The object is to remove tiny deposits of sulfation that form even though the battery "seems" full. Once those dots of sulfation are allowed to harden they anchor expanding sulfation. To keep this in perspective, if a battery is kept at float voltage, the sulfation process is dramatically reduced. But not eliminated. Top charging virtually eliminates micro deposits of sulfation. Remember, plate surfaces are porous to a great degree. I verified the validity of top charging by years-long testing, and sampling. Ripping the batteries apart, shedding the separators and examining the plates using a 10X loupe. Forget the technical's. The battery lasts longer and that's what I am interested in.
