This document says you must charge the battery at constant current of half the ah rating which is not correct. it sais that if a battery is 100ah you must charge at 50A.
If you are referring to this link: http://www.exide.com/Media/files/Downloads/TransAmer/Battery%20Care%20and%20Maintenance/Battery%20Charging%20&%20Storage%20Guidelines%20%205_9_13.pdf , I don't see any such statement therein.