What is this wire
Fuse and inline holder/fuse block rated for just above ALT max amps or fusible link wire (3 sizes smaller than the correct wire gauge for circuit under continuous load and not in a bundle with other wiring. Link should be about six inches long, no more than 9, and not bundled with other wiring):
McMaster-Carr
Direct solder or if your skills soldering are not excellent, reducing butt splice and heavy gauge heat shrink or good tape:
McMaster-Carr
This traditional cotton tape holds better than common plastic tapes (also at hardware stores):
McMaster-Carr