Truck charge trailer battery?

[Texasdeere]

I have a 2001 2500 Truck with the Tow Kit and Factory Harness.

Wanted to know. If my truck would charge the trailer battery, when towing the trailer. My truck has the factory 7- way connector.

 

[RedRamer]

Yep.

Does a prety decent job too.

 

[Lurch]

It will also drain the truck batteries if sitting hooked up. Need an isolator if your trailer doesn't have one, or pull the plug.



Lurch

 

[TowPro]

I was just wiring my slidin camper to my 7pin factory connector.

I have 2 connectors, one on the hitch (factory) and one inside the Bed I installed for my 5th wheel.



I seem to remember that the Hot wire was dead until I turned the key on? I will have to check it again.



Thursday I took the truck/slidin out for its first ride after wiring it, the camper battery was at 50% charge according to my deep cycle battery charger before I left. I drove for about 45 minutes, came home and hooked up the charger again, its now at 75% charge so yes, it will charge the battery, in fact faster then my 10amp charger will.

 

[GeneA]

One caution, though. Those wires tend to get corroded around that rear bumper, so test your hot wire connection, occasionally. Last year, my trailer batteries drained, and on checking I had a dead conection.

 

[BV]

Charge line

My 99 was hot all the time so I added an isolator so I don't have to remember to unplug while parked.

 

[RustyJC]

Yes, the +12VDC pin in the 7-pin connector is hot all the time, key on or off. If you're dry camping with no generator, better unplug the truck or you won't be happy when it's time to start the truck to leave.



Rusty

 

[Texasdeere]

Thanks for the timely info guys... MH

 

[RedRamer]

btw...

the voltage you get at the camper battery will be less than what you get at the truck battery. The percentage difference can be used to calculate how much the truck will charge your camper battery as you need the same voltage at the camper as at the truck to get fully charged.

I think its' the wiring size that makes the voltage drop a bit. But a bit is all it takes as the difference between 12. 65v and 12. 0 volts is about 50% charged up battery.

 

[lizzyhermit]

fyi, my voltage drop is about . 04 at the connector pin.

 

[Mark_Kendrick]

When the batteries are dead they draw quite a bit of amperage and the voltage at the plug while charging will drop. As the batteries reach full charge the voltage will rise to near 14. 4. If you regularly run the batteries low you should run a larger wire back and put a relay on it and a fuse/breaker at the battery. A dead battery charging through those small wires will generate significant heat and take their toll on your electrical system.



Later,

Mark