But will just setting the power supply to that voltage be enough? Do you have to also a throw a current limiting circuitry there?
Unfortunately not, if you want to make sure your batteries last. Over charging your batteries will cause excessive electrolysis causing hydrogen to be release dehydrating the cells and causing sulphur deposits (sulfation) on the lead plates. Sulphur deposits act as like insulators blocking plate surface area need to run the chemical reaction to produce electricity. A good SLA charger will have three modes (if I recall correctly):
1. High current charging mode, which will provide lots of current when the battery voltage is low. Current is constant and charging voltage is maintained within a few volts difference, but not excessively high to cause dehydration and sulfation. (Athough, my understanding is that battery temperature is an important factor in charging but I suspect few charges include temperature monitoring).
2. A low current charging mode, when the battery voltage is near full charge. This takes place when the battery voltage reaches need its full charge, and the voltage difference between the charging voltage and the battery voltage drops below ~1V ( I think around 1.2V)
3. A Floating charing mode that constantly monitors the battery voltage and tops off to address self-discharge.
Also consider that in 24/36/48 voltage system where several batteries are connected in series. Some batteries will recharge faster than others. Good chargers will have charging taps to monitor and change all batteries in series equally so that all get properly charged. Otherwise some batteries will get overcharged and others undercharged.
Consider that Batteries are expensive and there replacement cost is high. Better off buying a quality charger than a cheap charger that becomes expensive when you have to prematurely replace your batteries.