I have two 60 watt panels, one 45 watt panel, an a 7 amp charge controller. I have 6 six volt batteries, and a 750+ power inverter. My problem is my panels, and my charge controller, are all checking out but my charge controller is only reading 13.5 during the day and at night 11.9? I only run one 5 watt bulb at night, batteries have begun gurggling about three to four hours after dark, and the six 6 volt batteries were just pruchased in june of 2010. Any ideas?
Another question, if I have four 60 watt panels what size of a charge controller do I need, and how many six volt batteries should my bank need?