Running new wiring circuits along side existing RV wiring(?)

[jpmtz]

I'm converting a cargo trailer and I have a question about running the DC wiring. Naturally, it's powered by a 7-pin connector... I'm guessing I should leave all the wiring for exterior lights (brakes, turning, clearance, etc.) in place and undisturbed(?) One question I have is about the two factory-installed interior lights; should they be disconnected from the existing factory wiring and just added to the new circuits that I'll be running from a DC distribution box? I'm a Youtube-trained amateur electrician and I'm concerned about back-feeding DC through the 7-pin connector. (I'm installing an all-in-one solar power system, btw.) So, my grand scheme is to run all new wiring in this trailer for lights, outlets, etc. while leaving the existing factory wiring in place. (POINTERS, TIPS/TRICKS, AND ADVICE ARE APPRECIATED.)

 

[acdoctor]

I would disconnect them from the black wire in the 7 pin otherwise when you are disconnected from the truck those won’t work. I would check every connection on the exterior lights. I had a clearance light quit working on the way home from picking it up. The connection in question is not behind the upper cabinets on the left. It would be devastating trying to get to now. I ended up replacing all the exterior light wiring except the 7 wire cable that ran underneath and soldered all connections. Also I left the break emergency battery on the hitch. My trailer battery is 24 volt.

 

[John Frum]

One option is to not do any dc distribution at all in this type of "from scratch" build.
However all-in-one's tend to have very high idle draw with meh efficiency.

Are you considering a dc2dc charger like these examples

Orion-Tr Smart DC-DC Charger Non-Isolated - Victron Energy

The Orion-Tr Smart DC-DC charger is a professional DC to DC adaptive 3-stage charger with built-in Bluetooth. For use in dual battery systems in...

www.victronenergy.com

The coexistence of the 7 pin cable, breakaway system and a dc2dc charger add some complication.

 

[rmaddy]

I have an enclosed cargo trailer that I converted to a camper so I have been through this myself. What I did is to completely leave the stock trailer electrical system in place. I have a dual-axle trailer with electric brakes and a small battery on the tongue for the emergency brake. The trailer of course has all of its external lights including turn signals and brake lights. All of that is powered and controlled by the 7-pin connector. I didn't touch any of that with one exception. The interior of the trailer had a small LED dome light on the ceiling. I removed that light and its wiring.

For everything related to the electrical/solar system of the camper I added a whole new set of independent wiring and battery. The two systems are not connected in any way. Everything is so much simpler this way. I make no attempt to power the camper's battery using the tow vehicle or the 7-pin. My camper power comes from either solar or shore power (99% solar).

 

[jpmtz]

I have an enclosed cargo trailer that I converted to a camper so I have been through this myself. What I did is to completely leave the stock trailer electrical system in place. I have a dual-axle trailer with electric brakes and a small battery on the tongue for the emergency brake. The trailer of course has all of its external lights including turn signals and brake lights. All of that is powered and controlled by the 7-pin connector. I didn't touch any of that with one exception. The interior of the trailer had a small LED dome light on the ceiling. I removed that light and its wiring.

For everything related to the electrical/solar system of the camper I added a whole new set of independent wiring and battery. The two systems are not connected in any way. Everything is so much simpler this way. I make no attempt to power the camper's battery using the tow vehicle or the 7-pin. My camper power comes from either solar or shore power (99% solar).

Thanks! What you've done is exactly the way I've envisioned doing my trailer.

 

[12VoltInstalls]

Also I left the break emergency battery on the hitch

That’s the best way- 7-pin pos(+) will keep that charged.

two systems are not connected in any way

In the situation described that solves several things, and secures that the power system isn’t adversely effected by the vehicle never mind system voltage differences