Replacing external Alternator with internal Alternator questions

10 gage is NO WHERE near large enough for a 100 A. No 6 minimum no 4 would be better.

Or you could parallel about 3 no 10 I guess

What about the wires? If you are sure you never need them cut the connector and safely tape them and tuck them away. The blue alternator field wire, and the blue regulator connector wire has switched 12V "ignition run" on it.