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Author Topic: 6volt batteries discharging while towing  (Read 260 times)

Brookskat

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6volt batteries discharging while towing
« on: November 08, 2017, 07:46:21 AM »
Could anyone tell me why my 2 (6 volt) deep cycle batteries are discharging while towing in my RV. The one time the trailer was hooked up to the truck for 3 days and my truck batteries were dead. Any help appreciated. Kathy. The batteries we had prior to these worked fine.
« Last Edit: November 08, 2017, 07:53:04 AM by Brookskat »

Gary RV_Wizard

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Re: 6volt batteries discharging while towing
« Reply #1 on: November 08, 2017, 07:58:55 AM »
Could you please explain a bit more? Is it the trailer batteries that are dead, or the truck battery(s). Or maybe both?

You trailer uses some modest amount of 12v (battery) power for things like the LP gas detector. The fridge uses a bit too, if turned on (even using LP gas for cooling).  You may have a few other things that use some power to keep alive, and if you have an inverter it too draws some power unless turned completely off. Can't really address that without a lot more detail about your trailer and equipment.

While connected to the truck for towing and the truck engine is running, the trailer batteries should not discharge at all. However, it is possible that the 12v power wire from truck to trailer was not properly hooked up, or that a fuse is blown in the truck. I do not thing that is the case, since you appear to be saying the trailer drained the truck battery while parked, but its something to verify.
Gary
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8Muddypaws

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Re: 6volt batteries discharging while towing
« Reply #2 on: November 08, 2017, 11:35:52 AM »
Make sure you didn't leave one or more cabinet lights on.

Make sure your breakaway switch is working and no current is going through it with the pin is all the way in.

How old are the batteries in the trailer?
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Arch Hoagland

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Re: 6volt batteries discharging while towing
« Reply #3 on: November 08, 2017, 03:28:10 PM »
There is a wire that goes from the 12 volt system in your truck to your trailer.  I call it the charge line as it charges the trailer batteries while traveling. It's in the bundle of wires that you plug into the truck.

When I pulled travel trailers I purposely did not connect that line in the plug for this exact reason. I never wanted my RV wiring mixed with my truck charging system.

My suggestion is to unplug your trailer from your truck when you are camped.
« Last Edit: November 09, 2017, 12:03:01 AM by Arch Hoagland »
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grashley

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Re: 6volt batteries discharging while towing
« Reply #4 on: November 08, 2017, 05:05:40 PM »
Welcome to the Forum!

It would help if you told us what truck and camper you have.

You have several different issues, I believe.

1.  The dead truck battery was likely caused because the trailer wiring remained connected to the truck, and the truck battery supplemented the camper batteries.  ALWAYS disconnect the wire harness once parked.

2.  The above has established that the truck SHOULD charge the camper batteries while traveling, assuming the same truck.  If it is not charging, it is likely a blown fuse somewhere.  Again, since #1 shows it does not run through the ignition switch, check the wiring harness for 12V.  I believe it is pin 6 to ground, but my memory is not that good!  Someone will correct me if I'm wrong.

3.  As others have said, there will be draws on the battery when traveling.  How much draw depends on what is left on and whether the truck is providing any charge.

I hope this helps!
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Old_Crow

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Re: 6volt batteries discharging while towing
« Reply #5 on: November 09, 2017, 03:17:40 AM »
There is a wire that goes from the 12 volt system in your truck to your trailer.  I call it the charge line as it charges the trailer batteries while traveling. It's in the bundle of wires that you plug into the truck.

When I pulled travel trailers I purposely did not connect that line in the plug for this exact reason. I never wanted my RV wiring mixed with my truck charging system.

My suggestion is to unplug your trailer from your truck when you are camped.

When I was pulling a TT, I had an isolator relay wired into the charge wire.  That way there was no connection to the RV when the key wasn't turned on, so I didn't have to worry about unplugging.
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Old Blevins

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Re: 6volt batteries discharging while towing
« Reply #6 on: November 09, 2017, 10:07:23 AM »
Some trucks turn off the hot wire to the trailer plug when the ignition is turned off, but yours appears not to be one of them.  Your rv batteries are being drained most likely because you have something in the rv thatís pulling more power than your truck alternator can supply.  Hereís how to run that down.
1. Buy a cheap 12V test light at an auto parts store.
2. Unplug your trailer from your truck. Make sure everything in your rv is turned off.
3. Disconnect the ground wire from your trailer batteries.
4. Connect the test light to the ground wire and the battery ground post.  The light will most likely come on, indicating something in the rv is pulling power.
5 inside the rv, pull the 12v fuses for the CO/propane detector and the radio.  Thatís because the detector always pulls power, though itís too little to be causing your problem. Same thing for many radios which have a small power draw to remember presets and time.
6. Check your test light.  If itís off, you probably donít have a problem.
7. If itís still on, doing one at a time, pull each fuse and check the test light.  Leave the fuse out until youíve done them all.  Iíd suggest taking a picture of your fuse panel so you can put them back into the correct slots.
8. When you pull a fuse, if the test light goes out, youíve found your problem circuit.  If itís something youíd expect to pull little power, you probably have a short you need to run down.  If itís something that can pull more power, see if somehow it got left on.

Thatís a start.  Welcome to the exciting world of RV electrical problems.
Jim
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