"To learn, tweak voltage to 14.7 and see how many amps the fully charged battery wants to accept"
Mex, thanks but also please address the main fear I have--
If the batt is down 50% and you put say a 55 or 75 amp charger on it set to Vabs of 14.7, I think it will initially accept the 55 or 75 amps for a time before amps taper down to the spec 30% capacity amps "limit"
So is that harmful in that time if the battery accepts the higher amps than the spec amps for charging? (as long as it does not overheat, blow the vents)