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Old 07-07-2012, 02:09 PM   #1
1 Rivet Member
1973 21' Globetrotter
Virgin , Utah
Join Date: Jun 2010
Posts: 15
Risk of draining truck battery (is there ?)

Just installed a new converter, fuse block and 'battery minder' - the battery minder is so revealing of where and what is draining the power.

When I hooked my truck and started the engine, I noticed I was getting a charge to the A/S battery - which is fine I guess - as it helps to recharge when on the road.

The question is, when parked up (and still connected ie: truck to A/S) is there a risk of the truck battery draining down too - would utilities in the A/S pull power from both batteries ?


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Old 07-07-2012, 02:23 PM   #2
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1991 34' Excella
Princeton , New Jersey
Join Date: Aug 2003
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I think it depends on the age of your TV. Newer truck isolate the TV from the trailer when the TV is turned off. Older TV will supply current to the trailer with the ignition off.

Yes if you are hooked up for a prolonged period you may have a dead battery in the TV with the older systems.
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles

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Old 07-07-2012, 06:47 PM   #3
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2010 27' FB Classic
N/A , Texas
Join Date: Apr 2008
Posts: 1,806
Likewise, if the trailer is plugged into shore power and the trailer and truck are still connected with the umbelical cord, it should charge the batts in the truck. Right?
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Old 07-07-2012, 07:08 PM   #4
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2005 19' Safari
Join Date: Aug 2004
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Even in older tow vehicles, if the "hot" wire was installed properly, it should have a relay in the circuit that is tied to the ignition switch. When the tow vehicle ignition is turned off, the "hot" line in the umbilical should be dead.

If the hot wire circuit did not include a relay, it can be easily added. Usually, an old Ford starter relay is wired inline between the tow vehicle battery and the umbilical connector. And, this is activated by a wire that runs to some connection that is hot when the vehicle ignition is on. It's probably easiest to have a tech at someplace that installs hitches do this for you (e.g., U-Haul). However, the actual installation is very simple.
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