This is the Veracitor model, and the fuse/relay box got corroded and shorted to negative

there is a 60 amp alternator mega fuse, make sure you're fuse is good. disconnect the negative terminal and reconnect after charging the battery, is there a large spark when connecting the battery with the key off?

Remove positive cable off of battery. Take a standard 12v test light. Hook gator clip to cable, then take light end and touch it back to positive post on battery. If test light lights up, up have a draw somewhere. Bare in mind, i have seen bad new batteries, starters ,and alternators.
Removing the hot wire from starter and alternator from each, one at a time, will eliminate whether they have shorted or not. Bad battery cables can also cause severe voltage drop. Especially when loaded.

try turning on the ignition and see if your ground appears?
maybe the ecm controls the ground? (seems unlikely though as you need ground full time to energize the machine when you turn the ignition on before starting it).
just thinking outside the box here ;o)

but on a more conventional thought...
my first thought is your ground cable to frame isn't making connection, it's open

I put my meter on the positive cable and touched the frame...no continuity.

Definitely a dead short. Try taking battery wire off altrrnator and starter and see if voltage still drops.