[grambo]

The biggest thing to look for in a charger is the "three stage" charging. Essentially what that means is that the charger will go thru these stages: First, "bulk" stage: hit the battery with 6amps and wait for the voltage to rise (near about 14.6V). Second, hold the voltage at that "overcharge" mark (14.6V) until the current drops to 1/10th of that original 6amps. Finally, drop the voltage to the "float" mark (about 13.5V) pretty much assuring that when you unplug the battery from the charger it is as full as it can be.

Cheaper chargers will do various things, generally like if you have a lab supply and set it for 13.5V, 6A and then hook the battery to it, it'll dump 6A intot he battery until it gets to 13.5V, and simply taper the current back as the battery reaches that point. These will generally have timers and aren't very good for cyclic use of the battery as you miss out on the overcharge part of the cycle. ...for "standby" use, these chargers are perfectly fine, like for emergency lights and such.