12v to trailer turns off when ignition off

[Crumm]

I am thinking of installing a battery inside the trailer to power the 12V trailer lights and an inverter for 110V AC for other misc. uses (like an AC radio). Could I just use one of those battery isolator units they use for RV's to tap re-charging current from the trailer harness going to the truck? This way it would re-charge the trailer battery when the truck is running only. Would anyone have a wiring diagram for something like that??

What year truck do you have? Your 7-way plug should already have a 12v charge wire in it.

 

[Ezzie]

It's a 2006 F350 Crew DRW with the trailer package.

So there should be a seperate accessory wire and a charge wire in the 7 position plug or is this the same thing?

My trailer has electric brakes with a small battery for the safety breakaway so I should be able to tap into this line and run it to the + post of the auxiliary battery (basically putting the breakaway battery and the aux. battery in parallel).

 

[iracemine]

yup.

 

[drmjf]

Most Isolator will come with a diagram on how to hook them up. Your trailer batteries should charge from the truck when running.
I run an isolator connected to the deep cycle battery in the bed of my truck. I use that battery to run the stereo and radio gear, that way I can use them with the truck off and still start my truck if it does go flat.