Upgraded my batteries from (2) Group 27 12 volts to 2 Trojan T105 6 volts. This swap was mandated by waking up one morning at Stone Mtn GA campground to the smell of sulfur/rotten eggs, yep I officially cooked on of my factory interstate batteries. The water level was check religiously so I am going to blame the factory single stage charger. Before I installed the new Trojans I installed a new Progressive Dynamic 4655v charger converter. This unit is a 4 stage charger that monitors your batteries...