Most battery chargers are 4Ah so it will take 20 hours to charge a 100Ah battery. I would be swaping for a new battery. It souds like at first the battery just has enough grunt to pull the contact in on the starter motor and tries to turn it then it drains the battery real quick. That is when you get the clicking.
It has enough guts to pull the contact in then it dies from the extra load on the battery at this time and repeats itself