Option 1: Automatic SLA Charger (preferred style)
This product is designed for safely charging sealed lead acid batteries without overcharge occurring. The charger begins operation at a specified rate and tapers as the battery voltage climbs. At end of charge, the unit switches into a pulsing mode so that the charger can be left connected to the battery indefinitely. This product is offered with an optional LED indicator. When utilized, the LED burns brightly during initial charge. As the battery reaches the end of the charge cycle, the LED dims and will begin to flicker. End of charge voltage can be adjusted to meet the specifications of the battery being used. (more)

E.D.S. is now offering a Universal Input (100-240 V) Automatic SLA Charger for 12 volt batteries rated 3 A. (more)

Option 2: Non-Regulated Taper Charger
This product is designed so that initial current tapers down as battery voltage climbs. While this is the least expensive form of charging sealed lead acid batteries, it also has the most potential to shorten cell life since no overcharge protection is provided. In addition, designing to achieve the best taper produces a charger with significant output current fluctuation over varying line voltage conditions. The taper charger should only be used in cyclic applications where prolonged connection to the battery is not expected. In addition, a taper charger should not be used in quick or fast charge applications.

Resources:
Design Considerations
Stock Chargers