the generator.

The generator charges the batteries fine but my truck is no longer charging them as I drive. When it is plugged in it is fane as well now. I don't get it.


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## Ecam (Dec 4, 2012)

Check the power at the bumper socket on the truck.  One of the top two termainals is the battery supply (the other at the top is the running lights, with park lights on both should be hot).  On some factory wired rigs, the key has to be in the run position to power up the battery lead.  Most rigs have a fuse or circuit breaker in that circuit - many have relays too.  If it is run through a circuit breaker, the breaker may be weak and "breaking" before it can send juice to the RV batteries.  Circuit breakers are much like old school flashers, the bi-metal spring heats up and opens the circuit, when it cools the ciruit is closed again and the bulbs light and heats the spring again......


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## Chris (Dec 4, 2012)

I'll check into it. I think it has done this in the past and it was a fuse but i could be dreaming of a different truck. This one is my 06 Super Duty V10 with factory tow package.


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