wiring help

[clap]

I have a 7 X 14 enclosed trailer. It has electric brakes with a breakaway switch and battery. What I want to do is add a battery to operate the interior lights and maybe some 12V accesories. I also want this battery to be charged with the truck while towing. By the way I am new here but have been reading your stuff for quite a while now. And this place is great for all kinds of info. Thanks for having me Dave c

[Dale M.]

Generally if TV (tow vehicle ) has a 7 pin (RV style) connector it has 12 volts supplied to pin #4 ( black wire) that charges "break away" battery, by coincidence it is also same circuit that can charge larger high capacity 12 volt battery for trailer lighting and battery powered accessories.... Only issue may be to have some sort of diode isolation between small break away battery and main trailer battery so if you run down main battery you also do not discharge smaller brake battery...



IF TV is not wired for +12 volts on pin #4 (black) its usually standard practice to run wire from power source under hood through a fuse (30-40 amp) the through relay that is controlled by ignition switch that cuts off trailer battery system from TV system when engine is shut off in tow vehicle...

Also its wise to check that "ground" conductor, pin #1 (from plug to frame) of tow vehicle ( and trailer) is sufficient to carry "return load" for current (amp) rating of trailer/auxiliary/brake circuits.

Wiring up a 12 volt battery and lighting is a whole completely different thread and as you have probably noticed there is lots of information about "how to" here...

Dale