Could the regulator/rectifier be bad again?

vt750c honda shadow. reg/rect plugs melted had a friend hard wire the wires together. i bought a new reg/rect and still ate the battery. upon closer inspection found the black wire after the plug on the reg/rect was broken. could the reg/rect went bad from running the bike with a broken wire. the reg/rect tested 15.86 at a idle and at 17.02 at 5000 rpm . the book says this is too much. could i have bought a bad reg/rect or could the broken wire made it go bad. the alt and stator tested good. what do you think?