stovebolt409,
I don't know the details of your dilemma but do know that a battery will boil during charging. You said 'vent' so you must be working with a maintenance free battery.
A 2 amp charge rate should hardly be enough to boil the acid, plus your 'automatic' charger should have tapered down to where this wouldn't happen. If your battery is actually a sealed unit, it sounds like it may be no good now.
Was your little charger toggled to 'automatic' or 'maintenance free'. I have a small charger and the settings are a bit ambiguous.
Stuart
