Trailer/Tow Vehicle Wiring

[flick]

I am building my first small utility/camping trailer, and was wondering of pluses or minuses of going with either 4 way flat wiring or 7 way.
* I'm not going to have brakes, so that is not a need.
* Not sure about any aux lighting right away on the trailer.
* Would like to, down the road, have a battery on the trailer, that possibly is charged by the running of the tow vehicle, for anything electrical off of the trailer. Lights/radios/whatever else

Thanks in advance for questions, that will help me think this out, and for your responses.

Flick

 

[R_Lefebvre]

Run 7 wires now. Easier to do now than it will be to fix later.

 

[elmo_4_vt]

The 7-pin setups are also a little more robust than the flat-4 and lock in place to help prevent being dragged on the ground.

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[ntsqd]

If you wire the tow rig for 7 pin, then you can adapt into any connector that any trailer might have. It is possible, but harder to go the other direction.