The charging system tracks nominal new battery capacity and calculated current battery capacity, due to aging, in order to prevent overcharging cumulative damage.

One ampere-hour of overcharge changes 0.335 grams of electrolyte water to gas. When gas pressure exceeds some small pressure < 3 psi it is vented overboard.

A well maintained AGM battery can last almost ten years, and a thousand cycles if the average State of Charge (also tracked by the IBS) is maintained above 70%.

__________________
Believe nothing read or heard without verifying it oneself unless it, Weltanschauung congruent, fits ones worldview.