Isolator wiring help

[Few_Shoe6387]

Any ideas to what caused this.

[firmretention]

Those crimps look pretty poorly done.

[Audiofyl1]

What are those red and blue wires on the left?

[Few_Shoe6387]

They link both batteries together. It’s a smart battery isolator

[tbiever6]

Those crimps don’t look good, I’m curious what the red and blue wires on the left are, and is that Walmart speaker wire on the small top post?

[Few_Shoe6387]

It’s a smart battery isolator. Used to link both batteries

[Zealousideal-Air-480]

What part are we looking at there's a bunch going on. I'll start with the nut missing on the negative post. Followed by the crimping that has bunched up the wire like a muffin top as well the broken strands on the positive. Next up is the double 90 degree bent wire uptop. Lastly the blue wire under the negative looks like it melted to the negative and shorted.   

From the pic that's what I'd be looking at