With all due respect to Jerry, for I appreciate all the wise advice he gives on this forum I beg to differ on this one.
Let's say 'frinstance that the ol' girl doesn't want to start on a particularly cold morning. You crank and crank but she finally roars to life. Now, what should you see on the ammeter?
My contention is if it says 100, run like H@!! 'cause it's about to turn into a fireworks show. As I understand the regulator, be it external or internal, the initial charge voltage will rise to about 2 volts above the sensed battery voltage, and as the battery charges will continue to rise until it's limited at about 14.2V. As far as I know, the maximum safe charge rate of a lead-acid battery is 10 amps or so.
If anyone has actually witnessed a 100 amp charge current (into the battery) please enlighten this ol' guy, I'm still learning!