Wish I still had my lab. The area over curve, meaning the charge receptivity of the battery maximum versus amperage potential of the charger needs to be studied and charts made up. Take 200 ampere hours of batteries...
What is the ampere absorbsion limit at maximum acceptance? Time versus amperage. How many minutes until droop amperage "waypoints" are reached?
When OEM plays around with lead purity, antimony and calcium alloy percentages it changes the amperage receptivity plus it changes the Charge Efficiency Factor.
Wanna hear someone stutter and pause, talk to one of the geniuses who limit amperage absorbsion time and ask him how he arrived at a specific time. "Jusr enough time to allow all the cells to start bubbling gently" ain't in the program.