Equalizing means MAKING THE ELECTROLYTE IN ALL CELLS EQUAL. With unlimited time meaning power source at your disposal 15.5 volts is possible as a top tier voltage but a badly sulfated battery can take 3 days @24 hrs/day to equalize and TEN DAYS to equalize at 15.5 volts. These figures come from experience not guesswork.
Pointing a shotgun into the sky and pulling the trigger and hoping a duck runs into the discharge somehow is not using skills or expertise. Sort of like letting a 5-year-old mix your martinis. You need to know how badly or not your batteries actually are and you need to know h much charging is necessary to remove accumulated sulfation from the plates.
Simply pressing a button and hoping for the best is like throwing a bucket of paint at your house and assuming it's going to paint itself.
Smart Chargers are stupider than snot when it comes to equalization. But if press a button and hope for the best is your bag - go for it. Your battery distributor will love you for it.
http://www.batteryuniversity.com
Has several paragraphs how to do it right.