Thanks all for the inputs. These batteries are the 8A31DT, 'valve-regulated, Absorbed Glass Mat Technology' batteries. They recommend a 13.5 - 13.8v float voltage.
I will need to check with the Morningstar folks about this... there is no provision for adjusting that voltage (other than a jumper selecting between 'flooded' or 'sealed' battery. The repeater will only be running either 2.5 or 10 watts (not determined yet), but the duty cycle will be very low, so the 6A controller should be more than sufficient. It also has a low voltage disconnect. Guess I won't worry about any gas issues! Thanks again to all. Tim
