Help Needed HELP with trailer charging!!!

[iracemine]

Hey guys I am going to put a 12V battery in my trailer for dry camping. When I am done camping and the battery is discarged, how will the alternator know not to go balls out charging and burn out the wires???

Do I grab the positive of the trailer/brake wire battery terminal?? Or is there some sort of seperate mother board that I need to pick up. Or do I not worrie at all abou that because the alternator takes care of that. I am hoping TG might help out on this one since he was in the RV biss for a while.

 

[Tail_Gunner]

One of the contacts inside the oem factory 7 pin trailer plug in on the back of the truck, is a switched 12v source. Most commonly, it is used for charging the battery in a camper. As set up at the factory, the superduty will have a fuse & relay in the truck to protect the wiring and ensure the trailer battery only charges when the truck is running.

For the trailer to be able to use the battery charging function, it will either have to have a 6-pin plug in or the more common 7 pin plug. If you have just a 4 pin flat connector, then there is no wire/connector provision for battery charging.

The voltage regulator in the truck will prevent cooking your trailer battery just like the truck's batteries.

 

[iracemine]

The voltage regulator in the truck will prevent cooking your trailer battery just like the truck's batteries.

And there's my answer. Man I love this place (and my truck)
was worried that if the trailer battery was way low from a night of TV watching the alternator would go full blast and cook the 12V charging wire or the alternator its self.

Thank you sir!

 

[Tail_Gunner]

No problem, glad to help.

 

[jestersv]

and if you want to know which terminal in the plug does the job look here also a good reference to keep in the glove box.

http://www.hopkinstowingsolutions.com/doc/trailer_wiring_codes.pdf

 

[BIG JOE]

and if you want to know which terminal in the plug does the job look here also a good reference to keep in the glove box.

http://www.hopkinstowingsolutions.com/doc/trailer_wiring_codes.pdf

THANKS.. Printed that.. stuck it in my zippered Owners Manual thingy.

(also added it to my "Favorites" list ?)

 

[iracemine]

OK guys. Time to restart this thread.

Now I have a xantrex 1000W inverter/charger plugged into a group 31 battery. Now this works great for my florescent and tv and satellite radio and all, but only for one night and maybe the a bit of the morning.

However the way I planned on charging the battery was with the truck. But even with a 2 hour trip it barely charges the battery. The voltage at the battery with the truck running is 13.1. The voltage at the alternator is 14.4, is there that much of a voltage drop to be expected through the 10 gauge wires back to the trailer???

Is this normal? Do all of you guys that RV just charge your house battery's through the generators and shore power???? Or am I doing something wrong.

Thanks again guys.

 

[Stroked68]

Look into a solar charger or wind turbine. Both would work great when camping. The solar charger would work some on cloudy days too. They've come a long way. You could get a really big one that would charge yer battery no prob and you can use yer inverter.

 

[Tail_Gunner]

10 ga. wire is pretty stout for a 12v system. Voltage drop with that gauge wire should not be an issue. But there are other things to keep in mind.

Your electrical system has to have a return path i.e. ground. If the ground is not up to the same capacity as the 10 ga. supply line, you will see voltage drop. All trailer connectors have a ground wire. If the ground wire should be damaged or not be making good contact, certain small demand items like trailer's tail lights may still function by grounding thru the trailer hitch ball. But higher demand items may stop functioning properly. You can test for this by connecting the trailer electrical connector to the truck, but not lower the hitch onto the ball.

Also consider the electrical connectors. Unless they are all good & solid, again you will experience a voltage drop or current restriction. Poorly crimped connectors can cause this. But the first place to look is the connector that plugs into the back of the truck. When was the last time you inspected & cleaned the contacts inside the plug? I'm betting there is at least some light corrosion, dirt or grease on the contacts.

 

[BIG JOE]

10 ga. wire is pretty stout for a 12v system. Voltage drop with that gauge wire should not be an issue. But there are other things to keep in mind.

Your electrical system has to have a return path i.e. ground. If the ground is not up to the same capacity as the 10 ga. supply line, you will see voltage drop. All trailer connectors have a ground wire. If the ground wire should be damaged or not be making good contact, certain small demand items like trailer's tail lights may still function by grounding thru the trailer hitch ball. But higher demand items may stop functioning properly. You can test for this by connecting the trailer electrical connector to the truck, but not lower the hitch onto the ball.


Also consider the electrical connectors. Unless they are all good & solid, again you will experience a voltage drop or current restriction. Poorly crimped connectors can cause this. But the first place to look is the connector that plugs into the back of the truck. When was the last time you inspected & cleaned the contacts inside the plug? I'm betting there is at least some light corrosion, dirt or grease on the contacts.

X2

With the volt meter hooked up to the trailer wiring.. give the plug a wiggle.. any movement of the needle (or digits).. will tell a tale.

A trimmed down cardboard nail file, doubled over, works well for cleaning the plug contacts. Also, inspecting & cleaning the RV battery connections is a Good Thing.

Joe