At 14.4 volts, the battery probably will not get as warm, and probably will last longer. At 14.8 volts, that is probably the maximum voltage that they should be charged at.
When I would charge my batteries, if I was really low, I would set the charger to only 50% and keep the amperage to around 35 amps, so that they did not warm the battery, or boil off to much water.
Normally I would use the solar system to charge the battery, and it would take all day, slowly charging at 21 amps, tapering off near nightfall. This provided me with 13 years of battery life from the factory 4 Trojan batteries.
Good luck!
Fred.