Engineer Guy

Most all Trailer Brake Controllers require a 30 Amp Circuit. This is because 3 Axle Trailers - say, large 5th Wheel or Horse Trailers - need just under that maximum Current to power 6 sets of Brake Shoes. Thus, the 7 Pin Connectors can handle that level of Current. You can also get a sense of what's appropriate by looking at a 20 Amp House Receptacle, or the Blade size of a 30 Amp Electrical Stove Connector. Higher Currents require more metal Contact area. It's as simple as that. Keep them Trailer Contacts clean, too.

Another Data Point is to look at the size of Headlight Lamp Connector Blades. They draw about the same amount of Current as what you're proposing, and do so through Connector Blades that often have smaller surface area than a 7 Pin Connector.

Part of successfully executing your idea is to use sufficient size Wire to minimize Voltage drop. This includes having a sufficient Ground Wire/Ground Return Path. See a Wire Table ~3/4ths of the way down this Webpage. There's other great information, here, too...

The 12 Volt Side Of Life

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desert_rat

No trailer brakes, it is a light weight tent trailer. Yes, the interior lights run off of 12v but the converter takes care of that from shore power. I won't be dry camping with young kids.

tomb1269

I had a 2005 jayco popup that came from the factory with a 3 way fridge (ac/dc/propane) and I always ran it on DC while traveling. I di tended to disconnect the trailer when stopped so as not to draw down the vans battery.

desert_rat

Well, looks like I am not going with the ac/dc fridge that I originally posted about. I acquired a used norcold refrigerator that was OEM in my trailer and I am going to install that. Looks like I will be installing a battery after all since this thing draws too much current from the tow harness. Thanks for all the replies though.