Vdc Power Supplies Recommend! Can You Charge A Lead Acid Battery With A Regulated Power Supply?

Can you Charge a lead acid battery with a regulated power supply? - vdc power supplies recommend!

I use a regulated 3 A Radio Shack 13.8VDC
Support for up to 12 volts 3 Ah sealed lead-acid batteries are the battery with the Charing source ruin? You will explode or anything.
Having them in a few hours (current millamps) up to about 4 millamps
Battery life will do when the power supply, something for the batteries.

I'm just worried for them exploded or something will happen when the bill