Need help with my sketchy battery cable situation

Cut all that tape and junk off. Get some crimp butt splices with heat shrink, heat gun, marine tinned wire of same gauge and of proper colors, closed lug ring terminals that match both the battery stud and wire, weather tight fuse holder for the positive side, heat shrink tube as needed in proper colors, quality wire crimper.... and get busy :B

And if you ever charge from a generator replace the entire battery loop with #4 marine cable and update the converter as needed.

Now you are sorry you asked ;)