Please Help with 12V Power

Not really a good idea having this trailer on the road without the battery system working. It is a State DOT Safety law to have a working 12VDC system for the breakaway Trailer Brake operation. This is an enforceable law... This could also go against your insurance coverage for damages for not following the safety laws.

Its like anything else however - you gotta do what you gotta do at times just be aware...

Getting sparks is a good indicator you are hooking up to the wrong polarity... The RV WORLD uses BLACK LEADS for HOT and WHITE LEADS for GROUNDS. The AUTOMOTIVE WORLD uses RED LEADS for HOT and BLACK LEADS for GROUND. Sometimes this is all mixed together when working with batteries... The best solution is find the word NEG or the symbol '-' on the battery case and make sure this cable comes from the Trailer FRAME GROUND connection just inches away from the battery location... Any wires that has fuses etc in most connection always goes to the POSITIVE SIDE of the battery. If you do have RED and BLACK wires groups there along with BLACK and WHITE wires groups then you are going to be placing a RED WIRE and a BLACK WIRE on the same terminal as you trace them out. The old timers will be turning over in their graves hehe...

The dealer where you purchased this trailer should have had all of that done for you before letting you tow the trailer. If it was a private sale then its up to you then to get everything hooked up properly.

Roy Ken

What is the battery voltage on the battery terminals.
Do you have a battery switch inside the RV?

That would be my guess, negative ground somewhere isn't making contact.

Go through your wire connection again, but do not disconnect the battery wires. First, just try the extra wire from battery negative to 12 volt panel negative. If that makes it work you have a negative problem. If it doesn't, try just the battery positive to 12 volt panel positive. If that works you have a positive problem.

My problem proved itself to be the negative, and I fount a loose negative main wire at the 12 volt panel, tightened it up and every thing worked.

Do you have pictures? The battery feed needs to get from the battery to the inverter and there needs to be a solid ground to the battery (you don't mention where the battery ground connection is made currently).

The positive wire, trailer brake wires, and trailer wires (that hook to the tow vehicle) come through the front of the frame then up into the trailer in the front underneath the bench seat of the kitchen table. There are many wires spliced and capped together in this area. Then a stream of wires go to the front of the trailer to the left around all the appliances back to the area underneath the couch. All the circuit breakers and power inverter are in this area. The 120AC pigtail also comes in on this side and hooks to the breaker box. What makes no sense to me is when I have all the wires outside hooked up as they were to the battery and I run separate wires to the power box itself it will just spark as it is narking but when I unhook those wires coming into the trailer and run single wires to the power box the lights come on and no sparks or narking.

They like to hide auto-resetting breakers in places you wouldn't suspect.
You might look in back of the converter or underneath the trailer near the junction box where the umbilical cord comes in. If that doesnt get you anywhere, follow the pos lead from the battery until you come to the breaker.

There will be an inline 30A fuse between the battery+ and the junction box under the front of the trailer.