Since I know that there are a few very knowlegable electrical types on this list, what charger would you reccomend for my friend who has a battery bank of 4-Grp 31's totalling 500 amps. Also 1-grp 27 for starting. Battery charging is a problem over the winter when the boat is on the hard. He can only leave the charger on for one 24 hour period per month. Yard rules. So we need (I think) a three stage, bulk charge, equalizer (or conditioning) cycle and a float. During the sailing season he is on a mooring and the charger is not used. I would appreciate reccomended brands and models.