Originally Posted by lojoma
I'm updating my setup...photos show the way it is NOW. Previous owner took out Univolt and put in Progressive Dynamics PD9245 and a little fuse panel.
I have seen various wiring setups and I have a few questions about whether I need to correct anything here.
1) The little breaker/battery cutoff switch on the battery cable is a 300A breaker. I can't understand why it's that high. I have a 30A one ready to install but wanted to make sure that's the correct size.
2) The blue wire (currently) connects directly to the power in on the fuse panel, as seen in the second photo. Doesn't seem this wire has any fuse protection as-is. I think the photos I have seen of Univolts have that on a 40A fuse. Should it be attached to one of the fused circuits at top with a 40A fuse? I have also seen that wire connected to the positive on the converter, which seems wrong.
3) Is the general "big wire" layout correct here? I'm particularly concerned about the red wire from the battery. It connects to the breaker, and on that same side of the breaker, a wire goes to the converter. Should the wire to the converter be on the other side of the breaker so it's protected?
If you spot anything else that's odd or wrong, I appreciate it!
1. The battery cutoff switch needs to be able to interrupt excessive currents. If Airstream believed 300A was the right number, I'd stay close to that. If it was put in by a previous owner, ask yourself what is the maximum current that could be flowing in that line. If the batteries are severely discharged the converter can put out 45A. If there is a short somewhere in the trailer you are looking at the output current capacity of the batteries which could be hundreds of amps.
2. In my trailer there is a blue wire that feeds the breakaway switch for the brakes. It is on a 20A auto-resetting breaker by itself. You don't want a fault anywhere else to take out the braking capability if the trailer becomes detached.
3. In my trailer there are 50A auto resetting breakers in series with the main battery cables. The other side of those breakers is connected directly to the converter.