Large lead-acid batteries have low internal impedance, so can supply high current. Power supplies, generally, are not designed to absorb power from their output terminals. The consequence of this is, if you wish to use a power supply as a lead-acid charger, you must set its output voltage, turn output on, and THEN connect it to the battery to be charged (yes, there is a small spark). When charging is complete, disconnect the leads before turning the supply off.
There is a further issue with many power supplies made for sensitive transistor circuits, using OVP (over voltage protection) devices. These cannot be used as battery chargers, as they intentionally short their outputs together when a voltage is supplied there.