Chasing Electrical Gremlins - Questions

[BigDogF250]

So, keeping the story short, trailer was working for 8 hours after travel, then in the middle of washing my hands, the whole trailer went dark, losing all power.
At all times the battery checks at 12v, but I will load test tonight.

The ?'s
- Why does the converter control the ground? From the frame to the converter then to the ground bar where all other connections go. I add a direct ground and that helped (for a while).
- Do I need to keep it that way? Seems like a recipe for issues.
- When not working I was seeing as high as 3v and as low as 1 volt at the inside of the trailer. Battery checked at terminals, 12.8v.
- When running on generator it's fine, meaning the converter seems to be working. So I put about 16 hours on the gen this weekend.

Welcome any comments. I am very familiar with 12v wiring, but this one has me stumped. My next plan is to replace the wiring and fuses from the battery to the panel with a single cable, probably 4 gauge unless something bigger presents itself. I really have no intention of adding an inverter unless the converter is faulty, my camping style works well with 12v. Then bigger cable to the batteries and maybe 2 outlets live on the inverter.

That and 2 flat tires on the MX bike made the weekend less fun but the tequila and beer were cold so it all worked out.

[nayther]

BigDogF250 wrote:
Nayther, you made me almost laugh coffee out my nose. It's a WW built in 2005, the "common bus" is wire nuts! One more thing I found wrapped in electrical tape this weekend that needs to be replaced.

At this point I am starting with running proper grounds and new positive from the battery to a real common bus, replacing the funky 8 fuse and rigged 3 fuse add on they used instead of a proper fuse panel and seeing where that gets me. Hopefully it's just corrosion or gremlins in one of those systems.

"bus" was a relative term, you got my intent.

I'm like you though, might as well tear it up and do it right at this point.

[BigDogF250]

2btowed wrote:
use meter and check both sides of disconnect switch,move it around and make sure it does not disconnect on its own.Mine did,when replacing it fell apart in my hands...quality.went back with marine grade rotater,works great.

Thanks for the reminder to order that. I did check the one in there, and actually swapped to a spare, but I'm moving to a marine rated one because it's built for the cable sizes I am running. The 75 amp push/pull on the trailer uses a pretty small and somewhat flimsy screw into tab design that I don't like.

[2btowed]

use meter and check both sides of disconnect switch,move it around and make sure it does not disconnect on its own.Mine did,when replacing it fell apart in my hands...quality.went back with marine grade rotater,works great.

[BigDogF250]

Nayther, you made me almost laugh coffee out my nose. It's a WW built in 2005, the "common bus" is wire nuts! One more thing I found wrapped in electrical tape this weekend that needs to be replaced.

At this point I am starting with running proper grounds and new positive from the battery to a real common bus, replacing the funky 8 fuse and rigged 3 fuse add on they used instead of a proper fuse panel and seeing where that gets me. Hopefully it's just corrosion or gremlins in one of those systems.

[nayther]

start by checking for a good ground, if the ground was compromised that could lead to excessive amps drawing from the battery. If that checks then start from the battery and work your way to the 12v common bus at the fuse panel while maintaining the good ground at the battery. At least that's the method I'd go to.

[BigDogF250]

I checked the ground at the battery (and cleaned it) but need to chase to frame to check there.

The is no circuit breaker at the battery, it's using fuses. I pulled, cleaned, and adjusted tension on them to make sure there is good contact. Planning to replace with a breaker style because I hate having to maintain the fuses (clean and reset).

[enblethen]

Have you checked the ground connection at the battery?
Check for a circuit breaker adjacent to the batteries?

[BigDogF250]

Yes, the converter has it's own chassis ground to the frame. It also has two white wires, one connects to the frame and the other connects to the ground bar for the rest of the trailer. Adding a direct ground from the frame to the ground bar made things work for a full day, then it happened again.

Thanks for the input, reinforcing my thoughts that it has to be between the batteries and the electrical panel. That run is about 20 feet with the way WW ran the wiring, mine will be about half that.

[SCVJeff]

DanNJanice wrote:
Just so I understand correctly.
You were running on 12V and everything was working normally. Then suddenly no power...correct?

When you plug in and the convertor takes over, everything works OK...correct?

Sounds like an open between the convertor and the 12Vdc battery. Check all connections, fuses, battery cutoff switches, also find the self resetting breaker(I have seen these fail in just the way you describe).

cept he's implying that playing with a ground seemed to make things better?

It's meter time!

[DanNJanice]

Just so I understand correctly.
You were running on 12V and everything was working normally. Then suddenly no power...correct?

When you plug in and the convertor takes over, everything works OK...correct?

Sounds like an open between the convertor and the 12Vdc battery. Check all connections, fuses, battery cutoff switches, also find the self resetting breaker(I have seen these fail in just the way you describe).

[enblethen]

There should be a converter case ground.
Then there is a 12 volt negative that goes to the 12 volt system.
Don't get them confused.
I go along with a circuit breaker at the battery(ies) or in the 12 volt DC panel.
Another thing to do is go through all the 12 volts connections. Make sure they are clean, have electrical grease on any tinned copper or aluminum connectors and buss bars, and insure they are tight.

[voodoo101]

Some RVs have a cb where the battery connects to the distribution buss. But then there would be no 12v into the house. On mine it is tiny hard to find. Meter would tell you if 12v is getting across to the distribution lines. It just isolates the batteries, Good luck.