Originally Posted by blw2
I could be wrong, but I think that can be a symptom of a bad converter.
I agree with that as well.
I have pretty much convinced myself that a boiling battery is the result of too much charging current in overcharge.
This then necessarily means the charger is outputting too much voltage for that battery.
Whether it is the result of a bad converter, a bad battery, or a combination of the two is the thing to determine.
For example, a shorted cell could cause the remaining cells of the battery to go into overcharge at normal voltages.
Lots of possibilities.